Once touted as the savior of coal power and the future of clean coal generation, integrated gasification combined cycle (IGCC) technology has seen its prospects swamped by soaring costs and technological challenges. Though it remains controversial, its proponents are not ready to give up.
If you’re an energy sector observer with an interest in integrated gasification combined cycle (IGCC) generation, the last few years have been much like attending a performance of Samuel Beckett’s classic play, Waiting for Godot, in which the performers spend two acts tediously waiting for someone who never appears. And, much like Beckett’s characters, who are never quite sure if they’re waiting in the right place or are unknowingly repeating the same scene each day, the generators working on IGCC have been struggling for years to find a viable path forward.
The newest operating IGCC plant in the U.S., Duke Energy’s Edwardsport Generating Station in Indiana, has struggled to maintain consistent operations since coming online last June (though it was still named a POWER Top Plant for 2013). Duke stated at the time that it planned to slowly ramp the plant up to full operation, and in that at least, it has fulfilled expectations. It reached 60% capacity in August, only to suffer mechanical failures this past winter that reduced output to a trickle in January and February. Duke said things improved later in the spring, but CEO Lynn Good acknowledged in the company’s first-quarter earnings call, “Edwardsport is a large, complex project, and it has taken time to work out technical issues.”
Edwardsport reached commercial operations two years late and about $1.5 billion over budget, but that record fairly shines in comparison to Mississippi Power’s Kemper County project, which will be the first to incorporate carbon capture and storage (CCS) technology (Edwardsport is “CCS-ready” but does not have it installed). The Kemper County plant has seen costs spiral from an initial estimate of $2.2 billion to more than $5.5 billion in the most recent revision in April. That update again pushed out the plant’s in-service date to May 2015, a year beyond the original plan. Missouri Power’s parent, Southern Company, blamed early miscalculations on the type and amount of piping needed for many of the problems. With the state having set a cost cap of $3.87 billion, the overruns have cost Southern about $1.6 billion.
None of this has stopped the U.S. Department of Energy (DOE) and the Environmental Protection Agency from touting IGCC with CCS as the future of coal generation. “I consider seeing this plant a look at the future,” DOE Secretary Ernest Moniz said at an event at Kemper County last November. “We’re going to need not 10, maybe 100 more of these plants across the country.”
Yet only two other such plants are under active development in the U.S., the Texas Clean Energy Project (TCEP), near Odessa, and Hydrogen Energy California, planned for a site near Bakersfield; both are still in search of financing despite years of work (see “Is Polygeneration the Future for Clean Coal?” in the March 2014 issue). Most recently, in April, developer Summit Power requested yet another extension from the DOE, with financial closing now hoped for in June 2015. Director of Projects Laura Miller said the company’s goal between now and then is to cut “hundreds of millions” of dollars from the current $3.5 billion estimate.
These numbers are naturally a deterrent to future investment. Jeff Phillips, manager of the Electric Power Research Institute’s (EPRI’s) Advanced Fossil, Carbon Capture, Utilization and Storage research program, told POWER, “The combination of the substantial cost overruns at the two U.S. IGCC projects built this decade and relatively low natural gas prices present in North America has dried up interest in IGCC among U.S. power producers.”
Overseas, the picture is more nuanced.
According to the Gasification Technologies Council (GTC) database, there are only six commercially operating coal-fired IGCC plants worldwide, including Edwardsport. Of those, four came online in the 1990s and one, at Nakoso, Japan, in 2007 (Figure 1).
|1. Trailblazer. The 250-MW IGCC demonstration plant at Nakoso, Japan, owned by Mitsubishi-Hitachi Power Systems, has been operating successfully since 2007. Courtesy: MHPS|
A seventh plant, China’s GreenGen project in Tianjin, has mostly completed the second phase of its development in which the first, 250-MW unit has been successfully fired on syngas, though it is not yet fully commissioned. A second, 400-MW plant is under development on the same site.
Worldwide, according to DOE and GTC data, about a dozen coal-fired IGCC projects are in various stages of active development, though the commercial prospects for several of these are doubtful. About five or six appear to be under construction, though reports conflict. Nearly all of them seem to have experienced varying degrees of cost overruns, delays, and doubts about their viability.
GreenGen, for example, was originally planned for full operation in 2015, but completion has now been pushed out to 2020. The cost overruns for the project are not publicly known, but reports suggest they have been substantial. (The developer, Huaneng Group, is a state-owned firm.)
There are success stories, however. Mitsubishi Heavy Industries’ thermal power division (now part of Mitsubishi Hitachi Power Systems, MHPS) began developing the 250-MW IGCC demonstration plant at Nakoso in Fukushima Prefecture in the early 2000s, and brought it online in late 2007 (when it was named a POWER Top Plant). The plant uses a single MHPS 701DA turbine that burns syngas from an air-blown gasifier. It operates at 42% net efficiency and has achieved very low SOx and NOx emissions of 1.0 ppm and 3.4 ppm, respectively.
MHPS is actively marketing its IGCC technology and believes that efficiencies over 48% are achievable with its advanced G-series gas turbines operating at higher inlet temperatures. Despite the high costs experienced with current IGCC projects in the U.S., MHPS believes such plants can be competitive with conventional coal generation.
According to Terry Fujino, project coordinator and manager, boiler and IGCC engineering, for MHPS, the Nakoso plant has met and exceeded all performance guarantees and targets since it began initial operation. In April 2013, it was transferred to commercial operation and renamed as Unit 10 of Nakoso Power Station.
Based on the results at Nakoso, Tokyo Electric Power Co. has announced plans to build two new coal-fired IGCC plants in Fukushima Prefecture with outputs of approximately 500 MW each, using the same air-blown MHPS gasification technology as the Nakoso plant.
Room for Progress
One thing on which there is agreement is that IGCC is a technology with a lot of efficiencies and improvements remaining to be captured. A 2012 report from EPRI lists a number of areas in which IGCC plants can be made more economical and productive:
■ Advanced air separation methods to improve efficiency of oxygen firing.
■ Improved designs and materials to increase gasifier component life and to allow larger gasifier sizes and higher gasifier pressures.
■ Use of flue gas or other low-grade heat sources to reduce costs and energy consumption for coal drying.
■ “Dry solids” pumps or use of supercritical CO2 instead of water for preparing coal slurry.
■ Higher-temperature particulate removal devices and hot gas desulfurization.
■ Advanced shift catalysts using less steam, and membrane separation of CO2 and H2.
■ Hydrogen-firing gas turbines, improved aerodynamics, and materials advances to allow higher firing temperatures and larger blade sizes that improve efficiency and output.
Research into all of these areas is ongoing, though commercialization is closer for some than for others. Recent improvements in natural gas–fired turbine performance are also applicable to this field, and advanced turbines optimized for IGCC are in development by GE, Siemens, and MHPS. Gasifier technology is also a robust area of research and development.
What happens next may depend in large part on the success of the new Asian plants. “If those projects can avoid the large cost overruns that were encountered by the U.S. IGCC projects,” Phillips said, “it will open the door to more IGCC projects not only in Asia but possibly elsewhere. If they cannot, it could doom the technology.”
The generators and manufacturers are so far undaunted. Fujino said MHPS “continues to move forward on IGCC and gasification projects.”
Duke Energy’s Good, for her part, was optimistic about Edwardsport in the same earnings call. “Since the in-service date we have been monitoring our success by progressing through GE’s new product introduction protocol, conducting detailed performance testing and optimization procedures, and obtaining valuable operating experience with the new facility,” she said. “All major technology systems have been validated and we continue to focus on final performance testing and optimization. We are on track to be within the total revised project estimate of $3.5 billion.”
Stay tuned. Godot may yet put in an appearance. ■
— Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine).