Biomass Feasibility Project Final Report - Xcel Energy

plant characteristics and plant expenses were derived from the source material. The
documentation for each power plant template uses quite different financial assumptions. These
were standardized across power plants, with the exception of the income escalation variable for
the CHP plant, which was modified to account for the potential for rapidly increasing natural
gas prices.
50 MW wood- fired stoker boiler
This template was generated using documentation relating to the Big Stone II coal power plant
(Burns & McDonnell, 2005).
The template is meant to represent the costs for a wood-fired stoker boiler built as an additional
generating unit at an existing coal fired plant. The expenses included in this template include
fixed O&M costs, non-fuel variable O&M costs, and insurance. In addition to wood fuels this
plant is assumed to be adaptable to corn stover and switchgrass.
35 MW Biomass Co-Firing (Incremental Costs) and 600 MW Pulverized Coal Plant
w/ 35 MW Biomass Co-Firing
The co-firing cost estimates are derived from documents published by the Chariton Valley
Biomass Project (Alliant Energy, et. al., 2002) and documents relating to a proposed pulverized
coal plant in South Dakota (Burns and McDonnell, 2005), The Chariton Valley documents were
used to create a template for a co-firing operation that could be added to a coal plant
template to estimate the blended costs of a co-firing operation. The capital costs for the cofiring
template include the costs of the fuel storage, handling and processing facilities needed
for a co-firing operation. The operational costs include the additional labor, administrative and
maintenance costs needed to operate a co-firing operation. The cost estimates for the coal
plant are meant to be representative of the expected costs for a new 600 MW pulverized coal
unit built adjacent to an existing coal plant. The expenses included in this template include fixed
O&M costs, non-fuel variable O&M costs, and insurance. The 35 MW Co-firing template can be
used to estimate the incremental costs of a co-firing operation. The blended template including
the 35 MW co-firing template and 600 MW pulverized coal plant can be utilized to estimate the
average cost of energy for a co-firing operation.
Industrial CHP with Gasifier and 4 X 1.3 MW Gensets
This template is based on an economic and technical feasibility study of a biomass gasification
CHP system at a large malting facility (Trillium Planning and Development, 2002). A number of
scenarios were examined for the study. The template is based on the most economic scenario
examined in the study. It includes four Jenbacher Engine sets with a total net capacity of 5.4
MW. The natural gas savings from the thermal energy captured from the system are accounted
for as “Other Income”. The electrical efficiency represents the Net Electrical Efficiency based on
the energy content of the biomass prior to gasification, not the electrical efficiency of the
combustion of syngas by the turbine or genset. The operating costs included in this template
include labor, maintenance and the cost of standby electrical service.
135 kW Genset w/ Manure Digester
This template is based on the Haubenschild Dairy Farm Digester near Princeton, MN (Kramer,
2004). The farm operates a plug-flow digester that powers a 135 kW engine generator set.
Thermal energy recovered from the genset’s cooling jacket is used to heat the barn. The
electrical efficiency represents the system efficiency taking into account the efficiency of the
Identifying Effective Biomass Strategies: Page 129
Quantifying Minnesota’s Resources and Evaluating Future Opportunities