Ruben Walker is commercial director and co-founder of African Clean Energy (ACE), the Lesotho-based manufacturer and distributor of the ACE 1 Solar Biomass Cookstove. Cooking causes a lot of problems in developing countries around the world, where it is often done on open fire or using dirty fuels. The smoke kills some 4 million people per year, the inefficient fuel use is very damaging to the environment, and the fuel cost in time or money is a major driver of poverty. By burning a wide range of biomass forms smokelessly and efficiently, the ACE 1 goes a long way to solving these problems. Ruben studied Environmental Engineering at Monash University in Melbourne, Australia, and before that completed the IB-Program at Nanjing International School in China.