US companies funded by WRPEB are to study the feasibility of integrating an EPI gasifier with an existing coal-fired boiler and replacing 15 per cent of the coal with gas produced primarily from waste wood.

The Western Regional Biomass Energy Program (WRBEP) has selected Black and Veatch, Energy Products of Idaho (EPI) and Nebraska Public Power District (NPPD) to perform a feasibility study to determine the practicality of adding a fluidised bed biomass gasifier to a coal fired plant operated by NPPD. The WRBEP is funded by the US Department of Energy.

The study will examine the feasibility of integrating an EPI gasifier with an existing coal-fired boiler and replacing 15 per cent of the coal with gas produced primarily from waste wood. The project, partially funded by a WRBEP grant, will consider implementation of the proposal at the two unit Sheldon Station, a 225 MW power plant near Hallam, Nebraska.

The scheme would add a biomass component to the power plant and reduce its net greenhouse emissions. If sufficient biomass were available, a fluidised bed gasifier might, in principle, replace all the coal required to fire the boiler.

According to Black and Veatch, a retrofit of this type has a much lower cost that a green field biomass power plant and represents a competitive green power option. The Sheldon Station study aims to demonstrate technical feasibility and economic viability of the approach.

The analysis will feature the use of Vista, an evolution of a coal quality impact model developed by Black and Veatch for EPI in 1989. This will analyse the effects of biomass gas on the existing unit’s performance, availability, on fuel costs, on operation and on maintenance costs. Combined with other information, this is expected to provide a comprehensive economic model of the retrofitted plant. The study is scheduled to take around five months.