One of the great ironies of bioenergy is that, despite the rapid proliferation of 1st-generation ethanol fuel production in the US/Brazil and the vast resources being devoted to the development of cellolosic ethanol and advanced drop-in renewable fuels, the majority of human consumption of biomass for energy still occurs in the developing world, principally the burning of wood or charcoal in simple stoves for residential cooking. Such cooking is typically characterized by low combustion and heat transfer efficiencies, and the resulting pollutant emissions are a significant source of climate forcing and cause of morbidity on the same scale as diseases like malaria and tuberculosis due to excessive indoor air pollution (IAP). CSU has been a leader in the development of clean-burning cookstoves through an active research program at the EECL; the resulting non-profit spin-off company Envirofit International has manufactured and distributed several hundred thousand improved stoves worldwide.
While most improved cookstove designs can increase efficiency and reduce emissions by 1/3 to 1/2, they fall short of the order-of-magnitude reductions necessary to relegate IAP to safely manageable levels. However, growing awareness of the health benefits of improved cooking technologies coupled with nascent initiatives to leverage carbon financing to subsidize stove dissemination programs has set the stage for paradigm-shifting innovations in this area. Advanced bioenergy conversion technologies are just starting to be applied to the domestic cooking sector in developing countries. The process of biomass gasification (the controlled partial oxidation of soild biomass to yield flammable gases) has been scaled down for household cooking in multiple stove designs; the resulting well-mixed gas-phase combustion is capable of lowering emissions by 80-90%, and the biochar produced as a by-product has value for local agriculture.
Equally interesting has been the recent partnership between NGO CleanStar Mozambique, major enzyme producer Novozyme, and bank Merrill Lynch to introduce alcohol stoves and ethanol production infrastructure to sub-Saharan Africa:
Such liquid-fueled stoves have the potential to be even cleaner and safer than other advanced cookstove designs, and the associated ethanol plant (which at 300,000 gallons annual production is quite comparable in total ethanol output to the New Belgium brewery) provides markets for agricultural surpluses from local subsidence farmers.
Technology transfer coupled with carbon finance is thus starting to spur innovation in the largest bioenergy markets worldwide, with the potential for significant health, economic, and environmental co-benefits for those populations with the heaviest reliance on this most basic form of energy.