Mandatory portfolio standards have different implications for different technologies.
The federal government and several state governments are considering programs to increase the share of electricity produced by renewable generation resources to 20 percent or more. If these programs are implemented and pursued successfully, they will trigger a dramatic change in the role of renewable generation and the requirements placed upon it by the market.
State by state, or region by region, renewable generation must transition from a "source of opportunity" to a consistent, reliable source of power as the percentage of renewable generation exceeds the "reliable source" generation capacity reserve margin. This transition has different implications for the various renewable generation technologies.
The U.S. electric reliability concerns extend from generation, through transmission and distribution, to the point of consumption. The issue is complicated by industry restructuring and the emergence of a competitive wholesale market for electricity, which is altering historical supplier/customer relationships and historical power transmission paths. Continued U.S. population growth and resultant increases in electric consumption and demand, as well as proposed CO2 emissions caps and reductions could further complicate the electric reliability scenario.
The U.S. population growth of approximately 1.3 percent per year would result in a doubling of population every 50 years and approximately 500 million U.S. citizens by 2050. U.S. energy consumption is growing slightly faster than population, at approximately 1.5 percent per year; electricity consumption is growing at approximately 2 percent per year. Thus electric consumption could increase approximately 150 percent by 2050.