REVIEW OF NEW ZEALAND’S
WIND ENERGY POTENTIAL TO 2015
Energy Efficiency and Conservation Authority
PO Box 388 – Wellington
May 2001
1
Energy Efficiency and Conservation Authority
Review of New Zealand Wind Energy Potential to 2015
Table of Contents
Executive Summary: ......................................................................................................... 5
1. INTRODUCTION ..................................................................................................... 7
2. AVAILABLE WIND RESOURCE .......................................................................... 8
2.1
Location of Resources ....................................................................................... 8
2.2
Potential Supply and Variability ..................................................................... 11
3. WIND TURBINE TECHNOLOGY ....................................................................... 13
3.1
Introduction ..................................................................................................... 13
3.2
Turbine Size .................................................................................................... 13
3.3
Configuration .................................................................................................. 14
3.4
Power Control Technology ............................................................................. 14
3.5
Reliability ........................................................................................................ 15
3.6
Safety ............................................................................................................... 15
3.7
Wind Turbines for New Zealand ..................................................................... 15
3.8
Addressing Off-Site Effects ............................................................................ 16
3.9
Smaller Wind Turbines for Remote Applications ........................................... 16
3.10 Limitations ...................................................................................................... 17
4. USE OF WIND ENERGY IN NEW ZEALAND .................................................. 18
4.1
Present Use ...................................................................................................... 18
4.2
Present Constraints/Barriers ............................................................................ 18
4.2.1
Cost ...................................................................................................... 18
4.2.2
Dependability ....................................................................................... 19
4.2.3
Consentability ...................................................................................... 19
4.3
Favourable Types/Forms of Development for the Future ............................... 20
5. POTENTIAL USE OF WIND ENERGY IN NEW ZEALAND ......................... 21
5.1
Constraints/Barriers ......................................................................................... 21
5.1.1
Economics ............................................................................................ 21
5.1.2
Access Issues ....................................................................................... 22
5.1.3
Resource Consents ............................................................................... 24
2
5.2
Analysis of RMA Policy Statements and Plans .............................................. 26
5.2.1
Introduction .......................................................................................... 26
5.2.2
Hierarchy of Policies and Plans ........................................................... 26
5.2.3
New Zealand Coastal Policy Statement (NZCPS) ............................... 27
5.2.4
Regional Policy Statements ................................................................. 28
5.2.5
District Plans ........................................................................................ 29
5.2.6
Opinion Survey .................................................................................... 29
5.3
Market Trends and Competition ..................................................................... 30
5.4
Other Government Policy Directions .............................................................. 30
5.5
Forecasts .......................................................................................................... 30
5.6
Comments on Forecasts .................................................................................. 32
6. SOCIAL AND ECONOMIC IMPLICATIONS ................................................... 34
6.1
Introduction ..................................................................................................... 34
6.2
Social and Economic Implications .................................................................. 34
7. CONCLUSIONS AND RECOMMENDATIONS ................................................ 36
APPENDIX 1: WIND TURBINE TECHNOLOGY – DETAILS .............................. 39
APPENDIX 2: SPECIFIC ENVIRONMENTAL/CONSENT
CONCERNS ASSOCIATED WITH WIND ENERGY DEVELOPMENTS .......... 48
3
Acknowledgments
A number of people have made valuable contributions to the preparation of this
publication. EECA would especially like to acknowledge Montgomery Watson who
prepared the initial version of this report in association with PB Power and East Harbour
Management.
The report was project managed by Erin Roughton, EECA who can be contacted at
erin.roughton@eeca.govt.nz if you would like further information about any contents
in the report.
All material in this report can be reproduced with due acknowledgment of EECA.
However, while every care has been taken to ensure that the report contents, and
interpretations thereof, are as accurate as possible, neither EECA nor the authors accept
any liability for loss or damage occurring as a consequence of reliance on any
information and/or analysis contained in this publication.
 EECA May 2001
4
Executive Summary:
Wind resource and technology
 Reliable technology for converting wind power to electrical energy, along with an
extensive wind resource, provide a potentially major opportunity for electricity
generation from a renewable resource. Proven technology at known costs exists for
converting wind energy into electrical energy.

New Zealand has a significant wind energy resource. While its physical energy
potential could provide in the order of 100,000 gigawatt hours per year in the long
term, to date there is lack of hard data to allow accurate predictions and assessments
on a number of sites. In theory wind turbines are capable of meeting all future
growth in electricity demand in the foreseeable future.

New Zealand is well suited to wind energy development since it lies across the
prevailing north-westerly winds, with a long coastline and relatively strong winds
throughout the year. Thirteen general areas of land have been identified as suitable
for potential wind farming, with most being on the coast since coastal winds are
generally of a higher speed and consistency throughout the year.

Electricity generation from wind, as with other renewable options, avoids the carbon
dioxide production associated with electricity generation by fossil fuels. At this
point the contribution to the reduction of carbon dioxide production would be small,
but this could become significant if widespread adoption of the technology occurs.

Reliable turbine technology is such that ‘off the shelf’ product is available and
suitable for use in New Zealand. Recent advances in technology mean that larger
turbines are available than those installed to date, which may be used in the future if
they are cost-effective.
Economics and energy supply
 There are three existing grid connected wind turbine installations, in Wellington, the
Wairarapa and near Palmerston North. Other smaller turbines are used for standalone supply, and wind power is used for pumping water, drying timber, crops and
clothes.

Wind energy currently provides approximately 150 gigawatt hours per year of
electricity, or under 0.5 percent of New Zealand’s electricity generated. This study
has reviewed earlier assessments and shows that if economic and resource consent
conditions were favourable, New Zealand’s wind resource could provide
approximately 23% (7,900 gigawatt hours per year) of the country’s present
electricity needs at costs of up to 10 c/kWh within 10-15 years.

Wind power is not economic at present, except in niche opportunities. Wind energy
generally costs more than competitive forms of energy generation, and would be
expected to add to overall energy/electricity cost. Market indicators are that the cost
of new wind energy generators (about 5 to 6 c/kWh at the best sites) at present is
typically 1 to 2.5c/kWh above the cost of the next alternative new generation.
5

There are significant barriers to the widespread adoption of wind power, the largest
of these is cost in comparison with other power generation options. There are
perceptions of unreliability due to fluctuations in wind flow, although there are wellfounded arguments to contest this view. A further major barrier is perceptions of
difficulty in gaining resource consents under the RMA, which adds to the
uncertainty in uptake. To date this perception is more apparent than real.
Possible Uptake of Wind Energy
9000
8000
7000
Best Case
GWh
6000
5000
Worst Case
4000
3000
2000
1000
20
15
20
14
20
13
20
12
20
11
20
10
20
09
20
08
20
07
20
06
20
05
20
04
20
03
20
02
20
01
0
Year

The critical factors of wind power development in the near future include equipment
and installation costs, the amount of wind resource available close to load centres
(i.e. cities and industry), probability of gaining resource consents with acceptable
conditions, uncertainty over operation and maintenance costs and wind turbine life.

The forecasts included in this report are provided on a flexible time base of 10 to 15
years. The start date would be at present, if policy or other mechanisms provide a
non-market related “boost” to wind energy, or a delayed start date of three to eight
years under a “business as usual” scenario.

Under these scenarios wind will substitute for a significant amount of fossil fuel
generation. The level of substitution achieved will depend on the mix of other
generation installed over this period. On the basis that combined cycle gas fuelled
electricity generation will still be significant at this time, the two scenarios discussed
would reduce annual carbon dioxide emissions from one to three million tonnes by
2015.

Wind energy has significant potential in New Zealand, but if it is to be adopted,
active steps will be needed to ensure its uptake over the next decade or so. Without
intervention, it is possible that some wind turbines, generating a few hundred
megawatts, maybe installed in the next decade,
6
1.
INTRODUCTION
This report updates information relating to the potential for, and likely uptake, of
wind energy for electricity generation under the consent regime, under the
Resource Management Act 1991 (RMA).
This report refers to an earlier investigation undertaken and jointly published by
EECA and the Centre for Advanced Engineering at the University of Canterbury
as “New and Emerging Renewable Energy Opportunities” in 1996 (the
EECA/CAE Report). It included a substantial section on wind energy
generation. In the context of other renewables, the earlier report identifies wind
energy development as making the second largest contribution of all renewables
to New Zealand’s electricity supply over the period between 1996 and 2010, and
still expanding in production at the end of that date. This expectation is based on
New Zealand’s abundant wind resource and assumptions about technology and
uptake rates.
The present report reviews the material from the earlier report, adds new
material, and updates some of the assumptions, deductions and conclusions from
it. In the period since the earlier report there have been substantial changes in
the organisation of the electricity sector, and practice under the RMA has
evolved. There is also now more practical experience with wind energy
generation through the consent and installation of three wind farms or facilities
differing sizes.
This report includes all the above aspects and reviews the contribution that wind
energy development can make to New Zealand’s total generation capacity.
7
2.
AVAILABLE WIND RESOURCE
New Zealand has a very significant wind power resource. In theory wind
turbines could be installed that would be technically capable of meeting all
future growth in electricity demand in the foreseeable future. In addition, the
total long-term potential has been assessed to be in the order of 100,000 gigawatt
hours per year, three times our present generation. This assumes that 1% of the
land area in New Zealand would be suitable for wind farming. However because
accurate site-specific resource information is unavailable or inadequate to
confirm the supply cost-quantity relationships for most of this potential neither
the number of wind turbines needed to achieve this level of production, nor the
cost of electricity generated from such a scenario has been calculated.
On the assumption that resource consents would be granted for specific
proposals, and applying engineering judgement to the data that does exist, New
Zealand could obtain during the next 15 years electrical energy equivalent to
around 23 percent of present day consumption at costs of up to 10 c/kWh.
Within this, some hundreds of megawatts could at present be installed for
around 6 c/kWh (at September 2000 exchange rates).
2.1
Location of Resources
New Zealand is well suited to wind energy development since it lies across the
prevailing north-westerly winds. It also has a long coastline, where sea breezes
and lack of topographic interference result in consistent and relatively strong
winds throughout much of the year. Most regions of New Zealand have a wind
resource that could be practically developed.
In Europe, there is increasing focus on the development of offshore wind power
projects. The main incentives driving these offshore wind power developments
are a lack of space for additional onshore developments, particularly in the
densely populated areas of Western Europe. Generally, the wind resource is
greater offshore. However, there are significantly higher construction and
maintenance costs associated with such developments. In New Zealand these
higher costs would not be fully offset by the assessed increased energy yields of
offshore projects, and the delivered energy cost of offshore projects would be
higher than land based projects. It is also likely that such projects would
experience considerable difficulty in obtaining approval under the RMA.
Thus while the development of offshore wind energy projects in New Zealand is
a possibility for the future, such developments are unlikely in the short term and
so this resource assessment does not include the offshore resource.
The EECA/CAE Report identified twelve general areas for land based wind
farm developments throughout New Zealand, on the basis of available wind
resource. While the study on which the EECA/CAE Report resource assessment
was based had a number of limitations, it forms the basis of the supply curve
8
estimates in this report. An additional region, “North Island East Coast Hills
and Coast”, has been added, bringing the number of general areas where wind
energy development by wind farms of various sizes is likely to be feasible, to
thirteen. Another category, “Distributed Generation”, has also been considered
in this report. This refers to the possibility of installing single wind turbines in
locally windy places in areas that have not been specifically identified as having
good wind resource.
Figure 1 shows the thirteen areas considered suitable for wind farms.
The possibility of installing wind farms close to load centres, and thus reducing
electrical losses incurred in the transportation of the energy through the national
grid, is an important consideration in the uptake of wind energy development.
The population statistics for New Zealand urban areas provides a good
indication of where there is substantial load. The main population centres and
their locations are:
Whangarei
Auckland
Hamilton
Tauranga
Rotorua
Gisborne
Napier/Hastings
New Plymouth
Wanganui
Palmerston North
Wellington
Nelson
Christchurch
Dunedin
Invercargill
coastal environment
coastal environment
inland
coastal environment
inland
coastal environment
coastal environment
coastal environment
coastal environment
inland
coastal environment
coastal environment
coastal environment
coastal environment
coastal environment
Other areas may have significant industrial load.
specifically identified for the purpose of this report.
These have not been
The large majority of load centres are thus near the coast. Since coastal winds
are generally of higher speed and more consistent throughout the year than
inland winds, wind farm sites most likely to be developed in the foreseeable
future are mostly in the coastal environment. The main exception is the area
around the Manawatu Gorge, close to Palmerston North. While the major wind
farm development to date has been in this area, there is a limit to its capacity,
and the majority of any significant developments in the future are more likely to
be in the coastal areas.
9
Gisborne
Figure 1: Locations Most Suitable for Wind Energy Development (with regard to wind
resource).
10
2.2
Potential Supply and Variability
Table 1 gives the calculated average annual energy production levels from the
areas identified in Figure 1. The potential energy output is significant.
Table 1: Potential Wind Farm Areas – Resource Information
Region
Estimate
Resource
Base
Case
Area (km2)
MW
1. Far North
2. West Coast Auckland
3. Coromandel/Kaimai Ranges
4. Cape Egmont/Taranaki Cost
5. Manawatu Gorge
6. NI East Coast Hills and Coast
7. Wellington Hills and Coast
8. Wairarapa Hills and Coast
9. Marlborough Sounds Hills
10. Banks Peninsula
11. Canterbury River Gorges
12. Inland Otago
13. Foveaux Strait and SE Hills
14. Distributed
(typical wind
speed in m/s at
50 mAGL)
8
8
9
7
10
8
10
9
8
8
7
7
9
7
35
8
4
30
10
30
25
30
8
10
12
30
35
40
350
80
40
300
100
300
250
300
80
100
120
300
350
400
307
3,070
Total
Base
Case
Base
Case
GWh/y
1,070
250
140
710
410
920
1,030
1,080
250
310
280
710
1,260
950
9,370
The base case energy calculations used in this study incorporate the following
assumptions:
 Thirteen areas with high wind resource were considered, plus a general
“distributed generation” category covering any locally windy places
throughout the remainder on the country. Offshore and island resources
have been excluded.
 The technically viable resource estimated to cost up to 10 c/kWh has
been identified, i.e. mostly areas with good wind resource and existing
infrastructure (transmission lines, roads, etc).
 Some areas have been excluded due to known significant resource
consent issues, such as National Parks, areas of outstanding landscape or
natural character values.
 Some areas have been excluded because of physical inaccessibility for
construction and transmission.
 A conservative estimate of 10 MW per square km is used, which is based
on a nominal three by seven rotor diameter spacing between wind
turbines. An allowance has been made for local terrain, and buffer areas
around roads and residential development within the wind farm.
 The energy generation is calculated from the approximate wind resource
figure for the area, using an overall loss factor of 92 percent, which
includes availability, wake, electrical and other losses (eg hysteresis
losses1, air density, etc).
1
Hysteresis losses are associated with automatic shut-downs.
11
Also built into the above estimates is general information on the resource itself.
The annual wind pattern variation in New Zealand is typically around 10 percent,
rainfall variation is typically around 20 percent. The wind resource variation can
be to some extent forecast, calculated and allowed for. Seasonal variation
patterns are generally predictable. The annual resource for particular sites can be
accurately predicted following a period of site-specific wind data collection and
can be used to develop better forecasts regarding energy generation in New
Zealand as a whole.
12
3.
WIND TURBINE TECHNOLOGY
3.1
Introduction
Wind turbine technology has evolved rapidly over the past three decades.
Appendix 1 gives details of the technology and comments on some aspects of its
application in relation to New Zealand conditions. The key aspects are
addressed below.
3.2
Turbine Size
The size of wind turbines continues to increase. When the EECA/CAE Report
was prepared in 1996, wind turbines were commonly sized between 250 kW and
500 kW, with machines up to 1 MW becoming commercially available. Today
the most common turbine size range is in the 600 kW (0.6 MW) to 1.8 MW size
range, with 2 MW and larger machines either under development or just entering
production. Table 2 gives an indication of dimensions related to generation
capacity.
Table 2: Size/Generation Relationships of Modern Turbines
Rated
(kW)
Power Rotor diameter (m)
General
600-750
800-1,500
1,500- 2,000
40-50
50-65
65-80
Typical
NZ
45
55
70
Hub Height (m)
for General
40-50
50-65
65-80
Typical for NZ
45
55
70
Often, in low wind speed situations such as parts of Europe, larger rotors and/or
taller towers are used to increase the energy yield of the turbines 2. A 65 metre
high tower might be used on a 600 kW turbine or a 1.8 MW turbine might have a
100 metre tower.
The increase in size has been driven by a search for increasing cost effectiveness,
energy production, and more recently as wind turbines are increasingly
developed for offshore use. High access and foundation costs for offshore wind
turbines mean that larger turbines are likely to have a cost advantage over
smaller turbines. For New Zealand land based situations, the most cost effective
turbine sizing is considered to be in the 600 kW to 1 MW range at present.
Larger turbines may be more attractive where space or environmental constraints
mean that a limited number of turbines can be installed.
2
Wind speed generally increases with height above land.
13
Turbines up to about 1 MW in size are relatively easily transported and erected.
The nacelles can often be shipped in standard containers, and the blades can be
packaged around standard container lifting points. These turbines can also be
lifted with cranes of approximately 200 tonne capacity, which are available in
New Zealand. Turbines of this size are a mature technology, with thousands of
units having been produced.
The nacelles and blades of larger, MW class machines are larger and heavier.
The nacelles cannot generally be transported in standard containers. This means
that more specialised transportation equipment is needed for these turbines.
Large cranes, with capacities of 400 tonnes or greater are normally required for
turbine erection. Cranes would need to be imported for such installations in New
Zealand.
Because of the difficulties in transporting and erecting large MW class turbines
in New Zealand, it is expected that these will probably not be used here.
Smaller turbines (less than 250 kW) are still manufactured by a number of
companies (for example Lagerwey, Nordex, Vestas and Enercon) and have a
niche market in remote community power supplies. Examples include Thursday
and King Islands and Denham, in Australia.
3.3
Configuration
In the past decade the configuration of wind turbines has almost exclusively
standardised on three bladed horizontal axis machines with upwind rotors. Even
the direction of rotation has also been reasonably standardised across the
industry with most turbines rotating in a clockwise direction when viewed from
upwind3.
However it is not possible to rule out advances in technologies that could see
some alternatives, such as vertical axis or 2-bladed wind turbines, being installed
in the future.
3.4
Power Control Technology
Advances are continuing in power control technology. These advances result in
less stress on the wind turbines and provide improved electrical power quality.
While manufacturers have tended to remain with their traditional blade pitch or
stall control technologies, there have been developments within each field. Pitch
control turbines have developed with the inclusion of variable speed technology,
either narrow or wide band, to significantly reduce torque spikes in turbine drive
trains and to improve power quality. Most pitch controlled wind turbines now
have some form of variable speed.
3
It is possible that the configuration of turbines for offshore installation could vary, as noise and visual
impacts are less of a concern with these turbines. There is still developing technology for such situations.
14
Stall control turbines are being developed with “active stall” technology,
whereby the pitch of the turbine blades is adjusted to better control the stall.
This results in better power curve control, with consequent increases in energy
yield, as well as greater ability to withstand extreme wind gusts. Active stall
technology is mainly confined to turbines of about 1 MW capacity or greater at
present.
The adaptability of wind turbines to weak grid situations (which might exist in
some areas of New Zealand where wind farms could be built) is being improved
by the increased use of power electronics, particularly in variable speed
machines. Variable speed turbines are generally able to control the import and
export of reactive power, as well as supplying active power. Both reactive and
active power is limited by the wind conditions at the time. The wind turbines at
Hau Nui, Wairarapa are an example of this type of turbine. The grid
characteristics of other turbines are also improving, with emphasis on soft start
technologies, power factor correction, and flicker control. These features are
somewhat counterbalanced by the increasing trend to larger turbines which,
despite having improved power quality features, may not be able to be easily
accommodated at grid points where the installation of a smaller turbine may have
been possible.
3.5
Reliability
Wind turbines tend to be very reliable, with availabilities typically averaging 98
percent or better. While some problems can develop when new models are
produced (recent examples included blade and gearbox manufacture), these
problems are usually discovered in early production models and the design is
modified, with any costs of remedial action being borne by the wind turbine
supplier if under warranty.
3.6
Safety
Wind turbines have an impressive public safety record. A perfect public safety
record was marred recently when a change in wind conditions caused a
parachutist to be blown into a wind turbine in Germany. Apart from this recent
incident, there has been no known record of a wind turbine killing or injuring a
member of the public. Safety levels for construction and maintenance staff are
similar to equivalent industries.
3.7
Wind Turbines for New Zealand
Because of the ease of transportation and erection, and the cost effectiveness of
600 kW to 1 MW machines, such machines are most likely to be installed in
New Zealand in the near future. While larger MW class machines may improve
in cost effectiveness with increasing production, specialist equipment would
have to be imported into New Zealand to allow their installation. This is likely
to delay the introduction of these machines in the New Zealand market.
15
Not all wind turbines available on the world market are suitable for New Zealand
conditions. The low price of electricity in New Zealand means that only high
wind speed sites (with hub height wind speeds of approximately 9-10 m/s) will
initially be economically viable. Wind turbine designs are often optimised for
lower wind speed European conditions (typically 6 to 8 m/s at hub height), and
are therefore not always suited to New Zealand conditions. Nevertheless, it is
possible to find a range of turbine designs suitable for most New Zealand sites
and thus ensure that wind turbine supply contracts are competitive. Site specific
certification for some turbine models (taking into account wind speed, wind
shear, turbulence, and terrain effects) may be required, as the site conditions may
not comply with the general certification for the turbine in some aspects.
The above assumptions would see the wind turbines installed in New Zealand in
the coming few years having rotor diameters of approximately 40 to 60 metres
and tower heights from approximately 40 to 70 metres4.
3.8
Addressing Off-Site Effects
The adverse off-site effects generally associated with the installation of wind
turbines are acoustic noise and visual impact.
There has been an emphasis by manufacturers on significantly reducing tonal
noise in wind turbines, as tonal noise is particularly distinctive. The remaining
noise generated by wind turbines is largely aerodynamic in nature and is
normally broadband in character (“white noise”). While some larger turbines
may be slightly noisier, the use of fewer larger turbines generally reduces the
overall noise levels produced by a wind farm, when compared to the same
installed capacity using more, smaller turbines.
The use of larger turbines also has an impact on the appearance of the wind farm.
Larger turbines need to be spaced further apart for technical reasons. Hence a
wind farm of larger turbines is likely to appear more open than one using smaller
turbines. Larger turbines also rotate more slowly than smaller turbines, and
appear more “graceful” when in motion.
The trend to larger turbine sizes may to some extent change the perception of
off-site effects of wind farms.
3.9
Smaller Wind Turbines for Remote Applications
As well as the large grid connected wind turbine market, there is a market for
wind turbines to supply electricity in remote locations. Examples include the
supply of electricity to remote development such as houses, farms, lighthouses
and telecommunications facilities. Unlike the larger grid connected wind
turbines that generate electricity controlled with respect to voltage and
frequency, small wind turbines for remote applications are usually optimised for
4
The 48 wind turbines installed at the Tararua Wind Farm have a 45 m hub height and 47 m rotor
diameter.
16
battery charging. Inverters to generate grid quality electricity can in turn use this
battery power.
Wind turbines for remote applications vary in capacity from a few hundred watts
to about 10 kW. The consequent rotor diameters vary from less than a metre to
about seven metres. Tower heights for these wind turbines typically range in
height from 10 to 30 metres.
A turbine used to supply a single remote household would typically be rated at
about 1 kW. Such a wind turbine can often not be placed in a resource optimised
location as proximity to the user is the most important factor. Also some of the
energy from the wind turbine will not be able to be accepted by the system (eg. if
the batteries are already full). These two factors mean that the maximum
effective capacity factor for such a turbine is likely to be approximately 30
percent. This compares with capacity factors of up to 50 percent for wind farm
installations in optimum sites. In order to generate the same amount of
electricity as the 32 MW Tararua Wind Farm, it is estimated that the installation
of 50,000 small turbines would be required.
Hence the installation of small remote area wind turbines is unlikely to make a
significant contribution to New Zealand’s energy supply. Despite this, they are
likely to be of increasing importance in providing energy services to areas where
alternative energy supplies are uneconomic.
Any adverse environmental effects from remote wind turbines are likely to be
confined to the users themselves. Emission offsets from the generation of a unit
of electricity generated by a remote wind turbine are likely to be higher than
from a grid connected wind farm on a per kWh basis. This is because the energy
generated displaces electricity that would have been generated by small
relatively inefficient petrol or diesel engines.
3.10
Limitations
Despite earlier concerns that the characteristics of New Zealand’s wind resource
(such as extreme gusts) may have meant that there were limitations to the use of
internationally developed wind generation technology in New Zealand, that has
not proved to be the case for the majority of technologies available. The
operations and maintenance costs are related to the amount of energy generated,
and so are higher in absolute terms than for typical European wind farms, but
similar on a cost per kWh produced.
In practice, the limitations on the use of wind energy generating technology in
the New Zealand context are more likely to be related to aspects not connected to
the technology or the resource itself. Aspects include access to areas or lines,
construction capacity (including availability of lifting equipment), grid
characteristics, turbine and construction costs, and the ability to obtain resource
consents.
17
4.
4.1
USE OF WIND ENERGY IN NEW ZEALAND
Present Use
The utilisation of the New Zealand’s wind resource has begun in a limited way.
Significant grid connected installations to date include:



Wellington Wind Turbine comprising one Vestas 225 kW V27 unit in
1993 in Wellington.
Hau Nui, a 3.5 MW wind farm in the Wairarapa in 1996, consisting of
seven Enercon E40 wind turbines.
Tararua Wind Farm, a 31.68 MW wind farm on the Tararua Ranges near
Palmerston North installed in 1999 and consisting of 48 Vestas V47 wind
turbines.
All these projects are located in the lower North Island, where high wind speeds
and reasonable proximity to electricity load centres make wind energy
developments favourable.
These projects together are about 0.44 percent of the total installed generation
capacity in New Zealand, and generate just under 0.5 percent of the national
electricity consumption of approximately 34,000 GWh. A number of smaller
wind turbines are used to generate electricity for stand-alone supply5.
In addition, the wind’s energy is used in a wide range of activities that offset
other sources of energy, ranging from sailing to water pumping and drying
timber, crops and clothes. These other wind energy activities have not been
considered in this report.
4.2
Present Constraints/Barriers
While wind energy generation has been increasing over the past decade, its
uptake has been somewhat slower than anticipated in the EECA/CAE 1996
report. There have been several reasons for this, some more perceived than real,
as outlined below. The following chapters examine these in more detail.
4.2.1 Cost
The largest current barrier is cost. About 70% of the cost of a wind farm is for
the actual wind turbines (not including tower) which are manufactured entirely
overseas at present. The balance of plant (towers, civil works, electrical,
engineering and project management) is supplied locally, although some of the
materials such as steel and electrical cables may be imported. The manufacturer
usually supplies the wind turbine installation personnel, with balance of plant
using local contractors. Overall the personnel employed are mainly local. Local
5
Examples include urban and remote households, a restaurant/restroom at the Rimutaka Hill summit, and
widespread use on small boats.
18
employees perform on going Operation & Maintenance, after a suitable training
period. Tararua Wind Farm is a typical example. The issue of cost is commented
on in more detail in Section 5.1.1.
4.2.2 Dependability
Wind power is often viewed, mistakenly, as being an unreliable fluctuating
power source, which will have a detrimental effect on the reliable supply of high
quality electricity. Understanding the possible impact of wind power on the
reliable operation of New Zealand's electricity network requires evaluation of
five issues:





Lack of replacement generation during calm periods
Power fluctuations due to wind farm operation
System voltage fluctuations due to wind farm operation
Harmonic disturbances due to wind farm operation
Network failure
Analysis of each of these issues reveals that:



It is possible to forecast the power output of wind farms to some extent, and
thus be able to take action to increase the dependable delivery of energy to
the consumers.
The voltage fluctuations of wind turbines are small.
A smoothing effect on the power output of wind farms occurs in proportion
to the number of wind turbines.
Appendix 1 provides more information about short-term power, and longer-term
energy fluctuations.
Most electricity contracts are time-of-use contracts. As identified in Appendix
1, the operation of a grid-connected wind farm requires back-up from other
electricity generating sources to provide firm power and energy to meet these
contracts. Back-up is required when there is little or no wind or in conditions
where there is high wind speed and the turbine is shut down for its own
protection.
4.2.3 Consentability
The ability to obtain resource consents for wind farms is regarded in the industry
as a significant barrier to future development. To date, this expectation can be
shown to be more apparent than real. At present one consented wind farm has
not yet been built, with another where the first stage of about 50 percent of the
consented capacity has been built. It cannot therefore be said that consents have
limited overall development of wind generating capacity. The perception
nevertheless exists, and may itself be beginning to be a barrier. Resource
consents can take some time to obtain, with a reasonable lead time of two years
or more, if there are appeals. If resource consent applications are being delayed
now because of a perception of resource consent related difficulties within the
19
industry, this may delay uptake should other barriers be reduced or removed in
future.
4.3
Favourable Types/Forms of Development for the Future
The critical factors to wind power development in the near future include
equipment and installation costs, the amount of wind resource available close to
load centres, uncertainty over operation and maintenance costs and wind turbine
life.
Energy outputs are very sensitive to average wind speeds. Site selection based
on careful measurement is therefore crucial.
The wind speed required for a viable development depends on the life cycle
costs compared with alternative electricity supply costs. In Europe a 6.5 m/s site
is fairly good, 7.5 m/s good and 8.5 m/s very good. Low electricity prices in
New Zealand mean that the higher wins speed sites will be economic initially.
This means locating development at those high wind sites that have few
environmental issues to address, and that are close to major load centres.
At present the wind speed that is required for an economically viable project is
high due to the relatively low electricity price. To make wind power come close
to being economic in the short to medium term, a site with a wind speed of
10 m/s or higher is needed. However there is also an upper limit set by the
maximum wind speed that the wind turbines must survive, which is somewhat
associated with the average site wind speed. In general terms it can be said that
the annual average wind speed should not be higher than 12 m/s.
Equipment cost is also a critical issue. The wind turbine cost is about 50-80
percent of the total development cost. It seems difficult to reduce this in the short
term. Hence it is important to find sites with a high average wind speed with low
turbulence levels, which are easily accessible and which have a nearby electrical
infrastructure that is appropriate.
It is expected that most future wind farm installations in New Zealand over the
next few years will use 600 kW to 1 MW sized turbines, possibly increasing
over the next one to two decades to larger turbines if they become cost-effective.
Most wind farms will be dispersed with less than 50 MW capacity, and located
in the general areas identified in Figure 1, with priority development in areas
closest to urban centres or possibly to major industries. As well, there will be
some degree of wind energy development as distributed generation.
In a number of niche situations, lower wind speed sites may provide a more even
spread of output. Customers want dependability of supply rather than a peak
supply that may be less certain.
20
5.
5.1
POTENTIAL USE OF WIND ENERGY IN NEW ZEALAND
Constraints/Barriers
5.1.1 Economics
As identified earlier the most significant barrier at present and into the future
relates to the cost of generation of electricity from wind energy compared to the
price of electricity from alternative forms of generation such as gas-fired power
stations, which produce electricity at lower cost6. Market indicators are that the
cost of new wind energy generators (about 5 to 6 c/kWh at the best sites) at
present is typically 1 to 2.5c/kWh above the cost of the next alternative new
generation.
Although a wind farm can be developed on a modular basis so that total capital
cost can be somewhat spread, the cost of electricity from wind energy is
nevertheless dominated by capital cost factors. Such costs may include land
purchase, costs of sub-station and connecting lines, and construction costs, as
well as the turbines themselves. Turbine costs are usually the most significant
item. While the cost of manufacture of turbines in the country of origin is
generally trending downwards, the capital cost in New Zealand terms has
recently risen due to adverse exchange rate movements7, with the Euro being the
currency that is most relevant to the supply of wind turbines. Interest rates are
also an important factor in the cost of wind energy.
Another cost factor is that wind farms are very site specific and may be distant
from sufficient electricity demand, or from connection to adequate capacity
transmission lines. Therefore the cost of connection to transmission lines can be
a significant cost penalty for some sites.
The value of electricity from wind energy is effectively set by the electricity
market or markets, with the dominant market being the electricity pool or spot
market. The recent predominant supply-side additions to this market have been
gas-fired generation, with economics that are better than wind. Further planned
gas-fired power stations have been identified in media statements. The cost of
additional gas-fired combined-cycle generation is estimated as 4.3 to 4.5 c/kWh
with a forecast baseline wholesale price of around 3.9 c/kWh in 2000, rising to
about 4.5 c/kWh in 2005, and then to 6.5 c/kWh in 20158. If investments in gasfired power stations proceed, they will provide additional supply-side capacity
6
Resource scarcity of gas is not considered to be an issue likely to modify the economics of such
development within the next 10-15 years.
7
This also has some effect on the overall cost of electricity using other generation technologies, such as
gas turbines.
8
This information is taken from “New Zealand Energy Outlook to 2020: February 2000” by Energy
Modelling and Statistics Unit, Ministry of Commerce, February 2000.
21
that could otherwise be provided by wind energy, inevitably delaying any
significant investment in wind farms compete in the electricity pool.
Wind energy is non-firm energy9 and as such is valued at the average spot price.
It is thus sold at a lower price than generation that is controllable in terms of time
and quantity. This lower price adversely affects the economics of electricity
generation from wind energy, as few customers are prepared to pay for “as
supplied” energy, instead preferring “as required” energy.
The 1998-99 split of the lines and energy businesses in the electricity sector was
a change that may have affected some potential wind energy developments in
New Zealand. This split effectively meant that opportunities for lines companies
to invest in wind energy projects became extremely limited.
A government decision in October 2000 to allow lines companies some scope to
invest and develop wind energy projects10 should, for future developments by
line companies, reduce some of the effects of the split. This initiative should
increase the potential for “embedded generation” to occur, and may result in
investment in some smaller wind farms or distributed generation proceeding. It
is still under discussion whether, due to limited opportunities for economic
distributed generation, and the site-specific nature of the wind resource, this
initiative alone will result in a significant uptake of wind energy opportunities.
5.1.2 Access Issues
Market Access
The most significant access issue is one of access to electricity markets. As
discussed earlier, there is ready access to the electricity pool or spot market
where the price commanded is based on non-firm energy because wind strength
can not be relied on. This is thus a barrier only to the extent that wind energy
cannot reliably obtain top prices on the spot market.
While there is some evidence of “green” market sales of wind power, these are in
the nature of contract sales. Any green market is probably very “thin” and not
expanding.
9
Non-firm energy is the energy from a source that can not be depended on by the power station operator
to produce electricity at a pre-determined MW level for any specific half-hour period.
10
The Electricity Industry Reform Act 1998 will be amended to allow lines companies to own distributed
generation up to two percent of the network's maximum demand or 5MW, whichever is the greater. The
Electricity Industry Reform Act 1998 will also be amended to allow lines companies to own distributed
generation beyond these restrictions, provided that the source of such generation is a new renewable
energy resource and that the generation activity is carried out in a separate company subject to the “arms
length” rules set out in Schedule 1 of the Act. Lines companies will be required to publicise their
intentions to construct distributed generation 30 days prior to entering binding contracts including giving
reasons for proposals and demonstrating that alternatives have been considered. Terms and conditions for
the connection of distributed generation to distribution networks will be determined under the distribution
pricing methodology developed by the Governance Board, and be subject to dispute resolution under the
new market rules to be developed by the Board. Legislation will give the Government regulation-making
powers in case the industry fails to deliver an effective arrangement.
22
Voluntary "green pricing" schemes have the potential to support renewable
energy projects such as wind farms, when the renewable projects are not
financially viable on their own. TrustPower has recently launched a green
pricing scheme, in which 16,100 New Zealanders are invited to contribute $2 per
week to help support the existing wind farm.
Land Access
Because the resource is site specific and wind turbines are a land-based activity,
it is essential for any potential developer of a wind farm to gain an interest in the
land. This is usually accomplished by either outright purchase of the land or by
an agreement with the landowner for rights to install and operate wind turbines.
To date the ability to gain such an interest in suitable land has not been a
significant barrier to wind energy development. However, most of the “best”
sites have now been identified and acquired by some particular interest, and
individual investment decisions may mean that those are not developed in the
logical, most productive or most cost efficient order. This in itself may be a
factor delaying some wind energy development, although its extent cannot be
known.
As access rights for the most favourable sites are taken up, there is likely to be a
greater number of sites with lower wind speeds that will then become the focus
of developer interest. Figure 2 illustrates the increasing availability of sites at
lower wind speeds. The extent to which a developer will take up an interest in a
wind farm site depends on their perception of both the likelihood of wind energy
generation from that site becoming economic in the near term and the consenting
risks applicable to the particular site.
Figure 2:
Wind Resource vs Potential Installed Capacity
11
Wind resource (m/s at hub height)
10
9
8
7
6
5
0
1000
2000
3000
4000
5000
6000
7000
8000
Potential Installed Capacity (MW)
23
Transmission Access
Access to transmission facilities at reasonable cost is also an issue for potential
wind farms. While the exact connection point of a wind farm to the electricity
network may not be important so far as reducing electrical losses is concerned, it
can make a significant difference to the costs of delivered energy if that
connection has to be to Transpower’s system rather than being embedded in the
local network, or if the output from wind generation is greater than the demand
at the Transpower point of supply. This regime may favour the first wind farm
connection at a particular location, but can penalise any subsequent wind farm
development in the same area.
5.1.3 Resource Consents
A frequently cited barrier to wind energy generation uptake is the risk and
difficulty of obtaining resource consent.
It is widely perceived throughout the energy industry that wind farms are
difficult to consent. There is some basis for such concern, however the actual
experience has been:

Only one wind farm project has declined by a local authority11.

One wind farm (Hau Nui in the Wairarapa) was handled as a non-notified
application and gained a straight forward consent12.

One turbine (Brooklyn in Wellington) was one of the first applications
handled by the particular local authority under the RMA. The consent
was specifically sought for a limited period of 15 years.

A single “experimental” Vortec turbine (reduced scale but still large) in
Waikato District was consented without difficulty.

Two relatively large wind farms have been consented in the vicinity of
Palmerston North, following the normal processes of the RMA. One
raised specific concerns with telecommunications interference, as well as
the more general work and visual concerns13. Only one has since been
11
A proposed wind farm at Baring Head was declined in 1995 by Lower Hutt City Council. This was on
a site identified in the Regional Policy Statement (and in previous Regional Planning Schemes) as having
outstanding landscape significance and outstanding geological significance. The location was also
identified by local tangata whenua as being of cultural significance in relation to Kupe’s arrival in
Wellington Harbour. It was opposed by a range of parties including tangata whenua and residents on the
opposite side of the harbour. As a non-complying activity it was found to be contrary to all relevant
policy statements and plans, and to have effects that were greater than minor (relating to landscape and
natural values) and thus did not pass any of the statutory tests that would have enabled its consideration in
terms of Part II of the Resource Management Act. Most potential wind farm sites do not face such welldefined statutory difficulties.
12
It is unlikely that any wind farm application would be handled non-notified in the present case law
context of the interpretation of Section 94 of the RMA, which has tightened considerably since the
Hau Nui consent was obtained in 1996.
13
This experience has resulted in a greater industry understanding of the potential pitfalls of seeking
consents on very defined projects, as they are difficult to modify later should conditions change.
24
built, to an initial stage of about 50 percent of the maximum that the
consent provides.

Numerous small turbines have been installed without any consent being
needed, or with minimal difficulty14.

No project has proceeded to be heard by the Environment Court.
Thus the actual experience of consenting wind energy generation has not been
particularly negative. However, it is fair to say that:

The costs in providing adequate information for applications have been
high. This is because the technology has been new to New Zealand and
its effects are not well understood by affected communities or consent
authorities. The RMA has very high information requirements and
“proof” of effects is subject to much more rigorous analysis than almost
anywhere else in the world15.

There is a high risk involved in the process, as most wind farm projects
are discretionary activities (or sometimes non-complying) and must be
evaluated in terms of national, regional and local policies. They also
evaluated on the basis of effects (as defined in the RMA), as well as under
the more general “sustainability” criteria in Part II of the RMA. In
practice, the process of consultation and participation under the RMA
involves a high level of risk as to whether consents may be able to be
obtained or not.

The cost of public consultation and provision of good documentary
evidence of the potential visual and noise effects to surrounding land
owners means that only large well funded investors can consider
investment in wind farms.

All notified resource consent applications that attract submissions can be
appealed to the Environment Court by a submitter. At that stage, other
parties can also join the process16. While many appeals are settled quite
quickly through a mediation process, this involves a risk assessment by
parties and an intransigent appellant may not be prepared to mediate.
Urgency is rarely granted by the Environment Court, and would not be, in
the normal course of energy development projects. Delays associated
with the Environment Court can add two years or more to the normal six
14
Some small turbines installed in some urban locations (ie suburban residential sections) have resulted in
neighbourhood complaints.
15
EECA has published a useful general and still current guide to resource consenting in “Wind Energy
Guidelines for Wind Energy Developments” 1995. Some additional comments are included in Appendix
3 to this report.
16
Other parties who can join at this stage are limited to those directly affected, or those who represent a
relevant aspect of public interest.
25
month consent process for a notified application17. This delay, the risk
inherent in the decision, and the cost, can be perceived as a strong
deterrent to potential developers.

The expectation of developers is that a consent must be taken up within
two years unless a longer period is applied for as part of the application.
Councils have granted up to six year “start up” periods, so the uncertainty
associated with short term consents should not be seen as a real barrier.
While distributed generation may be able to be handled more efficiently through
consent processes (ie non-notified consents with neighbours’ written approvals),
this may be very site dependent, and may not be well known by potential
investors. If notification processes are involved, the public consultation and
assessment of effects effort for a single turbine in a controversial location may
approach that for a large wind farm. If this is so, it may add significantly to
project costs.
This may be seen as a significant barrier to investment by small investors into
single turbines or small wind farms. On a unit cost basis, which is the dominant
commercial driver for investment in electricity generating assets, concentration
of turbines onto a single site reduces these costs.
5.2
Analysis of RMA Policy Statements and Plans
5.2.1 Introduction
To endeavour to ascertain the extent to which consent processes are a real
barrier, and to address the aspects of the brief relating to the size of the resource
likely to be used over the next few years, an evaluation of the relevant plans and
policy documents was undertaken. The contents of plans, along with the
outcome of the participatory process, have a significant bearing on the ability to
obtain resource consents for any type of wind farm development.
For the areas identified on Figure 1, regional policy statements and relevant
district plans were obtained and assessed.
5.2.2 Hierarchy of Policies and Plans
The RMA sets in place a hierarchy of policies and plans which need to be taken
into account.
Over-riding all these, except when an activity is identified as non-complying in a
plan and has specific standard tests to overcome prior to being considered18, is
17
The Resource Management Bill currently before Parliament includes a mechanism whereby more
controversial projects can be referred directly to the Environment Court. This may reduce delays to some
extent, if the provisions are introduced.
26
Part II of the Act. This encapsulates a range of “sustainable management”
criteria which often conflict or offset each other in any particular circumstance
and therefore policies and plans developed under the legislation are used as a
basis for interpreting Part II19.
Generally, for any area for which a wind farm may be proposed, it would be
necessary to evaluate the contents of:



The NZ Coastal Policy Statement20 (except for inland areas)
The relevant Regional Policy Statement
The relevant District Plan
Regional plans may also trigger the need for a consent, but the most likely
situation in which this would happen would be for land disturbance, in which
case any consent requirement would apply to the construction phase only, and is
not expected to be a difficulty.
5.2.3 New Zealand Coastal Policy Statement (NZCPS)
This has strong policies protecting parts of New Zealand’s coastal environment
from “inappropriate subdivision, use and development”.
The interpretation of what is “appropriate” depends very much on the site chosen
for an activity and the specific details of a project, as interpreted by expert
opinion – usually the opinion of landscape architects or designers.
Generally, the NZCPS strongly limits development in wilderness coastal areas,
or areas of very predominant natural character where it is likely that, for reasons
of scale, size or location, development would compromise the existing values.
Case law has indicated that natural character is strongest where there is
indigenous vegetation and a complete absence of visible structures, progressing
through modified rural environments (including pastoral and forestry areas) with
few structures and roads to rural environments which have considerable evidence
of human activity, and finally to rural residential and urban areas, where natural
character may have been largely lost. Consents are most likely to be obtainable
in areas with less natural character, but this may bring wind farm development
into conflict with rural residential or urban development.
The NZCPS also promotes the avoidance of sprawling or sporadic development,
which also may require some interpretation where wind farms are concerned.
18
Non-complying activities must be able to demonstrate that either they are not contrary to objectives and
policies in relevant plans or that their effects are no more than minor. If they cannot get through one of
these statutory “gates” they must automatically be declined.
19
Part II includes in section 5 a general provision that the legislation is enabling, in that people and
communities can provide for their social, economic and cultural wellbeing and their health and safety.
However, section 6 in Part II places considerable emphasis on protection of the coast and outstanding
landscapes from “inappropriate” use and development, and sections 6, 7 and 8 emphasise the importance
of Maori cultural values, including protection of special places and the role of tangata whenua as Kaitiaki.
20
This relates to the “coastal environment” which is undefined but generally has been found to include
land to the top of the first ridge of hills behind the coast.
27
A principle with possible positive future importance for wind farm development
is that the NZCPS recognises that some activities can only take place in the
coastal environment, and some provision must be made for such types of
development.
It is expected that the principles and policies in the NZCPS will be interpreted
and modified to clarify their application in specific local areas, and that more
detail will be found in the regional policy statements and district plans.21
5.2.4 Regional Policy Statements
The areas shown in Figure 1 encompass the territories of eleven of the fourteen
Regional Councils in the country, and three of the four unitary authorities which
have both regional and territorial authority functions under the RMA. Thus
fourteen separate regional policy statement documents were evaluated.
The evaluation sought to identify areas of special protected status that should be
discounted from the process, policies that would actively discourage wind energy
generation, and policies that may provide a basis for positive arguments in
favour of wind energy development.
The findings are broadly summarised as follows:



Most regional policy statements contain policies strongly supporting the
use of renewable energy and many (but not all) promote its development.
The extent and details of the policy framework largely depend on the
perception of local renewable energy resources. For example, Northland,
Southland and Wellington specifically identify wind energy, but Waikato
and Otago emphasise hydro power generation. Taranaki does not address
renewables, but has strong policies in favour of energy efficiency for gas
use.
Often such policies are “subject to” or counterbalanced by landscape
protection policies. Landscape protection provisions in different regional
policy statements may relate to broad areas of landscape such as the
Ruahines and Kaimanawas in Manawatu-Wanganui22, or to very specific
sites such as Baring Head and Mt Victoria in the Wellington Regional
Policy Statement, where the very specificity of identification guarantees a
high level of protection. Overall, regional policy statements generally
leave areas of particular landscape significance to be identified in district
plans.
The extent to which the provisions of the NZCPS are incorporated in
specific regional policy statements varies, and only in a few locations has a
regional policy statement provided specific guidance through policies of
areas or specific types of coast to be avoided by any development.
21
A recent Environment Council decision (Kotuku Parks Kapiti Coast DC A015/01) has however
indicated that the NZCPS principles and general policies can over-ride locally-prepared and recent district
plans.
22
These policies have not proved an impediment to wind energy development in this area because of the
large scale of the landscapes identified.
28
5.2.5 District Plans
As a result of the RMA encouraging an effects-based approach and general lack
of experience in plan making, there is great diversity in district plan contents and
style throughout the country. District plans prepared by 24 district councils and
three unitary authorities, together covering most of the areas identified in Figure
1, were assessed. Because of their variety, it is difficult to generalise. However,
the following points can be made:




In only two districts were wind turbines or windmills identified as
specific activities in rural areas, and both listed these as discretionary
activities. In some plans energy generation is incorporated in utilities
provisions, but these would become discretionary through turbine height.
In most other plans wind energy development would be discretionary. In
some plans, the height of the turbines may result in the activity being noncomplying.
Most plans identify areas of outstanding landscape value or significance.
These are usually quite limited in extent. Exceptions are the Marlborough
District where approximately half the Sounds area is protected as
outstanding landscape. Urban “greenbelt” areas may be protected through
such policies (Dunedin and Wellington).
Many plans identify areas of significance to tangata whenua and policies
particularly emphasise consultative process in such locations.
In summary, it is difficult to draw anything, other than general conclusions, from
the analysis and any specific wind farm would require careful evaluation in terms
of site specific effects, as well as in terms of plan provisions.
5.2.6 Opinion Survey
To help evaluate optimistic and pessimistic scenarios for future development, it
was considered desirable to get an indication of the likely interpretation of the
plan contents in the local context. A brief phone survey of senior planning
advisers to the relevant council was undertaken. They were asked to rank
generally the ease of consent for a wind farm of 10-150 turbines in their districts
under the present plan provisions, and for distributed generation as one-off
scattered turbines.
The ranking pattern indicated by the survey supports the concerns about the lack
of certainty in the consent process identified earlier in this report. Less than half,
seven of the 20 respondents, indicated a “better than 50 percent” chance of
obtaining consents for a wind farm.23 Generally, respondents indicated a higher
chance of consent for distributed generation in their areas.
Information from this survey has been incorporated in the evaluation of “Best
Case” and “Worst Case” consent scenarios.
23
Most indicated that issues and concerns would be site specific. One indicated a better than even chance
only in areas outside those identified as of landscape significance.
29
5.3
Market Trends and Competition
As noted earlier in this report, wind energy is not economically competitive in
New Zealand at present.
With a wide range of competitive generators, market forces will inevitably result
in other forms of generation being developed in preference to wind energy. At
present the most cost-effective form of generation is by gas-fired combined cycle
plant, which adds modules of 300 to 400 MW capacity at a time. Market
indicators are that the cost of new wind energy generators at present is typically
1 to 2.5c/kWh above the cost of the next alternative new generation.
It is anticipated that, on current generation installation cost trends, electricity
price projections, and some minor carbon costing, wind energy generation would
only again become economic in about 2008. Under this regime no additional
significant wind energy generation can be anticipated before then. However,
there may be uptake of existing consents, and some small farms or distributed
generation to meet specific markets or needs, particularly by line companies.
The forecasts included in this report are thus provided on a flexible time base of
10 to 15 years. The start date would be at present, if policy or other mechanisms
provide a non-market related “boost” to wind energy, or a delayed start date of
three to eight years under a “business as usual” scenario.
5.4
Other Government Policy Directions
The Energy Efficiency and Conservation Act 2000 requires there be a national
strategy to promote the purpose of the Act by October 2001.
The government has also signalled its intention to ratify the Kyoto Protocol to
the United Nations Convention on Climatic Change. Under this protocol, the
country will be committed to reduce greenhouse gas emissions to 1990 levels
over the period 2008 to 2012.
Both these actions indicate emerging policy directions, which may add impetus
to the uptake of wind energy development. These have not been taken into
account in developing the scenarios below.
5.5
Forecasts
Table 3 below describes “Best Case” and “Worst Case” scenarios.
The two scenarios incorporate the following:


Assumptions of present pricing of plant and electricity.
The foreseeable technological changes (largely in efficiency of
production) likely over the next 10 to 15 years.
30

Assumptions relating to resource consents taking into account the
findings of the assessment of Regional Policy Statements and District
Plans24 for the area and the following:
Protection of landscape, coastal areas, ridges.
Presence of rural residential/lifestyle development in areas
favoured for wind energy development.
Maori land ownership and identified Maori values expressed in
plans.
Attitude of councils to development (as expressed by key
informants).
In the scenarios, the “worst case” scenarios represent basically minimum
development of some low-intensity small scale wind farms in less prominent
areas, with distributed generation having little role. The “best case” scenario
assumes that areas that appear to have a favourable policy framework, few
impediments for development under relevant plans and experience almost no
impediment through the resource consent process, begin to be developed.
Table 3: Future Scenarios for Wind Energy Generation
Estimated
Resource
Base
Case
Best
Case
Worst
Case
(typical wind speed in Area (km2) Area (km2) Area (km2)
m/s @ 50 mAGL)
Regions
1. Far North
2. West Coast Auckland
3. Coromandel/Kaimai Ranges
4. Cape Egmont/Taranaki coast
5. Manawatu Gorge
6. NI East Coast Hills and Coast
7. Wellington Hills and Coast
8. Wairarapa Hills and Coast
9. Marlborough Sounds Hills
10. Banks Peninsula
11. Canterbury River Gorges
12. Inland Otago
13. Foveaux Strait and SE hills
14. Distributed
Total
Proportion of existing
8
8
9
7
10
8
10
9
8
8
7
7
9
7
35
8
4
30
10
30
25
30
8
10
12
30
35
40
25
4
4
20
10
20
25
30
8
10
12
30
35
20
5
1
1
5
5
5
5
8
1
1
5
8
8
1
307
253
59
Base Best
Case Case
MW
MW
Worst
Case
Base
Case
Best
Case
Worst
Case
MW
GWh/y
GWh/y
GWh/y
350
250
50
1,070
770
150
80
40
10
250
120
30
40
40
10
140
140
40
300
200
50
710
470
120
100
100
70
410
410
290
300
200
50
920
610
150
250
250
50
1,030
1,030
210
300
300
80
1,080
1,080
290
80
80
10
250
250
30
100
100
10
310
310
30
120
120
50
280
280
120
300
300
80
710
710
190
350
350
80
1,260
1,260
290
400
200
10
950
470
20
3,070
2,530
610
9,370
7,910
1,960
38%
32%
8%
28%
23%
6%
There is nevertheless a high level of uncertainty in the projections given in
Table 3. The time by which the scenarios will be achieved is highly uncertain, as
it is as likely to be governed by cost and price influences as well as decisions
The Brief refers to “the near future” in terms of resource consents. Regional policy statements have a
life of 20 years, and district plans a life of 10 years before they must be reviewed. Thus the documents
evaluated, many of which are still at proposed stage, are likely to be still current for the projection period.
24
31
made by other players in the competitive electricity market. At best, Table 3
gives 10 year projections. At worst, these projections cover the period to 2015.
Figure 3
Possible Uptake of Wind Energy
9000
8000
7000
Best Case
GWh
6000
5000
Worst Case
4000
3000
2000
1000
20
15
20
14
20
13
20
12
20
11
20
10
20
09
20
08
20
07
20
06
20
05
20
04
20
03
20
02
20
01
0
Year
The information from Table 3 is graphed in Figure 3, showing the best case and
the worst case values. The graph indicates a low level of uptake (little more than
is currently consented) prior to 2006 or 2007.
For the best case this includes assumptions of uptakes ahead of the point at
which the cost/price economics margin closes, and an early start and quick
passage through consent processes. For the worst case, an uptake is assumed at
or behind the point at which the cost/price economics margin closes, exacerbated
by a more difficult and extended passage through the consent process with a
much lower level of success in consenting.
5.6
Comments on Forecasts
Comparisons between the base case (Table 1), and best case and worst case
(Table 3) figures indicate that there are some real constraints in the areas of
resource consents. Limitations in plans and consent expectations account for the
loss of some 70 km2 or 700 MW of installed capacity (approximately 25 percent
of the total at best, and 250 km2, or 2500 MW of installed capacity)
(approximately 80 percent of the total) at worst, out of the total Base Case
resource.
The timing of developments, and whether the “lost” areas in the base case
eventually gain consents (under increased pressure to utilise the resource), or the
base case resources area expands to incorporate areas with lower wind speeds,
are unknown.
32
The forecast figures cover the period from now until about 2010 to 2015.
Whether uptake is delayed, or continues on a smooth upward curve from the
present is uncertain. Whether new wind generation will be brought on in small
incremental additions, or in larger “chunks” is not known. Wind energy
capacity, like some of the other renewables, can be added to on a smooth and
modular basis.
Under these scenarios wind will substitute for a significant amount of fossil fuel
generation. The mitigation achieved will depend on the mix of other generation
going in over this period. On the basis that combined cycle gas will still be
significant at this time, the two scenarios would mitigate from one to three
million tonnes of annual CO2 emissions by 2015.
33
6.
6.1
SOCIAL AND ECONOMIC IMPLICATIONS
Introduction
This chapter comments on the social and economic implications of the present
situation and the scenarios presented in Table 3. To a certain extent the social
and economic effects of both are the same, with the effects (positive and
negative) being more spread out over time with the worst case scenario.
6.2
Social and Economic Implications
Table 4 provides comments on the type of effects and the impact at a range of
levels relating to wind energy development within the range of the scenarios
presented in Table 3.
This is a broad-brush analysis, but it gives an indication of the potential range of
effects, costs and benefits, and indicates how different levels of the community
may be impacted.
34
Table 4: Social/Economic Effects of Wind Energy Development Scenarios
Social/Econo
mic Effect
Increased
cost
of
generation
Description
National
Regional
District
Local
Individual
As wind energy generation broadly costs more than
competitive forms of generation, if the scenarios are
taken up (and assuming no policy or other changes)
there will be an additional cost. The costs will be
greater the sooner the generation is added.
Will add to overall
energy/electricity costs (at
present 5-10% additional
per unit sold).
Same as regional,
but some areas may
benefit
from
embedded
generation.
Same as for district, but
local areas may have
reduced
costs
with
distributed or embedded
generation.
Small turbines can reduce
costs,
especially
if
generating at peak price
periods. Electricity cost is
a significant household
expenditure item.
“Green
Energy”
A small effect in a country
where renewable sources
already dominate.
Same as region.
Same as district.
Same as region.
Same as district.
Can
avoid
use
of
alternatives such as diesel
generators, where not grid
connected.
As above.
Capacity
enhancement
With growing awareness of problems of greenhouse
gas, and environmental implications of other
generation methods, there is support for use of “green
energy” from renewables such as wind power.
Wind generation (as with other renewables) avoids
CO2 production that would be associated with fossil
fuel generation.
Wind farms can be small additions to total capacity, or
a farm can be built in stages.
Cost would be differentially
allocated by region by individual
companies.
High use regions would probably
experience greatest effects although
distribution companies may smooth
this out.
Can make a significant contribution
in regions which are low in other
renewable resources. Opportunity
to raise awareness.
Important in areas which are short
on other renewables “Regional
accounting” may be undertaken.
Same as national
Same as region.
Distributed
generation
can be made available for
small communities.
Employment
–
construction
phase
Wind turbines are likely to be imported. Towers,
foundations and possibly blades may be manufactured
locally. Construction workforce will be regionallybased.
Contracts in any region are likely to
be one-off.
Same as region.
Same as district.
Other social
impacts –
construction
phase
Wind energy construction involves small impacts,
unlike some energy projects (eg hydro) which may
involve large scale workforces and significant social
consequences in remote areas that must be planned for.
Same as for national.
Same as for region.
Impact unlikely to be
noticed, as projects likely
to be tendered to
established contractors.
One-off
installation.
Minimal effect.
Environment
al effects –
construction
phase
Environment
al effects –
long term
Construction and commissioning may involve new
roads, temporarily increased traffic volumes, heavy
transporters, earthworks and some noise. Most effects
can be mitigated.
Some effects of varying significance, especially visual
impact and possibly noise. Site choice and mitigation
measures can generally limit effects.
Same as for national.
Same
as
national.
for
Same as for local.
for
Effects on
other land
uses
Tourism
effects
May be some local
disruption to access and
some
other
effects.
Temporary and minor.
May be of concern for
specific
communities.
Rural residential dwellers
seem most concerned
about potential effects.
Same as for district.
Same as district.
Same as local.
Same as for district.
Offers a level of self
sufficiency.
May provide complete self
sufficiency.
CO2
avoidance
Supply
security/safet
y effects
A small contribution, but
rising
to
become
significant.
Offers
efficiency
in
meeting rising demand
curves over time. Less
market distortion.
A small number of
engineering firms may
expand as a result. New
specialist
component
makers may emerge.
Very
minor,
as
construction spread over
time
and
regions.
Construction phases are of
short duration.
Localised effects only –
not of national importance.
Not
of
significance.
national
Generally
not
of
regional
significance.
Intervisibility can
become an issue if too many farms
in one area.
Same
as
regional.
Small areas of land actually used, and can co-exist with
a range of productive or recreational activities.
Not
of
significance.
national
Not of regional significance.
Early wind farms were tourist attractions. Can provide
viewing areas and open new vistas to the public.
Novelty values now not as great as it was.
May continue to operate if other sources inoperable.
Not
of
significance.
national
May be of regional significance, if
an exceptional site.
Not
of
district
significance.
Can
enhance rates base.
Same as regional.
Could be of some national
significance if widespread
disruption
of
other
systems.
Same as for national, but beneficial
effects
may
be
enhanced
regionally.
35
Same as for region.
Distributed generation can
be
provided
as
an
individual household, farm
or other basis.
One-off
installation.
Minimal effect.
Same as for local.
Same as local.
7.
CONCLUSIONS AND RECOMMENDATIONS
This review has re-examined material relating to wind energy generation included in the
1996 EECA/CAE Report. In the intervening period there has been some uptake of wind
energy potential, but a number of circumstances have meant that the uptake has not
been as fast as anticipated.
This study supports the scale of wind resource in New Zealand indicated by the earlier
EECA/CAE studies and has increased it in some areas.
This study also confirms that reliable technology at known costs exists for converting
wind energy into electrical energy.
This study has also found there are broad barriers to the uptake of wind energy. The
barriers identified are:

Cost in comparison with other options (particularly generation by gas-fired thermal
stations). This is the most significant barrier at present.

Perceptions of energy delivery reliability. This is a barrier that is reducing in
significance with improved technology and better understanding of total systems.

Access to land and transmission facilities. This is not a significant barrier at present
but may become so in the future.

Resource consent issues – particularly the high risks and cost involved. This barrier
is more apparent than real at present, but perception of consent processes as a barrier
may in itself become a barrier in the near future.
In contrast to the constraints identified, there have been advances in technology since
1996, which will probably result in the use of fewer and larger turbines in wind farm
generation. The potential for distributed wind energy uptake may also have been
enhanced in the period by improved technology at all scales of generator equipment.
Technology improvements and reducing costs of generator equipment mean that a
somewhat larger area of New Zealand can be considered as suitable for wind energy
generation than when the EECA/CAE report was done.
A small number of wind energy generation projects have been consented and installed
over the past decade. This now represents a small sector of generation capacity and
actual production within New Zealand. The experience has led to improved
understanding of the practical and consenting issues associated with such development.
The report has investigated the policy and planning framework that applies in various
parts of the country, in some detail.
36
This study has confirmed concerns about levels of certainty for future consents and thus
for future investments, as significant costs in investigation and consultation, and
significant risks overall, are involved.
The analysis of past and present barriers has been translated into future expectations,
and assessments have been made of the “best case” and “worst case” uptake over the
next decade or so. The projections involve high levels of uncertainty over time, and
need to be considered as estimates only. Policy initiatives could reduce the time period
over which the scenarios are achieved. The potential for uptake of wind energy remains
high, although it is unlikely that the “base case” generation potential will ever be
achieved because of a number of barriers identified which are related to the areas in
which the resource is located.
There are a number of social and economic implications associated with wind energy
development.
These include cost, localised environmental effects, some job
creation/retention opportunities, and greenhouse gas avoidance. The social benefits
potentially outweigh the economic costs, but cost is presently seen as the most
important barrier to increased supply of energy from wind generation systems.
Wind energy, as a “new renewable” form of generation is a valuable resource, and will
in future be able to contribute a significant proportion of New Zealand’s electricity
generation.
37
References
EECA, “Our Energy Future”, September 2000-10-11
NZ Government, Resource Management Act, 1991 (and amendments)
NZ Government, Energy Efficiency and Conservation Act, 2000-10-11
EECA, “Wind Energy – Guidelines for Renewable Energy Developments”, June 1995
EECA and Centre for Applied Engineering, “New and Emerging Renewable Energy
Opportunities”, June 1996.
Sanders, I, “A Renewable Resource Assessment Atlas of New Zealand”, EnergyWise
News, Issue 66, June 2000-10-11
EnergyWise Monitoring Quarterly, “Dynamics of Energy Use Patterns and Trends in
the New Zealand Residential Sector”, Issue 16, June 2000-10-11
Ministry of Commerce, “New Zealand Energy Outlook to 2020”, February 2000.
NZ Wind Energy Association, “Achieving a Sustainable Energy Future: Why NZ
Needs Wind Generated Electricity”, February 2000 (Working Draft)
Regional and Territorial Local Authorities, Regional Policy Statements and District
Plans
38
APPENDIX 1: WIND TURBINE TECHNOLOGY – DETAILS
39
1.
INTRODUCTION
Wind is caused by atmospheric temperature and pressure gradients. It can be
used in a variety of ways to provide electrical and mechanical power. The power
available in the wind varies in proportion to the cube of the wind speed. Small
increments in wind speed can therefore significantly alter the resource potential.
Energy production depends on the shape of the annual wind speed distribution
curve, combined with the control and power generating characteristics of the
wind turbine generator.
Wind turbine generators (wind turbines) can produce alternating current (AC) or
direct current (DC) electricity as required by the application, eg. DC for small
remote power systems or AC for grid connections.
Wind turbines can be located on land, or at sea with towers fixed to the seabed or
on pontoons. Normally at sea the wind is stronger, more consistent, and less
turbulent, however capital costs are greater.
2.
SYSTEM ELEMENTS AND SCALE
The main elements of a wind turbine generator are the turbine rotor system, the
drive train and generator, support structure, and ancillary works (see Figure A1).
2.1
Wind turbine rotor system
This consists of blades attached to a hub with blade control mechanisms, if any.
Two configurations are common (see Figure A2):
1) the vertical axis wind turbine (VAWT), where the blades move
around a vertical line, perpendicular to the wind direction. Machines
of this type are no longer produced in significant quantities
worldwide.
2) the horizontal axis wind turbine (HAWT) with one, two or three
blades, with the horizontal axis in line with the wind. This is the
predominant commercially available turbine.
2.2
Support structure
A typical grid-connected machine stands 40-70 metres tall with rotor diameter of
40-70 m. The tower normally supports a nacelle, which houses the drive train,
generator and mechanical controls. Towers are normally tubular steel or
concrete, or steel lattice. The bottom of steel tubular towers can accommodate
electrical control and switchgear equipment.
2.3
Drive train and generator
The rotor hub is connected to an electrical generator through a drive train. Most
drive trains include a gearbox, however direct drive generators are becoming
more common.
40
FIGURE A1: Main Elements of a Wind Turbine Generator
(a)
(b)
FIGURE A2: HAWT (a) VAWT (b) Wind Turbines
41
2.4
Ancillary works
These normally include control cubicles and buildings, power distribution lines,
transformers, substations, maintenance facilities and access roads.
2.5
Current technology status
Commercially available wind turbines installed today are durable, efficient and
proven. They are cost effective and financially competitive with other forms of
electricity generation in many parts of the world. These turbines are the building
blocks for wind farms.
About 95 percent of the turbines installed today are of the three bladed design.
The blades are rigidly mounted to a horizontal main shaft. The rotor is coupled
to a generator through a speed-up gearbox. The average size wind turbine
installed last year in Northern Europe was approximately 800 kW.
The last two decades of wind turbine development has seen a rapid improvement
in wind turbine reliability and increase in size of wind turbine models. Only a
few years ago the average size of commercially-available wind turbines was
around 250 kW. At present 1.8 MW units are commercially available and 23 MW wind turbines tested by manufacturers are expected to become
commercially available in 2001-2002. These larger machines are particularly
being developed for offshore installations where high foundation and
transportation costs provide cost advantages for large machines.
The wind turbine converts the available energy in the wind into useable utility
grade electricity. It is designed to extract as much energy as possible out of the
wind, up to the so-called rated wind speed. At the rated wind speed (for most
turbines around 12-16 m/s) it produces its nominal or rated power. Between the
rated wind speed and the cut-out wind speed (for most turbines between 2535 m/s), the wind turbine control system limits the output power to (on average)
the rated power. In this operating window, the wind turbine “spills” excess
energy.
The two main control mechanisms used to limit the output power are pitch and
stall control. Both are aerodynamic control systems. The pitch control system
uses an electronic feedback control mechanism while the stall control uses the
inherent aerodynamic characteristics of the airfoil (passive control system). Both
systems and certain technology derivatives are used in the wind turbine industry.
Recently, some manufacturers have begun to combine these two approaches in
what is called an “active stall” power control mechanism. In these turbines the
blades are pitched towards stall rather than the more conventional pitch towards
feather.
42
3.
TYPES OF SYSTEMS AND APPLICATION
Wind power can be used to directly power machinery, as in history where wind
mills have been used to pump water and grind grain. More recently, wind
turbines are being used to generate bulk utility grade electricity, generate power
for remote villages (village electrification) or produce end products such as ice,
hydrogen, desalinated water etc.
New Zealand has opportunities for hybrid wind diesel projects. These consist of
one or more wind turbines combined with a diesel generator to provide
continuous electricity, and can be installed on many of New Zealand islands or at
the end of long distribution lines with small loads.
The most common application of wind power is wind turbines with an installed
capacity ranging from 600 kW to 1.8 MW supplying utility grade electricity to
power companies. These wind turbines are usually arranged in wind farms multiple wind turbines forming a single managed unit in a generally contiguous
area. The modular nature of wind turbines means wind farm capacities can be
variable to suit land availability, load demand and other factors. Generally wind
farms have a capacity of up to several MW. Medium size wind turbines (600kW
to 1MW) are probably best suited to New Zealand conditions, due to cranage and
transportation constraints (the installation MW class turbines requires cranes
with capacities of 400 tonne or more, and the nacelles cannot fit into standard
container sizes).
4.
TECHNICAL STATUS
Wind power technology is a mature technology and many commercial plants are
available. However there has not been enough experience with modern plant to
fully prove energy output, Operations and Maintenance (O&M) costs and plant
lifetime and some other life cycle issues, particularly when the average site wind
speed is as high as 10 m/s as is common in New Zealand. A lot can be learned
from the US and Europe, however there is no high wind speed site in Europe or
the US where a long record is available regarding the above issues. The wind
turbines installed over the last few years in high wind speed sites in New Zealand
have begun to build experience in this area.
O&M costs tend to increase through the life of a wind turbine. Overall life is
unclear - it may be 15 to 25 years with possibly a major overhaul after 10 years.
Wind power Research and Development (R&D) started with both very large and
small sized machines. Designs then converged to intermediate sizes. Height and
power output are now increasing to take advantage of better wind conditions at
higher elevation, and better economics with larger scale, particularly for offshore
use. A better understanding of fatigue and other material stress issues helps this
trend.
Wind turbines designed by the end of the seventies and in the beginning of the
eighties were optimised to extract as much energy from the wind as possible
without consideration of fatigue. It was only in the beginning of the eighties that
43
fatigue issues received appropriate considerations. Fatigue now constitutes a
large amount of wind turbine R&D effort.
Unlike hydro power plants, the inflow of energy in a wind turbine is turbulent
and chaotic, unsteady, varies with elevation (wind shear) and changes direction
continuously. Modern wind turbines have to deal with this time and space
variable energy inflow which together with the 100 million plus rotor
revolutions, makes the fatigue life of a wind turbine an important issue.
There are three schools of thought regarding the fatigue issues and how to ensure
a cost-effective, reliable and durable design:
1)
Design and build a wind turbine rigidly, which means that it can deal
with large fatigue loads. This results in the before-mentioned three
bladed, rigid hub fixed speed designs.
2)
Design and build a wind turbine as flexibly as possible so that the load
amplitudes are reduced (but not the number of cycles). This results in
designs with flexible blades and/or towers.
3)
An alternative approach is to use a rigid design and reduce fatigue loads
by letting the rotor move as a rigid body in response to gusts. Variable
speed is one approach to achieve this. A teetering hub can be used as well
on one or two bladed rotors.
The number of stress cycles is predominantly affected by the number of hours
that the wind turbine is in operation, the operational rpm of the wind turbine and
the wind spectrum (turbulence, gust cycles). The last two decades have seen
many different designs. The wind turbine learning curve has been very steep for
the designers and many design lessons have been learned.
New advanced wind turbines are likely to use one or more of the following
technologies:









Variable speed rotors to extract more energy with less power output
variation.
Variable speed rotors to reduce fatigue loads in the rotor and drive train.
Direct drive (no gearbox).
Advanced airfoils.
Advanced materials.
Power electronics.
Flexible components.
Teetering rotors.
Diffuser technology.
The Commission of European Communities is actively supporting R&D and
demonstration projects to improve wind turbine reliability, efficiency and
economics as well as to improve resource assessment and analysis.
The majority of wind turbine manufacturers are investigating or producing
variable speed machines, using power electronics to supply a constant alternating
voltage and frequency to the grid. The rotor speed of these machines varies over
44
a wide range (eg. 18-42 rpm). A number of these companies are investigating
the possibility of eliminating the gearbox from the drive train by using advanced
low speed electrical generators.
Advanced technologies such as flexbeam rotors and teetering hubs, will reduce
the stress amplitude cycles. However the cost effectiveness of these methods
have not been proven.
A wide variety of tower designs have been developed to deal with different
ground conditions, material availability, preference for different capital/O&M
cost splits etc; steel tubular and concrete towers (low O&M), lightweight guyed
towers (higher O&M).
Foundations vary from massive concrete dead weights for poor ground
conditions (eg. peat) to little more than grouted bolts on solid rock sites.
5.
APPLICATION AND INTEGRATION LIMITS
The key issues include the need for backup power supplies and satisfactory
integration with the national grid. These issues are similar for all power stations.
Wind power is not continuous so it cannot be relied upon solely unless there is
an energy storage system (eg. hydrogen production - fuel cell generation or
hydro storage lakes). It is well suited to work with other sources that can cover
any wind shortfall, and can be integrated up to a limit with a national grid
system.
Grid systems dominated by thermal power generation will limit wind power
penetration. The cost of significant spinning reserve (thermal turbines ready to
instantly provide power) erodes wind power benefits. However resent research
is showing that integration may be less of a problem than previously thought.
For example, in Denmark, the installed wind capacity is approximately 20
percent of the total system capacity, which is dominated by relatively inflexible
combined heat and power plants. Despite this, there have not been significant
problems with the integration of wind into the system, and Denmark is targeting
an increasing share of wind power for its future electricity requirements.
The hydro domination of New Zealand's grid means the integration of wind
power this is even less of an issue than with thermal dominated systems (hydro
can be quickly activated). In fact, up to a point, there is a synergy between wind
and hydro power. Hydro dams could be seen as providing storage for wind
energy (when wind energy is available hydro storage is increased). Wind energy
can, in effect, increase New Zealand’s reliability of supply (through a diversity
of energy sources) if a coherent control strategy is adopted.
It is noted that none of the potential problems will occur during the early stages
of wind power in New Zealand. The first wind farms will be small in comparison
to the total New Zealand system.
45
Several potential developers are studying the feasibility of large scale wind
generation. New Zealand has a large number of possible sites throughout the
country (see Section 2). Some sites have been identified as being able to supply
several hundred megawatts.
Even though there are theoretical limits to the penetration of wind power into the
existing electricity system, these limits are at present academic on a national
basis.
It is estimated that more than 30 percent of our present day electrical energy
needs could be met by wind power before reaching the integration limit. In
today's terms this would mean that about 2500 MW can be installed. It is
unlikely that such a large amount of installed capacity will be developed in the
near future. These integration limits apply because, of all the wind turbines
presently installed, the majority use induction generators to produce electricity.
The utilisation of synchronous generators and/ or power electronics will increase
the possible grid penetration, because with these technologies both active power
and reactive power can be controlled. Variable speed wind turbines with
synchronous generators and/ or power electronics can have theoretically a 100
percent grid penetration, if demand and supply can be matched. In the long term
all the electricity load growth could therefore be met from wind power. The
potential resource is huge, with the main constraint being economic. This means
that, as the price of electricity increases, and turbine prices decrease, lower wind
speed and more remote sites will become economic.
6.
SHORT TERM POWER FLUCTUATIONS
Sub-second and second and minute by minute power fluctuations of a single
wind turbine are a function of the variability of the wind speed as well as the
technical characteristics of the wind turbine.
The nature of wind power is such that single wind turbines have fluctuating
power output but a vital point is that this variation decreases dramatically as
increasing numbers of units are installed. Fluctuations in power output have also
been reduced by technologies that introduce drive train compliance, such as
variable speed.
7.
LONGER TERM ENERGY VARIATIONS
Scheduling the power generation of other generating plants and forecasting of
the wind resource easily accommodates the hourly and daily variations in wind
speed. The same smoothing effect on the variable energy contribution but on a
longer timeframe occurs if wind farms are installed at different geographical
locations throughout New Zealand.
The forecasting of wind speeds at particular wind farm sites for a time period of
15 minutes in the future can be achieved with a reliability of +/- 10 percent. The
forecasting of tomorrow's weather can still be fairly accurate although the
forecasting wind speed bands will be described only as "strong winds" or
46
"moderate winds". These can be translated to expected amounts of wind energy
and thus the expected alternative generation can be adjusted accordingly.
Numerical weather forecasting models are improving in accuracy (due to
advances in modelling software and hardware) and hence more reliable wind
forecasts are also becoming available.
It is expected that the majority of future New Zealand wind farms will be smaller
than 50 MW, and that these wind farms will be spread around the country. This
spread will ensure that the existing electrical network can take timely action to
ramp up (or down) additional capacity as the wind farm outputs change.
In addition, a network/wind farm operator will be able to forecast a possible high
wind speed shutdown probability, and forewarn network operators. Shutting
down parts of the wind farm, in a controlled manner to facilitate the smooth
transition from wind power to conventional power generation, is thus possible.
High wind speed shutdown situations may occur only a few times per year
(depending on the site characteristics), but are the most problematic in regards to
the power output variability because of the fast transition between full load to no
load. It is noted that several manufacturers are addressing this issue and it is
expected that this potential problem will be solved before it can become a
significant problem in New Zealand. In a wind farm situation, not all the wind
farm will shut down simultaneously due to high wind speeds, as different parts
of the wind farm will experience different wind characteristics.
The movement of weather systems influences daily wind speeds, however it is
known that deterministic diurnal effects also play a role. On low lying or coastal
land, it is observed that the wind speeds are sometimes significantly higher in the
afternoon than at other times of day (this diurnal pattern phenomena is more
marked at lower than higher altitudes). Diurnal wind patterns can be variable,
but nonetheless system power planners can often use it to advantage.
47
APPENDIX 2:
SPECIFIC ENVIRONMENTAL / CONSENT
CONCERNS ASSOCIATED WITH WIND
ENERGY DEVELOPMENTS
48
Environmental Effects
Aspects of wind energy developments that can have an effect on gaining
resource consents include possible visual, acoustic noise, wildlife, electromagnetic and other environmental impacts. Various actions can be taken to
reduce or overcome these barriers. All these issues need to be addressed on a
site by site basis, ensuring there is early consultation with the local community
to clearly establish the range of local concerns.
Visual impact is likely to be a significant issue when seeking resource consents
for a wind farm or wind turbines, particularly when located on visually
prominent sites. The visual effects can be reduced by careful design of the
turbines and their layout within the wind farm. While the choice of a less
prominent site is sometimes seen as an alternative, there is almost always a cost
involved to the project, as the wind energy available is likely to be reduced.
Acoustic noise from wind turbines should be less of an issue with modern wind
turbines than with older designs. Noise, as an issue related to wind turbines, has
received significant publicity. Because of this, the question of noise is often
raised as an issue. Compliance with the New Zealand Standard 6808 (1998)
“Acoustics – The Assessment and Measurement of Sound from Wind Turbine
Generators”, should materially assist in managing noise issues for both a
developer and the community through the consenting process.
Electro-magnetic interference can be of concern to owners and operators of
telecommunication and radar equipment sited near to a wind power site. These
owners and operators might object to a proposed development if they have no
standards, guidelines or prior experience to enable them to determine that the
wind farm layout will not affect the operation of their equipment. This barrier
can be reduced by careful consultation to ascertain the most acceptable form or
layout for the development.
Effects on wildlife is another area that has received some publicity although
sometimes the perceived impacts may be greater than they possibly are.. Wind
turbines have caused some bird fatalities. For this reason areas close to
populations of rare species that are known to fly in the altitudes that would be
occupied by wind turbines should be avoided. The authors are not aware of any
recorded occurrences of “bird strike” associated with any wind turbines in New
Zealand, and overseas research can be applied here.
Other environmental impacts or concerns can include the appropriateness or
otherwise of man-made structures in the context of the natural environment. The
coastal environment has strong protection under the New Zealand Coastal Policy
Statement, where it has predominantly natural character, and can therefore be
said to be an inappropriate location for wind turbines. The coast is often where
the best wind conditions are found, and this aspect can only be evaluated on a
case by case basis.
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