Colmac Energy, Inc. (CEI) is a California corporation that was formed to build, own and operate a 47.0 megawatt (net) biomass-fueled small power production facility on approximately 104 acres of land on the Cabazon Indian Reservation near Mecca, California.
Design and engineering of the Mecca plant began in 1989 and construction was completed in 1992. Colmac Energy is a very efficient plant that consistently operates at a high capacity factor (low 90%'s).
Fuel for the Mecca plant consists of agricultural residues, municipal and commercial wood-wastes, petroleum coke and natural gas for startup and occasional stabilization when needed. Fuel is burned in two Combustion Engineering circulating fluidized bed (CFB) boilers (VAX units). The ASEA Brown Boveri steam turbine generator produces electricity for sale to Southern California Edison (SCE) under a Standard Offer #4 Power Purchase Agreement for firm power sales of 45 MW. The electrical energy is wheeled from the Mecca plant site via transmission facilities of the Imperial Irrigation District to an interconnected substation of SCE in the Coachella Valley.
Steam to drive the turbine is generated in the CFB boilers. These boilers were designed to burn a mixture of wood and agricultural waste fuels that are gathered by various fuel suppliers from wood based manufacturing plants, agricultural fields and solid waste landfills. An amendment to the EPA Permit has been approved that allows the Mecca Plant to burn petroleum coke as part of the fuel mix. The Plant typically runs 2-15% petroleum coke. Solid waste residues (ash) remaining from the combustion process are separated into bottom ash used as landfill cover and into fly ash to be used as a construction fill additive ready-mix concrete additive, road base, leachate control in gold mines and/or specialized grading applications.
The combustion process produces emissions that are strictly controlled to meet permitted emission limits set by the United States Environmental Protection Agency (EPA) and monitored by the South Coast Air Quality Management District (SCAQMD) as EPA’s local representative. Nitrogen Oxides (NOx) are controlled by controlling combustion temperatures and by injection of ammonia into the flue gas stream. Sulphur dioxide (SO2) (of which there is almost none) is controlled through injection of limestone into the fluid bed. All particulates are removed from the flue gas stream by a multi-clone separator and a Goretex fabric filter in series. Remaining emissions, such as carbon monoxide, are controlled in the combustion process.
Water for the facility is provided from on-site deep wells. Water is used for steam production and cooling as well as for housecleaning and personal uses. Water is recycled to take advantage of lower quality needs throughout the plant. Waste water is utilized to the maximum extent possible for landscape irrigation, ash conditioning and fugitive dust control.
Colmac Energy, Inc. was named as Power Plant of the Year by Power Magazine in 2010. “The Colmac team was second to none”.