Why “Zero Carbon”? Climate Change and Global Energy Demand Stephen Stretton Cambridge Zero Carbon Society

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 (CO 2 ) and Methane absorb re- radiated heat in the ‘Greenhouse Effect’. The combustion of fossil fuels such as coal, oil and natural gas, releases CO 2 into the atmosphere, increasing this effect. Sources: CO 2 graph shows trend shown without seasonal fluctuation. Data from Mauna Loa Observatory, Hawaii; Cover Photo © Nasa; Temperature graph from

CO 2 concentration & temperature Current CO 2 Concentration Pre-industrial CO 2 Concentration Data from Antarctic ice cores CO 2 concentration (global) in black Reconstructed local temperature in red Positive Feedback? How much will global temperatures increase for x2 CO 2 ? Ice Core Data. From Vostok, Antarctica; Main Source: Petit J.R., et al. (1999); c.f. EPICA (2004); Graph:

Effects of Climate Change (1) Source: Adapted from Warren, R (2006) (Present Day) – Some effects already seen Oceans damaged Greenland ice melts (raising sea levels eventually by 7m) Amazon rainforest collapses, releasing CO 2 Increases in extreme weather (e.g. hurricanes) Agricultural yields fall Tropical diseases spread Global heat circulation system collapses? Hundreds of millions at risk from hunger & drought CO 2 released from forests and Soils Methane released from peat bogs & oceans? Desertification of large parts of Earth’s surface World ecosystems cannot adapt Positive Feedback: Warming causes further release of greenhouse gases

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 CO 2 concentration? Climate models suggest increase in temperature of °C associated with anthropogenic doubling of CO2 With positive feedback the range is °C We assume that a doubling of preindustrial levels causes an increase in temperature of 4°C

Energy demand is rising rapidly * 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 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

Dangerous Threshold Passed ( 550ppm ) (2100 CO 2 concentration 920ppm) (CO 2 Now: 380ppm) 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: Sources: Sceffer, M et Al. (2006), Defra (2006). “Business as usual” would lead to disaster within a few decades

A expansion in low-carbon energy can stabilise emissions… …But temperatures may still pass “dangerous” threshold Source: IEA (2003)… Dangerous Threshold Passed (460ppm) 500ppm)

Conversion to a zero carbon economy + less total energy used… Source: IEA (2003) Sustainable Development (SD) scenario with additional reductions. Danger Avoided! 400ppm)

All countries convert (but some delay) Source: IEA (2003) Sustainable Development (SD) Scenario. (450ppm) Some danger: but most severe impacts avoided.

CO 2 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 CO 2 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

Trains Electric Cars Heat Pumps 2030Now Total energy = ‘Final Energy’ net of refinery and generation losses 2030: Total energy does not include other uses for nuclear heat. Plus: Sufficient Low-Emissions Energy!!

How do we convert our economy to use low emissions electricity? Stephen Stretton Cambridge Zero Carbon Society

The Potential Solutions Energy crops Fossil fuels with CO 2 Sequestration Nuclear Renewables Wind Solar Hydro Tidal Wave Waste Electricity Liquid Fuels or Electricity Energy Source Main Energy Vector

Energy Crops: Not Enough Cropland 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 CO 2 sequestration.

Problem: Electricity is not always suitable for transport, heating & industry Energy Crops Renewables (12%) Fossil fuels with CO 2 Sequestration Nuclear Energy Source Can Only Generate Electricity What about transport, heating and industry?

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 can be installed in both new and existing houses 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. Image: Heat Pump theory From Wikimedia Commons 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.

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 If we use non-emitting electricity (e.g. nuclear or micro- generation), CO 2 emissions from domestic heating could be reduced by 99%. Building regulations must ensure that all new houses have low emissions. Combining a heat pump with a well - insulated hot water tank allows energy to be consumed overnight when prices are low.

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 Image: Toyota Prius From Wikimedia Commons 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 Hydrogen can be produced using next-generation nuclear power stations.

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, CO 2, congestion) Ban night flights Image: Eurostar Travelling by rail uses much less energy than travelling by car or by plane.

British Energy Policy 2006 Background: DTI Energy Review Main Goals: –CO 2 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) : Reductions in Use70 Renewables & Nuclear** Coal-Gas with (partial) Sequestration# Oil ## Total Reduction in CO 2 Emissions: 90% *Does not include excess heat used in industry and homes or desalination # Using gas turbines with CO 2 Sequestration (85% reduction in CO 2 eliminated relative to gas alone). ## For Aviation, Heavy Industry, Road Freight etc Also includes other unavoidable CO 2 emissions

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 / DTI (2006) 'Our Energy Challenge', Energy Review Consultation Document / EPICA (2004) Eight glacial cycles from an Antarctic ice core Nature 429, 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, 26 th May 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: 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 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 – and Wikimedia - commons.wikimedia.org Wikisource Images use World Energy Council (2000) Energy For Tomorrow's World