Page 25 - Sustainable On-Site CHP Systems Design, Construction, and Operations

4 CHP B a s i c s

• Data centers
• Jails and prisons
• Oil refineries
• Wastewater treatment plants
• Pharmaceutical industries
• Industries requiring heating processes
• Residential systems

The necessary key condition for a sustainable on-site CHP system, in addition to a
need for power, is a simultaneous need for heating and/or heat-produced cooling and/
or other thermally activated technologies, although thermal storage can offer a way of
shifting when loads are served. CHP is primarily driven by several factors, but two
major drivers are (1) the return on investment (ROI) and (2) the perceived concern about
outages affecting reliability and/or profitability. Main reasons motivating end users to
consider CHP also include price, availability of electricity, and capital funding con-
straints. CHP systems are usually most economical when an existing facility distribution
infrastructure system exists, or when CHP systems are installed as part of new facilities,
or when utility electricity distribution systems are constrained, and/or when electric
utility purchase costs versus fuel costs are relatively high.
Typical fuel sources today include natural gas and fuel oils; however, other
common more sustainable fuels include biomass, biofuels (liquids such as ethanol and
biodiesel), gas, landfill gas, and municipal waste. CHP offers a proven method to reduce
CO emissions by recovering useful heat and avoiding fuel combustion.
2
Most CHP plants are interconnected with the local utility and operate in parallel. In
some cases, the CHP plant may be able to operate totally separated from utility power
and is know as island mode.
When properly planned, designed, constructed, and operated, sustainable on-site
CHP systems offer a proven method (1) to lower overall facility energy consumption
and costs, and (2) to reduce total overall utility system fuel consumption. Additionally,
there is a need to rethink current and future requirements for expanding electric power
infrastructures to meet demands in an era of growing energy uncertainties. This is espe-
cially true in areas with old, constrained electrical infrastructures; CHP offers an oppor-
tunity to effect reduced reliance on prime energy sources for power generation (utility)
and to reduce power transmission system strains.
Sustainable CHP at a minimum is a plant that is cost-effective on a life-cycle cost
basis versus conventional remote power generation, and capable of at least a projected
annual 70 percent prime energy utilization factor. The use of biofuels (solid, liquid, or
gas) can further enhance CHP sustainability as carbon is resequestered during the
growing process. Recognize that global warming concerns demand that alternative
means to satisfy the world’s growing population and power need to be sought while
simultaneously curtailing annual carbon dioxide emissions. This remains the foresee-
able challenge and CHP is part of both short- and long-term sustainable solutions.

Why CHP?
CHP systems can use less than 60 percent of the source fuel required by conventional
utility power plant systems and local facility heating boilers. In a conventional electric
power generation plant, the combustion of fuel provides the energy to produce electric