Hydroelectric power
By Andrew Verney
NBS-MO16
The hydrological cycle
t
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Courtesy Queen Mary University of London
Hydro Power Potential
3 Types of Hydro Power
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Run of River schemes – use the natural
flow of the river and there is continuity of
flow.
Storage – water is stored behind a dam
and released through the plant
Pumped Storage – the plant can be
reversed to pump water uphill when
surplus power is available
Source: DECC
Scales of Hydro Power
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Pico: <5kW
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Micro: 5kW – 50kW
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Small / Mini: 50kW –
20MW
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Large: >20MW
Source: DECC
Hydro Power: UKGeneration
In 2008, hydro power using natural flows generated
approximately:
 18.6 PJ of electricity, or
 24 % of electricity generated from renewables in the
UK
Hydro power from pumped storage generated
approximately:
 19 PJ of electricity, or
 1.11 % of all electricity sold in the UK in 2008
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http://www.decc.gov.uk/en/content/cms/statistics/source/renewables/renewables.aspx
Advantages of Large-Scale HEP
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Once the dam is built,the energy is very cheap
Water ‘energy’ can be stored above the dam
Much more reliable than other renewables
No waste or pollution produced
“Switch off and onable”
Reservoirs are multi-purpose amenities – leisure;
irrigation; flood control and wetland habitats
Constraints of Large-Scale
HEP
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Dams are very expensive
Dams cause environmental upheaval upstream
and downstream
The UK is running out of suitable sites
Siltation reduces life expectancy
Pumped storage requires available ‘baseline’
power and is not renewable
Small Scale Resource and Limitations
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675MW of unexploited hydroelectric power in
Scotland alone according to recent survey
Design life is high, investment cost relatively low
Generate electricity for 3p/kWh
Short construction times cf Large Scale
Requires a suitable watercourse
Initial capital cost is significant
Environment Agency may not be supportive
Multiple ownership of land, fishing and water
abstraction rights causes confusion and delay
Assumptions – Large Scale
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Used Declared Net Capacity (DNC)
figures from DUKES 2008
Load factor will improve slightly as
control management systems improve
Changes in rainfall are ignored
Glendoe online in 2009
Pumped storage is a management tool
not additional capacity
19
99
20
01
20
03
20
05
20
07
20
09
20
11
20
13
20
15
20
17
20
19
20
21
20
23
20
25
20
27
20
29
Estimated Contribution (PJ)
Projections – Large scale
20
18
16
14
12
10
8
6
4
2
0
Year
Assumptions small scale
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Government incentives such as feed-in
tariffs promote small-scale development
Planning and environmental restrictions do
not counteract Government incentives
Current improved load factors remain at 38%
Three Scenarios – Current rate of growth –
Doubled rate of growth or halved rate of
growth
Estimated Contribution (PJ)
Projections – Small Scale
Current Trend
Optimistic
Pessimistic
20
18
16
14
12
10
8
6
4
2
0
2004
2009
2014
Year
2019
2024
Conclusions
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Large Scale development promoted by the
Scottish Government could see one or two
more large power stations come online.
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Small scale pant could see a significant
increase in percentage terms but remains a
small sector.