How Less Became More

Wind Generation: The Energy Option?

By John Lange, BENTEK Energy, LLC

Renewable portfolio standards (RPS) that rely on wind and criteria standards of the Environmental Protection Agency (EPA) are potentially on a collision course.

Using actual hourly generation data from every coal and gas boiler over 25 MW, BENTEK Energy investigated the efficiency losses at coal generation facilities attributable to renewable generation in the Public Service Company of Colorado (PSCO) and the Electric Reliability Council of Texas (ERCOT) operating areas. The results indicate that due to the provisions of RPS, wind energy is a must-take resource and causes utilities to cycle their coal and natural gas-fired power plants. Cycling coal power plants (and to a much lesser extent, gas plants) make their operation vastly less efficient and increases their emissions of CO₂, NO_X and SO₂. Cycling also causes significantly greater wear and tear on the plants, thus adding to their maintenance costs and shortening their useful lives.

These findings have national policy implications. Integrating must-take, intermittent generation resources have caused severe system reliability and efficiency problems in ERCOT and Colorado at less than 10 percent renewable penetration levels even though flexible generation facilities comprise a significant component of the generation stacks in each area (25 percent in Colorado and 48 percent in Texas). If 20 percent to 30 percent RPS standards are mandated in areas where natural gas or other flexible generation is not adequate, coal plants will be cycled, and the potential emissions benefits from using wind will be dramatically reduced.

Good Intentions

Renewable policies have been implemented with the best of intentions. Reducing emissions, lowering electricity costs and creating a sustainable source of domestic energy have been priorities for at least the last three administrations. Of the many options for renewable energy, wind generation has been touted as the most feasible and cost-effective means of lowering emissions. As such, the generation capacity of wind projects has increased exponentially over the past decade.

In addition to emissions reduction, wind generation was thought to lower electricity costs because there is no variable power cost associated with wind blowing. Offering lower electricity rates to American voters is appealing to politicians who have pushed for renewable energy mandates.

Wind generation was also thought to provide a sustainable, renewable and domestic energy source that does not tax the environment, in contrast to hydrocarbon-based natural resources. Last but not least, reducing America’s dependence on foreign resources has been a priority of nearly every administration over the past five decades.