by Kevin Crapsey, Eco Power Solutions
Coal has been the mainstay of the North American electricity industry for nearly a century, but recent, increasingly stringent environmental regulations threaten its future as a driver of local and national growth.
The Mercury and Air Toxics Standards (MATS), Cross-State Air Pollution Rule (CSAPR) and updates to the Maximum Achievable Control Technology (MACT) rules fall heavily on coal-based energy producers and industrial producers of cement, steel and aluminum.
Because these industries are responsible for 80 percent of total U.S. emissions of sulfur oxides (SOX) and nitrogen oxides (NOX), they must identify, implement and plan for more emission-reduction requirements in the future. Compounding their challenges are the risks and costs associated with these alternatives.
The Environmental Protection Agency’s (EPA’s) regulations have changed the playing field in the power industry. “Game changer” might be the most overused adjective for technologies, but the power industry must adopt its own game changer to win now and in the future.
Several Options, Many Drawbacks
Electricity generators are considering shutting down emitting facilities all together. A major drawback to this option is lost assets because older facilities are already off the books. This path has tremendous grid reliability implications and can affect the reliability of electricity delivery to customers, especially in remote areas.
Another option is switching to a different, cleaner fuel source—typically natural gas—and shouldering the large expense of a fuel-change retrofit despite no assurance natural gas prices will remain low.
When evaluating these two solutions, one must understand their context. According to 2008 figures from the Edison Electric Institute, the association for shareholder-owned electric companies, roughly 800 U.S. coal-fired power plants—or some 65 percent of U.S. capacity—are between 31 and 60 years old. Retiring or replacing all or a portion of the capacity with cleaner fuels is not feasible for power companies obligated to serve customers and investors.
Some utilities are considering another approach: using emission-reduction technologies to capture targeted emissions and meet new government standards. Though cheaper than building a new plant or switching fuels at an existing plant, this option carries a significant price tag. The space required for equipment, especially at older facilities that are typically already packed tightly into a limited land area, is another constraint.
A New Approach on the Market
Multipollutant control systems are a more recent option and hold promise to overcome several drawbacks of the other approaches.
Several companies offer this option, which uses a single system to remove multiple targeted pollutants from flue gas before it is released into the atmosphere. Through extensive testing, this system has shown it can capture mercury, particulate matter, CO2 and NOX and SOX, halogens, and other heavy metals.
Multipollutant control systems offer extensive benefits to utilities searching for an option to meet deadlines at a less-disruptive cost.
These systems regularly require a lower capital investment than a series of their traditional counterparts needed to eliminate the same number of pollutants. The all-in-one approach also allows systems to be installed quicker and with a smaller footprint.
In addition, some systems use a modular design that ensures scalability and offers the potential removal of CO2, allowing companies to hedge against potential future regulations.
“Multipollutant emissions control systems provide power generators with an all-in-one solution and have the potential to be installed more rapidly and with lower capital investment than a series of traditional scrubber or flue gas desulfurization technologies,” said William J. Sim, Midlothian Associates CEO and former senior vice president of Pepco Holdings Inc. and CEO of Pepco and Atlantic City Electric (ACE). “Customers will benefit from utilities that look for a technology with a quicker installation timeframe that provides a shorter glide path to incorporate compliance costs into their rate structures.
These technologies can be a cost-effective way to continue operating current electric generating units while meeting the newly instituted EPA standards well ahead of the 2015 deadlines.”
The EPA in its preliminary MATS ruling included Eco Power Solutions’ multipollutant emissions control technology on its short list of technologies that “offer the potential of reduced compliance costs and improved overall environmental performance.”
For two years, two units have been operating at the company’s Louisville, Ky., technology center and have demonstrated the ability to reduce emissions of mercury, arsenic, chromium and nickel more than 95 percent and cut NOX and SOX emissions 98 percent.
The system’s capital costs are 25 percent lower than alternatives, and the cost per ton of emissions reduction is 20 to 40 percent lower than traditional technologies.
The technology can be installed and running in 30 months, providing companies the opportunity to bring plants into compliance within the three-year deadline of the MATS rule.
The process captures the flue gas stream, then sprays it with a chemical reagents mist that converts the pollutants into an oxidized, water-soluble compound that is condensed out of the fuel gas into a waste stream that is treated, neutralized and disposed safely.
Figure 1 provides more details. Ozone is injected into the flue gas stream of the power plant to convert NOX into forms that can be extracted more easily and completely.
The exhaust gas then passes through a series of foggers that inject a hydrogen peroxide and water mix into the gas stream to oxidize the pollutants and make them water-soluble.
Removed acids are sent into a condensation collection system for neutralization and eventual disposal.
An injection of water and condensing media remove any remaining acids, heavy metals and particulates, and acids in the wastewater are neutralized using limestone, quicklime or caustic approaches.
Limestone, the lowest-cost method, also releases CO2, which then can be treated.
Another technology on the EPA’s list is a system from Lextran Ltd. This system can reduce SOX by 99 percent, NOX by 95 percent and mercury by 98 percent.
After processing, the catalyst is released and recycled back into the process, leaving by-products that can be transformed into beneficial materials for internal or commercial use. The absorption is realized by reacting the pollutants with the catalyst in a wet scrubber environment process.
ReACT, from Hamon Research Cottrell, is another EPA short-list candidate. It can capture 30 to 60 percent of NOX, 90 percent of mercury and 98 percent of SOX with a net reduction of particulates in the range of 50 percent. This system produces a salable by-product, and the system’s dry process is especially suited for sites with water use, treatment or discharge issues.
How to Win When the Game Has Changed
Between environmental regulations and increasingly competitive alternative fuel sources, the energy game has changed since nearly a century ago when coal-fired generation became America’s primary fuel source.
And the game will continue to change. In addition to addressing MATS, CSAPR and MACT, smart power generators should anticipate further regulations. The EPA’s March proposal to cut CO2 levels at new power plants signals a potential for carbon restrictions for all electricity generators.
The power industry must face the public health costs and disruptive market force of fossil-fired generation and respond with a disruptive technology such as multipollutant emissions control systems.
These innovative technologies offer many beneficial attributes such as overall efficiency, lower capital costs, easy and rapid retrofit, reduced footprint and the potential to address future emissions-reduction requirements.
“For electricity generators to win on this new playing field, they will need to adopt technologies that allow them to continue meeting customer demand reliably and cost-effectively,” Sim said. “Technologies such as Eco Power’s offer the benefits of multipollutant removal in a modular format that has great promise for coal-burning utilities, especially for the smaller units where existing technologies have proved expensive solutions.”
Kevin Crapsey is vice president of corporate strategy and development at Eco Power. He has more than 20 years in energy, environmental and technology industries.