System Analysis of the work Energy and environmental Problems

from http://www.i-sis.org.uk/whichRenewables.php

The electricity industry currently contributes about 37 percent of the world’s carbon emissions, predominantly from burning fossil fuels while electricity is generated [1]. The best option for reducing carbon emissions is to substitute renewable energy resources for fossil fuels. Our recent report [2] Food Futures Now (ISIS publication) shows how a radical change in the way we produce and distribute food as well as energy can indeed free us from fossil fuels altogether. Renewable energies such as solar and wind do not emit carbon dioxide while generating electricity, and have the further advantage that it can improve the efficiency of energy use considerably. Big power plants are located far away from most users, so the electricity generated has to be transported long distances over power lines where more than 7 percent may be lost before it is used. In addition, some 60-70 percent of the energy is lost as ‘waste’ heat while generating electricity. In contrast, solar panels and wind turbines are readily installed on or near homes and farms and the electricity generated as well as the heat can be consumed directly without much loss.

‘Cradle-to-grave’ life-cycle assessment

A ‘cradle-to-grave’ life-cycle assessment (LCA) is one that includes upstream processes such as mining, refining, transport and plant construction, the production of the device or equipment, the generation and distribution of electricity, and downstream processes such as decommissioning and disposal of wastes. This will give us a clearer idea as to how much better off we are with renewable electricity generation, and how different renewable options compare with one another. In LCA, the main environmental performance indicators are as follows [3]. Energy intensity h, is the ratio of the total energy used for construction, operation and decommissioning E, to the electricity output of the plant/device over its lifetime Et. h = E/ Et (1) Et = P x 8760h/y × l x T where P is the power rating, l is the load factor (def) and T the lifetime. The inverse of energy intensity is the energy payback ratio (EPR), and is considered one of the most reliable indicators according to the International Energy Agency. A high EPR indicates good environmental performance. An EPR of 1 or less indicates it consumes as much energy as it generates, so it should never be developed. Energy payback time (EPBT) is the time it takes for the energy technology to generate the total energy requirement for construction, operation and decommission. EPBT = E ×εfossil × T/ Et (2) where εfossil is the conversion efficiency. Both EPBT and EPR tell us how much conventional energy we use today in order to obtain energy to-morrow. Environmental impact (EI) assesses impact on the ecosystem. The general categories are acid rain potential, photochemical oxidants, global warming potential, etc. Other categories are impact on wildlife, loss of biodiversity, water quality, especially applicable to geothermal and marine energy technologies, including run-of-river hydro, tidal energy and wave energy, which still need to be carried out. There are two major approaches to LCA: a process-based model developed mostly by the Society of Environmental Toxicology and Chemistry (SETAC) and the US Environment Protection Agency (EPA), and an economic input-output analysis referred to as EIO-LCA. The SETAC-EPA approach divides each product into individual process flows and identifies and quantifies EIs. This model includes all the various manufacturing, transport, mining and related requirements for making the product or service. The EIO-LCA traces out the various economic transactions, resource requirements, and environmental emissions required for a particular product or service. It uses sectors of the economy rather than specific processes, and also has difficulties analysing the use and disposal phases of certain products. The renewable technologies for which most of the LCA work has been done are biomass, photovoltaic and wind energy. For example, the EPBT for onshore and offshore wind turbines in Denmark in 2000 were 0.26 and 0.39 y respectively, excluding glass and polyester because data did not exist, and about 94 percent of the materials of the wind turbine can be recycled. A study published in 2005 on 2.7kW PV systems found it consumed only 23 percent of the total primary energy of an oil-fired steam turbine plant, but its EPBT was a couple of months higher. The lifetime GHG emissions for the oil-fired steam turbine plant were about four times those of the PV systems. For biomass electricity, the LCA of wood-fired power plants in the range of 5 to 30 MW in Britain, the energy intensity is 0.25 to 0.27, and the CO2 emission is 65 g per kWh. A further analysis showed that an integrated biomass gasification combined cycle (IBGCC) power plant is superior to an integrated coal gasification combined cycle (IGCC) plant in terms of resource depletion and GHG emissions, whereas IGCC is better in terms of acidification and eutrophication.

LCA identifies factors contributing to environmental performance

Many factors contribute to environmental performance. The lifetime, power ratings, load factor (the output of a power plant compared to the maximum output it could produce), type and maturity of technology, country of manufacture, the type of material used, and method of decommissioning, all influence the energy intensity. For example, in the case of a wind turbine, it is 0.049 for a steel tower and 0.041 for a concrete tower. The manufacture of a 500 kW German wind turbine in Brazil requires almost twice as much primary energy as one manufactured in Germany. And it is less energy intensive to recycle completely, or overhaul and reinstall after the service life is over than to recycle individual components. Different LCA methodologies will also give different energy intensity for the same wind turbine. For example, the input output analysis gave higher energy intensity than process analysis because the former included more detailed information. The environmental performance of PV technology differs in different countries. For Germany, the low irradiance reduces the EPR, but because it substitutes for a relatively dirty grid, CO2 emission is reduced by 10.1 tonnes per kW of PV installed.

LCA for different scenarios

LCA can be used to assess the environmental performance of alternative energy scenarios. It has been shown that the CO2 emission per kWh for PVs can be reduced from 217 g to 68 with three improvements: in manufacturing technology, by changing the supporting structure to reduce aluminium use, and by increased efficiency of the solar cell. A study published in 1996 showed that the EPR could be increased from 2.4 to 6.7 using a ‘solar breeding system’ in which PV technology supplies electricity to produce further PV technology. For bio-energy (biomass and biofuels), inorganic nitrogen fertilizer inputs have a strong influence on overall performance, accounting for 37 percent of non-renewable fossil energy input. Substituting for inorganic N fertilizer with sewage sludge ‘bio-solids’ could increase the EPR of willow biomass crop production by more than 40 percent.

LCA for comparative analysis of different renewable technologies

A 2005 LCA showed that amorphous silicon solar cells emit 44 g CO2/kWh of electricity generated compared to 75 g for multicrystalline cells. Another LCA published in the same year found that the installation of 2.5kW PV on the ground yields 141 g CO2/kWh electricity generated, which is an order of magnitude higher than hydro and wind, but an order of magnitude lower than coal. For comparison, a summary of the EPR and CO2 emissions of different renewable and non-renewable energy power plants are listed in Table 1 [3]. Table 1. EPR and CO2 emissions of different renewable and non-renewable energy power plants As can be seen, conventional coal power plants have the highest emissions followed by oil, natural gas, biomass. Hydro and wind have the lowest emissions. Photovoltaic technologies are advancing rapidly; the environmental indicators improve year by year [4] (see Solar Power Getting Cleaner Fast, SiS 39) and approaching those for wind and hydroelectric.

References

1. World Emission trading system to meet Kyoto target. http://www.panda.org/about_wwf/what_we_do/climate_change/news/index.cfm?uNewsID=50480
2. Ho MW, Burcher S and Lim LC. Food Future Now, Organic, Sustainable Fossil Fuel Free, ISIS & TWN, London, 2008.
3. Lund C and Biswas W. A review of the application of lifecycle analysis to renewable energy systems. Bulletin of Science, Technology & Society 2008, 28, 200-9.
4. Ho MW. Solar power getting cleaner fast. Science in Society 39 (to appear)

System Analysis of sustainable Energy production

http://www.satyacenter.com/news-global_visionaries-food-fuel-during-climate-change?page=2


From web portal
How to be Fuel and Food Rich During Climate Change
Page 2: So what's the real solution?

So what's the real solution?There are many solutions in renewable energies that are truly sustainable. Solar power, for example, is getting cheaper, more versatile and more efficient everyday. The world�s energy needs can be satisfied with solar panels at even a low 10 percent efficiency covering just 0.1 percent of the earth�s surface. They can be incorporated into existing building structures and are ideal for local micro-generation [10]. I want to concentrate on energy from biological wastes, which has enormous potentials not only in terms of energy that can be harvested, but also in reducing carbon emissions. But not I hasten to add, not incineration, which is also what the Blair government is supporting [11]. First and foremost is anaerobic digestion to harvest biogas, which is 60 percent or more methane that can be used the same way as natural gas.

Anaerobic digestion of biological waste There are numerous advantages of anaerobic digestion, which has the potential to provide 11.7 percent of all energy needs, or 50.2 percent of transport fuels in the UK. Methane can be used both as fuel for mobile vehicles or for stationary combined heat and power generation. Methane-driven vehicles are already in the market, and they are the cleanest vehicles on the road by far, ranking top green cars of the year in 2005 [12]. Sweden has thousands of them, supported by hundreds of filling stations; many operated from locally produced biogas. Biogas methane is a renewable and carbon mitigating fuel; it is more than carbon neutral. It saves on carbon emission twice over, by preventing the escape of greenhouse gases methane and nitrous oxide into the atmosphere and by substituting for fossil fuel. Anaerobic digestion conserves plant nutrients such as nitrogen and phosphorous for soil productivity. In fact, many third world countries started to use anaerobic digestion for making good fertilisers before they began to use the methane for energy. Anaerobic digestion prevents pollution of ground water, soil and air with nitrates, methane, nitrous oxides, and other contaminants. It improves food and farm hygiene, and has been shown to destroy disease bacteria. It can be adapted to produce hydrogen either directly or from methane. And if and when research and development in hydrogen storage and fuel cells become further advanced, anaerobic digestion can link up quite easily. There�s a company, Organic Power Ltd, run by Chris Maltin in Somerset here in Britain, which produces its own biogas methane to run methane-powered Mercedes people carriers (�Organic waste-powered cars�, SiS 30). Anaerobic digestion of biological wastes can provide 11.7 percent of UK�s energy needs and saves at least 15.8 percent of carbon emissions Here are the calculations showing how UK�s biological wastes can potentially provide more than half (50.3 percent) of transport fuel and 11.7 percent of all energy consumed in the country. UK produces 434 Mt of solid wastes a year, of which 25.5 Mt of municipal solid wastes and 62.143 Mt of commercial and industrial wastes are organic and suitable for anaerobic digestion. These numbers are extracted from a report written for the Office of National Statistics published in January 2005 [13]. From FAO statistics [14], I gathered that UK�s total agricultural production in 2005 was 41.6915 Mt, counting cereals, fruits, pulses, vegetables, oilseed rape, sugar beet, potatoes, and mushrooms. Assuming that waste constitutes fifty percent of the harvest, i.e., 41.6915 Mt, the total amount of biological waste that can be treated in anaerobic digesters is 129.3345 Mt. This includes high-yielding feedstock such as fats and grease, bakery wastes, food scraps, grass silage, green clippings and brewery wastes, producing 961 to 120 cubic metres of methane per tonne [15]. In addition, there were 11.887 million cows, 43.851 million sheep, 7.719 million pigs and 128.261 million poultry in the UK in 2005 [16], producing 208.685 Mt of livestock manure, according to estimates of per capita livestock manure production given by the report from the Office of National Statistics [13]. The different manures yield 25 to 80 cubic metres methane per tonne [15]. Taking a conservative average of 200 cubic metres for the organic wastes and 30 for the livestock manure, we get enough to produce 1 285 PJ (1015J) of methane energy per year. The total energy consumed in the UK in 2005 was 10670 PJ, or which 3643 PJ were transport fuels [17]. Thus, methane from wastes can potentially supply 11.7 percent of UK�s total energy requirement, or 50.3 percent of transport fuels. This is quite remarkable. The carbon emissions saved is even more astonishing. The total volume of methane potentially available from biological wastes each year is 32 070 million cubic metres. Assuming a global warming potential of 22, this is equivalent to 508.0 Mt of carbon dioxide, which comes to a whopping 90.6 percent of the national emissions of 561 Mt [16]! The same amount of methane substituting for fossil fuels save 88.8 Mt, a more realistic 15.8 percent of the national carbon dioxide emissions. These figures suggest to me that we have seriously underestimated the greenhouse gases emitted by the mountains of biological wastes in this country, indeed in any country that go into landfills; and that methane mitigation will contribute an extraordinary amount to reducing actual greenhouse gases in the atmosphere. Green algae for carbon capture and sustainable biodiesel A league table compiled by the Guardian newspaper showed that the five biggest polluters in the UK are all power stations, and together produced more carbon dioxide than all the country�s motorists [18]. EON UK, the electricity generator that owns Powergen, UK�s top, emitted 26.4 Mt carbon dioxide in 2005, slightly more than Croatia. The five (EON UK, RWE Npower, Drax, Corus and EDF) together produced over 100 Mt, while the country�s 26 million motorcars produce 91 Mt. Another big solution considered by the UK government is CCS, carbon capture and storage. It is a process literally to capture the carbon dioxide from the exhaust of big power stations and store it deep underground. This method is clumsy and uneconomical, and even the US Department of Energy appears not to favour it [19]. So what is the real alternative? Green algae actually don�t mind growing in the exhaust gas from power generation (�Green algae for carbon capture & biodisel�, SiS 30). A suitable species can mop up 40 percent of the carbon dioxide, and 86 percent of nitrous oxide when bolted to the exhaust, where it grows prolifically. Some species can yield up to 50 percent oil by weight, and you can get up to 15 000 gallons of biodiesel an acre a year, as opposed to 60 gallons from an acre of soybean. Putting all the appropriate technologies together How can we put all these technologies together to be food and fuel secure or even food and fuel rich? Just as we cannot depend on imported energy, we may not be able to depend on imported food. All the predictions are that global warming will impact negatively on food production, particularly as water is also depleted as well as oil, and conventional industrial agriculture is addicted to both of them [20] (�Sustainable food system for sustainable development� SiS 27). To make things worse, our globalised food trade uses up a lot of energy and spews extra mega tonnes of carbon emissions into the atmosphere. The social, environmental, and economic costs of food transport in the United Kingdom estimated in a report commissioned by DEFRA amounted to �9 billion a year, or 34 percent of the total value of the food sector [21] ("Food miles and sustainability"). There is every reason to be self-sufficient in food and to consume food produced locally. It is healthier, more nutritious and saves on energy and carbon emissions. The same goes for energy. Energy use at the point of production saves 69 percent on efficiency alone, as the �waste� heat can be used in combined heat and power generation, and also avoids the average 7.4 percent loss incurred in long distance transfer of electricity through the grid [22]. Dream Farm I for energy and food self-sufficiency Things all come together in Prof. George Chan�s idea of integrated food and waste management system, which I have described as [23] (�Dream farms�, SiS 27), �abundantly productive farms with zero input and zero emission powered by waste-gobbling bugs and human ingenuity.� We are very fortunate to have Prof. George here to say a few words to us ( �Complete recycling of all resources for sustainability�, this series). In George�s farm, which I call Dream Farm I, the anaerobic digester is the key technology. You can have two, three or more in series or in parallel. The anaerobic takes in livestock manure plus wastewater, and the naturally occurring bacteria in the manure ferment the wastes and generate biogas, which provides all the energy needs for heating, cooking and electricity.

The partially cleansed wastewater goes into the aerobic digester, shallow basins where green algae produce by photosynthesis all the oxygen needed to detoxify the water, making it safe before it goes into fishponds. The algae are harvested to feed chickens, ducks, geese and other livestock. The fishponds support a compatible mixture of 5-6 fish species. Water from the fishponds is used to �fertigate� crops growing in the fields or on the raised dykes.

Aquaculture of rice, fruits, vegetables and flowers can be done in floats on the surface of the fishpond, saving backbreaking work involved in weeding and watering. Water from the fishponds can also be pumped into greenhouses to support aquaculture of fruits and vegetables, where the remaining nutrients are removed, and the water polished clean to return to the aquifers. The anaerobic digester yields a residue rich in nutrients that is an excellent fertiliser for crops. It could also be mixed with algae and crop residues for culturing mushrooms after steam sterilisation. The residue from mushroom culture can be fed to livestock or composted. Crop residues are fed back to livestock. Crop and food residues are used to grow earthworms to feed fish and fowl. Compost and worm castings go to condition the soil. Livestock manure goes back into the anaerobic digester, thus closing the grand cycle.
The result is a highly productive farm that�s more than self-sufficient in food and energy, and saves substantially on carbon emissions. George�s farms make happy animals. They are organically fed and toilet-trained to deposit their manure into a sump that goes to the digester, so the animals and their housing are spotlessly clean. Another aspect worth stressing, especially in times of water shortage and floods is that the fishponds in Dream Farm I are great for water management, it provides water conservation, purification and flood control. As the dykes are raised above the surrounding levels from the mud dug up, they can accommodate much more water without overflowing in times of heavy rain, and provide an effective reservoir in times of scarcity. Aquaculture on the surface of the pond also helps reduce evaporation losses. Dream Farm II Based on Dream Farm I, we have proposed to set up a Dream Farm II[24] for education/demonstration and research purposes (�Dream Farm II, how to beat climate change and post-fossil fuel economy�, SiS29), to act as incubator for new technologies, new designs and ideas, and as information exchange to support real farms like this springing up all over our countryside and all over the world. Such farms can supply nearby schools, old peoples� homes, towns and cities with fresh healthy foods all year round, reducing their enormous ecological footprints immeasurably, and also contribute to revitalising the rural economy. The additional elements are all forms of renewable energies suitable for local energy generation at the medium, small to micro-scale. Solar panels, wind turbines, suitably scaled down and improved for aesthetic design. The farmed livestock, fish and crops will be based on indigenous species and local varieties as much as possible, providing an opportunity for Britain to recover its rich heritage of natural and agricultural biodiversity that has been decimated by decades of industrial agriculture. It would enhance the local cuisine and restore healthy diets to the nation. Jimmie Oliver would be ecstatic about this farm, which could support an on-site gourmet restaurant as well as an analytical laboratory. Our approach is to get the farm up and running on core technologies while newer technologies are integrated or substituted at the periphery as time goes on, including hydrogen technologies, and carbon capture using algae by passing the exhaust from the combined heat and power generator through the algae culture, and turning the algae into biodiesel. The possibilities are endless. Giving up fossil fuel not only gives us a greener and healthier planet, it will unleash all the bottled up creativity and energies that work for people and planet. Dream Farm and the new paradigm Dream Farm is also a concrete demonstration of a new paradigm at work. The important features of zero-emission, zero-waste systems are the same as the �zero-entropy� model of organisms and sustainable systems I first proposed in 1998 in my book, The Rainbow and the Worm, the Physics of Organisms. The zero-entropy model predicts balanced development and growth as opposed to the dominant economic model of infinite, unsustainable growth. The alternative to the dominant model is definitely not an end to growth, as too many critics are advocating. Instead, the key to how organisms survive and thrive is the same as what makes a system sustainable. It involves maximising reciprocal, cooperative and synergetic relationships rather than the competitive; it is to use the output of each cycle to feed another, and closing the big cycle in a balanced way. In the context of the farm, it is to turn �wastes� into resources. In the dominant model, the system grows relentlessly, swallowing up the earth�s resources without end, laying waste to everything in its path, like a hurricane. There is no closed cycle to hold resources within, to build up stable organised social or ecological structures. By contrast, the archetype of a sustainable system is a closed lifecycle, it is ready to grow and develop, to build up structures and perpetuate them, and that�s what sustainability is all about. Closing the cycle creates a stable, autonomous structure that maintains itself and renews itself. In other words, it is self-sufficient. The cycle contains more cycles within that help one another thrive and flourish, as in the minimum integrated farm, with farmer, livestock and crops. It can perpetuate itself as such, or it can grow by incorporating more life-cycles, more crops, more productivity, more farm workers, more jobs. The carrying capacity of a piece of land is by no means a constant. It can be ten times more productive, depending on how it is organised. That is why productivity and biodiversity always go together. Industrial monoculture, by contrast, is the least energy efficient in terms of output per unit of input, and less productive in absolute terms despite high external inputs, as documented in recent academic research. Biodiversity is nature�s way of maximising the reciprocal, symbiotic relationship that sustain all and make the whole ecosystem thrive. That is the lesson we need to embrace for a paradigm shift to the wonderful life without fossil fuels.
This article is based on her presentation in the Which Energy? Launch Conference, House of Commons, 25 May 2006, London, UK References
1. Perlack RD, Wright LL, Turhollow AF, Graham RL, Stokes BJ, ErbackDC. Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply, US Department of Energy and Department of Agriculture, April 2005. 2. Biodiesel Project Development, Biofuels Corporation plc, April 2006, http://www.biofuelscorp.com/project.html 3. Ho MW. Biofuels for oil addicts, cure worse than the addiction? Which Energy?, ISIS Energy Report, pp. 22-24, ISIS, London, 2006. 4. Kavolov B. Biofuel Potentials in the EU, Technical Report Series, EU21012EN, Institute for Prospective Technological Studies, European Commission Joint Research Centre, January 2004 5. �Food crisis feared as fertile land runs out�, Guardian unlimited, 6 December 2005, http://www.guardian.co.uk/food/Story/0,,1659112,00.html 6. �Forests paying the price for biofuels�, Fred Pearce, NewScientists.com news service, 22 November 2005, http://www.newscientist.com/article.ns?id=mg18825265.400 7. �The most destructive crop on earth is no solution to the energy crisis�, George Monbiot, The Guardian UK, 6 December 2005, http://www.truthout.org/issues_05/120605EA.shtml 8. �Food industry urges caution on biofuel promotion plan�, Ahmed ElAmin,Food navigator.com, Europe, 4 May 2006, http://www.foodnavigator.com/news/ng.asp?n=67478-ciaa-biofuel-rapeseed 9. �Green fuel revolution a challenge for grain sector�, Christine Stebbine, Reuters, 11 October 2005, http://www.sydneybiodiesel.com/content/view/52/9/ 10. Ho MW. Solar power for the masses. Which Energy? ISIS Energy Report, pp. 35-36, ISIS, London, 2006. 11. Innis G. Thermodepolymerization, not incineration. Letters to the Editor, Science in Society 2006, 30, 6. 12. Ho MW. Organic waste-powered cars. Which Energy? ISIS Energy Report, pp. 51-52, ISIS, London, 2006. 13. Gazley I and Francis P. UK Material Flow Review, Office of National Statistics, January 2005,

14. FAOSTAT Database Query,

15. See Which Energy?, ISIS Energy Report, p.61, ISIS, London, 2006. 16. Defra Economics & Statistics, Agricultural quick statistics, http://statistics.defra.gov.uk/esg/quick/agri.asp 17. Energy statistics, dti, Government News Network, 30 March 2006, http://www.gnn.gov.uk/environment/detail.asp?ReleaseID=193538&NewsAreaID=2 18. �New figures reveal scale in industry�s impact on climate�, David Adam and Rob Evans, Guardian Unlimited, 16 May 2006, http://www.guardian.co.uk/climatechange/story/0,,1775689,00.html 19. Ho MW. Green algae for carbon capture and biodiesel. Which Energy? ISIS Energy Report, p. 50, ISIS, London, 2006. 20. Ho MW. Sustainable food system for sustainable development. Science in Society 2005, 27, 33-35. 21. Ho MW and Gala R. Food miles and sustainability. Which Energy? ISIS Energy Report, pp. 53-54, ISIS, London, 2006. 22. Philips G. Domestic energy use in the UK, power conversion, transport and use. PowerwatchSpring 2000, http://www.powerwatch.org.uk/energy/graham.asp 23. Ho MW. Dream farm. Which Energy? ISIS Energy Report, pp. 55-57, ISIS, London, 2006. 24. Ho MW. Dream farm II. Which Energy? ISIS Energy Report, pp. 58-65, ISIS, London, 2006. Reprinted with the kind permission of the author & ISIS.


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Dr. Mae-Wan Ho is a Visiting Reader in Biology at London Open University and a Visiting Biophysics Professor at Catania University in Sicily. She has been one of the most influential figures of the last decade in the debate within the scientific community regarding the use of genetically modified organisms. She is a highly respected global scientific figure and a well-known critic of neo-Darwinism and reductionist thought in Biology and Physics. Dr. Ho has authored hundreds of scientific articles and many books on a variety of subjects.

In 1999, she founded The Institute of Science in Society (ISIS), a London-based nonprofit organization that works globally to promote social responsibility and sustainability in scientific research and scientific practice.

ISIS provides extensive online archives of articles, scientific papers, and press releases written by Dr. Ho and her colleagues related to biotechnology, including genetically modified organisms, sustainable agriculture, environmental issues, Gaia theory, holistic health, nanotechnology and alternative energy.

ISIS also co-ordinates global campaigns including the The Global Campaign for a GM-Free Sustainable World and Sustainable World: A Global Initiative.