Biomass has its place in the sustainable energy mix. Often it is used for fringe of grid applications where the cost of transmitting energy to remote areas makes biomass cost competitive. Furthermore, the burning of wood mallee which is used to combat salinity issues in parts of Australia allows the subsidising of salinity programs with the added benefit of energy productions on the fringe of the grid. Biomass plants can be pretty much any size as they are essentially thermal power stations, however often they are no more than 5MW as this is the largest size unit that sits in a cost competitive price point. (At least in WA I am told)
Pictured on the right is a 1 MW biomass power plant I visited in Germany. This takes organic waste on the farm and converts it into electricity to be sold back into the grid. I believe in this location it is cost competitive, although Australia has very different tariff structures and grid feed in mechanisms.
The potential displacement of food crops makes the development of biofuels a risky business, and although it has its place in the renewable energy mix, I feel it is best to focus on other forms of energy for our large scale interests. Biofuels could have an important role in the aviation industry in years to come, as our world runs out of oil.