Glicksman replies: Some important issues are raised by Rebecca Barthelmie. I couldn’t agree with her more that the energy crisis requires an integrated approach comprising both environmentally acceptable supply options and substantial improvements in consumption efficiency. My major point was that most current efforts are heavily weighted toward supply-side solutions. Contrary to her assertion, many economic measures can be accomplished quickly to substantially improve the efficiency of existing buildings. For example, a number of programs to recommission commercial buildings, including actions as simple as reprogramming building controls, have resulted in 15–20% overall energy savings. Similar savings in the residential sector can be obtained by simple improvements such as sealing leaks, setting thermostats back at night, and using compact fluorescent lights that pay for themselves in less than a year. New construction, especially in developing countries, is particularly important in meeting future global climate goals. China, for example, is constructing approximately 10 million new residential units per year. The new buildings can be made twice as energy efficient as existing ones with little or no cost increase.

Possible environmental impacts of any new energy sources must also be considered. Covering many buildings in an urban area with photovoltaic systems will, for instance, have the negative consequence of enhancing heat-island effects. And a few studies suggest that large-scale wind farms would create “nonnegligible climatic change at continental scales” 1 or would affect local meteorology. 2 It is clear that further study is needed to determine the severity of any long-term effects.

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