Renewable Energy
Prof. Peter Seligman, D.Eng
Inspired by Sustainable Energy –
without the hot air
by
David MacKay FRS
Google: withouthotair
Definitions:
Renewable: we can continue indefinitely
Sustainable: we can do it for a long time but
eventually will have to come up with something
different.
Zero carbon: we may run out in the foreseeable
future but it’s still worth doing.
How much energy do we use?
from ABARES
Australian Bureau of Agricultural and Resource Economics
abare-brs.gov.au
Primary energy:
Domestic: 5.8 exajoules per annum
Export: 13.8 exajoules per annum
Exajoule = 1018 Joule
Our domestic primary energy use:
Domestic: 5.8 exajoules per annum
= 5.8 x 1018 joules or watt seconds
divide by 3.6 x 106 = 1.6 x 1012 kWh/annum
divide by number of people: 22 x 106
= 73,200 kWh/annum/person
divide by hours in a year: 365 x 24
= 8360 Watts/person
Our domestic primary energy use:
8360 Watts/person
x by 24/1000
= 200 kWh/person/day
UK/Europe = 125 kWh/person/day
Primary energy: 8000 watts/person
Heating
Electricity generation
Transport
80% efficient
30% efficient
20% efficient
Average efficiency
50%
End-use energy: 4000 watts/person
Where do we use energy?
• Personal
–
–
–
–
–
–
–
Food
Electricity
Gas
Petrol
Flying
Stuff we buy
House construction
• Public
–
–
–
–
–
–
–
–
–
–
–
Factories
Offices
Shops
Hospitals
Schools
Universities
Public transport
Sporting facilities
Street lighting
Cinemas, theatres
Construction
About a quarter of our energy use is
personal:
1000 watt/person
Three quarters of our energy use is
public:
3000 watt/person
Our energy use
• Private 1000 watts (ten 100 watt globes)
Our energy use
• Public 3000 watts (thirty 100 watt globes)
Total end-use energy
• Per person: 4000 watts (forty 100 watt globes)
Distribution of total energy use
Elec industrial
Elec
commercial
Elec
domestic
Elec Misc
Fuels other
than elec
generation
Electricity use
National average electricity generation 25 GW
over 22 million people:
1100 watts/person
Distribution of electricity use
Elec misc
Elec
commercial
Elec
industrial
Elec
domestic
How much power can a 1000 watt
photovoltaic system produce?
= 160 watts average
How much power per person?
= 40 watts average
(remember we use 4000 watts each)
Output of a 1 kW solar panel
• 1000 watts nominal peak in bright sunlight
• 800 watts under realistic conditions
(temperature and inverter efficiency)
• 400 watts taking into account night time
• 320 watts taking into account sun angle
• 160 watts taking into account cloud
• 40 watts each for a 4 person family
Role of domestic solar PV
• Elec. price rises due to distribution, not
wholesale price
• Increase distribution costs due to aircons
• Each $1500 aircon adds $7000 to
infrastructure cost
• PV can provide power locally when it is
most needed (best facing NW at steep
angle)
We can’t solve a big problem by
thinking small
Renewable energy system
•
•
•
•
•
•
Wind
Solar
Geothermal
Wave
Utility scale energy storage
High voltage DC (and AC) links
How much power from the wind?
5 turbine diameter separation between turbines
2 watt/m2
2 – 3 turbine diameters in non-prevailing wind
directions
Typically: 4.5 watt/m2
Land is still suitable for farming
Wind Power
• Turbines now up to 7.5 MW
• Technologically mature
• Capacity factor 30%
• Average output 2.3 MW per turbine
Turbine technology
•
•
•
•
•
Enercon E126 turbines
7.5 MW
Gearless design
138m hub height
127m blade diameter
A question of storage
Wind power in South Australia and Victoria
From Wind farming in South Australia
Large scale solar - California 1984
345 MW peak: 75 MW average
http://www.itas.fzk.de/deu/tadn/tadn013/image37.jpg
Andasol 1 to 3 Granada Spain
50 MW turbines 20MW average
courtesy Ferrostaal AG.
Molten salt storage
Torresol Gemasolar Molten Salt Solar
• solar power at night
• “Baseload” “Dispatchable” solar – better than coal
Gemasolar in Spain 2011
20MW turbines 12.5MW average
Large scale solar courtesy Ferrostaal AG.
Liquid salt storage tanks courtesy Ferrostaal AG.
How much power from the sun?
Solar radiation: 1000 watts/m2
• Taking into account night-time and cloud
160 watts/m2
• Taking into account 15% efficiency
24 watts/m2
• Taking into account shading and access
4.5 – 15 watt/m2
How much of Australia?
• 200 km
square
• 4.5 watt/m2
• 8000
watt/person
Geothermal
energy from
hot dry
rocks
http://sen.asn.au/renewables/geothermal
Geothermal resources in Australia
• Hot Dry Rocks
• Heat build-up in radioactive granite
+ residual heat from earth’s core
• Typical power flow 50 – 100 millwatts/m2
• Not renewable but usable over 400 years
• Could supply about 800 watts per person
(end use)
Geothermal resources in Australia
http://www.ga.gov.au/image_cache/GA10036.pdf
How much power from waves?
•
•
•
•
2000 km of Australian south coast
100 – 160 kW/linear metre
Extraction efficiency: 5 – 10%
Could supply about 900 watts per person
(end use)
Tidal power?
• North West Australia
10 metre tides: 150 watts per person (end use)
• Port Phillip Bay 10 watts/Melbournian
Supply, demand and curtailment
From BZE Zero Carbon Australia Stationary Energy Plan
Nullarbor pumped seawater electricity
storage
Bunda cliffs
From Google Earth
200 GWh battery
Okinawa pumped seawater electricity
storage
High Voltage DC links
• Low loss power transmission over long
distances
• No current due to line capacitance
• No eddy current losses is wires
• Lower peak voltage (or higher average
voltage)
High voltage DC links
• 1700 km in the Congo, built 1982
• Longest 2100 km, China
• Highest power: 6400 MW, China and India
• Basslink: 300km cable, 600 MW
http://en.wikipedia.org/wiki/List_of_HVDC_projects
More HVDC details
• May use monopole (earth return)
• DC is the only practical solution to
undersea cables
• Power loss: 2% / 1000km, 1.5% in
converters
http://www.utilities-me.com/article-690-electricity-highway-powers-throughchina/
AC-DC-AC Converter
http://www.energy.siemens.com/hq/pool/hq/power-transmission/HVDC/HVDCClassic/TSQ-Valvehall-b.jpg
Transformer for High voltage DC
power line
Courtesy Siemens AG
Wiring diagram for Oz
An energy strategy for Australia
Resource
Watts/person
Proportion of resource
Hydro
73
Existing
Geothermal
682
Currently measured resource fully
used
Wave
18
3% of coastline
Solar
909
0.06 % of country
Wind
909
0.13% of country compatible with
farming
Total
2600 (end use
UK, Europe)
Transport
•
•
•
•
•
•
Biofuels from algae?
Unwanted CO2 as feedstock for algae.
Hydrogen
Ammonia – NH3 ?!
Electrification of road transport
Use of transport batteries for large scale
energy storage
Efficiency and waste
Why do we need to do this?
We don’t have a Planet B!
(Madeleine Trau – 8 years old)
Beyond Zero Emissions
ZCA2020 Available
online and in print from
MEI:
www.energy.unimelb.edu.au
or…
www.beyondzeroemissions.org