The United States had resisted endorsing the Kyoto Protocol, preferring to let the market drive CO2 reductions to mitigate global warming, which will require CO2 emission taxation. The administration of Barack Obama has proposed an aggressive energy policy reform, including the need for a reduction of CO2 emissions, with a cap and trade program, which could help encourage more clean renewable, sustainable energy development. Modern society uses large amounts of electrical power. This is normally generated at power plants which convert some other kind of energy into electrical power. Each such system has advantages and disadvantages, but many of them pose environmental concerns. The efficiency of some of these systems can be improved by cogeneration and geothermal(combined heat and power) methods. Process steam can be extracted from steam turbines. Waste heat produced by thermal generating stations can be used for space heating of nearby buildings. By combining electric power production and heating, less fuel is consumed, thereby reducing the environmental effects compared with separate heat and power systems. This book tackles this question of social value versus economic impact, discusses how each is measured, and examines how both measures are needed to assess a proposed environmental action or policy in terms of both efficiency and equity.