RED’s principals, Tom Casten and Sean Casten, previously managed plants at Trigen, Turbosteam, and Primary Energy. Between 1979 and 2006, these plants achieved double to triple the delivered energy efficiency of conventional central, remote generation plants.

In the graph below, the green dots represent plants built by Trigen and its predecessor companies, commissioned between 1979 and 2000. The large brown bar represents 188 steam turbine installations designed and built by Turbosteam between 1986 and 2007, all of which achieve in excess of 80 percent net energy efficiency. The blue oval represents five facilities with 450 megawatts of capacity built by Primary Energy that convert steel plant waste energy streams into heat and power. They are shown as 100 percent efficient, but, in fact, burn no incremental fuel.

These facilities are all located at or near industrial or commercial hosts and recycle the normally wasted by-product heat from electric generation to displace boiler fuel, or they recycle waste energy streams from the host to produce fuel-free power with zero pollution. In total, these facilities built by organizations RED principals managed represent roughly $2.0 billion of capital investment. Nearly all of these plants remain in service.

Opportunities to recycle waste energy

A variety of industrial waste energy streams can be recycled into useful heat and power. These include hot exhaust gases, low-grade fuels (some of which are typically flared), and high-pressure steam and gas. Proven technology can profitably convert the energy in hot exhaust (600 degrees F or higher) from any process into steam that drives turbine generators and produces electricity. Coke ovens, glass furnaces, silicon production, refineries, natural gas pipeline compressors, petrochemical processes, and many processes in the metals industry vent hot exhaust that can be profitably recycled to produce fuel-free power.

Another way to recycle waste energy is by burning presently flared gas from blast furnaces, refineries, or chemical processes to produce steam and electricity. Factories producing carbon black (used in tire manufacturing) typically waste enough flared gas to produce three times their electrical needs.

The energy potential in pressurized gases also can be recycled into electricity. Examples of pressurized gas include steam, process exhaust, and compressed natural gas in pipelines. Gas pressure drop can be converted to mechanical energy with expanders, which then drive an electric generator. Many industrial producers generate streams of high-pressure gas that can power a backpressure turbine connected to an electric generator in order to produce fuel-free power, with zero pollution.

For example, most industrial and commercial boiler plants were designed to generate steam at high pressures to pack the distribution pipes. This approach allows the plant to install smaller distribution pipes, reducing first cost. These plants then deflate steam pressure at points of use by means of valves. A backpressure turbine can convert the pressure drop into fuel-free power. Nearly every college and university campus, as well as most industrial complexes, could produce some fuel-free power from steam pressure drop with a backpressure turbine generator.

Gas transmission pipelines burn approximately 8 percent of the gas being transported to drive compressors that pack the remaining natural gas into transcontinental pipes. The gas pressure is then reduced at each city gate with valves, typically wasting the potential energy of the pressure drop. Gas expanders can recycle this pressure drop at the points of gas flow into local distribution systems. Capturing this natural gas pressure drop across the United States would require roughly $8-10 billion of new investment and would result in 6,500 megawatts of clean energy. The resulting generation would produce roughly 28 trillion kilowatt-hours per year of fuel-free power with zero pollution. At present, we know of only two locations in North America that capture this opportunity. To achieve a comparable amount of clean energy would require 22,000 megawatts of new solar collectors (at a current capital cost of $130-170 billion) or 6-7 nuclear plants.

Many industrial processes—such as catalytic crackers at petroleum refineries and blast furnaces at steel mills—also emit hot exhaust at above atmospheric pressure. Top-gas recovery turbines could produce 15 to 35 megawatts of fuel-free power at every blast furnace and every oil refinery. The overwhelming majority of U.S. blast furnaces and oil refineries currently waste this potential clean energy due to their focus on their “core business” and corresponding underinvestment in energy assets.

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