A Greener City: Powering the future

A huge dragline that stands more than 20 stories tall claws into the blasted earth and strips away enough dirt and rocks with each bucket load to fill a four-car garage. The exposed coal is shoveled into giant dump trucks that carry more than 300 tons of coal in every load — enough coal to power a home for 40 years.

This is the country’s largest coal mine — Black Thunder — a name befitting pits so vast they have become man-made canyons.

Everything related to the Powder River Basin is massive, including San Antonio’s desire for more of this coal.

In a move that will increase the city’s contribution to global warming for decades to come, CPS Energy five years ago decided to build a large new coal plant — its fourth — at Calaveras Lake to burn more Wyoming coal.

To some, the plant is at odds with the utility’s increasingly green direction, as shown by its investment in wind energy and its desire to buy solar power. When the plant’s furnace fires up in 2010, it’s going to be a massive smokestack, not towering windmills or sparkling solar arrays that accounts for the largest part of the city’s new power generation.

CPS Energy, like most American electric companies, views coal as a vital part of its energy mix. The federal government says domestic coal reserves won’t run out for at least 200 years. Coal is abundant, cheap and reliable.

Coal is also, despite a public relations campaign to clean up its image, the dirtiest and most carbon intensive of all major fuel sources. When burned, it produces mercury and other pollutants that help create smog. It’s also a chief source of carbon dioxide, the main culprit in global warming.

This makes the CPS decision, in many eyes, a big gamble for a future almost certain to include a new regimen of global-warming regulations that punishes those who add to the problem. “We’ve known for a long time that coal is the dirtiest way to produce power,” said Alice McKeown of Worldwatch Institute. “You’ve got to ask how they justify the risk they are taking here.”

On a hot summer afternoon, when demand is the highest, it takes about 4,400 megawatts of electricity to run San Antonio. That’s roughly the power generated by six or seven large plants. Today, coal makes up nearly 40 percent of CPS Energy’s generation, barely edging out nuclear for the top spot. When its new 750-megawattcoal plant is running at full strength that number will jump to 54 percent, but decrease in the long run.