The Republican (Springfield, Mass.), December 16, 2007

EXPERTS RETHINK COAL

By Stan Freeman sfreeman@repub.com

It is the fuel of centuries past -- black sooty chunks of energy, sold from the back of horse-drawn wagons and then shoveled into stoves and furnaces.

But it may also be the fuel of decades to come -- transformed into a liquid so clean that it's drinkable, but possessing the chemical muscle to run cars and power plants.

With anxiety rising over the energy future, coal is again being taken seriously. After all, it is a fuel that America has in abundance beneath its soil, perhaps enough to run all the nation's power plants for two centuries or more.

However, with anxiety about global warming also rising, the fact that burning coal releases an abundance of carbon dioxide, a greenhouse gas, is creating a compelling fear for many that relying on it too heavily to satisfy our growing energy needs is dangerous.

"We've got a lot of coal, but of all the fossil fuels, it is the worst in terms of adding to greenhouse gases. Somehow, we have to accommodate these two conflicting issues," said Michael K. Jensen, of the Center for Future Energy Systems at Rensselaer Polytechnic Institute in Troy, N.Y.

What Saudi Arabia is to oil, America is to coal.

About a third of the world's reserves of coal can be found in this country. There are an estimated 300 billion tons of recoverable coal beneath U.S. soils.

Coal has long been a four-letter word for environmentalists, though. While it accounts for about half of the electricity produced in this country, coal-fired power plants also account for more than a third of the U.S. releases of carbon dioxide into the atmosphere from all human sources, including cars and trucks.

In addition, the plants produce sulfur dioxide gas that becomes an ingredient of acid rain, which has spoiled lakes and ponds throughout New England. And they produce airborne mercury, which can make fish inedible.

The one large coal-fired power plant in Western Massachusetts, Mount Tom Station on Route 5 in Holyoke, has long been criticized by environmentalists for its air pollution. In 2003, the plant was the second-ranked polluter in the state, emitting nearly 1.2 million pounds of pollutants of all kinds, according to the U.S. Environmental Protection Agency. (Nevertheless, the plant does meet all state and federal pollution standards.)

Mount Tom Station provides power to the New England electric grid, which ties together the six states and the more than 300 power plants operating within them.

In 2006, FirstLight Power Resources Inc. bought the Holyoke plant as well as hydropower stations at Turners Falls and Northfield from Northeast Utilities. In September, the company announced a $57 million project to reduce pollution at Mount Tom Station. Over the next 20 months or so, modern pollution control equipment will be added that is expected to reduce mercury, sulfur dioxide, hydrochloric acid and hydrogen fluoride pollution by 95 percent.

James A. Ginnetti, a spokesman for FirstLight, said the upgrade is necessary to meet new state regulations for mercury emissions that take effect Jan. 1. Some thought was given to changing the plant's fuel source, he said, "but it would have been a major rebuild. We thought this was the best alternative."

John Murray, the Holyoke plant's manager, said, "We evaluated the pros and cons of making this sizeable investment and decided that it was the right thing to do from both an environmental and economic perspective."

In the national discussion about energy, what has moved coal to the forefront are two developments. One is a new take on a nearly 80-year- old technique, called the Fischer-Tropsch process, that can turn coal to a liquid fuel. The other is a process for creating electricity from coal that allows the pollutants to be separated out before they reach the atmosphere.

Invented in 1923 by two German scientists, the Fischer-Tropsch process involves a chemical reaction in which coal and a catalyst (a metal that encourages the reaction) are combined with steam and subjected to pressure. The resulting chemical reaction converts the ingredients into carbon monoxide and hydrogen, a gas (called "syngas") that in turn can be converted to a highly potent liquid fuel capable of powering cars and trucks and heating homes. In recent years, the efficiency of the process has been improved.

Syngas can also be used to run a new generation of power plants called integrated gasification combined cycle, or IGCC, plants. They plants can separate out the vast majority of the pollutants associated with burning coal -- carbon dioxide, sulfur, mercury and others.

If the carbon dioxide gas from IGCC plants were simply released into theatmosphere, though, there would be little improvement in the environmentalequation in regards to coal. However, there are proven methods to separate the carbon dioxide from the rest of the flue gases, then liquefy and inject it deep underground.

For example, liquid carbon dioxide can be injected into semi-depleted oil reservoirs, thus helping to get more oil out of these reservoirs. It also can be injected into deep, brine-filled reservoirs that underlie much of the United States and elsewhere. There, the carbon dioxide would dissolve in the salty water. What isn't proven, though, is whether the sequestered liquid carbon dioxide would stay there forever. It is possible that some of the liquid will vaporize and leak back into the atmosphere.

"If the leak is concentrated enough, that poses a risk for the population and the ecology. Carbon dioxide is not toxic, but it is suffocating and at some concentration it may cause central nervous system effects," said Dan S. Golomb, of University of Massachusetts in Lowell, who is studying carbon dioxide sequestration under a federal energy grant.

The places underground where carbon dioxide could be injected are abundant, he said, and there is enough capacity to absorb almost all the man-made carbon dioxide.

"However, it is not only an environmental problem," Golomb said. "It is also an economic problem. No private utility will invest in building an IGCC plant with carbon dioxide capture, and the pipeline to a disposal site because it is too much of an investment. Such a scheme may need a government subsidy."

Currently, there are only two IGCC plants generating electricity in this country, in Indiana and Florida, and neither is sequestering the carbon dioxide it produces. However, it's estimated the plants are removing more than 90 percent of the mercury and nitrogen oxide and more than 98 percent of the sulfur dioxide during the process, making them substantially cleaner than traditional coal-burning power plants.

Carbon dioxide has been successfully sequestered in other countries, though. And in North Dakota there is a closely watched demonstration project in which carbon dioxide is being piped into a depleted oil field as a way to increase the pressure so that more oil rises to the surface.

David O. Dapice, an associate professor of economics at Tufts University who has studied the economics of these new coal-burning technologies, said that the cost to sequester carbon dioxide currently is estimated at about $100 to $300 per ton but research at the Department of Energy and elsewhere could reduce this by 90 percent in less than a decade.

"The feasibility of storing carbon at, say, $200 per ton depends on the price of oil. Certainly at current oil prices, it is profitable. But if some of the lower-cost technologies can be developed, there is no question that (capturing carbon and sequestering it would be profitable at) any likely price of oil," he said.

With so much on the line, research to improve all facets of these various coal-burning processes is increasing.

In February, for instance, researchers at the Massachusetts Institute of Technology said they found a mechanism for capturing carbon dioxide emissions from a coal-fueled power plant and injecting the gas into the briny porous rock beneath ground where it would be trapped naturally as tiny bubbles and remain there indefinitely. The carbon dioxide eventually dissolves in the saltwater and a small portion adheres to the rock as minerals.

In Kansas, a Cambridge company, GreenFuel Technologies, is testing a process where carbon dioxide from a coal-burning power plant is pumped into an enclosed greenhouse to stimulate the growth of algae (which convert carbon dioxide to energy) that is then harvested to make biofuels.

Environmentalists have not dismissed any of these so-called "clean coal" technologies out of hand (although one famously said that "clean coal" is the equivalent of saying "safe cigarettes").

"I think we have a long way to go, but if it's a choice between a conventional coal plant and IGCC, obviously IGCC is better," said Robert M. Sargent, senior energy policy analyst for U.S. Public Interest Research Group. "But for it to really have the appropriate impact on the environment, the carbon dioxide emissions from the plant have to be sequestered."

He acknowledged that there are examples of carbon dioxide beneath ground successfully, "but to do it on the wholesale basis and to use those examples as an argument for the continued use and growth of coal is a monstrous gamble."

"You can't assume we can find enough places to pump this stuff into the ground and feel confident it will stay there," Sargent said.

"The folks advocating this are thinking of it as a way to live with coal for a long, long time. That is a lot of coal plants and a lot of carbon dioxide stored underground and I would have to think at an incredible cost. To me it is not sustainable as anything but a temporary fix," he said.

Instead, energy planners should be thinking first of conservation and technologies, such as wind and solar power, that are cheaper and less complicated, Sargent said.

"Sure, we need to keep looking at IGCC and carbon sequestration as an option. We need to keep it on the radar screen and run a pilot program to see if it works. But an energy policy that puts that ahead of renewables and efficiency is idiotic," he said.

Copyright 2007 The Republican