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Why “Zero Carbon”? Climate Change and Global Energy Demand Stephen Stretton Cambridge Zero Carbon Society http://camsoc.zerocarbonnow.org Contents • Introduction, • Climate Change • Global Energy Demand • Energy-Emissions model • Converting our economy • UK Energy Policy 2006 • What will it take to save the planet? • Next Steps Introduction: Greenhouse Effect • Gases such as Carbon Dioxide (CO2) and Methane absorb reradiated heat in the ‘Greenhouse Effect’. • The combustion of fossil fuels such as coal, oil and natural gas, releases CO2 into the atmosphere, increasing this effect. Global Concentrations of Carbon Dioxide ppmv 400 380 360 340 320 300 280 1959 1969 1979 1989 1999 Sources: CO2 graph shows trend shown without seasonal fluctuation. Data from Mauna Loa Observatory, Hawaii; Cover Photo © Nasa; Temperature graph from http://www.globalwarmingart.com/ CO2 concentration & temperature Data from Antarctic ice cores • CO2 concentration (global) in black • Reconstructed local temperature in red • Positive Feedback? • How much will global temperatures increase for x2 CO2? Current CO2 Concentration Pre-industrial CO2 Concentration Ice Core Data. From Vostok, Antarctica; Main Source: Petit J.R., et al. (1999); c.f. EPICA (2004); Graph: www.globalwarmingart.com Effects of Climate Change (1) (Present Day) – Some effects already seen Oceans damaged Greenland ice melts (raising sea levels eventually by 7m) Increases in Amazon rainforest collapses, releasing CO2 extreme weather (e.g. Agricultural yields fall CO2 hurricanes) released Tropical diseases spread from forests Methane World ecosystems cannot adapt and Soils released from peat bogs & Hundreds of millions at risk from Global heat oceans? hunger & drought circulation system Desertification of large parts of Earth’s surface collapses? Positive Feedback: Warming causes further release of greenhouse gases Source: Adapted from Warren, R (2006) Effects of Climate Change (2) • Wholesale desertification of Earth possible within 100 years. • Large population centres (China and India) at risk Source: Lovelock, J (2006) How Sensitive Is the Climate? • • • What is the committed temperature rise for a certain level of CO2 concentration? Climate models suggest increase in temperature of 1.5-4.5°C associated with anthropogenic doubling of CO2 With positive feedback the range is 1.6-6.0°C We assume that a doubling of preindustrial levels causes an increase in temperature of 4°C How much would the Earth eventually warm up with a doubling of preindustrial CO2 concentrations? Increase in Temperature (degrees Celsius) • 7 6 5 4 3 2 1 0 Without Postive Feedback With Positive Feedback Energy demand is rising rapidly Energy Demand (GW) 45,000 40,000 Reference Scenario 35,000 Fast Economic Growth - A1T 30,000 25,000 20,000 15,000 10,000 5,000 1990 2000 2010 2020 2030 2040 2050 Year Notes • All energy (not just electricity) is expressed in terms of GigaWatts (GW)*. • 1 Gigawatt = 0.75 Million Tonnes of Oil Equivalent per year = 8.8 Terawatt-Hours per Year • 1 Gigawatt is the usual size of a nuclear power station or large coal power plant * In agreement with the recommendations from the Royal Academy of Engineers Sources: Reference Scenario, IEA (2004) World Energy Outlook; A1T Scenario IEA (2003) Energy to 2050 “Business as usual” would lead to disaster within a few decades (2100 CO2 concentration 920ppm) "Fast Economic Growth" (A1) Business as Usual Scenario Low Emissions Energy Temperature 30,000 4 3 (CO2 Now: 380ppm) 20,000 2 10,000 1 - 1990 2000 2010 2020 2030 2040 2050 Rise Dangerous Threshold Passed Fossil Fuel Energy Committed (CO2-induced) Temperature Energy Consumption (GW) 40,000 (550ppm) • Model committed temperature (the temperature rise expected as a result of emissions up to that point). • Note that temperature rises do not include the effect of other greenhouse gases such as methane. • For spreadsheet model and discussion of assumptions see website: www.zerocarbon2030.org. Sources: Sceffer, M et Al. (2006), Defra (2006). A expansion in low-carbon energy can stabilise emissions… …But temperatures may still pass “dangerous” threshold "Fast Economic Growth" Scenario converting to Low Emissions Energy 40,000 Energy Consumption (GW) Low Emissions Energy Dangerous Threshold Passed Fossil Fuel Energy 30,000 Temperature 4 3 20,000 2 10,000 1 - 1990 2000 2010 2020 2030 2040 (Stabilisation @ 500ppm) Committed (CO2-induced) Temperature Rise (460ppm) 2050 Source: IEA (2003)… Conversion to a zero carbon economy + less total energy used… Sustainable development (lower growth) with complete conversion to lowemissions energy plus additional reductions in consumption Danger Avoided! Reduction In Use Low Emissions Energy 30,000 Fossil Fuel Energy Temperature 4 3 (Stabilisation @ 400ppm) 20,000 2 10,000 1 - 1990 2000 2010 2020 2030 2040 Committed (CO2-induced) Temperature Rise Energy Consumption (GW) 40,000 2050 Source: IEA (2003) Sustainable Development (SD) scenario with additional reductions. All countries convert (but some delay) 4 Low -emissions Energy Fossil Fuels 30,000 (450ppm) 3 Temperature 20,000 2 10,000 1 - 1990 2000 2010 2020 2030 2040 Temperature Rise 40,000 Committed (CO 2 -induced) Energy Consumption (GW) 'Sustainable' development (lower growth) with Large Exansion in Low-emissions Energy 2050 Some danger: but most severe impacts avoided. Source: IEA (2003) Sustainable Development (SD) Scenario. CO2 Emissions by Geographical Region Source: IEA (2003) - Energy Related emissions only How can we save the planet • International Agreement on climate is difficult (‘tragedy of the commons’). • Massive cuts in emissions (80-90%) are required (Kyoto not sufficient). • Need a country or countries to take the lead in converting to a zero carbon economy. • Other countries may in fact act simultaneously. A 90% Reduction in CO2 emissions by 2030 – What will it take? 1. Immediate Reductions in Energy Consumption 2. Large Increase in Sustainable Energy Supply 3. Conversion of economy to use low emissions electricity or hydrogen Now 2030 Trains Total Energy 230GW Other 3% Electricity 17% Gas Residen tial-20% Plus: Oil for Road Transport 24% Gas Other 13% Oil: Industry/ Other 15% Electric Cars Oil for Aviation 8% Low-Emissions UK CO2 Emissions162 Million Tonnes pa Other 8% Residen tial-15% Electricity Generation 29% Sufficient Energy!! Heat Pumps Other industries 17% Refining Aviation etc 5% 6% Road transport 20% Total energy = ‘Final Energy’ net of refinery and generation losses 2030: Total energy does not include other uses for nuclear heat. How do we convert our economy to use low emissions electricity? Stephen Stretton Cambridge Zero Carbon Society http://camsoc.zerocarbonnow.org The Potential Solutions Energy Source • Energy crops • Fossil fuels with CO2 Sequestration • Nuclear • Renewables •Wind •Solar •Hydro •Tidal •Wave •Waste Main Energy Vector Liquid Fuels or Electricity Electricity Energy Crops: Not Enough Cropland Theoretically, how much land would be needed to power the world? Proportion of total world cropland 800% 700% 2000 2020 600% 2050 500% 400% 300% 200% 100% 0% Energy Crops Wind Solar (PV) Nuclear • Available cropland will diminish with global warming and population growth. • Fertile land is needed for climate regulation and growing food. • Energy Crops are NOT green!!! Source: Estimated from Socolow (2006) and IEA (2003) Comparing Emissions Fossil Fuel Energy Low Emissions Energy • Also: Energy Crops, Waste Incineration, Tidal & Wave • Fossil Fuels with CO2 sequestration. Problem: Electricity is not always suitable for transport, heating & industry Energy Source • Energy Crops • Renewables (12%) • Fossil fuels with CO2 Sequestration • Nuclear Can Only Generate Electricity UK CO2 Emissions160m Tonnes pa Other 8% What about transport, heating and industry? Residen tial-15% Electricity Generation 29% Other industries 17% Refining Aviation etc 5% 6% Road transport 20% Heating, Transport and Industry Domestic heating (currently mostly gas) Transport (currently oil) Industry (coal, oil & gas) How do we convert to low emissions electricity? Converting Domestic Heating Heat pumps • Move heat from a low temperature heat source (such as the ground outside) and transfer it to a high temperature heat sink. • Powered by electricity (from nuclear or renewables). • Uses up to 80% less energy. • Using pump to heat a domestic water tank can smooth demand & store energy. A heat pump uses electricity to move heat from outside to inside a home. It works on the same principle as a refrigerator reversed. Heat pumps use 50-80% less energy than gas boilers. Heat pumps can be installed in both new and existing houses Image: Heat Pump theory From Wikimedia Converting Domestic Heating (2) The Zero-Emissions House Ground source heat pumps + Better house insulation + Underground air circulation + In/Out heat exchanger = 90% reduction in energy consumption Combining a heat pump with a well insulated hot water tank allows energy to be consumed overnight when prices are low. If we use non-emitting electricity (e.g. nuclear or microgeneration), CO2 emissions from domestic heating could be reduced by 99%. Building regulations must ensure that all new houses have low emissions. Converting Transport: Short distance Electric Cars • Technologies developing quickly, following success of Toyota Prius • Full conversion possible by 2030 Reductions in car use • Charge for road congestion • Health benefits of walking and cycling, especially for children • Better urban planning & public transport Electric cars store energy in batteries when recharged overnight (when electricity prices are low). Hydrogen fuel cell technology developing and may be in use by 2030. Hydrogen can be produced using next-generation nuclear power stations. Image: Toyota Prius From Wikimedia Commons Converting Transport: Long Distance Rail • Improve network • Build new freight lines • Upgrade urban transit systems (Crossrail) • Reduce ticket prices Aviation • Tax aviation more heavily (noise, CO2, congestion) • Ban night flights Travelling by rail uses much less energy than travelling by car or by plane. Image: Eurostar British Energy Policy 2006 • Background: DTI Energy Review • Main Goals: – CO2 Reduction – Security of Supply – Economic Efficiency • Planning? • Economic Instruments – Carbon Taxes – Price Guarantees Energy Supply Vision 2030 Energy Emissions Intensity* Total Emissions (GW) (t C/ GW) (Mt CO2 / year) 2005 230 162 2030: Reductions in Use 70 Renewables & Nuclear** 125 0.04 4.84 Coal-Gas with (partial) Sequestration# 20 0.13 2.63 Oil ## 15 0.55 8.21 Total 160 0.26 15.7 Reduction in CO2 Emissions: *Does not include excess heat used in industry and homes or desalination # Using gas turbines with CO2 Sequestration (85% reduction in CO2 eliminated relative to gas alone). ## For Aviation, Heavy Industry, Road Freight etc Also includes other unavoidable CO 2 emissions 90% Objectives 1. “We must immediately make substantial lifestyle changes and efficiency improvements aimed at using less energy, particularly in regard to road and air travel. “ 2. “We must construct sufficient low-emissions generation (renewable/ nuclear electricity) for all our energy needs. We must also significantly increase research into renewable energy and energy efficiency.” 3. “We must get ready to transform domestic heating, transport and industry to use and store clean, low-cost electricity instead of burning fossil fuels (e.g. with electric cars). Any new homes must be constructed on an ecologically sound, zero-emissions basis (including heat pumps for domestic hot-water tanks).” References Budyko, M. I. (1982), The Earth’s Climate: Past and Future, Elsevier, New York Defra, (2006) Avoiding Dangerous Climate Change, Cambridge University Press, Cambridge / www.defra.gov.uk DTI (2006) 'Our Energy Challenge', Energy Review Consultation Document / www.dti.gov.uk EPICA (2004) Eight glacial cycles from an Antarctic ice core Nature 429, 623-628 IAEA (2000) Annual Report IEA (2003) Energy to 2050 Scenarios for a Sustainable Future IEA (2004) World Energy Outlook IEA (2005) Key World Energy Statistics Harte, J and Torn M. (2006) Missing feedbacks, asymmetric uncertainties and the underestimation of future warming Geophysical Research Letters, Vol 33, L10703, 26th May 2006 http://www.agu.org/journals/gl/gl0610/2005GL025540/ Hoyle, F (2006) The Last Generation, Eden Project Books Lovelock, J (2006) The Revenge of Gaia, Penguin, London Nuttall, W. J. (2005), Nuclear Renaissance, IOP Publishing Petit J.R., et al. (1999). Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica. Nature 399: 429-436 Royal Academy of Engineering (2004): The Cost of Generating Electricity Royal Commission on Environmental Pollution (2000) Energy - The Changing Climate Sceffer, M et Al. (2006) Positive Feedback between global warming and atmospheric CO2 concentration inferred from past climate change Geophysical Research Letters, Vol 33, L10702, 26th May http://www.agu.org/journals/gl/gl0610/2005GL025044/ Socolow, R. (2006) et al.: Stabilization Wedges: An elaboration of the concept in Defra (2006) Warren, R (2006): Impacts of Global Climate Change at different Annual Mean Global Temperature Increases in Defra (2006) Wikipedia – www.wikipedia.org and Wikimedia - commons.wikimedia.org Wikisource Images use http://en.wikipedia.org/wiki/GNU_Free_Documentation_License World Energy Council (2000) Energy For Tomorrow's World