US Dept Energy on Biomass Power Systems

There are several ways to produce power with biomass fuels according to the US Department of Energy (see title's link for full report):

1. Burn 100% biomass to create steam: The efficiency of direct-fired biopower facilities is typically 20%-24%.

2. Burn coal plus biomass: The biomass used in a cofiring application is converted to electricity with 33%-37% efficiency. Cofiring involves substituting biomass for a portion of coal in a power plant furnace. It is the most economic option for the near future to introduce new biomass power generation. When low-cost biomass fuels are used, cofiring systems can result in payback periods as low as 2 years.

A cofiring plant requires sophisticated equipment costing from $100 - 200 Million dollars and should be not less than 100 MW in size. The technology is considered "experiemental" because it is not as controllable.

3. Burn 100% biomass to create a gas: The efficiency of gasification-based biopower systems can reach 60%. A gasification plant requires a capital investment of perhaps $1 Billion dollars in equipment and should generate not less than 200 MW in order to achieve good economies of scale and profit.

Gary Faagau Says:

The system used in Pepeekeo will be steam to electricity (number 1 on your list). This is set bythe equipment in place. It is the least efficient way to produce electricity but because the equipment is there, the cost is minor.

Being inefficient, it produces a lot of greenhouse gases, CO2, carbon dioxide.

Option 2 and 3 requires new plants.