Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
100% renewable energy wikipedia , lookup
Climate change mitigation wikipedia , lookup
Open energy system models wikipedia , lookup
Energiewende in Germany wikipedia , lookup
Low-carbon economy wikipedia , lookup
Decarbonisation measures in proposed UK electricity market reform wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Climate Change – The Greatest Threat to Mankind? The fifth fuel – Energy Conservation? Park Lane Methodist Church 28th May 2006 Keith Tovey CRed Keith Tovey (杜伟贤) M.A., PhD, CEng, MICE, CEnv Energy Science Director: Low Carbon Innovation Centre School of Environmental Sciences, UEA 1 Climate Change – The Greatest Threat to Mankind? The fifth fuel – Energy Conservation? • Last Week • We have hard choices to make • Promote all renewables • Energy conservation – each of us to reduce consumption by 1.5% each and every year – i.e. by 20+% by 2020 • Even then we would see gas consumption rise by over 60% and up to 70+% will have to be imported from countries like Russia and Middle East • We delayed making a decision about nuclear in 1997 • Now it will be very difficult to avoid a small nuclear new build 2 Electricity Consumption (TWh) Historic and Future Demand for Electricity 500 450 400 350 300 250 200 150 100 50 0 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 Number of households will rise by 17.5% by 2025 and consumption per household must fall by this amount just to remain static 3 Electricity Options for the Future Low Growth Scenario Carbon Dioxide Emissions 300 Capped at 420 TWh 250 • Means everyone must reduce consumption by 1.5% each year. MTonnes CO2 200 • Assume Renewable targets are met but we are currently falling well short 150 Actual 100 Gas • 33% CO2 reduction cf 1990 No Renewable Increase 50 • 68 % increase in gas consumption cf 2002 0 1990 1995 2000 2005 2010 2015 2020 2025 •CAN WE JUSTIFY THIS INCREASE IN GAS? Renewable assumption we achieve target Carbon Dioxide Emissions 250 10 times as many wind turbines as present Nuclear option – 62% reduction in CO2 Mix option retains nuclear proportion at ~ 20% ~ 5 new nuclear to replace 13 existing ones MTonnes CO2 200 150 100 50 0 1990 Actual Gas Nuclear Coal 40:20:40 Mix 4 1995 2000 2005 2010 2015 2020 2025 Implications of some of the Scenarios In addition we would need 11000 MW of installed capacity of biomass – or 30000 sq km devoted to biomass cultivation or we would need many more wind turbines. Number of New Nuclear Stations Nuclear Station Requirements 10 9 8 7 6 5 4 3 2 1 0 Mix Low Growth Mix High Growth But we are exploiting resources of developing countries such as Malaysia – should we continue to do so and increase this exploitation? 2010 2015 2020 2025 Numbers of Wind Turbines Percentage Renewable Generation 25 14000 Meeting Targets 20 Meeting Targets 12000 Realistic ? 10000 % No 15 Realistic ? 8000 6000 10 4000 5 2000 0 0 1990 1993 1995 1997 1999 2002 2005 2010 2015 2020 2025 5 1990 1993 1995 1997 1999 2002 2005 2010 2015 2020 2025 Climate Change – The Greatest Threat to Mankind? The fifth fuel – Energy Conservation? • By 2050 we could readily have a renewable an low carbon future. • However we cannot now have a non-nuclear scenario in the period 2015 – 2030, • Unless – we wish to be dependent on Russia and the middle east for are heating and electricity generation for almost all our electricity and heating. • Or – we wish to see a return to coal and global warming exacerbated. By 2030 significant possibilities will exist for carbon sequestration, • Or – we make more drastic cuts in energy use – a 20% cut will only see us stand still • But conservation measures often do not achieve the theoretical savings predicted because of “comfort taking” 6 Climate Change and our insatiable appetite for energy So where does it all go? Per Capita Consumption in Watts ~ 5 kW 1970 816 623 1379 411 1980 882 786 1069 414 1990 902 1076 855 425 2002 1060 1207 769 442 Conversion and Transmission 1712 1565 1745 1844 Total Non-Energy 4942 240 4716 165 5004 249 5321 241 Domestic Transport Industry Other • Transport Energy use has risen 10.5% in last decade • Domestic use has risen by over 10% 7 Climate Change – The Greatest Threat to Mankind? The fifth fuel – Energy Conservation? • Opportunities for Conservation – Reduce transmission losses • Local generation of electricity (8.5% in case of electricity) – Make more effective use of energy during conversion. – Reduce demand • Technical means • Promoting Awareness 8 Local Provision of Energy Solar Pump Normal hot water circuit Solar Circuit 9 Local Provision of Energy It is all very well for South East, but what about the North? House in Lerwick, Shetland Isles - less than 15,000 people live north of this in UK! 10 Saving Energy – A Practical Guide Ways to Reduce Your Carbon Footprint Micro CHP Heat Pumps Micro Wind 11 Involve the local Community • Many residents on island of Burray (Orkney) compaigned for a wind turbine. • On average they are fully self-sufficient in electricity needs and indeed are a net exporter of electricity 12 8. Generation of Electricity - Conventional Largest loss in Power Station Overall efficiency ~ 35% Diagram illustrates situation with coal, oil, or nuclear Gas Generation is more efficient - overall ~ 45% 13 8. Generation of Electricity - Conventional. Superheated Steam 563oC 160 bar Multi-stage Turbine Generator Boiler Why do we condense the steam to water only to heat it up again?. Does this not waste energy? Pump NO!! Thermodynamics? Condenser Steam at ~ 0.03 bar Simplified Diagram of a “generating set” 14 includes boiler, turbine, generator, and condenser 8. Generation of Electricity - Conventional Chemical Energy Coal / Oil / Gas 100 units Power Station Heat Energy 90 units Boiler 90% Turbine Generator 95% Electrical Energy 48% 41 units Mechanical Energy Electricity used in Station 3 units 38 units 15 8. Generation of Electricity - Conventional. Why not use the heat from power station? - it is typically at 30oC? Too cold for space heating as radiators must be operated ~ 60+oC What about fish farming - tomato growing? - Yes, but this only represent about 0.005% of heat output. Problem is that if we increase the output temperature of the heat from the power station we get less electricity. Does this matter if overall energy supply is increased? 16 8. Generation of Electricity - CHP Overall Efficiency - 73% •Heat is rejected at ~ 90oC for supply to heat buildings. •City Wide schemes are common in Eastern Europe 17 8. Generation of Electricity - Conventional. 1947 Electricity Act blinked our approach for 35 years into attempting to get as much electricity from fuel rather than as much energy. Since Privatisation, opportunities for CHP have increased on an individual complex basis (e.g. UEA), unlike Russia A problem: need to always reject heat. What happens in summer when heating is not 18 required? 9. Applications of Thermodynamics. Combined Heat and Power 19 Engine Generator Generation of Electricity with a Gas Engine 61% Flue Losses 3% Radiation Losses 36% efficient GAS Engine Generator 36% Electricity 20 Combined Heat and Power at UEA 3% Radiation Losses 11% Flue Losses 81% efficient Exhaust Heat Exchanger GAS Reduces conversion losses significantly Engine Engine heat Exchanger 45% Heat Localised generation can make use of waste heat. Generator 36% Electricity 21 Performance of CHP units Before installation 1997/98 electricity gas oil 19895 35148 33 MWh Total Emission factor kg/kWh 0.46 0.186 0.277 Carbon dioxide Tonnes 9152 6538 9 15699 After installation 1999/ 2000 Electricity Heat Total CHP export import boilers CHP site generation MWh 20437 Emission kg/kWh factor Carbon Tonnes dioxide 15630 oil total 977 5783 14510 28263 923 -0.46 0.46 0.186 0.186 0.277 -449 2660 2699 5257 256 10422 This represents a 33% saving in carbon dioxide 22 Load Factor of CHP Plant at UEA Demand for Heat is low in summer: plant cannot be used effectively More electricity could be generated in summer 23 Before and during the break • Use the computers to model the carbon emissions at home and to identify the issues which are of greatest importance. • The model is approximate and will not necessarily indicate total consumption, but it will identify the issues you should think about 24 The Heat Pump A Heat Pump or refrigerator High Pressure Warm Temperature Heat to building High Pressure High Temperature Condenser Work In Throttle Valve Compressor Evaporator Low Pressure Cold Temperature Heat from outside Low Pressure Cool Temperature • 3 to 4 times as much energy out as energy in!! • Works with thermodynamics – NOT against it 25 Normal Air-conditioning Adsorption Air-Conditioning Heat from external source Heat rejected High Temperature High Pressure Desorber Heat Compressor Exchanger Condenser Throttle Valve W~0 Evaporator Absorber Heat extracted for cooling • • • • Low Temperature Low Pressure Adsorption Heat pump uses Waste Heat from CHP Will provide most of chilling requirements in summer Will reduce electricity demand in summer Will increase electricity generated locally 26 The Norwich Heat Pump Original Paper by John Sumner Proc. Institution of Mechanical Engineers (1947): Vol 156 p 338 27 The History of the Site • The building was unique - the very first heat pump in the UK. • Installed during in early 1940s during the War. • Built from individual components which were not ideal. • Compressor was second hand built in early 1920’s ! for Ice making. • The evaporator and condenser had to be built specifically on site. • Refrigerant choice was limited during War - only sulphur dioxide was possible. • A COP of 3.45 was obtained - as measured over 2 years. • Even in 1940s, the heat pump was shown to perform as well as, if not better than older coal fired boiler. 28 The History of the Site Evaporator Compressor Condenser 29 • The Norwich Heat Pump - note the shape of the columns The Norwich Heat Pump 30 The Duke Street Project Domestic Units – Rebuild/Refurbishment of existing façade on Duke Street Location of former Heat Pump – the first in the UK Domestic Units – Refurbishment of former Electricity Board Offices Commercial /Hotel Development Model of the Redevelopment Site showing relationship between Domestic and Commercial parts of Site. 31 A concluding thought 650 m Our Wasteful Society We behave as though we call in the RAF The Heat Pump is the analogy with the crane In memory of John Sumner 21 m 32 273 m Climate Change and the Environment The greatest threat to mankind? • • • • Our insatiable appetite for Energy Potential of Energy Resources Hard Choices Ahead The fifth fuel – Energy Conservation? • Next Week Crunch Time! – What can you do in your homes or as a community? 33 To discuss next week • 1. When cooking vegetables on a stove. How much energy (as a percentage) is saved by putting a lid on the saucepan.? • 2. What are the major sources of heat loss from a house? List the conservation measures which should be adopted in order of effectiveness, and also cost? What measures would you take to improve the energy efficiency of your home? • 3. By time switching the heating in a house so that it is off from 11pm until 7am the next morning, a saving of one third in energy will be possible. Is this correct? What disadvantages are there from time switching ? • 4. It is often argued that with a well insulated hot water tank it does not matter if the heating source is left on. In what circumstances is this statement correct, and in what circumstances is it not? • 5. Fluorescent lights use as much energy when switched on as they do in running for 15 minutes [some people say 30 minutes] or is this a myth?. What evidence can you use to confirm this or otherwise. Remember to bring your data you have been collecting with you 34