Halesworth U3A Science Group

Transcription

1 Halesworth U3A Science Group POWER FOR THE FUTURE Wind, Solar, Gas, Fusion + Storage Ken Derham Includes quotations from publicly available internet sources

2 Wind Power. First Law of Thermodynamics Energy can not be created nor destroyed Second Law of Thermodynamics High Levels of Concentrated Energy become Disipated into Dispersed Low Level Energy

3 Wind Power Carbon Emissions. Some Carbon Dioxide and other Pollutants are emitted in the manufacture and installation of wind turbines Operation of wind turbines is carbon-free In the first few months of operation, wind turbines more than offset the environmental impact of their manufacture.

4 The Contribution of Wind Power. About 7,000 wind turbines are currently installed in and around the UK Wind provided 11% of electricity in UK and Europe in 2015 Expected to rise to 25% by 2030 UK is one of the windiest places in Europe. Spain and Scandinavia also. Wind energy has overtaken hydro as the third largest source of power generation in the EU with a 15.6% share of total power capacity

5 Cost & Subsidies of Wind Power. Difficult to get reliable comparable costs All forms of power generation are subsidised Some overtly, some less clearly Costs of most renewables are falling Costs of cleaning from fossil fuel use (eg carbon capture) are rising Generally wind power is considered to be one of the cheapest Lower cost per MWh than offered for Hinkley Point

6 Offshore Wind. UK surrounded by relatively shallow seas Plenty of offshore wind UK has expertise in offshore technology

7 Onshore Wind. A typical wind farm of about 20 turbines extends over about 102 sq kilometres Only about 1-2% of this land is occupied by turbines Rest of the land can continue to be used, eg for agriculture

8 Environmental Considerations RSPB supports wind power Carefully scrutinises proposals and objects to only 6% There is little risk of bird strike provided wind farms are located away from major migration routes and important feeding/roosting areas

9 Solar Energy Most of our energy supplies ultimately come from the sun The Solar Energy reaching the Earth s surface exceeds human energy demand several times over The difficulty is in capturing, storing and utilising that energy Various schemes:

10 Passive, e.g. Solar Energy Greenhouses for horticultural and commercial use Buildings designed to capture and utilise sun s energy Biomass Water heating Good in hot sunny climates Also good for large volume, low temperature heat, eg swimming pools Water purification, especially in less developed countries Photovoltaic conversion

11 How Photovoltaic Solar Cells Work

12 Growth in Photovoltaics Worldwide growth in photovoltaics is exponential Source - Wikipedia

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14 Installed Solar Power Capacity in 2015 (MW) # Nation Total Added Capacity Capacity - European Union 94,570 7,230 1 China 43,530 15,150 2 Germany 39,700 1,450 3 Japan 34,410 11,000 4 United States 25,620 7,300 5 Italy 18, United Kingdom 8,780 3,510 7 France 6, Spain 5, Australia 5, India 5,050 2, South Korea 3,430 1,010

15 SOLAR IN NUMBERS 99% of the UK s solar photovoltaic capacity has been deployed since May GW of solar capacity has been installed in the UK, enough to power 2.2 million British homes 3.6GW of capacity was installed in 2015 alone 2.2% of the total electricity generated in the UK in 2015 was from solar sources 49% of the total EU investment in solar photovoltaics was made in the UK 13GW of solar capacity in total is expected to have been installed in Britain by 2020 Source: Decc

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17 GAS The UK's remaining coal-fired power stations will be shut by 2025 Without carbon capture and storage (CCS) technology, gas-fired electricity would have to fall to 10% of the mix to meet emissions targets for 2050

18 Pros and Cons of Gas PROS Relatively cheap when used in conventional gas turbines Flexible Plentiful CONS Becomes expensive with carbon capture and storage Supply now less secure or reliable Direct heating is better use than electricity generation

19 Relative Costs Estimated levelised costs (pence/kwh) of low-carbon electricity generation technologies [20] Technology 2011 estimate 2040 central projection River hydro (best locations) Onshore wind Nuclear CCGT with carbon capture Wood CFBC Geothermal Offshore wind Energy crops Tidal stream Solar PV Tidal barrage

20 KEEP IT IN THE GROUND There is about three times more fossil fuel in reserves, that could be exploited today, than is compatible with limiting global temperature rise to 2 C. (International Energy Agency - World Energy Outlook) In order to limit average temperature rise to no more than 2 C, globally, over 80% of coal, 50% of gas and 30% of oil reserves are unburnable before 2050 under the goal.

21 Gas from Fracking We need to reduce use of gas There is no absolute need to find and utilise new gas reserves The only motivation for Fracking is political and commercial While the gas remains in the ground the carbon in it is locked away from exacerbating climate change KEEP IT IN THE GROUND

22 FUSION ENERGY Energy generated by nuclear fusion. Fusion reactions fuse two lighter atomic nuclei to form a heavier nucleus. It is how stars release energy from matter. A major area of plasma physics research attempts to harness such reactions as a source of large scale sustainable energy. In most large scale commercial programs, heat from neutron scattering in a controlled reaction is used to operate a steam turbine that drives electric generators. Many fusion concepts are under investigation. The current leading designs are the tokamak and inertial confinement by laser. As of January 2016, these technologies were not viable, as they cannot produce more energy than is required to initiate and sustain a fusion reaction Source: Wikipedia

23 STORAGE Energy storage is a collection of methods used to store electrical energy on an electrical power grid, or off it. Electrical energy is stored during times when production (especially from intermittent power plants such as renewable electricity sources such as wind power, tidal power, solar power) exceeds consumption, and returned to the grid when production falls below consumption. The main method of electrical grid storage is pumped-storage hydroelectricity. Areas of the world such as Norway, Wales, Japan and the US have used elevated geographic features for reservoirs, using electrically powered pumps to fill them. When needed, the water passes through generators and converts the gravitational potential of the falling water into electricity. Pumped storage in Norway, which gets almost all its electricity from hydro, has an instantaneous capacity of GW expandable to 60 GW enough to be "Europe's battery". Source: Wikipedia

24 DOMESTIC ENERGY STORAGE Batteries Lead Acid Accumulators Storage Heaters Good Insulation

25 Limitations of Batteries A state of the art electric car battery costs ~ 8,000 Contains toxic materials Degrades over a few years Must be carefully designed and maintained to avoid overheating A kilogram of petrol contains about 4KWh of useful energy About 30 times as much as current Tesla batteries

26 Beyond Batteries Ultracapacitors Store electric field between electrodes Use porous carbon as electrodes with high surface area Good for fast storage and discharge Not so good for long term energy storage But good to help smooth peaks and troughs in supply and demand In vehicles can be charged by regenerative breaking

27 Questions Discussion - Ideas