Our energy fu ture: “renewable” or not?

2. Our energy future: “renewable” or not?

3. OUR ENERGY FUTURE: “RENEWABLE” OR NOT Presentation to the Warrawee Probus Club 24 May 2013 Dr IanFalconer School of Physics, University of Sydney Some of the slides shown in this presentation were provided by: Dr Joe Khachan, University of Sydney Professor John O’Connor, University of NewcastleDr John How, ITER Organization Much material for this presentation was taken from: David JC MacKay Sustainable Energy — without the hot air (2009)UIT Cambridge Manfred Lenzen (2010) “ Current State of Development of Electricity-Generating Technologies: A Literature Review” Energies 15462-591

4. ENERGY AND POWER • What is energy? • What is power • How do we measure energy & power • Energy in the 21st Century

5. What is energy? • Energy is that which allows us to do work (Physics definition) • Lift something up • Move from A to B • I’m lifting this weight from the energy I get from the food I eat • Over the past 200-odd years in particular humanity has used the energy stored in coal and oil to extend the work we do beyond that we are capable of using muscle energy alone - and do many more really exciting things

6. Energy and power • Energy is measured in joules (Physics definition) • Power is the rate at which energy is supplied or consumed – how fast we use energy • Power is measured in joules per second – watts • A small electric radiator consumes electricity at the rate of 1,000 joule per second – 1,000 watts or 1 kilowatt – abbreviated 1 kW • Energy is also measured in kilowatt hours (kWh) • A 1 kW electric radiator, when operated for 1 hour, consumes 1 kilowatt hour of electrical energy.

7. Generating electricity: big numbers Liddell power station (Muswellbrook) 4 x 500 MW generators (steam turbine alternators) Total installed capacity: 2 GW 1 megawatt (1 MW) = 1,000 kW = 1,000,000 watt 1 gigawatt (1 GW) = 1,000,000 kW = 1,000,000,000 watt Australia’s installed electrical capacity (2008-2009): 51GW

8. Energy in the 21st Century • Starting in the late18th Century humanity began using coal - and in the 20th Century, oil – to extend what could be done by muscle power alone. • This required the development of many ingenious bits of machinery to replace muscle power - and do much more Mechanical gadgets Food mixers, electric drills, vacuum cleaners, washing machines – all sorts of labour-saving devices Transport Electric trains, cars, aircraft, giant and fast cargo ships Heating and coolingHome heating, air conditioners, refrigerators and freezers CommunicationRadio, phones, TV, the internet

9. How important is electricity? VERY Primary energy sources – the ultimate source of our energy:Coal, oil, gas, wind, the sun, uranium, thorium, and – for fusion – deuterium, and lithium Secondary energy sources – the energy we use directly:Coal, oil, gas, hydrogen, electricity

10. THE ENERGY PROBLEM

11. The world has real energy problems • We are fast running out of oil, natural gas, (and uranium) • Burning of fossil fuels generates carbon dioxide (CO2) For every tonne of oil or coalused for generating energy, around THREE tonnes of CO2 are generated • Per capita energy consumption increases as nations become wealthierThink about India and China For these reasons, we URGENTLY need an energy source to replace fossil fuels (and it must be “portable” - like petrol – so it can be used in cars and trucks)

12. Why do we need more and more energy: standard of living

13. Why do we need more and more energy: standard of living World

14. Why do we need more and more energy: standard of living AUSTRALIA World

15. How long will it last? Oil ~50-100 years Natural gas ~60-100 years Coal Several hundred years Nuclear fission energy (U235 burners) 50 to ~100 years Nuclear fission energy (breeder reactors) Thousands of years Solar, wind, geothermal, tidal energy Renewable Fusion energy Millennia

16. WHICH ENERGY SOURCE?

17. Wind Wind farm near Yass

18. Advantages: • Wind is cheap • Disadvantages: • Wind is not a steady source of electricity: wind speed is highly variable • Suitable (low cost) sites are limited Cairngorm mean wind speed in metres per second, during six months of 2006. Red line: daily average Turquoise line: half-hourly average

19. Installed wind generating capacity in Australia: 2.6 GW (2012)

20. Solar photovoltaics

21. Advantages: • Produces electricity directly • Ideal for remote locations • Disadvantages: • Output depends on instantaneous amount of sunlight falling on surface • Output depends on time of day (very much) cloud cover, and season of year • Cost is still rather large – but falling rapidly A photovoltaic cell is similar in construction to a transistor

22. Solar Thermal

23. Solar hot water “A no-brainer” David McKay, author, Sustainable Energy — without the hot air Water in pipes underneath flat black plates is heated by sunlight absorbed by the black plates. The plates are coated with a selective surface – a coating that strongly absorbs the visible sunlight, but only weakly emits infra-red (heat) radiation. Maximum energy is absorbed, but not much radiated by the hot plates. Flat plate solar collectors

24. Evacuated tube solar collectors • A double-walled glass “tube” is evacuated – heat can only be transferred though a vacuum as radiation • The inner surface of the glass is coated with a selective absorbing material • Heat absorbed by this surface is transferred to water inside the tube

25. Electricity from large-scale solar thermal plants A way of using the sun to provide a steady supply of electricity Concentrating solar collector systems • Advantages: • Provides “baseload” electricity supply – to some extent • Disadvantages: • Cost is still rather large • Unreliable baseload Parallel raysof sunlight Parabolic reflector Glass envelope Absorber tube with selective surface

26. A “typical” modern solar thermal plant Collector tube coated with selective absorber Sunlight Heatexchanger Tank of molten salt Reflector Heatexchanger Superheated steam to turbines

28. Geothermal • Water pumped deep underground in to hot rock is converted to steam, which rises up another drill hole to drive an electrical generator • Advantages: • Clean, low environmental impact • Disadvantages: • Rock cools, so that the plant has a limited life

29. Nuclear

30. The pros and cons of nuclear power? • Advantages: • NOT a (direct) source of greenhouse gases • Little non-nuclear waste and pollution • Volume of nuclear waste small • Relatively low-cost • Disadvantages: • Nuclear reactors are regarded as “unsafe” as nuclear accidents, although infrequent, have serious and widespread consequences • Radioactive waste remains a hazard for many years * Plutonium and other “transuranics” for hundreds and thousands of years * Fission products have decayed to a “harmless level in around 1,000 years • Proliferation of nuclear weapons is a concern

31. Does nuclear have a future? YES • Waste disposal is a political problem, not a technical problem • Plutonium can be separated from other waste and be “burnt” in a reactor to produce even more nuclear energy • Most waste is low level • Fission products – the waste from the energy-generation process – are highly radioactive, but decay away to become harmless in around 1,000 years • Modern reactor designs are inherently less accident-prone • Thorium – another “fissile” element – can also be used to fuel a reactor. Thorium cannot be used in nuclear weapons, and thorium reactors are inherently safer than uranium reactors.

32. Fusion Fusion energy powers the Sun

33. What is fusion? • The release of the energy stored in the nuclei of “heavy hydrogen” atoms - deuterium and tritium Hydrogen: nucleus consists of 1 proton Deuterium: nucleus consists of 1 proton and 1 neutron Tritium: nucleus consists of 1 proton and 2 neutrons Chemically these isotopes are the same, but the deuterium and tritium store considerable energy in their nuclei – this is the energy that holds the nuclei together

34. The Most Promising Fusion Reaction

35. How do we harness fusion energy? • Bang a deuterium nucleus and a tritium nucleus HARD together so they “fuse” • To make lots atoms move really fast a mixture of deuterium and tritium gases must be heated to a very high temperature if the nuclei are to “fuse” – about 100 million degrees! Under these conditions all the atoms are ionized and form a PLASMA • These high temperatures can only be achieved if the gases are contained in a “bottle” constructed from a really strong magnetic field • And a high density of colliding nuclei is required if we are to get more fusion energy from the reactor than we put into it

36. Toroidal field produces greater confinement A TOKAMAK

37. ITER – “the way” International Thermonuclear Experimental Reactor An international project to produce a prototype fusion reactor • ITER partners • European Union • Japan • China • Russian Federation • USA • South Korea • India • (and possibly Brazil – and Kazakhstan)

38. ITER Person ITER – the next generation tokamakDesign completed – construction has just commenced

39. SUMMARY HOW MUCH WILL WE PAY?

40. What will clean energy cost?

41. External costs: “estimated” impact costs to the environment, public and worker health. Prospects for fusion electricity, I. Cook et al. Fus. Eng. & Des. 63-34, pp25-33, 2002

42. THAT’S ALL, FOLK And, for further reading, I recommend:David JC MacKay Sustainable Energy — without the hot air Available online as a FREE .pdf file from www.withouthotair.com. www.withouthotair.com