Without warning, the August 14, 2003, power blackout removed electricity for millions of people in the United States and Canada. The next day manufacturers still had no power, contributing to an estimated cost to the U.S. economy of $6 billion.

Meanwhile, in Ontario, New York, Harbec Plastics, which machines complicated plastics parts, operated during the blackout without interruption, owing to an array of 25 Capstone microturbines. Fired by natural gas, each microturbine produces 30 kilowatts (kW) of electricity and virtually no pollutants. The array's waste heat is recovered and used both to heat water and air (in winter) and cool the building space in summer.

Typically, about two-thirds of the fuel energy used to generate electricity in central power stations is discarded as waste heat and then as losses incurred in power transmission and distribution. By the time the power reaches the point of use, total efficiency can drop to 30%. However, efficiency can be raised to more than 70% by locating each power source close to the customer and productively using the source's waste heat for heating, cooling, and controlling humidity in each appropriately sized commercial or institutional building. Since the 1990s the Department of Energy and the private sector have worked together to develop such distributed energy (DE) technologies, also called cooling, heating, and power (CHP) units and, more recently, integrated energy systems (IES).

DOE is seeking to demonstrate that IES units in operation throughout the United States can increase the nation's energy efficiency, reliability, and security, reduce dependence on imported oil, and simultaneously lower emissions of pollutants that threaten health and a stable climate. DOE's goals are to develop the next generation of clean, efficient, reliable, and affordable DE technologies, integrate these technologies into appropriately sized end-use sites, and capture waste heat, or thermal energy, to more than double energy efficiency for heating and cooling of buildings.

Ready for Prime Time.

DOE asked ORNL to focus on three types of energy sources, or "prime movers," for IES units: industrial gas turbines, reciprocating engines, and microturbines. All of these sources can burn natural gas and produce two types of energy: electricity and waste heat. These sources would be integrated with a "thermally activated" technology, such as an absorption chiller for cooling, a desiccant wheel for dehumidification, or a steam generator or heat exchanger for heating water or air.

ORNL supported the development by UTC Power, a United Technologies Company, of the UTC PureComfort- system, a reliable IES with ultra-low emissions that features a 112-ton absorption chiller powered by waste heat from four to six 60-kW microturbines.

The double-effect chiller provides cooling and heating from the same unit, conserving space and simplifying design. In summer the chiller uses waste heat from the microturbine as the source of energy for driving the fluid that extracts heat from water to chill and provide air conditioning. The CHP technology has an efficiency of up to 80%.

ORNL scientists have teamed with industrial partners to figure out how to capture heat from each turbine or engine and transfer the heat to a thermally activated system to provide cooling, dehumidification, or heating. ORNL's Jim Sand has promoted the use of waste heat for dehumidification in schools and other buildings to improve air quality and prevent the growth of mold and other allergens. Waste heat from engines and turbines can be combined with a desiccant system to create a more comfortable environment where temperature and humidity are controlled independently. Air can be passed through a desiccant wheel, which absorbs the moisture and sends the resulting dry air into the building. The waste heat dries the desiccant wheel so that it can again pick up moisture from indoor air.

In 2001 DOE asked ORNL to solicit proposals from companies that manufacture engines, turbines, and heat exchangers, as well as from end users that can benefit from IES units. ORNL personnel served as technical project managers in cost-shared contracts between DOE and industry, which bore 43% of the cost. The ORNL project managers provided technical expertise to the industrial partners and helped identify the best ways to capture waste heat for making what the end user wanted, such as chilled water for air conditioning or heat for steam. By 2004 several partners had met the DOE goal of combining individually optimized products on-site.