An ongoing failure provides some good news on the world energy tech front. This failure is the solar cooker efforts.
Solar cookers are one the enduring faith vs reason battles when aiding the poor in third world countries. The current leading solar cooker costs about $10, uses mostly local materials, and meets about 75% of cooking needs. Clouds, bad weather, and high temperature needs drive the remaining 25%. They continue to fail in response to:
- High efficiency wood/brush cookers. These cost now about $2, use entirely local materials, and can meet 100% of cooking needs. They have efficient designs and flues, so that the problems of smoke, accidental fires and burns are tremendously reduced. They consume less fuel and can burn scavenged brush. The net effect is also a 75% reduction in fuel use. It's fairly obvious why these are tremendously popular and solar cookers are not.
- Gobar gas systems are spreading steadily through South Asia. These convert livestock manure into low grade gas. They are highly popular in India and Nepal, with use slowly spreading elsewhere. They are an easy transition for people who previously were using dried dung as fuel. The gobar systems use dried dung, plant wastes, and controlled amounts of liquid in a gas digester to produce usable gas for cookers. Gas cookers are much cleaner, safer, and more efficient than dung fueled heaters. These systems are too expensive for the really poor, but subsidies bring them within affordable reach of the successful farmer with a livestock herd. They are climate limited to places where the dung can be dried naturally. This includes much of South Asia.
- Variations on Gobar systems are showing up in other agricultural areas. Indonesian pig farming, Thai pig farming, and US dairy farming all have introductory systems in operation. These will become much more popular as the technology is understood, made more reliable, and the information about its use spreads.
These all act to reduce the deforestation in South Asia, and the manure gas systems also reduce the methane emissions from livestock. They lower the immediate demand for fossil fuels, although this reduction is a very small percentage of world use. They primarily make the agricultural areas much less dependent on fossil fuels. There is only a little excess production to support more urban uses. Variations on the cooker technology are also sold in Africa, where wood fueled cookers are also used.
The gobar systems may even improve life in Afghanistan if the civil war ever subsides enough to enable reconstruction of permanent fixtures like the qanats and construction of gobar gas generators. The Gurkhas are certainly pushing for it (toward the end of the article).