Cogeneration is a power system concept and design that allows for more of an efficient use of energy inputs than conventional utilization. Cogeneration involves the recovery of otherwise wasted thermal energy that is used for industrial process steam and/or heating purposes. In the simplest of terms, cogeneration is the "simultaneous production of electricity and useful thermal energy from a single source, such as a power plant or an industrial boiler.

Cogeneration is defined as the "combined production of two forms of energy -- electric or mechanical power plus useful thermal energy in one technological process. The electric power produced by a cogenerator can be used on site or distributed through the utility grid, or both.  Cogeneration systems recapture thermal energy that would otherwise be wasted, usually from a heat engine that produces electricity (such as a steam turbine), and use it for space conditioning, industrial processes, or as an energy source for another energy component. Cogeneration system design represents the intersection of two types of systems, a system designed to produce electric power and a system designed to produce heat and steam for industrial use.

Based on these concepts, it becomes apparent that the nature of the resource inputs and environmental losses associated with cogeneration are similar, if not identical, to those associated with electric power production from fuel combustion. The primary difference rests in the scale of the power production facility. Emissions and resource use vary according to fuel type (e.g., coal, natural gas, biomass), capacity, and plant design.

Cogeneration, in and of itself, is an example of pollution prevention. Cogenerators, by using excess heat, may enhance the efficiency of total energy use by up to 80% or more from the typical 33-38% efficiency of electricity-only generation. A study of 143 cogeneration facilities filed with the Federal Energy Regulatory Commission (FERC) between 1988 and 1990 revealed an average thermal usage of 32%, for a total efficiency of about 65%.

With increasing energy costs (up to $.15 per Kw hour in some areas), process operations that do not generate the steam pressures and flows to power large turbines can still generate electrical power on a smaller scales. NESTCO's turbine-generator packages are fitted to these applications. The systems can be set up in discreet packages that can be activated, or shut down to coincide with the amount of steam energy being produced. The boilers being fired by biomass, gas, oil or coal are often not operated at full capacity year round. Processes and heating demands from the boiler vary weekly, if not daily.

A NESTCO turbine generator package presents a quick payback period for single or multiple packages, taking advantage of the steam flows available in the system.

Select the link below to view a sample 260Kw Turbine-Generator drawing in PDF format