The word "grid" is used to describe the system of wires and pipelines that carry energy, in the form of electricity or natural gas, to our homes and businesses. People are interested in using less energy from the grid for many reasons. One is that producing this energy often creates very large environmental problems--such as air pollution, global climate change, massive flooding in river systems, and others. Another reason is that the distribution system itself, with its tens of thousands of kilometres of wire and pipe, is costly to build and maintain and has its own environmental problems. Yet another is the expense to consumers: energy prices and utility bills are a frustrating part of owning or renting a home.