Energy solutions for a cleaner world

By Kate Brass

North America and around the globe, power producers and consumers continue to seek new and innovative ways to generate electricity while preserving the world's natural resources and reducing their impact on the environment.

GE Energy, one of the world's leading suppliers of power generation technology and services, is committed to the development of alternative and renewable energy solutions. Numerous GE Energy products are certified under ecomagination, a corporate-wide initiative to aggressively bring to market new technologies that will help customers meet pressing environmental challenges.

Two examples within the GE portfolio are integrated gasification combined-cycle (IGCC) or "cleaner coal" technology; and the use of biogas (including methane created through the digestion of agricultural or animal waste) as a fuel to generate electricity to support a farm's onsite power/heat requirements and potentially the local transmission grid.

GE's Jenbacher Gas Engines

GE Energy's Jenbacher business, based in Austria, is a leading provider of advanced gas engine technology that is durable and flexible enough to handle the fluctuating quality of a variety of specialty gases, including biogas generated from the anaerobic digestion of animal waste (cow manure, for example)-an application that is beginning to take hold in both Canada and the United States after being widely practiced in Europe for decades.

Biogas is an attractive alternative to conventional fuels in areas where the waste fuel source and the energy demand are co-located. Using biogas for power generation allows for economic, highly efficient combined generation of power and heat. The residual products from the biomass fermentation process provide additional benefits to the process as it can serve as valuable fertilizer that can be used by the operator or sold to create a revenue stream.

Biogas digester projects provide a way to capture and reduce the ventilation of methane, a potent greenhouse gas, which aids U.S. and Canadian efforts to reduce their respective industrial greenhouse gas emissions levels.

The benefits of biogas power generation are being realized today on a 36,000-head feedlot in Vegreville, in the Canadian province of Alberta. As part of a pilot-scale project, Highmark Renewables has installed a one-megawatt (MW) GE Energy-Jenbacher cogeneration system to utilize the biogas created during the anaerobic digestion of cow manure.

The application is also becoming increasingly popular in dairy regions of the United States, including the Norswiss Farm in Wisconsin, where GE Energy supplied a Jenbacher JMS 316 generator set that was installed by the Dairyland Power Cooperative as part of a cow manure digester-biogas project. The Jenbacher unit was commissioned in March 2006, and generates 848 kilowatts (kW) of electricity. Thermal power from the system is used to heat water to support the manure digestion process.

The demand for GE's Jenbacher biogas engines for such methane-digester projects has been steadily growing in North America, driven by new regulations and incentives adopted in both countries to promote the development of new renewable energy sources.

A Cleaner Choice for an Abundant Fuel

Historically, the use of coal-one of the world's most abundant fuels-has been associated with concerns about increased air pollution. IGCC power systems provide a cost effective way to reduce the emissions levels associated with power generation from pulverized coal.

Gasification technology has been available and proven for many years but has experienced a number of barriers to widespread commercialization, including cost and the perceived performance challenges relative to other technologies such as pulverized coal and gas turbine combined cycle.

GE has resolved these challenges by creating an IGCC product offering that integrates gasification and power generation technologies. GE created a single-point IGCC solution for customers, by forming an alliance with Bechtel Power, to develop a standardized commercial offering for projects in North America. This turnkey reference plant has been designed for optimized plant performance and reliability, while also providing the commercial cost, schedule and performance guarantees required for a customer to confidently move forward with a project.

Three of the key focus areas for the reference plant design are environmental performance, capital cost and cost of electricity. One of the critical drivers for IGCC is its strong environmental performance; emissions targets set for the reference plant design approach the emissions achieved by natural gas combined cycle plants.

Historically, an IGCC plant would cost 20-25 percent more than a comparable supercritical pulverized coal (SCPC) plant. The GE and Bechtel alliance's reference plant is targeted at cutting the capital cost premium for IGCC in half for a state-of-the-art, greenfield pulverized coal plant of the same size. This reduction will be realized as the volume of plants in operation increases over time. Early cost premiums can be offset by incentive programs such as the Federal Investment Tax Credits (ITC) and state and local incentive programs.

Another measure of critical importance to power generators when evaluating their new generation alternatives is the cost of electricity. Environmental benefits of IGCC will reduce the cost of electricity from avoided emissions credit costs. IGCC's emissions are 33 percent to 90 percent lower than a comparable SCPC plant equipped with state-of-the-art emissions control equipment. When combined with an IGCC plant's lower water usage, reduced waste disposal costs and potential to use lower cost fuels, electricity cost is further reduced.

Another factor that must be considered is the likelihood of a coal project being permitted. Coal plants have come under greater scrutiny and public resistance. Several coal projects have recently been cancelled. Failed projects ultimately drive utilities to higher cost sources of electricity or failure to meet demand. Because of its superior environmental performance, IGCC is more likely to receive public and government support towards successful permitting.

With carbon constraint regulations approaching on the regulatory horizon, coal plants are likely to be required to capture and sequester CO2 (or purchase carbon credits). In this context, IGCC becomes a better solution both economically and environmentally than other coal-to-power solutions. The IGCC cost of electricity with 90 percent CO2 capture is projected to be 10 percent lower than that of an SCPC plant. IGCC has the advantage of being carbon-capture ready today and has the proven technology necessary to capture CO2 at commercial scale. Currently 25 GE gasification plants are capturing CO2 at levels up to 90 percent and 22 GE gas turbines are operating on hydrogen-rich fuel gas (up to 90 percent H2).

At GE, we're taking a new approach to solving some of our customer's toughest environmental problems as part of our ecomagination program. IGCC and Jenbacher Gas Engines are just two of the many products and services that we're bringing to market as part of our commitment to developing new, cleaner energy technologies. We are focused on continuing to find ways to develop new technologies that will use low-grade, waste and renewable fuels to meet the energy demands of a growing world. To us, it's about smart, resourceful-and sometimes unexpected-solutions to our customers' everyday challenges and helping address some of the world's most pressing environmental dilemmas, today and for generations to come.

Further information is available at www.gepower.com/ecomagination .

Kate Brass is Ecomagination Program Manager at GE Energy.

November/December 2007