The report says, for example, that utilities should be encouraged to pursue financial incentives for customers to cut use during peak hours, thereby lowering demand for new power plants and transmission lines. Financial incentives could reward customers’ installation of more efficient equipment or, more drastically, reward a factory for closing on a day when electricity supplies are expected to be tight.

The president of the council, Rick P. Sergel, said in a telephone interview, “The situation has existed for a long time, but we cannot let it continue.”

Planning for adequate capacity has become more difficult with the restructuring of the electric industry. Where a handful of top-to-bottom companies once generated power, transmitted it and delivered it, hundreds of companies are now involved in only one or two phases of the process. At the same time, getting permits to build new power lines has become more difficult.

The actual balance between supply and demand depends in part on changes in technology. Grid operators can now push more power through existing lines, plant operators have found ways to make generators more reliable and sharp increases in the efficiency of how electricity is used could slow demand.

The report predicts that demand will increase by about 19 percent over the next 10 years in the United States, and slightly less in Canada, and that the construction of power plants and transmission lines to carry that load will fall far short of what is needed. In this country, utilities have contracts with new power plants for only about a third of the capacity that will be needed; in Canada, the number is about two-thirds.