By Douglas J. Smith IEng,
Coal is critical for the continued economic growth of the U.S. Not only does coal account for 50 percent of the electricity generated in this country, it also accounts for 90 percent of energy reserves. Worldwide, coal is expected to double from the current 25 percent to 50 percent of worldwide energy consumption by 2015. For the foreseeable future coal will remain the primary fuel for electric power generation.
Although coal-fired power plants supply the majority of the electric power used in the U.S., many of them are old and inefficient. Because the electric power generated by coal-fired power plants is vital for the economic growth of the country, de-commissioning of these plants is not an option. However, if these plants are to continue operating it is essential that they be upgraded. Upgrading these plants would:
- Reduce emissions of SOx, NOx and particulates.
- Improve efficiency.
- Make them competitive in today’s deregulated electric power industry.
Optimizing the use of coal for electric power generation is imperative if the U.S. is to remain a world leader. We cannot afford to be dependent on other countries to supply our energy needs. Today, the U.S. depends on overseas suppliers for more than 60 percent of its energy needs.
On February 6, 2001, the U.S. Department of Energy (DOE) called for the energy industry to participate in a nationwide competition to develop new power plant technologies for burning coal. The program, called the “Power Plant Improvement Initiative,” is targeted at advanced clean coal technologies.
DOE is offering $95 million in federal matching funds for projects that will improve the efficiency of electricity production, help plants meet today’s more stringent environmental standards and improve the economics and overall performance of existing coal-fired power plants. Under the program, private sector energy companies will have to match the amount funded by the government. Similarly, the technologies must be mature enough to be commercialized within the next couple of years.
Some of the technologies that DOE suggest include: Advanced combustion systems, ultra low NOx burners, fine particulate control, state-of-the-art process control systems and steam cycle-improvements. A more in-depth summary of the Power Plant Improvement Initiative is available on DOE’s web site at www.netl.doe.gov under solicitations.
Since today’s coal-fired power plants on average only utilize 33-35 percent of the usable energy in the coal, even a small percentage increase would substantially boost the nation’s supply of electricity.
According to U. S. Secretary of Energy Spencer Abraham, the Power Plant Improvement Initiative will no doubt be part of a balanced and comprehensive national energy policy now being developed by the Bush administration.
According to the Coal Utilization Research Council (CURC), through 2005, the electric power generation sector will concentrate on two areas: optimizing the generation of electricity from existing coal-fired power plants and validating the commercial feasibility of new coal burning technologies.
By 2010, the continued use of coal for electric power generation will mandate that new generation technologies be commercially available if they are to effectively compete with natural gas-fired combined-cycle power plants. Future coal-fired power plants must not only be economically competitive, they must also operate with emissions at, or lower than, natural gas-fired combined-cycle plants, says CURC
CURC says that for a coal-fired power plant to be competitive with a natural gas-fired combined-cycle unit, its capital cost would need to be $800/kW and have a net plant efficiency of 45 percent (HHV). This assumes $400/kW for a gas-fired combined-cycle plant and the cost per Btu of natural gas twice that of coal.
Because of more stringent environmental regulations, electric utilities will increase their use of low sulfur western coals. DOE projects that the production of low sulfur coal will increase by 2 percent per year through 2020. Although low sulfur coal is expected to be the coal of choice, DOE says that there will still be opportunities for low cost, higher sulfur eastern coals.
The Case for Coal
At today’s current level of consumption, the U.S. has at least 200 years of proven recoverable supplies of coal, said Rick Whiting, Group Vice President and COO, Peabody Coal Group. Whiting was a panelist in the PowerGen International 2000 session “The Future of Coal-Fired Generation.” According Whiting, the states with the highest energy prices, California and those in New England, are also the states that use the least amount of coal for electric power generation.
Another panelist, Curtis Davis, Duke Power’s Senior Vice President of power generation, said that his company relies on coal to generate 7,700 MW of electricity. “Without coal Duke Power would not be able to meet current or future energy demand,” said Davis.
Sigfried Michelfelder, Senior Vice President, Babock Borsig Power Corp., also on the same Power-Gen panel, stated that although 200,000 MW of new coal-fired generation has been installed since 1970, emissions have not increased. Over the last 30 years coal burning has gotten cleaner, said Michelfelder. The reasons for this, he stated, is the addition of precipitators and scrubbers, and through more efficient combustion.
“If we replaced 50 percent of all coal-fired generation in the world with new coal-fired technologies, you would reduce the emissions of CO2 by 500 million tons per year,” said Michelfelder. In addition, you would generate 25 percent more electric power from the same amount of coal.
Withthe energy crisis in California caused primarily by a lack of capacity, plus the increase in the cost of natural gas, the market for coal-fired generation looks promising. The U.S. has been the leader in the development of clean coal technologies and should strive to maintain that lead.