Combined heat and power (CHP or cogeneration) for saving energy and carbon in commercial buildings

Combined Heat and Power (CHP) systems simultaneously deliver electric, thermal and mechanical energy services and thus use fuel very efficiently. Today's small-scale CHP systems already provide heat, cooling and electricity at nearly twice the fuel efficiency of heat and power based on power remote plants and onsite hot water and space heating. In this paper, the authors have refined and extended the assessments of small-scale building CHP previously done by the authors. They estimate the energy and carbon savings for existing small-scale CHP technology such as reciprocating engines and two promising new CHP technologies--microturbines and fuel cells--for commercial buildings. In 2010 the authors estimate that small-scale CHP will emit 14--65% less carbon than separate heat and power (SHP) depending on the technologies compared. They estimate that these technologies in commercial buildings could save nearly two-thirds of a quadrillion Btu's of energy and 23 million tonnes of carbon.