2010 Diary week 50
Climate Change: A strategy for action
Book Review
Below you will find Part 5 of the continuation of the review of Chapter 11 of Global Warming: The Complete Briefing by John Houghton with the title ‘Energy and Transport for the Future’. These are some snippets: “Hydroelectric schemes so not have to be large. Many units exist generating a few kilowatts only which may supply one farm or a small village. The attractiveness of small schemes is that they provide a locally based supply at modest cost.” “The United Kingdom produces each year somewhat over 30 million tonnes of solid waste, or about half a tonne for every citizen; this is a typical value for a country in the developed world. If it were all incinerated for power generation (modern technology enables this to be done with negligible air pollution) about 1.7 GW could be generated, about 5% of the UK’s electricity requirement.” “Uppsala in Sweden is an example of a city with a comprehensive district heating system. By 1993 energy from waste incineration and from other biomass sources provided nearly 80% of what is required for the city’s heating.” “It has been estimated that wind energy could within reasonable cost contribute up to 10% of the UK’s electricity supply.” “Annual investment in the world’s energy industry currently runs at between 3% and 4% of gross world product (GWP). The WEC estimates that cumulative world investment in energy supply will continue at least at the same level and up to the year 2020 will approach 30 million million US dollars at 1992 prices. The WEC estimate that investment of at least 2.4 million million US dollars in new renewable energy sources would be required up to 2020. Although this sum is less than 10% of the world’s total investment in energy, appropriate encouragement and incentives will be required if it is to be realized.”
GLOBAL WARMING
THE COMPLETE BRIEFING
JOHN HOUGHTON
Co-Chairman of the Scientific Assessment Working Group of the Intergovernmental Panel on Climate Change
CAMBRIDGE UNIVERSITY PRESS REPRINTED 1999
PART V
Chapter 11: Energy and Transport for the Future (Cont)
Renewable energy
• The energy incident on the Earth from the sun amounts to about 180 thousand million million watts (or 18,000 Terawatts or TW). This is about 15,000 times the world’s average energy use of about 12 TW. As much energy arrives at the Earth from the sun in 40 minutes as we use in a whole year.
• Providing we can harness it satisfactorily and economically, there is plenty of renewable energy coming in from the sun to provide for all the demands human society can conceivably make.
• If solar energy is concentrated by mirrors almost all of it can be made available as heat energy. Between 1 and 2% of solar energy is converted into wind energy. About 20% is used in evaporating water from the Earth’s surface which eventually falls as precipitation, giving the possibility of hydro-power. Hydroelectric schemes now supply about 6% of the world’s commercial energy.
• Living material turns sunlight into energy through photosynthesis with an efficiency of around 1% for the best crops. Photovoltaic (PV) cells convert sunlight into electricity with an efficiency of over 20%.
• The WEC scenario C assumes that ‘new renewable’ sources will make up 12% of the total energy supply in the year 2020.
Hydro-power
• It is estimated that there is potential for further exploitation of hydroelectric capacity to three or four times what has currently been developed, much of this being in the former Soviet Union and in developing countries.
• Hydroelectric schemes so not have to be large. Many units exist generating a few kilowatts only which may supply one farm or a small village. The attractiveness of small schemes is that they provide a locally based supply at modest cost.
• Many more possibilities exist for the exploitation of the potential of small rives and streams in many parts of the world.
• An important facility provided by some hydro schemes is that of pumped storage. Using surplus electricity available in off-peak hours, water can be pumped from a lower reservoir to a higher one.
• The efficiency of conversion can be as high as 80% and the response time a few seconds, so reducing the need to keep other generating capacity in reserve.
Biomass as fuel
• Second in current importance as a renewable energy source is the use of biomass as a fuel.
• The United Kingdom produces each year somewhat over 30 million tonnes of solid waste, or about half a tonne for every citizen; this is a typical value for a country in the developed world
• If it were all incinerated for power generation (modern technology enables this to be done with negligible air pollution) about 1.7 GW could be generated, about 5% of the UK’s electricity requirement.
• Uppsala in Sweden is an example of a city with a comprehensive district heating system. By 1993 energy from waste incineration and from other biomass sources provided nearly 80% of what is required for the city’s heating.
• The greenhouse gas carbon dioxide is produced from incineration, which contributes to the greenhouse effect. However, the alternative method of disposal is landfill which produces carbon dioxide and methane in roughly equal quantities.
• Only a fraction of the methane can be captured; the rest leaks away. Because methane is a much more effective greenhouse gas, molecule for molecule, than carbon dioxide, the leaked methane makes a substantial contribution to the greenhouse effect.
• If all United Kingdom domestic waste were incinerated, the net saving per year in greenhouse gas emissions would be equivalent to about 10 million tonnes of carbon as carbon dioxide.
• Since this is about 5% of the total UK greenhouse gas emissions, we can infer that power generation from waste could be a significant contribution to the reduction in overall emissions.
• These figures for electricity generation and saving in greenhouse gases could be about doubled if in addition to the domestic waste the potential for power generation from industrial and agricultural waste was also taken into account.
• Other wastes resulting from human or agricultural activity are wet wastes such as sewage sludge and farm slurries and manures.
• The third potential biomass contribution is from the use of crops as a fuel. Here the potential is large.
• In Brazil, since the 1970s large plantations of sugar cane have produced alcohol for use as a fuel mainly in transport, generating much less local pollution than petrol or diesel fuel from fossil sources.
• Because of the low efficiency of conversion of solar energy to biomass, it is important that land is not taken over which is required for food production. Plenty of suitable crops are available which could be grown on land only marginally useful for agriculture.
• The cost of electricity generated this way is currently about twice that generated from fossil fuels and the cost of alcohol from biomass is about twice the basic cost of petrol or diesel. However, with appropriate development these costs will be reduced.
Wind energy
• A typical large wind generator will have a two- or three-bladed propeller about 50 m in diameter and a rate of power generation in a wind speed of 12 m/sec (43 km/hr, 27 mph or Beaufort Force 6), of about 700 kilowatts.
• On a site with an average wind speed of about 7.5 m/sec (an average value for exposed places in many western regions of Europe) it will generate an average power of about 250 kW. The generators are often sited close to each other in wind farms.
• The power generated from the wind depends on the cube of the wind speed: a wind speed of 12.5 m/sec is twice as effective as one of 10 m/sec. It makes sense to mount farms on the windiest sites available.
• It has been estimated that wind energy could within reasonable cost contribute up to 10% of the UK’s electricity supply
• With the large growth during the last few years in the installations of wind generators, economies of scale have brought down the cost of the electricity generated so that it is approaching the cost of electricity generated from fossil fuels.
Energy from the sun
• In countries with a high incidence of sunshine, a black surface directly facing full sunlight can absorb about 1 kilowatt for each square metre of surface and it is a cheap means of providing hot water.
• In tropical countries, a solar cooking stove can provide an efficient alternative to stoves burning wood and other traditional fuels.
• Thermal energy from the sun can be employed effectively in buildings through passive solar design.
• To produce significant quantities of steam, the solar energy has to be concentrated by using mirrors. In the United States solar thermal installations provide over 350 MW of commercial electricity, at a cost of about three times that of most conventional sources.
• Sunlight can be converted directly into electricity by means of photovoltaic (PV) solar cells, with an efficiency of between 10% and 20%. The cost of energy from solar cells has reduced dramatically so they can now be employed for a wide range of applications, including large-scale generation of electricity.
Geothermal energy
• The presence of geothermal energy from deep down in the Earth’s crust makes itself apparent in volcanic eruptions, geysers and hot springs. It is currently only a small contributor (between 0.1% and 0.2%) to total world energy, but its contribution could rise during the next few decades.
Tidal energy
• The largest tidal energy installation is at La Rance in France, with a capacity of 240 MW. The Seven Estuary in the UK has the potential to generate a peak power of over 8,000 MW or about 6% of the total UK electricity demand.
The financing of renewable energy
• Renewable energy on the scale envisaged by WEC scenario C will only be realized if it is seen to be competitive in cost with energy from other sources. Under some circumstances such as Fair Isle in Scotland renewable energy sources are already competitive in cost.
• If renewables are to begin to displace fossil fuels to the extent required by scenario C, there will need to be financial incentives to bring about the change.
• At the basis of such incentives would be the principle that the polluter should pay by the allocation of an environmental cost to carbon dioxide emissions.
• In many countries substantial subsidies are attached to energy – worldwide they amount on average to the equivalent of about 40$US per tonne of carbon. A start with incentives would therefore be made if subsidies were removed from energy generated from fossil fuels.
• Another means of favouring renewable energy over against energy from fossil fuel sources could be through tradeable permits in carbon dioxide emissions.
Investment required
• Annual investment in the world’s energy industry currently runs at between 3% and 4% of gross world product (GWP). The WEC estimates that cumulative world investment in energy supply will continue at least at the same level and up to the year 2020 will approach 30 million million US dollars at 1992 prices.
• The WEC estimate that investment of at least 2.4 million million US dollars in new renewable energy sources would be required up to 2020. Although this sum is less than 10% of the world’s total investment in energy, appropriate encouragement and incentives will be required if it is to be realized.
Nuclear energy
• Nuclear energy has considerable attractiveness from the point of view of sustainable development because it does not produce greenhouse gas emissions.
• How much growth will be realized will depend to a large degree on how well the nuclear industry is able to satisfy the general public of the safety of its operations; in particular that the risk of accidents from new installations is negligible; that nuclear waste can be safely disposed of; that the distribution of dangerous nuclear material can be effectively controlled and that it can be prevented from getting into the wrong hands.
Technology for the longer term
• Power from PV installations is only available during the day. Means of storage and transport are therefore required. An important possibility is for hydrogen gas, generated directly from the PV electricity, to be used as a storage medium, at over 90% efficiency.
• The hydrogen can then be transported by pipeline or by bulk transport. Hydrogen is an extremely non-polluting energy source, which can easily be applied to most of the uses for which energy is required.
• Hydrogen can be turned into electricity through the use of a hydrogen-oxygen fuel cell at 50-80% efficiency. They are pollution free and so would be very suitable for transport vehicles. Their disadvantage is that as yet they tend to be large, heavy and expensive.
• All the technology necessary for a solar-hydrogen economy is available now, although the cost of energy supplied this way would at the moment be several times that from fossil fuel sources.
Policy instruments
• Action in the energy sector on the scale required to mitigate the effects of climate change through reduction in the emissions of greenhouse gases will require significant policy initiatives by governments in cooperation with industry.
• Substantial investment is needed in research and development associated with renewable energy sources and efficient energy use. Barriers to the diffusion and transfer of technology need to be reduced, financial resources need to be mobilized, supporting capacity needs to be built in developing countries and approaches need to be developed which will assist in the implementation of behavioural changes and technological opportunities in all regions of the globe.
• The policy options available include:
Putting in place institutional and structural frameworks;
Energy pricing strategies (carbon or energy taxes and reduced energy subsidies);
Reducing or removing other subsidies (eg agricultural and transport subsidies) that tend to increase greenhouse gas emissions;
Tradeable emissions permits;
Voluntary programmes and negotiated agreements with industry;
Utility demand-side management programmes;
Regulatory programmes, including minimum energy efficiency standards (eg for appliances and fuel economy);
Stimulating research and development to make new technologies available;
Market pull and demonstration programmes that stimulate the development and application of advanced technologies;
Renewable energy incentives during market build up;
Incentives such as provisions for accelerated depreciation or reduced costs for consumers;
Education and training, information and advisory measures;
Options that also support other economic and environmental goals.
Summary
• Growth in conventional energy sources at the rate required to meet future energy needs will generate much increased emissions of greenhouse gases. The WEC have taken a lead by proposing a future energy scenario (scenario C) driven strongly by environmental considerations which would lead to the stabilization of carbon dioxide concentration in the atmosphere by the end of the next century.
• Projections of energy production and use which the IPCC has developed demonstrate that alternative strategies exist for large reductions in fossil fuel emissions to be achieved.
• The achievement of scenario C will not be easy and will require both clear policies on the part of governments and cooperation from industry and individuals.
• Four areas of action are important:
Energy efficiency of 30% or more can be achieved at little or no net cost or even at some overall saving. Encouragement and incentives are required if savings are to be realized.
Much of the necessary technology is available for renewable energy sources which can go a long way towards replacing energy from fossil fuels. An economic framework with appropriate incentives will need to be set up.
Policy options available include the removal of subsidies, carbon or energy taxes (which recognize the environmental cost associated with the use of fossil fuels) and tradeable permits.
Arrangements are needed to ensure that technology is available for all countries to develop their energy plans with high efficiency and to deploy renewable energy sources as widely as possible.
With world investment in the energy industry at around one million million US dollars per year, there is a great responsibility on both governments and industry to ensure that energy investments take long-term environmental requirements fully into account.
• At the United Nations Conference on Environment and Development at Rio de Janeiro in June 1992, the countries of the world committed themselves in Agenda 21 to the action necessary to address the problems of energy and the environment. But the WEC are not optimistic that the necessary commitment exists to meet what is required, for instance to deliver their scenario C. They point out that ‘the real challenge is to communicate the reality that the switch to alternative forms of supply will take many decades, and thus the realization of the need, and commencement of the appropriate action, must be now’ (their italics).
Chapter 12: The Global Village
The preceding chapters have considered the various strands of the global warming story and the action that should be taken. In this last chapter I want first to present some of the challenges of global warming, especially those which arise because of its global nature. I then want to put global warming in the context of other major global problems faced by humankind.