High-tech coal energy cheaper than Texas wind power
Researchers find that electricity costs from some coal-fired plants with pollution controls are lower than those from wind power in Texas.
Popular wisdom is that wind power is the best choice for electricity generation, especially if the goal is to reduce the emissions of mercury, SO2, NOx, or CO2. However, in a paper published on ES&T’s Research ASAP website (es048024j), researchers report that consumers in Texas paid about 5.7 cents per kilowatt hour (¢/kWh) more for renewable power in 2002 than if the same power had been produced by state-of-the-art coal-powered plants designed to reduce these 4 significant air pollutants.
The analysis, conducted by Katrina Dobesova from the University of Economics, Prague, and Jay Apt and Lester Lave from Carnegie Mellon University’s Electricity Industry Center, examined the cost of renewable power in Texas, the U.S.’s largest power producer. The state has enacted a tough renewable portfolio standard (RPS), which requires that utilities obtain a certain percentage of their power from renewable sources. The authors focused on wind power, because it provided 87% of Texas’s renewable capacity in 2002. The state also produces a lot of air pollution: In 2002, Texas was the origin of 10% of the U.S.’s mercury, 19% of its CO2, and 14% of its NOx emissions.
The study found that the same pollution reductions could be reached more cheaply with an integrated gasification combined cycle (IGCC) coal plant that uses carbon capture and sequestration (CCS) than with wind power. Combined-cycle plants that use pulverized coal or natural gas and include CCS could obtain achieve the same costs. There are 11 IGCC plants operating in the U.S. and 112 in the world, Apt says.
The District of Columbia and 20 U.S. states have enacted some form of renewable policy for electricity generation, the authors say. Most RPS proponents favor non-fossil-fuel energy sources, Apt suggests. Several state legislatures are debating new RPSs right now.
As part of the analysis, the researchers considered the cost incurred by utilities for “fill-in power”—the energy usually bought from coal- or natural-gas-powered plants when the wind doesn’t blow. Texas wind turbines spin about one-third of the time on average, Apt explains. This means that utilities must purchase power for the other two-thirds of the time. These costs had been previously estimated at 1.1 ¢/kWh, Apt says.
Other factors that played an important role in their calculations included the federal wind-energy production tax credit for renewable energy, which they calculated as 1.8 ¢/kWh, and the loss of power as it moves along transmission lines from wind turbines typically located far from major cities, which they peg at 0.9 ¢/kWh.
In the end, Dobesova, Apt, and Lave conclude that an energy policy that is broader than an RPS might provide society with the least expensive, and least polluting, energy source. “Legislation like that enacted in Pennsylvania includes IGCC [technology] and thus addresses directly the issue of carbon control within the framework of a politically palatable mechanism,” the three write.
Mike Jacobs, deputy policy director of the lobbying group the American Wind Energy Association, says that the paper doesn’t explain that Texas’s rules are unique in the way that transmission costs associated with a new generator are allocated. No incentive exists in Texas to place the turbines closer to where people live, he says. As a result, utility officials can satisfy their RPS with wind rather than biomass or landfill methane, which are typically located closer to urban areas and have lower transmission costs, he says.
Not so, say the authors. The Texas RPS doesn’t favor wind and isn’t unique in this regard. Solar, biomass, landfill gas, and hydroelectric power are eligible choices for utilities, under the RPS. Yet, as many other authors have pointed out, wind is the most economical large-scale renewable resource other than hydroelectric power. However, population centers haven’t developed in windy areas, Apt says.
