Microturbines today are generating power, either on their own or in combined heat and power installations, on oil and gas platforms, and in transit systems around the world.
Microturbine sales in the US have leveled off while the global market is growing, perhaps accounting for more than 50% of company sales, and the industry is greening itself. For example, Capstone Turbine Corp. President and Chief Executive Officer Darren Jamison announced recently that the company was embarking on a green energy campaign.
Capstone has dominated this market since it sold its first units in 1998, following 10 years of research and development. It has shipped more than 4,000 units in these nine years, while its competitors, including new entrants, have shipped units numbering in the hundreds.
Ingersoll Rand is Capstone’s largest competitor, but is not close to matching the number of units shipped. (The company declines to say what that number is.) It did have an advantage until recently, however, with its 250-kW model (in addition to a 70-kW model), which Capstone didn’t have. Capstone was selling 30-kW, 60-kW, and 65-kW units until it announced the shipment in October 2007 of a $3.8-million order for its new 200-kW microturbines to Greenvironment Oy for biogas applications in Finland and Germany. It had been testing that model since 2004.
What Do The Markets Look Like?
Chip Bottone, president of Ingersoll Rand Energy Systems, says the last two years have been challenging. “I’m optimistic about the future but in the short term, the focus has to be global and on clean power production,” he says.
Bottone said international markets will grow faster primarily because the US has no energy strategy. Meanwhile, demand growth, global warming, and increasingly expensive electricity will spur the US market growth, he predicted.
What would drive the US market forward is the renewal next year of federal production tax credits, business tax credits, and the continuation of incentives. There is the potential that they may not be extended, but conversely, other countries are adopting them, Bottone said.
Furthermore, the industry needs utilities to embrace the microturbine technology. When they were first introduced in the marketplace it was thought that utilities would be the catalyst for applications, since installing them at the point of use would minimize utility investments. But utilities are not compensated for that, Bottone adds.
However, certain niche applications will always exist because of the need for clean, low emission technologies, Bottone said. The hard part to communicate, and what often gets lost, he said, is that combined heat and power installations are 65% to 85% efficient, while utility power plants range in the area of 33% efficiency.
Capstone’s Darren Jamison is touting Russia and China as key markets. He spoke to analysts in the company’s second quarter 2008 fiscal year earnings report in November, saying the company already has several installations in Russia. It has an office in Shanghai and is seeking distributorships in China.
Installations Are Diverse
Two new manufacturing companies have entered the microturbine market in recent years with their own designs. Elliott Energy Systems was founded in Stuart, FL, in 1996, and is still headquartered there. The privately held company was just purchased in November by Calnetix, Inc., based in Los Angeles, CA, which acquired it from Ebara Corp., a Japanese company.
Calnetix manufactures high performance motors, generators, magnetic bearings, and integrated drive systems. The company’s president and CEO, Brad Garner, describes the Elliott acquisition as “a strategic move ... that will enable us to provide a more complete, value-added power system solution for our global customers.”
Elliott manufactures a 100-kW microturbine, which it introduced in 2002. John Holbrook, sales manager, said the company has shipped several hundred units into the global market. In March 2007, it sold its largest order to the North American market. Holbrook says sales are growing in Asia, Europe, Russia, and North and South America, and characterized the market as growing slowly but accelerating every year.
The northeastern US, in particular, is very attractive for CHP, Holbrook says. In Europe alone, the company has put units in an auto dealership, a luxury condominium complex, schools, and medium size manufacturing facilities. In the oil and gas industry, it is installing units on platforms in the North Sea, the Gulf of Mexico, and the North China Sea.
Turbec SpA, a competitor of Elliott in Europe, is headquartered in Italy. It was originally founded by Volvo and ABB in 1998 to redesign a vehicle-based microturbine into a stationery application. Its first commercial model was delivered in September 2000 and commissioned in December of that year. In December 2003, API Com SrI, an Italian company, bought out Volvo and ABB’s shares and formed Turbec SpA in June 2004.
Turbec specializes in biogas applications. It currently has one 100-kW model. It’s not known how many units have been shipped, but there are at least two installations in California. However, it is no longer selling units in North America and its authorized distributors are all located in Europe.
In August 2006, Turbec announced that it was participating in the European Union project called SOLHYCO, in which the Turbec 100-kW microturbine will be driven by hot pressurized air heated to 950°C by a heliostat field of mirrors. The system will be backed up using biofuels to create a sustainable system with zero net emissions.
UTC Power has been very active in the area of combined heat and power and has integrated Capstone microturbines into its CHP installations, rather than manufacturing its own microturbines. UTC partnered with Capstone using funding from the Department of Energy’s (DOE) Advanced Microturbine program to develop its PureComfort combined cooling, heating, and power system, which utilizes 60-kW or 200-kW Capstone microturbines integrated into the system.
The Leader
Capstone can now provide up to 2 MW in one power system by paralleling multiple 200-kW units, just as it has been paralleling its classic smaller size microturbines. For example, in 2002, RMT Inc. designed, engineered, and managed the construction of a 360-kW microturbine plant utilizing 12 of Capstone’s 30-kW units to produce a gas-to-energy project at Antioch Community High School in northeastern Illinois.
The EPA had ordered landfill closure activities to be completed at the HOD Landfill located one-half mile from the school, including a landfill gas and leachate management system. A piping system was constructed to bring the landfill gas to the school to power the microturbine plant and produce electricity and heat the 262,000 square-foot school building.
A 300-kW array of biogas-fueled 30-kW Capstone turbines have been generating power at a San Fernando Valley landfill owned by the Los Angeles County Sanitation Districts, also since 2002.
The 960-kW installation at the Ronald Reagan Presidential Library in Simi Valley, north of Los Angeles, is an interesting but not an unusual application. Utilizing 16 Capstone 60-kW units, UTC installed three PureComfort packages with four turbines each. There are another four standalone Capstone units and a Carrier absorption chiller. These provide 95% of the electricity for the original 100,000-square-foot building and the Air Force One Pavilion that opened in October 2005. The direct exhaust-fired absorption chillers capture the thermal energy from the microturbines to provide 387 tons of refrigeration for cooling both the library and the pavilion.
Then, there is the installation at the SeaGate Convention Centre in Toledo, OH. It installed four Capstone 60-kW units with batteries. During power blackouts, the batteries give the microturbines black-start capability. (A full profile of the installation can be found in an article in the May/June 2006 issue of Distributed Energy entitled, “Toledo Plays with the Big Guys.”)
Hitting the Road
Capstone is pursuing the hybrid bus market and has just received a new order for deliveries to New York City, but details are not yet available. Completed sales include microturbines for three 40-foot hybrid electric buses, each powered by a pair of 30-kW HEV engines purchased by Silicon Valley Power in Santa Clara, CA. They are used as shuttles in the city. Ten HEV buses with 30-kW microturbines operate daily in Newcastle, UK, in its newly renovated quayside area. A fleet of four hybrid electric buses in New Zealand, operating on Capstone microturbines, have amassed a half-million miles of services in 14-hour-per-day schedules.
Of the more than 4,000 sales, Capstone microturbines can be found in luxury hotels in the US and Europe, a chemical production facility in Japan, offshore platforms in the Gulf of Mexico, gas pipelines in South America, and biogas applications on farms in the US and Europe. At an upstream oil extraction site in Russia, a pair of 30-kW microturbines operate on unprocessed wellhead flare gas providing power around the clock to site loads.
In the oil and gas sectors, Capstone microturbines are positioned to be the industry standard for less than 2 MW, says Jamison.
Ingersoll Rand
Ingersoll Rand sells 70-kW and 250-kW models for various applications, including projects to burn coal methane, landfill and digester gas, combined heat and power systems for office buildings and manufacturing facilities. As of August 2006, the company’s installed microturbine capacity was 14 MW worldwide.
Ingersoll Rand shipped its first 250-kW unit in 2004 to the Los Angeles County Lancaster Water Reclamation Plant where it burns digester gas to generate electricity and provide hot water for the plant’s onsite use.
An Ingersoll Rand microturbine is also part of a new compressed natural gas production and processing center at the Solid Waste Authority of Central Ohio in Grove City, OH. The microturbine will generate electricity for the CNG plant, its fueling station, and the administrative and maintenance buildings at the solid waste facility. FirmGreenSM Energy in Newport Beach, CA built the center, which is selling the CNG in addition to fueling the solid waste facility’s fleet.
In 2005, IN-based Utilimaster Corp. had installed a natural gas-fired combined heat and power system utilizing an Ingersoll Rand 70-kW unit. The electricity generated is used in Utilimaster’s facility, while the exhaust heat is used in three processes: it heats hot water used to regenerate a custom-designed desiccant wheel, which removes humidity and maintains air temperatures. Another portion of the hot water is used to preheat makeup air for a drying oven. Finally, additional exhaust heat is directed to the paint-curing booth.
In Emeryville, CA, Ingersoll Rand designed and installed a 750-kW energy system at EmeryStation, a 440,000-square-foot office, laboratory, and retail development. Ingersoll Rand owns and operates the energy system and sells the electricity and thermal energy to Emery Station at a discounted rate. The three 250-kW microturbines supply 30% of the building’s base electrical load. Water is heated by the exhaust heat for process and space heating. (For an in-depth profile of this project, see the article, “Taking a Chance on Microturbines,” in the September/October 2007 issue of Distributed Energy.)
On a smaller scale, Ingersoll Rand’s first agricultural installation was at Valley Fig Growers of Fresno, CA, the largest fig grower in North America. The 70-kW microturbine will burn digester gas coming from a covered lagoon digester to generate electricity and hot water. Mike Emigh, president of the company states that the $1.2 million wastewater treatment system will lower discharge levels of organic waste to the city of Fresno sewage system by as much as 90%, reduce Valley Fig Growers’ costs, and free up electric capacity.
In February 2007, Ingersoll Rand signed an agreement with UTC Power to incorporate its 250-kW unit into UTCs combined heating and cooling power systems that it sells in a diversified commercial marketplace. Until this year, Capstone was the sole supplier of microturbines to UTC. Tracy Reid, director of energy solutions for Ingersoll Rand Energy Systems, states, “This agreement opens new sales channels that align with Ingersoll Rand’s strategic growth objectives and increases our ability to deliver effective energy solutions for our customers.”
Finally, Ingersoll Rand reports that Singapore has begun to implement pro-distributed-generation policies and the city of Shanghai has implemented a policy supporting high-efficiency combined heat and power projects. In 2006, the company received what it said was the first grid-parallel permit from the government with a microturbine-based CHP project at the Munhang Industrial Estate.
DOE-Funded Research
The DOE funded a six-year program for $60 million that began in 2000 and concluded in 2006. Under the Advanced Microturbine Systems Program Plan, it signed cooperative agreements with Capstone, General Electric, Ingersoll-Rand, Solar Turbines, and UTC to develop the next generation of ultra-clean, high-efficiency microturbine product designs. Each of the companies shared partnerships with each other and with Kyocera, Honeywell Ceramic Components, and the University of California–Irvine, among others during the research phases.
The DOE asked the companies to improve fuel-to-electricity conversion efficiency to at least 40%, reduce nitrogen-oxide emissions to below 7 ppm, improve durability, reduce power costs to less than $500 per kilowatt-hour, and increase fuel flexibility. Not many of these objectives were met.
Capstone Develops 200-kW and 65-kW Models
Donald Geiling, microturbine project manager in the DOE’s National Energy Technology Laboratory, says Capstone was the only company to actually commercialize a product as a result of the program. The company accomplished two results with this funding, which was initially designated for development of its 200-kW microturbine. At the same time, Capstone developed the ultra-low emissions system used in its 65-kW unit that was released in October 2007. This unit is part of an integrated combined heat and power package and meets a minimum efficiency value of 60%.
The 65-kW unit was certified by the California Air Resources Board to meet its 2007 emission standard and has nitrogen oxide emissions below 0.07 ppm, carbon monoxide emissions at 0.10 ppm, and volatile organic compounds at 0.02 ppm. It combines ultra low emission lean premix combustion technology with a catalyst that requires no scheduled maintenance for the life of the system.
Ingersoll Rand Drops Ceramic Rotor Work
Ingersoll Rand’s DOE-funded project was to develop a ceramic microturbine, but after more than two years’ work, the company lost interest in continuing on the project because it didn’t fit into the company’s near-term business goals. It determined that business returns on the project would be longer than five years away and would require more than $5 million of additional funding, something that was not in their best business interest.
The project design in September 2000 was to develop and test a ceramic rotor for use in a microturbine with a firing temperature around 1,800°F. Metallic alloys would have been used for the turbine housing, downstream section, and recuperator. By the time it stopped work on the project, it had fabricated the rotating group, including a Kyocera nitride ceramic rotor and Inconel power turbine rotor.
GE Prototype Fails
Starting in October 2000, GE began to develop the next generation microturbine system. The 175-kW prototype “suffered a life-ending failure” in 2006 during testing to gain data at greater than 50% speed. The goal to demonstrate 35% efficiency was not achieved, but several advances were made. These included a significant improvement in the design of combustion systems. The combustor design featured the integration of combustion technologies associated with two distinct geometries, annular and can. This novel system produced world-leading emissions levels, according to Geiling. The combustion system design is now being considered for use in larger product line gas turbines.
Another significant achievement in the project was the demonstration of a novel casting method. This led to GE producing the thinnest casting ever of a GE-proprietary hot-gas-path material labeled GTD-222, used in many other hot-gas-path applications. Thinner castings are lighter and cost less.
Solar Turbines Develops Recuperator
Solar Turbines Inc., based in San Diego, signed the agreement with the DOE before its management decided to drop its microturbine product and focus on turbines 1 MW and larger. Doug Gyorke, acting division director at the National Energy Technology Lab, and a colleague of Geiling’s, says Solar then decided to apply its award to work on a new recuperator for microturbines that also could be used for its Mercury 50 turbine, then in development.
Gyorke says Solar developed a new alloy that is able to withstand higher temperatures of gas combustion and avoid the corrosion caused by water vapor and other gas compositions. He said the research was beneficial. The alloy is available and at a lower cost than other metals for microturbines.
UTC Adapts Rankine Cycle
United Technologies Corp. completed work on adapting an organic Rankine cycle as the bottoming cycle for its Power PureCycle system integrated with two Capstone 200-kW microturbines. The organic Rankine cycle recycles heat from the microturbine exhaust, or from any waste heat stream, and converts it into electricity without producing pollutants. Measured output during the final testing was 465 kW.
By using a water-cooled condenser with the recuperator instead of an air-cooled condenser, the efficiency of the Rankine Cycle portion of the cycle was increased from 9% to 13%.
UTC also found that ceramic turbine components can be designed and coated to meet realistic microturbine performance and life targets. It also found that a statically and dynamically stable natural gas-fired microturbine combustor can be designed to achieve ultra-low emissions over a wide turndown range.
Honeywell Investigates Manufacturing Process
Honeywell Engines, Systems and Services in Phoenix intended to design and develop a high-efficiency, low-emissions, and durable microturbine system with its DOE award, but restructuring at Honeywell and corporate decisions forced the division to abandon the original project. Honeywell and the DOE restructured and descoped it to investigate various manufacturing process issues.
Honeywell demonstrated a manufacturing process for ceramic gas turbine engine components, in particular, a ceramic nozzle ring. It also investigated the effects of heat treatment processes and process reproducibility in which a ceramic generic nozzling ring design was processed producing multiple parts per week.