Concerns for energy security, rising energy demand and costs, human health and the environment – particularly climate change –
have all created a new impetus for change in the energy sector. This has resulted in policies to control demand, improve efficiency, and to promote sustainable energy options including improved fossil fuel technologies and renewable energy sources.
Increasing energy efficiency may be the most effective way to curb air pollution in the short term. Improved energy efficiency offers several win-win options for better air quality, reduced greenhouse gas emissions, improved energy security, and financial savings. This is especially so in areas where air pollution represents a major threat to public health but non-fossil fuel technologies are either not available or not feasible; and also where large existing investments in fossil fuel based infrastructure
do not allow a short-term transition to renewable energy sources.
(total capacity of about two MW) in Nepal provided access to electricity to 15 000 rural families while allowing for income generating
activities (UNDP 2004b). A number of technologies to convert bioenergy to more convenient forms such as gases, liquids or electricity are now becoming commercially viable. Anaerobic digestion (without air), steam turbine technologies, and biofuels such as ethanol are already commercial and widespread. Gasification technologies, which produce a combustible gas from biomass, provide a clean fuel that can be burned directly for cooking or heating, or used in secondary conversion devices such as internal combustion engines for producing electricity. Biogas, produced by anaerobic digestion of readily available biomass resources, such
as dung, can be highly viable in rural areas. A biogas programme started in Nepal in 1992 has resulted in over 110 000 household
plants, with 20 000 additional plants being installed each year by private companies (Acharya and others 2005).
Some 95 per cent of the plants are still operational. Key factors in the success of the programme include a uniform technical design for easy replication; quality control and monitoring of production; installation and after-sales services tied with incentives for private companies; and financial support for end-users, through a subsidy of US$70–150 per household biogas plant plus easy access to financing through micro-credit schemes (Pandey 2004).
Industry and power sector
In the power and industry sector, many cleaner technologies are already mature and commercially available, like low-NOx burners, staged combustion, reburning and fluidized bed burners (Heinsohn and others 1999). Fabric filters and electrostatic precipitators can reduce particulate emissions by up to 99 per cent (US EPA 2003a and US EPA 2003b). Flue gas desulphurization systems can capture up to 98 per cent of SOx (US EPA 2003c), while Selective Catalytic Reduction can cut NOx emissions by 90 per cent (US EPA 2003d). Energy savings in the power and industry sector are also achievable through the use of Combined Heat and Power (CHP), or cogeneration. In conventional electricity generation a considerable percentage of the heat content of the fuel is dissipated to the environment, typically 55 to 65 per cent for conventional Rankine Cycle, and 40 to 50 per cent for Combined Cycle plants (Korobitsyn 2000). The concept of CHP is to use part of this wasted heat in industrial processes or district heating.
However, awareness and incentives are needed to promote the use of CHP by industries. In the Netherlands, for instance, the government provides free expertise to help industries install CHP. Technologies currently being promoted to deal with greenhouse gas emissions present further opportunities for co-benefits in controlling local air pollution while dealing with climate change. These include clean coal technologies and ‘carbon capture’ (removing emissions directly from industrial or utility plant exhausts and storing them in secure reservoirs such as deep saline aquifers). Nuclear energy has been promoted afresh in recent years as a solution to reduce greenhouse gas emissions from power utilities, but the three primary concerns of reactor safety, waste transport and disposal, and nuclear proliferation remain.
The increased cost competitiveness of renewables comes at an advantageous time, because there is a huge and growing demand for new capacity for power utilities, and for millions of systems to serve the 1 600 million people currently without electricity. Renewable sources already make a substantial contribution to global electricity production (Figure 11), although hydro accounts for more than 90 per cent of this. Existing renewable electricity capacity worldwide, excluding large hydro, totalled 160 GW in 2004. Small hydro and wind power account for two-thirds of this capacity (REN21 2005). Grid-connected solar photovoltaic (PV) is the fastest growing energy technology in the world in terms of per cent growth: installed capacity grew by 60 per cent annually from
2000–2004 (REN21 2005). Although the costs are still high on a kilowatt-hour basis, PV technology is also cost-competitive for a range of off-grid applications ranging from telecommunications to remote village power. PV technologies have dropped in price to
between one-third and one-fifth their cost in 1980 (Salwin 2004). Geothermal technology is mostly used for power generation, though its use for space heating is becoming increasingly important. Oceans offer various energy sources: tidal forces, ocean currents, wave power and thermal gradients can all be captured to produce electricity, and these are starting to be deployed. Ocean energy systems need a relatively extended research and development effort, but full-scale prototypes have been constructed.
In addition, cities like Delhi and Bangkok have shifted vehicle fleets to cleaner fuels such as compressed natural gas (CNG) or liquefied petroleum gas (LPG), with substantial benefits for air quality. The presence of lead in transport-related emissions continues to be a challenge in some parts of the world. Lead additives are still used in some countries in Africa, the Middle East and South America. The Dakar Declaration, adopted by representatives of 28 sub-Saharan countries in June 2001, agreed to phase out leaded gasoline in these countries by the end of 2005 – a goal that has been met. Twelve other African countries with
refining capacity have also committed to phase out lead.
The phase-out of leaded gasoline is but a first step in developing a more comprehensive approach to management of transport-related air pollution. Further steps would include improving fuel quality and developing new fuel specifications, including lowering of sulphur levels; upgrading the quality of vehicles and tightening emission controls; establishing baseline inventories of key pollutants and health effects; and developing an appropriate public information or awareness campaign. As the world transport fleet is still growing steadily, with high rates of growth in China, India and elsewhere, it is important to adopt fuel-saving and clean technologies soon so that the world is not saddled with large numbers of cars with unnecessarily poor performance in future years. Hybrid electric vehicles (HEVs), which could help reduce emissions by as much as 50 per cent, present considerable opportunities. HEV’s have been available to the public since 1997 in Japan. The first cars typically increased the efficiency from 11 km per litre (km/l) to 17 km/l, while recent models have improved to 20–22 km/l. Various governments have introduced tax incentives to stimulate sales of hybrid cars. With the recent energy price hike acting as further stimulus, the market for hybrid cars is expanding. Recently, there has been much interest in biofuels such as ethanol and biodiesel – fuels made from biomass that can be used as alternatives for transport. Production of biofuels exceeded 33 billion litres in 2004 – about three per cent of the 1 200 billion litres of gasoline consumed globally. Ethanol provided 44 per cent of all non-diesel motor vehicle fuel consumed in Brazil in 2004, and was being blended with 30 per cent of all gasoline sold in the US (REN21 2005).
Biodiesel, extracted from oil seed crops such as jatropha, rape and soy, is often blended with diesel in concentrations of 10–15 per cent to reduce exhaust emissions. However, the environmental and social impacts of large-scale plantations for biodiesel
and ethanol must be taken into account in policy making.
Many OECD countries and a growing number of developing countries also have active hydrogen and fuel cell research and development programmes, with aggregate public funding worldwide now running at about US$1 billion a year.
The largest programmes are in the US, Japan and the European Union. Three major multilateral initiatives were launched in 2003: the International Partnership for the Hydrogen Economy (IPHE), set up at the instigation of the US administration and including 12 OECD countries, the European Commission and Brazil, China, India and
Russia; the Hydrogen and Fuel Cell Technology Platform set up by the European Commission; and the IEA Hydrogen Coordination Group, aimed to enhance coordination of the public research and development programmes and policies of IEA
Indoor air pollution requires viable, costeffective interventions that can reduce exposures and improve health. Although awareness has been growing, indoor air pollution from household solid fuel use has not been a major issue on the global agenda in terms of international, bilateral, or national development assistance. Rather than focusing on health-damaging pollution, improved stove and fuel subsidy programmes in the past have been mainly directed toward reducing pressures on forests, improving the efficiency of crop residue utilization, alleviating fuel poverty in urban slums, and reducing the need for gathering fuel.
As a result, there is relatively little knowledge available about the ways that indoor air quality could be promoted in largescale sustainable efforts. Well-designed stoves with chimneys reduce air pollution in kitchens substantially, but unfortunately produce more modest
reductions in actual human exposures because the smoke is still released in the vicinity of the household. The methods used in
the past for reducing fuel use in stoves sometimes actually increased emissions, although good design can achieve both goals.
Previous programmes focused mostly on the design of the stove. A broader focus on the design and ventilation of the whole kitchen could provide multiple benefits, for example by including a raised platform for cooking and food preparation, thereby improving ergonomics, safety, and hygiene.
There is still need for improved engineering of stoves to achieve efficiency and health
objectives, as well as meet local cooking needs and cost constraints. In addition, lifetimes of many improved stoves have been
quite short, reducing their value and reputation. Use of stronger materials can increase lifetimes, help maintain performance,
improve acceptability, and result in overall lower social costs considering all factors. Improved fuels such as LPG produce fewer
emissions than biomass fuels, but are more expensive.
Where populations can afford them, for example in periurban areas wher households already pay for biomass fuels, partnerships between governments, nongovernmental organizations and the private sector can improve the reliability of LPG supply and lower the initial cost of buying stove and cylinders. Kerosene tends to be cheaper than LPG but may be associated with a higher risk of injuries, and must be burned in better-quality and well-maintained stoves to be adequately clean.
Non-toxic and clean-burning dimethyl ether (DME, sometimes called ‘synthetic LPG’) shows promise as a clean non-toxic fuel that can meet the same markets now served by LPG. A significant industry has developed in China to produce it from coal, although it could also be made from biomass. Other gaseous and liquid fuels made from biomass or coal show possibilities for providing clean, efficient fuels to households in some parts of the world, but more research is needed to establish the technology, economy, and safety of these fuel cycles (Larson and Yang 2004). Where the geographical location is suitable, solar thermal technologies such as solar cookers and water heaters are available for residential uses. For many applications these technologies are now mature, and recent cost reductions have brought them into the competitive range.
However, even in areas with sufficient solar radiation such as South Africa, solar cookers can only replace approximately 40 per cent of a household’s energy needs (GTZ and DME 2004). Commercial applications of solar thermal electric technologies which could generate in the range of a few kilowatts to hundreds of megawatts are technically feasible though not yet economically competitive. More efficient household appliances can reduce emissions, but they are usually more expensive and the majority of consumers buy the cheaper, but less efficient ones. Under these circumstances, economies of scale in production cannot kick in, and so prices remain high. Policies requiring manufacturers to provide efficiency information have proved successful.
For instance, efficiency ratings for refrigerators in Thailand, which gave consumers information on average energy consumption and savings on electricity, resulted in total savings of 1 992 GWh of energy and avoided 1.5 million tonnes of CO2 emissions during 1995–2004 (EGAT 2000). Information on thermal characteristics is also valuable for prospective homeowners – buyers can make better decisions if they know the energy efficiency of the house they are thinking of buying.