Washington, DC — An innovative clean coal technology project in Texas will supply electricity to the largest municipally owned utility in the United States under a recently signed Power Purchase Agreement, the U.S. Department of Energy (DOE) announced today ( January 17, 2012).

Under the agreement – the first U.S. purchase by a utility of low-carbon power from a commercial-scale, coal-based power plant with carbon capture – CPS Energy of San Antonio will purchase approximately 200 megawatts (MW) of power from the Texas Clean Energy Project (TCEP), located just west of Midland-Odessa.

The 400-MW TCEP plant is a first-of-its-kind Integrated Gasification Combined Cycle (IGCC) poly-generation facility believed to be the cleanest coal-fueled power plant operating anywhere in the world. The facility is capable of capturing 90 percent of the carbon dioxide (CO₂) it produces, as well as 99 percent of sulfur dioxide, 90 percent of nitrogen oxide, and 99 percent of mercury.

TCEP was a third round selection under DOE’s Clean Coal Power Initiative, a cost-shared collaboration between the Federal government and private industry aimed at stimulating investment in low-emission coal-based power generation technologies through successful commercial demonstrations. The $2.4 billion plant will receive $450 million in funding from the Clean Coal Power Initiative; of this, $211 million comes from the American Recovery and Reinvestment Act of 2009. The facility is expected to be fully operational in 2015.

Many experts view gasification technology as the future for coal-derived electricity. DOE’s Office of Fossil Energy has been instrumental in the research, development, and deployment of IGCC and other innovative energy technologies and is playing a pivotal role in advancing America’s energy future while helping to enhance environmental protection.

Gasification uses oxygen and steam at high pressures to convert coal into synthesis gas, also known as syngas, which is mainly a mixture of hydrogen and carbon monoxide. In a non-carbon-capture plant, the syngas is cleaned to remove impurities and sent to a gas turbine where it undergoes combustion to produce electricity. The hot flue gas from the gas turbine, containing CO₂, is used to generate steam, which is fed to a steam turbine to produce additional electricity and then vented to the atmosphere. This process is known as integrated gasification combined cycle (IGCC) because coal-fired gasification is integrated into a combined-cycle system that produces electricity from both the gas turbine and the steam turbine.

In the TCEP carbon capture plant, the carbon monoxide in the syngas will first be “shifted” to produce additional hydrogen and CO₂, cleaned of impurities, and then separated into pure streams of hydrogen and CO₂. The hydrogen will be combusted in an advanced combustion turbine, producing a carbon-free flue gas. Of the nearly 2.9 million metric tons of CO₂ that will be captured annually at the TCEP plant, approximately 83 percent will be used for enhanced oil recovery in the West Texas Permian Basin, a process that both prevents the greenhouse gas from entering the atmosphere and enables more oil to be produced from regional oilfields; the remainder will be to produce urea, a high value product. The production of a co-product in addition to electricity significantly improves the overall economics of the process.

Compared to traditional power plants, IGCC offers many advantages, including increased power plant efficiency and resulting lower-cost electricity. Unlike conventional power plants that remove environmental contaminants from the large-volume nitrogen-containing flue gas after combustion, IGCC power plants remove contaminants before combustion. Because gasification plants operate at high pressure with oxygen instead of air, the volume of gas that has to be treated is nearly two orders of magnitude lower, making the removal of environmental contaminants much easier. In addition, CO₂ is much easier to capture and is produced at higher pressures than that from conventional power plants.

Today, approximately 80 percent of the energy consumed in the United States comes from coal, petroleum, and natural gas, with coal-fired power plants accounting for approximately half of the electricity generated. With increasing global energy demands, coal is expected to continue to play a dominant role in meeting future energy needs. The implementation of clean, state-of-the-art coal-based technologies will ensure America’s energy security while mitigating the environmental impacts of fossil fuel use.

Source: US Department of Energy

Duke Energy Corp. subsidiary Duke Energy Indiana Inc. has informed Indiana officials that it could take more than three years and $380 million to equip the Edwardsport IGCC power plant, now under construction, with carbon capture equipment.

The $380 million does not include the cost for carbon storage, Duke said in a June 24 executive summary report that it filed with the Indiana Utility Regulatory Commission. The price would be outside the $2.72 billion cost cap Duke has proposed for the coal gasification power plant.

In the executive summary report, Duke Energy Indiana discussed its front-end engineering and design study for the plant. Parts of the report were not made public for confidentiality reasons.

Duke said this is the most detailed review to date of retrofitting any type of commercial coal plant with carbon capture. A Duke spokeswoman said recently that the integrated gasification combined-cycle plant is 75% complete and expected to enter service in 2012.

The state had ordered Duke to investigate carbon capture as a condition of the certificates of public convenience and necessity Duke received for the IGCC in November 2007.

In early 2009, Indiana approved Duke’s rate recovery of up to $17 million for the carbon capture study. The company has deferred about $15 million of study costs on its accounting books and records and accrued an additional $1.3 million of carrying costs through May 2011.

Also, Duke has filed a request to do a study of carbon storage options related to the Edwardsport IGCC, with a phase one site assessment and characterization study estimated to cost $42 million. That case is pending before the IURC.

As for the carbon capture retrofit project, it consists of a CO2 capture unit, a CO2 compression unit and CO2 dehydration unit, as well as supporting balance-of-plant systems.

The nominal rate of CO2 capture predicted in the FEED study is 23%, on the basis of carbon converted during the gasification of the coal feedstock. The estimated net power loss from implementing carbon capture is 54 MW, which would reduce the nominal net power output of the IGCC power plant to 564 MW, Duke said in its filing. The plant is scheduled to use locally mined Indiana coal.

Duke said it expects the carbon capture project to take 39 months to complete once regulatory permits are obtained, with capital costs an estimated $380 million. In the coming months, Duke will continue to evaluate the carbon capture study results along with the various carbon storage options.

The companies that worked with Duke on the study included General Electric Co. and Burns & McDonnell Engineering Co. Inc.

source: SNL Energy by Wayne Barber