How Green Is Green?

I n a world that has become acutely aware of the environmental impact of energy consumption resulting in global warming, and the increasing financial burden of oil after the price spiked this past July to US$145 per barrel, energy conservation has become a hot topic. This is an opportunity for pervasive computing to play an important role in conserving our planetary resources and moving us toward environmental sustainability. Pervasive computing’s primary green contribution is its ability to turn dumb technologies into smart power-aware technologies. By adding computing in combination with sensing and actuation, we can make systems automatically respond and adapt to their environment. Context-aware computing has long been applied to mobile systems, and has clear application in the design of smart power-aware systems that can respond to users’ needs. In practice, adding a modest amount of embedded computation to a system, such as a home’s heating, ventilation, and air conditioning system, can optimize the use of energy and still achieve the intended goal. However, the addition of embedded computation and control systems isn’t necessarily a free energy lunch. The question then becomes, “How much energy did it really take to manufacture the complex components to help us conserve?” Although the operation of these technologies might save energy, when considering the big picture, which includes manufacturing and transportation costs, the net saving might not be positive unless their operational life is sustained beyond the energy breakeven point. Most consumer devices are made from a variety of materials includ-