The 'oil crisis' of the 1970s has helped to focus the world's attention on the need to wean itself from a petroleum-based economy and to seek out other energy resources. One of the alternatives being studied is the production of food, fuel, feed, fibre, chemicals and fertilizer from plant matter, known as biomass. In plants, solar energy is converted into a stored product by means of photosynthesis, to produce a fuel supply equal to ten times the world's estimated annual energy use and 200 times our consumption of food energy. Before this abundant but somewhat neglected resource can be fully exploited, however, it must be shown to be efficient, cost effective and beneficial to the environment. Some current research is described on bio-solar energy in assessing its potential contribution to development in both the technically advanced and non-industrialized countries.