After Gutenberg

Green Car Congress schematic of GE Gasifier in an IGCC application

The European Network of Energy Agencies initiated the ATLAS Project, a major initiative aimed at establishing an information base to support energy research and technological development, on behalf of Directorate General XVII of the European Commission. One principle project focus is combined heat and power (CHP), a.k.a., co-generation.

More specifically, the Atlas Project involves research into development of combined cycles. Whereas co-generation can mean the use of waste heat for many different processes, such as space heating or drying, combined-cycle power generation is a two-cycle process. Electricity generation comes from the gas turbine generator and from the HRSG (Heat Recovery Steam Generator). The term, “combined cycles”, means that the heat from the first cycle is used to run a second cycle.

The gas turbine (Brayton) cycle is one of the most efficient cycles for the conversion of gas fuels to mechanical power or electricity. The use of distillate liquid fuels, usually diesel, is also common where the cost of a gas pipeline cannot be justified. Gas turbines have long been used in simple cycle mode for peak lopping in the power generation industry, where natural gas or distillate liquid fuels have been used, and where their ability to start and shut down on demand is essential. Gas turbines have also been used in simple cycle mode for base load mechanical power and electricity generation in the oil and gas industries, where natural gas and process gases have been used as fuel. Gas fuels give reduced maintenance costs compared with liquid fuels, but the cost of natural gas supply pipelines is generally only justified for base load operation. More recently, as simple cycle efficiencies have improved and as natural gas prices have fallen, gas turbines have been more widely adopted for base load power generation, especially in combined cycle mode, where waste heat is recovered in waste heat boilers, and the steam used to produce additional electricity. Atlas Project Overview of Gas Turbines

In regard to research into combined cycle power generation, one promising area of development, within the Atlas Project and elsewhere in the world, e.g., China and United States, is Integrated Gasification Combined Cycles (IGCC).

It is possible to build a power station where a gas turbine (GT) is used to generate electricity, and the waste heat from the GT is used to raise steam to generate additional electricity via a steam turbine. This system is known as a combined cycle. Where the GT is fired on a gas fuel derived from the gasification of liquid or solid carbonaceous materials, the cycle is known as an Integrated Gasification Combined Cycle (IGCC). IGCC’s are able to convert “difficult” liquid and solid fuels to electricity at high efficiencies and with low emissions. The IGCC (technology) benefits from the continuous development effort being expended on GT’s to raise their efficiency and performance.

When the European Commissioner for Environment recently addressed a business summit in Brussels, a theme that he stressed was increasingly scarce resources: air, water, energy and raw materials. IGCC is one technology that shows considerable promise in responding to such challenges.

One of the first things that Jeff Immelt did when he took over as GE’s Chairman and CEO was to purchase the patent on a coal gasification process from Chevron Texaco in 2004. from Chevron. Thus, syngas is one of the clean energy markets in which GE has invested substantially, part of an overall, Ecomagination business strategy of one of the world’s leading suppliers of power generation and energy delivery technology. As recently stated by Robert Kelly, Executive Officer of DKRW, a company that is building a clean coal plan in Medicine Bow, Wyoming:

“We chose GE because of its leadership in the coal gasification technology industry. We believe that utilizing US-based technology, such as GE’s, is an important step in making the US less dependent on foreign energy sources while improving its technology for the future.”

GE is focusing efforts on large-scale production, e.g., whereby power generation companies can increase the renewable energy component to meet renewable portfolio standards and / or their own commitment to cleaner energy. Smaller-scale CCGT could use turbines from Honeywell, Capstone, Ingersol Rand, or Elliott Energy.

As an example of recent development in large-scale power production, a proposed power generating station near Taylorville in Christian County, Illinois will be one of the first full-scale integrated gasification combined-cycle (IGCC) plants in the country. Illinois basin coal will fuel the plant, which is expected to to generate approximately 770 gross megawatts of power. GE will provide the process design for the gasification portion of the facility and the power island. Initially, the plant was designed to be a pulverized coal facility.

As a related example of recent development in smaller-scale power production, research results strongly suggest that Gas Turbine Combined Cycle is a crucial factor in the energy and emission benefits of biofuel production. There also is research into the production and use of DME by means of gas turbine combined cycles, plus promising initial results from combining fuel cells with gas turbines.

One of the principle reasons for examining this area of energy research and technological development is assessing its potential as alternative energy policy. As Frank Verrastro, Director and Senior Fellow of the Energy Program at the Center for Strategic and International Studies, recently observed, “our nation’s current energy strategy is clearly unsustainable.”

A value of vehicles that obtain power from the grid — battery powered all-electric vehicles, plug-in hybrid electric vehicles and plug-in, fuel-cell vehicles — is when combined cycles provide the generation, then while driving cleaner, cheaper, all-electric miles we use quite a bit less petroleum.

Engineer-Poet has performed some calculations:

Combined-cycle gas turbines turn fuel into electricity at about 50% efficiency; allowing 7% for transmission losses, 10% each for charger and battery losses and 20% at the motor, the overall efficiency would be 30.1%. Compared to burning fuel in a 17% efficient car you could burn the oil in CCGT plants, get 77% more miles per gallon and still have the steam-turbine exhaust for industrial process heat.

And, there are reasons, closer to home, why this post focused on combined cycle power generation. Not only is the location of the GE Global Center in New York State, but NYSERDA also has sharpened its focus on such a renewable energy strategy.

Despite that synthetic fuels do poorly in terms of aggregate increases in green house gases, the EPA gives a green light to clean coal technologies. And, there are other disadvantages. Mike Millikin notes:

“The Fischer-Tropsch process takes a synthesis gas (syngas) rich in hydrogen and carbon monoxide and converts it catalytically to liquid fuels and chemicals. The synthesis gas is produced by the gasification of carbon-bearing feedstocks (coal, biomass) or by the reforming of natural gas.”

With methane reforming of landfill gas there are heavy hydrocarbons (both aliphatic and aromatics such as benzene) as well as numerous chlorinated hydrocarbons and these trace compounds are in some cases toxic or hazardous and also cause rapid failure or engine and turbine components.

For more about IGCC, refer to the Energy Blog.