Urban energy opportunities

Comments on various renewable energy technologies to which urban areas may convert are made. Community- or city-scale use of solar and wind power cannot economically or practically compete with oil presently. Surface water and ground water both contain quantities of heat that can be extracted by using a heat pump or piping systems. The technology for extracting the heat is available for use on a neighborhood or industrial park level. Solid and liquid wastes and biomass hold promise for producing urban energy. One ignored energy source is better utilization of the fuel used for electricity production. The overall fuel efficiency of the plants can be improved if the waste heat is delivered to customers for use in heating and cooling their homes and businesses. The technology for transferring the heat by hot water or steam exists. The author then cites two examples of community scale use of energy systems. An analysis at Soldier's Grove, Wisconsin, revealed that the town could burn waste wood from nearby lumber mills in a central boiler to supply heating, cooling, and domestic hot water. The systems, only using oil for ignition, should pay back in about 2 years. An Argonne study showed that large cities' (Philadelphia) heating loads could be supplied profitably through district heating using power plant waste heat, at a cost of over $2 billion, but at a payback period of less than 9 years (1978 study). Other problems facing urban areas to exploit other energy sources are briefly noted. (MCW)