The obvious solution to lack of funds to invest in new on-site energy plant is to continue to get the best out of existing equipment. Clearly, sound operation, service and maintenance practices are essential and, as these accounts from GE Energy suggest, the performance of existing plant can also be boosted by equipment upgrade.
As the global recession continues to impact power generation resources and the feasibility of constructing new power plants, owners and operators of power plants are looking for solutions which will enable them to use their existing power generation equipment more efficiently and more cost effectively than ever before.
Additional factors driving the need for energy efficiency includes, but is not limited to, increasingly rigid emissions standards and a growing global demand for greater environmental responsibility.
In addition, an ageing global gas turbine fleet presents plant operators with significant challenges in maintaining competitiveness and reducing operating costs. From this perspective, improved output and efficiency are key drivers for power plants worldwide, including combined heat aand power (CHP) or cogeneration facilities.
In the United States, the current federal stimulus legislation, as well as anticipated legislation to reduce CO2 emissions, clearly encourages CHP applications. The CO2 legislation, though still pending, allows CHP to count as electricity savings under the proposed renewable electricity standard.
Fossil fuel prices remain low, and while there is an increasing need for new, renewable energy sources, many operators may continue to rely on traditional coal- and gas-fired electricity and CHP sources. In this environment, owners/operators of CHP and other power plants are seeking technology options that will help them achieve the highest levels of output and efficiency from their installed equipment.
Fortunately, technology exists today which, for relatively small incremental cost, can be applied to existing equipment – resulting in output and efficiency improvements and cost benefits.
In some cases, upgrading or retrofitting power plant equipment may avoid new permitting requirements and other costs associated with new green-field power generation installations. Retrofits also extend the life of the existing assets.
UPGRADE FOR GAS TURBINE
Responding to these industry trends, GE Energy has developed a three-dimensional (3-D), advanced aerodynamic stage three nozzle and bucket design for Frame 6B, 7E and 9E gas turbines.
The launch site for this new technology was an Edison Mission Energy (EME) partnership project. The EME facility was seeking to compete with other plants in the California area on the heat rate market and GE’s uprate offered the advantages of minimal plant operation disruption and immediate benefits. Two of the three GE Frame 7E gas turbines that were retrofitted with the new design recently completed 36,000 hours of successful operation, with the third completing 25,000 hours, helping the plant to achieve significant output and efficiency increases and overall cost benefits.
GE’s enhancements included:
- GE utilized three-dimensional advanced aerodynamic methods to develop the new E-class turbine heady duty bucket and nozzle components. Designed for easy installation, the new modification technology can be applied during a routine hot gas path outage.
- The improved airfoil design on the advanced aero stage three bucket creates a more favorable incidence angle to the exhaust frame strut. This reduces exhaust flow turbulence leading to improved reliability of the exhaust diffuser turning vanes. The new 3-D high efficiency airfoil is significantly thinner from hub to pitch, reducing stage losses.
- The tip shroud has been re-scalloped for greater efficiency.
- The stage three nozzle was redesigned for improved aerodynamic performance and an improved airflow exit angle. New material is interchangeable with the previous nozzle material, offering similar creep-resistance properties.
THE FIRST INSTALLATION
The Edison Mission Energy partnership plant includes three turbine trains each consisting of a GE MS7001E gas turbine, dry low NOx combustors and an unfired heat recovery steam generator. The cogeneration facility provides steam and power for use in thermally enhanced oil recovery activities; as well as electricity to Southern California Edison, Pacific Gas & Electric and the California Independent System Operator (CAISO) energy market.
The new GE technology was installed during a planned outage. Following the installation of the new bucket/nozzle design at the site, a performance test showed the technology exceeded GE’s guarantees and met all of the customer’s objectives. Overall plant efficiency has increased, helping this site improve its competitive position in the California power market.
The DUBAL aluminium production plant in Dubai
While the Edison Mission Energy Partnership’s specific financial data are proprietary and not able to be released, GE’s calculations indicate that the new technology, as applied to three Frame 7E gas turbines operating under similar conditions, would be expected to produce at a minimum:
- 1% output increase and 1% reduction in heat rate (at ISO conditions)
- Due to increased efficiency, CO2 emissions (in pounds per kWh) are reduced by 1%
- The extra 2.5 MW of output achieved through higher output would be enough to power 1225 US households (based on 12 MWh/year average US household consumption and 6000 hours/year operation)
- The bottom line: net customer benefits due to increased output and efficiency would add up to approximately US$750,000 each year (based on generic $5/MW electricity price and $4.5/MBTU fuel cost).
In today’s challenging global environment, power plant operators are turning to performance improvement upgrades to maintain a competitive edge.
LONG-TERM SERVICE AGREEMENTS FOR TURBINES IN DUBAI AND CHINA
GE Energy has signed a multi-year service contract for more than $45 million with Dubai Aluminium Company Limited (DUBAL), one of the world’s largest producers of premium quality aluminium. The agreement is designed to reduce the cost of aluminium production while maximizing the reliability and overall performance of 19 GE gas turbines that power the DUBAL production complex.
‘Performance and reliability of our power supply are very important for the production of aluminium,’ said Abdulla Kalban, president and CEO of DUBAL. ‘This service agreement with GE will help reduce our cost of generating electricity, which will lead to a lower cost of aluminium production.’
The GE gas turbines operating at the DUBAL power plant include six Frame 9E units, five Frame 9Bs and eight Frame 5s. As part of the service agreement, the NOx emissions of the Frame 5 units will be reduced by 15%.
The agreement covers the supply of parts, performance uprates, repairs and field services for planned outages for the gas turbines, over a period of seven years. In addition to addressing DUBAL’s performance and reliability requirements, the GE service agreement will help reduce DUBAL’s critical spare parts inventory, a key milestone in the company’s cost-cutting initiative.
All the repairs covered under the service agreement will be performed at the Gulf Turbine Services (GTS) facility in Abu Dhabi. The GTS facility, a joint venture between GE and Abu Dhabi Aircraft Technologies, was established to meet local and regional customer needs in the power generation and oil and gas industries.
Meanwhile, GE Energy has signed a $115 million service agreement with Fujian Jinjiang Gas Power Company Limited that helps address the need for reliable and efficient power generation to support the rapid economic growth of Fujian Province.
The nine-year agreement covers four Frame 9FA gas turbines at the Fujian Jinjiang plant, located on the coast of the Taiwan Strait. The plant produces more than 1560 MW and is a key part of the local government’s initiative to increase the province’s power generation capacity to 3500 MW by 2010. Based on GE’s core technology, the gas turbines were supplied by Harbin Power Equipment Company, a GE business associate in China.
GE E-class gas turbines similar to those employed at an Edison Mission Energy project in California
The scope of GE’s service agreement with Fujian Jinjiang will include parts, services, repairs and training and will cover one major inspection period for the gas turbines. The agreement helps to ensure the power plant will continue to meet its efficiency goals.
GE currently is managing service agreements for customers at more than 700 sites covering 2,000 turbines worldwide. Benefits to customers include performance guarantees, predictable maintenance costs and access to GE’s technology and global experience.
For more information go to GE Energy’s website: www.gepower.com
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