Energy efficiency driven by turbine replacement and upgrades

Paul Boughton

As the demand for electricity continues to grow around the world, the need for new and uprated turbines is also forging ahead. Sean Ottewell reports.

Emerson Process Management has successfully replaced existing controls on the Nikiski generation plant’s GE Frame 6B gas turbine with its Ovation control technology.

This marks one of the few times an outside vendor has been chosen to retrofit Mark VI controls, says Emerson. The plant, owned and operated by Homer Electric Association (HEA), is located southwest of Anchorage, Alaska (Fig. 1).

The controls replacement project was part of the first phase of a two-phase initiative to convert the 40MW, simple-cycle power plant to a 60MW, combined-cycle facility. The resulting 45 per cent increase in generation capacity with a minimal increase in fuel consumption will enable HEA to cost-effectively meet the electricity needs of the Kenai Peninsula.

An additional 20MW capacity is available through the use of duct-firing capability built into the existing heat recovery steam generator (HRSG). This brings the total plant capacity to 80MW, but requires additional fuel consumption.

In addition to replacing the Mark VI turbine controls, Emerson integrated the GE EX2100 excitation system into the new Ovation system, enabling it to remotely control its own functionality. Emerson also provided a simulation solution, which is used to test and verify control logic, as well as to train operators on the new system; and a remote dispatch capability that will give HEA greater operational flexibility and efficiency.

“As part of this major effort to convert the plant to a combined-cycle facility, we wanted to take advantage of every opportunity to ensure the plant would operate at peak efficiency for years to come,” said Brad Zubeck, programme manager for HEA.

“Moving to a single control platform is advantageous for many reasons, among them the ability to have tighter overall control of plant operations, as well as a clearer view of key plant and turbine parameters.”

Emerson’s comprehensive solution for phase one also included its AMS Suite predictive maintenance software for more efficient management of intelligent field devices, as well as its CSI 6500 Machinery Health Monitor. The CSI 6500 will enable HEA to detect turbine problems before they become critical by delivering comprehensive, real-time information that includes prediction, protection and performance monitoring, all fully integrated with the Ovation control architecture.

With phase one completed and the combustion turbine back in operation, phase two is now under way. Emerson is further expanding the plant’s Ovation system, providing direct control and monitoring of the upgraded HRSG, burner management system, feedwater and water treatment systems, substation equipment and balance-of-plant processes. The Ovation system will also provide supervisory control of the new steam turbine. [Page Break}


Alstom has been awarded two long term service agreement (LTSA) contracts for GT13E2 gas turbines in the Ivory Coast and Jordan.

The contract for the Azito power plant in the Ivory Coast covers a 15-year period and includes the delivery of spare parts, reconditioning services and inspection supervision for the gas turbines and generators. The contract for the Samra III power plant in Jordan spans a ten-year period and includes the delivery of new and reconditioned parts as well as supervision manpower for the execution of major inspections on all three GT13E2 units installed at the plant.

The Azito power plant, owned by Azito Energie, consists of two GT13E2 gas turbines operating in single cycle mode and is located close to the country’s capital Abidjan. The plant provides 288 MW of electric power to the grid and accounts for approximately 35 per cent of the total electricity production in the Ivory Coast.

For the Samra III power plant, owned by Samra Electric Power, Alstom has already provided two GT13E2 gas turbines and will commission the third turbine, generator and auxiliaries by summer 2013. In addition Alstom is currently supplying a steam tail to convert the existing Samra III 285MW single cycle to a combined cycle power plant. This conversion will increase the plant’s power generation capacity by an additional 143MW and is scheduled to enter commercial operation in 2015.

Hans-Peter Meer, senior vice president of Alstom Thermal Services, said: “These new service contracts confirm Alstom’s strong position in servicing and maintaining gas turbines and generators. Both the Azito and Samra power plants are located in regions with extreme climate conditions where reliable power generation is key. Alstom’s technology, solutions and services support our customers’ needs in these regions and we are committed to further building strong relationships with the local power producers.”

Proven solutions

To help meet the region’s power demands, Montana-Dakota Utilities (MDU) is to install a GE 7E 3-series gas turbine, formerly known as 7EA, adjacent to Montana-Dakota’s coal-fired Heskett generating station near Mandan, North Dakota. Operating on pipeline natural gas, the 7E 3-series will generate 88 MW of power when it begins commercial service in 2014.

“We needed to add a reliable, proven gas turbine to our fleet, to ensure that we can meet our growing capacity needs,” said Alan Welte, generation director for MDU. “We are confident in GE technology and were looking for a gas turbine that is highly reliable and cost-effective.”

The 7E 3-series gas turbine features low emissions. Operating with GE’s Dry Low NOx combustion technology, the 7E 3-series can achieve industry-leading emissions, enabling users to meet today’s increasingly stringent air quality standards (Fig. 2).

“Due to the simplicity of its durable architecture, the 7E 3-series gas turbine offers industry-leading starting reliability and can come to full speed in less than ten minutes,” said Paul Browning, president and ceo thermal products, GE Power & Water. “This allows the 7E 3-series to excel in peaking power applications, also making it an excellent fit for the quick addition of supplemental power to compensate for the intermittency of renewable energy.“

Finally, Hitachi has received an order from its Indian partner BGR Energy Systems and NTPC for two steam turbine generators for the Lara super thermal power project - a new 800 MW supercritical coal-fired power plant in the Indian state of Chhattisgarh.

NTPC is currently planning the construction of nine supercritical coal-fired power plants at four different sites, and in September 2011 BGR Energy Systems was awarded preferred bidder status for four steam turbine generators at two different sites. This order formalises the arrangement for two units at one site. A decision has also been made to proceed with two units at the Darlipali super thermal power project, the other site in the state of Orissa, and a formal order is anticipated in due course.

Demand for electric power in India is growing along with that nation's rapid economic growth, and this has resulted in power shortages becoming severe in some regions. To overcome this problem, a major increase in capacity up to 330GW, roughly twice the current level, is planned by 2017. Coal-fired power generation currently accounts for about two-thirds of India's total generation capacity, and it is anticipated that it will remain the primary energy source in the future.

Hitachi and BGR Energy Systems established a joint-venture, BGR Turbines Company Private Limited, in September 2010 to manufacture steam turbine generators for coal-fired power generation to the rapidly growing Indian market.

BGR Energy Systems is the lead contractor for this new order, and Hitachi will supply the key equipment for two steam turbine generators through BGR Turbines. Operation of two units for the Lara project is scheduled to commence in 2016. [Page Break}

Increased ratings for gas generator sets

Caterpillar has launched new, higher-rated Cat 12CM32C and 16CM32C generator sets, offering industry-leading power densities. Designed specifically for offshore drilling and production applications including drillships, semi-submersible rigs, FPSOs and production platforms, these generator sets offer 560 brake kiloWatt (bkW) per cylinder, a 12 per cent increase over the previously available models. The 12 cylinder option offers a power rating of 6,720 bkW at both 720 and 750rpm; the 16 cylinder power rating is 8,960bkW at both 720 and 750rpm.

“These new offshore generator sets provide our customers with significantly improved power to meet the rigorous demands of ultra-deepwater drilling and other offshore applications,” said Will Watson, Caterpillar Global Petroleum offshore product manager.  “The industry-leading power density offered by these generator sets further demonstrates our commitment to developing robust, reliable power solutions that will help operators get the most out of their vessels and their production operations,” he added.

The CM32C generator sets incorporate years of proven component reliability and durability in the offshore industry and meet IMO Tier II emissions standards. According to the company, they also feature a well thought-out complete package solution to enhance ease of installation and reduce complexity. The new generator sets allow for customisation options to meet exact customer specifications and reduce installation time, too.

Manufactured in Kiel, Germany, the new higher output 12CM32C and 16CM32C generator sets will be available later this year.

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