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Reducing Greenhouse Gas Emissions and Improving Environmental Degradation by Daniel M Kammen
[top] [end]The energy and environment crisisTwo billion people worldwide depend primarily on wood for their energy needs, while biomass burning leads to deforestation and contributes up to 40 per cent of the global emission of carbon dioxide and other greenhouse gases. Incomplete biomass combustion presents a serious health hazard in developing nations, and is firmly linked to acute respiratory infections (ARI), particularly in children, and results in an estimated 4.3 million deaths per year. Indoor air pollution is also linked to pulmonary disorders, including lung cancer, complications associated with pregnancy, eye infections and often, serious bums. In the face of population pressure and a global demand for energy expected to more than double in 20 years, the preservation of regional ecosystems and the global environment necessitates a change of strategy. Alternative and renewable energy systems hold significant potential to contribute to environmental preservation on both local and global scales. Modernized biomass stoves and solar ovens for household cooking can cut-traditional or fossil-fuel use by 50 per cent or more. These technologies represent a 'win-win' situation: reducing both the threat of global warming and indoor air pollution. While per capita carbon emission is small in developing nations, in total it contributes more than a quarter of the total global emission and is the fastest growing source.
[top] [end]Improved stoves and solar ovensOver the last decade, improved charcoal-burning stoves such as the Kenya Ceramic Jikos (KCJ) shown in Figure 2 which burn less fuel and thus produce less pollution have been widely promoted. In East Africa over 30 million people have learned about these stoves and over 700000 are in use. Kirk Smith and colleagues have chronicled a massive and largely unrecognized effort in China that successfully introduced over a hundred million improved cookstoves. While solar cookers date from the 1950s or earlier, only in the last few years has significant progress in publicizing and disseminating this 'prototypical' renewable energy technology been seen. The historical lack of widespread dissemination is surprising given that solar ovens are technically simple to construct (see figure 3). In Kenya, for example, the materials for a durable wooden solar oven cost less than the equivalent of US$30, a large sum where annual per capita income is around US$400, but not when weighed against the 30 to 40 per cent of family income frequently spent on fuel or the time that could be used for other activities. On the other hand, the reasons for the failure of many previous solar oven projects are not difficult to identify and must be addressed. Efforts to introduce solar ovens or other appropriate technologies were regarded as 'homespun', rather than part of a meaningful national development. One issue frequently cited as an impediment to the widespread use of solar ovens is the change in cooking style required, and the possible disruption of important cultural practices. However, in field tests in both Central America and East Africa, we found that while education and follow-up to illustrate solar cooking methods are required, no cultural obstacle impeded the steady increase in oven use. In a number of communities in Africa, solar ovens are now widely used and replace over half of the domestic wood use (Kammen, 1992). Solar oven programmes presented an even greater problem to much of the international aid community: direct interaction is needed with the end-users of the technology, invariably women.A survey of the more than one hundred solar oven projects worldwide reveals that, on average, solar ovens replace the use of roughly 50 per cent of traditional cooking fuels, and are most effective when used with improved wood stoves and other renewable energy sources. The dramatic rise in solar oven projects in Kenya is chronicled in Table 1.
Table 1. Solar Oven Projects in Kenya, 1977 - 1992
Cooking conditions and health The process of food preparation is arguably one of the most pressing health and development issues facing poorer nations. Biomass cooking on traditional stoves- 'three-stone fires', simple metal stoves and in some cases, 'improved' or modernized stoves - is a major source of smoke and concentrated local and indoor air pollution. Cooking smoke is often produced in confined indoor settings where women and children in particular, are exposed to dangerously high concentrations of a variety of noxious agents. The pollution levels in homes and cooking huts can therefore exceed those measured in industrial cities, and represent the equivalent of smoking several packs of cigarettes per day. Family homes in Kenya generally consist of small multi-purpose buildings, where the same room or few rooms are used for cooking, sleeping and working. In many cases the total indoor space is less than 30 cubic metres. A feature common to rural homes worldwide is inadequate ventilation for the large output of smoke from cooking fires. In a series of studies Kirk Smith has measured the air exchange rates in village huts. With doors and ventilation holes kept open, as during the dry season, exchange rates may exceed 50 per hour but during the rainy season or in cold spells or at high altitudes, rates of l 0 changes per hour may predominate. Urban overcrowding and the greater use of charcoal can increase outdoor pollution concentrations over entire neighborhoods to levels approaching those of indoor conditions. These unhealthy conditions can persist over the course of a day. In many countries the staple foods are grains, tubers or beans, which require long cooking resulting in increased indoor pollution. The people most continuously exposed to indoor air pollution are women, and the severe health implications of this were the focus of the 1992 World Bank Development Report and call for action. [top] [end]Impact of improved stovesThe energy ladder illustrated graphically in figure 4 compares stove efficiency and capital cost for different fuel type stoves, from dung and agricultural residues to electricity. In comparable cooking conditions, woodstoves typically release 50 times more pollutants than gas stoves. While a significant body of apropiate technology' literature exists on some of these stoves, quantitative analysis of the associated pollution emissions under actual field conditions is a rather new area of research. By an ongoing environmental health monitoring effort, we are beginning to quantify the indoor concentration of pollutants from cookstoves in rural Kenya. The concentrations of CO observed from both wood and charcoal burning in traditional and 'improved' stoves are significantly above the WHO one-hour recommended limit of 45.8 parts per million, (ppm), (or 40µg/m3). Only the kerosene stove reduced CO emissions significantly. Interesting are the pollution levels found in so-called 'improved stoves'. Because it is odourless and colourless, the high concentrations of CO may lead to poisoning without the warning signs of coughing and streaming eyes that are associated with hydrocarbons and particulates in woodsmoke. The health problems of pollution caused by improved stoves can be minimized if addressed directly in the educational component of stove dissemination programmes.
[top] [end]Energy in KenyaKenya, a relatively prosperous 'developing country', illustrates the paradox of international technical assistance. Despite high levels of donor aid there has been little progress away from a subsistence economy for the majority of people. Gross national product per person decreased from US$410 to 370 during the 1980s. The energy sector showed near stagnation, wood and other traditional fuels continuing to occupy the same share of the total energy mix as they did twelve years ago. Total energy consumption rose only from 13 to 19 GJ/year. Furthermore, international assistance has averaged about 10 per cent of the Kenyan GNP for the period 1979 to 1989, with energy projects given a high priority. It is therefore apparent that the traditional assistance and development approach should be revised. Kenya currently devotes over 40 per cent of its GNP to the purchase of imported fossil fuels. Like most developing nations Kenya is in need of projects that encourage energy diversity and reliance on renewable, and locally controlled, sources of energy. This situation is dramatically illustrated by current power shortages that have forced the Government to limit the residential electricity supply to 8 to 12 hours per day. While fossil fuels contribute only 24 per cent of the Kenyan national energy supply, and charcoal comprises roughly 9 per cent, the impact of these fuels is significant. The situation in semi-arid Kitui District illustrates the role of charcoal in the local economy. Wood harvesting and charcoal production, transport and sale in urban markets together constitute one of the largest sources of income for the rural inhabitants. In fact, over half of the families derive more than 30 per cent of their total cash income from the sale of charcoal. Charcoal production is the dominant cause of local deforestation in these areas, as large trees are felled primarily to supply wood for the most expensive (old growth/hardwood) variety of charcoal. It also contributes to habitat reduction, loss of biodiversity, and a stagnant economy. Few rural inhabitants can afford to use charcoal themselves[top] [end]North-South projectIn 1992 a North-South co-operative project was initiated. Earthwatch volunteers from the US, Japan and Europe and students from the University of Nairobi teach women's groups how to construct and manage solar ovens. Working in rural communities in eastern and southern Kenya. the goal is to 'transfer' the technology efficiently so that local groups and artisans can modify and exploit various renewable energy systems. integrating them into the local resource base.'Technology transfer' and 'North-South' co-operation are frequently echoed buzzwords in the international development an environment community. In this project, these concepts are put to work directly. EarthCorps volunteers spend a first week at the University of Nairobi learning (by doing) how to construct solar ovens, and then travel to field sites where they share their experience in workshops that result in readyt to use solar ovens. Additional tasks involve measurement of fuel use and carbon monoxide/dioxide and methane emissions from traditional cooking fires. This process could easily be formalized and presented to US, Japanese, European and Third World aid organizations, and to UNIP, WHO and the FAO. Even relatively modest - but long term improved stove and solar oven programmes supported by these organizations would generate widespread technology conversion due to the tendency of international assistance funds to 'seed' similar programme spending and attention by other bodies. The process of fully integrating a new technology, particularly when it involves a change in a part of lifestyle as fundamental as cooking, can take several years. However, only six months after the first visit to Zombe (one of the Kenyan solar oven pilot communities) Mrs Mwota, the secretary of the Renewable Energy Committee wrote to the author: A one day solar cooking seminar was [held] on September 26, 1992. It was a sunny day. We used two solar jikos (ovens) to cook tea,cake, rice mixed with meat, potatoes and tomatoes. Tea took 1 hour 45 minutes, cake took 4 hours and II minutes, rice took 3 hours and 41 minutes. All the food vas well cooked: it was very successful. In these community projects solar ovens do not necessarily replace biomass stoves or improved jikos (although they have in some areas). Solar ovens provide an additional energy resource that is typically used more and more as people become increasingly comfortable with the technology. It is rare that even the most wealthy families in Nairobi, for example, will discard technologies as they move up the energy ladder. A single family may regularly use six or more different fuels and types of stoves. [top] [end]Environmental health proposalsSuccessful environmental and development projects generally require a combination of community involvement and initiative, and technical or financial assistance. Although this proposal is a call for the integration of solar oven, improved cookstove, and other renewable energy technologies into the standard packages provided by assistance organizations throughout the world, a number of immediate changes can be made that will reduce greenhouse gas emissions and improve indoor air quality and health. As a starting point, these organizations could include solar ovens in all community projects in the tropics (15 percent north to 15 degrees south). The items listed below combine behavioral and hence educational, technological and policy programmes for community, national. multinational and non-govemmental organizations. The author proposes that aid organizations in industrialized nations (that generally produce large amounts of CO2 per capita) fund development projects that reduce CO: emission elsewhere in the world while receiving a credit towards their greenhouse gas quotas in the process. No new verification or experimental testing would be necessary to implement this plan. International aid organizations already monitor the outcome of their programmes (and perform enviromental- impact assesments). The reduction in biomass burning will be apparent in surveys of local fuel prices, national fossil fuel imports, funds spent on health care (such as the treatment of acute respiratory diseases), and in the general interest in and awareness of appropriate technology systems. If implemented, this proposal would direct international assistance towards projects - such as improved stoves and solar ovens that maximize energy efficiency and contribute significantly to local environmental health and global environmental sustainability as well as improving the health of women and children in the kitchen: a 'win-win' proposition.[top] [end]Contents: Boiling Point 34: Smoke Removal
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22 August 2007; Last edited:
01 December 2008; Version: 1 | |||||||||||||||||||||||||||||||
Pagename: ReducingGreenhouseGasEmissionsAndImprovingEnvironmentalDegradation @HEDON: WUGA | |||||||||||||||||||||||||||||||
