At the most recent annual auction for electric capacity in PJM, electric capacity cleared with lower volumes versus the prior year -- all because of lower demand.

Prices were lower than previous years in the Mid Atlantic Area Council (MAAC) region and higher than previous years in the rest of the Regional Transmission Organization (RTO). These intra-PJM price variations were anticipated due to the impact of new west-to-east transmission facilities, the economic downturn and the effect of recent EPA rulings on generator retirements.

Some of these effects were surprising including the contribution of demand response into the dynamics. Prior to the auction, analysts expected some amount of old or otherwise dirty coal-fired generation to exit the market altogether and for others to bid high prices to recover environmental capital expenditures to comply with EPA requirements under it's Clean Air Transport (CATR) rule of June 2010 and it's National Emissions Standards for Hazardous Air Pollution (NESHAP MACT) rule of March 2011.

Both of these expectations were realized. Compared to the prior auction, about 1,900 megawatts less of coal generation, enough to power more than 600,000 homes, were withdrawn from the market. It did not stop there. By the time the auction was over almost seven gigawatts less of coal generation from the prior year, or enough coal capacity to power more than 2.2 million homes, was out of the market because prices at which they bid -- as a result of environmental capital expenditure requirements -- were higher than where the market cleared.

While the jettisoning of these coal plants undoubtedly resulted in higher capacity prices than if the plants did not exit, it led to significant environmental benefits. If these plants share the same characteristics of a typical PJM region coal plant, according to EPA's eGrid database they would have operated just under 60% of the time in the delivery year, and produced approximately 36 million tons of carbon dioxide equivalents.

In global warming terms, eliminating this pollutant is the same as removing about 7 million passenger vehicles from the U.S. vehicle fleet. In addition, the plants would have produced 228 thousand tons of sulfur dioxide and 59 thousand tons of nitrogen oxides -- both precursors to acid rain and contributors to a host of pulmonary and other health problems.

Prices Checked

Using the market to generate the replacement sources for the withdrawn coal capacity resulted in significant economic benefits. As coal plants were removed from the supply stack, the new resources replacing them -- most significantly demand response -- held market prices in check.

Demand response contributed an additional 4,800MW of cleared capacity above the prior auction year. Indeed, PJM has reported that demand response mitigated unconstrained region-clearing price increases by 10 to 20 percent, and contributed 30 percent to the price reductions in the constrained region. These percentage savings translated to about $1.2 billion in direct payments to capacity providers.

Demand response is an outgrowth of smart grid technology and market based constructs for providing energy. Operating under these constructs, demand response providers search for economic megawatts available for curtailment and build networks of response sites to generate "negawatts," which represent the ability of end users to reduce or eliminate energy consumption in response to signals.

By making negawatts available at costs that are generally below those required to build and maintain generation plants, demand response lowers capacity costs in energy markets and offsets new build capacity.

According to FERC, there are currently about 37,000 megawatts of demand response capacity available in the United States. FERC further estimates that given the right market constructs, this capacity could grow to between 80,000 MW and 108,000MW by 2030, permanently eliminating the need to build power plants to serve that demand. PJM, with demand response registrations of 9,200 MW in 2010/11 and cleared demand response of 14,100 MW by 2014/15, is the largest demand response market.

Demand response also provides payments directly to end consumers who agree to curtail their energy use -- payments that can add up.

The benefits don't end there. Customers receiving payments from demand response providers often use them as leverage for capital expenditures in energy management and other energy efficiency projects, which generate "green collar" jobs. And by reducing peak demand, the technology is also serving to cut prices.

The success of consumer side participation in the PJM capacity markets opens a path to success in the long sought trifecta of winning policy as it relates to the environment, energy and economics.