The production of electrical energy represents the most interesting gas use modality. Currently, the vapour plants in which the direct combustion of the biomass takes place are the most widely used technology to produce electrical energy from biomass.

A possible use of the producer gas is the co-firing (co-combustion) with tradi­tional combustibles in vapour plants. In this way, there is a considerable saving of fossil fuel. Furthermore, the investment costs are low; resorting to co-firing requires only little modifications to the existing plants.

The most promising technology is represented by the combined gas-vapour cycles that are integrated with gasification (IGCC, integrated gasification com­bined cycle). In systems with powers of tens of megawatts, global earnings as high as up to 50% have been achieved. The plans proposed until now are essentially of three types:

• fluid bed atmospheric gasification with air and cleaning of the gas by humid cleaning;

• fluid bed pressurized gasification with air and hot cleaning of the gas;

• indirect heating atmospheric gasification with humid cleaning.

Commercially, the IGCC systems are not yet competitive, but they can become com­petitive in the short term, especially due to the possibility of realizing co-generation plants [2, 46, 48].