The rush to gas in the 1990s was driven by cheap natural gas prices— generally in the range of $2/MMBtu. Today’s gas rush is happening with gas prices four times as high and is being driven by electricity demand growth at a time when environmental opposition is also sidelining many coal plant projects. A complicating factor is that the time required to build coal and nuclear plants is simply too long for them to fill the gap between demand and capacity. But the next wave of gas-fired plant construction will differ from the last in many ways.
Power Engineering posed questions to three major gas turbine original equipment manufacturers. Speaking for GE Energy is Mas Fukumoto, gas turbine marketing executive. Representing Mitsubishi Heavy Industries is John Adams, senior vice president of new product operations. And responding for Siemens is David Boyce, manager, marketing and strategy, Americas. (A fourth OEM, Alstom, was unable to participate.)
Power Engineering: Unlike the last rush for gas, this one is predicated on high natural gas prices. How have your gas turbine offerings changed since the late 1990s to meet this new demand for additional gas-fired capacity?
Fukumoto: A key factor shaping the power generation market is lingering uncertainty about the use of coal for future power plant projects due to environmental concerns, escalating prices and longer cycle times. These factors are increasing the interest in gas turbines with their lower environmental emissions, higher efficiency, better cost certainty, short cycle times and greater operating and fuel flexibility.
heavy duty and aeroderivative gas turbines with greater capability to support dual fuel and alternate fuel sources. A wide range of operational flexibility enhancements enable customers to effectively use equipment for peak and cycling applications. The relative ease and speed of installation also give natural gas solutions an advantage when it comes to meeting emergent and urgent power demand.
A few examples are the LMS100, an aeroderivative turbine capable of a 10-minute start for lower megawatt applications; the 50 hz 9FB heavy-duty turbine, which improves upon the output and efficiency of our successful F-class technology; the newly-announced 7FA gas turbine with 10-minute startup capabilities; and the 7EA gas turbine, which offers liquid fuel flexibility capabilities.
Adams: Higher energy costs undoubtedly call for design efforts to improve efficiency. We have successfully focused on increasing the already high efficiency of our advanced G technology. Performance measurement executed during the commissioning of our latest 50 and 60Hz upgraded units (the M501G1 and M701G2G, respectively) have demonstrated efficiencies in excess of contractual values. It is worth mentioning that 1: 1 50Hz combined cycle efficiency in excess of 59. 3 percent has been measured at commercial plants. This number is very significant considering that 60 percent efficiency numbers are frequently announced in the industry but have rarely if ever been demonstrated.
In addition to high efficiency, Mitsubishi has focused on continuous improvement of G machine durability and reliability. It would be a partial success to increase efficiency if the availability and startup reliability do not match the high standard. The G fleet’s equivalent availability factor of 96 percent and starting reliability exceeding 99 percent clearly testify that the machines will operate
when needed.
These achievements have led a number of large utility fleets to opt for the newer G machines because the highest efficiency and high reliability will result in better operating profiles. Their forecast involves the M501G1 being the first machine to start and the last to shut down.
Boyce: In 2002, Siemens addressed rising natural gas prices by taking the proven technology of the SGT6-5000F, with its fast-start capabilities, and integrating it into the Flex-Plant 10 and 30 power plant solution. By utilizing the SGT6-5000F engines’ fast-start capabilities in the Flex-Plant solutions, there is a substantial decrease in the amount of fuel required to start the power plant, thus resulting in a fuel cost savings, as well as providing more dispatchable power quicker, reducing start-up emissions while maintaining high rates of efficiency (FP10, 48 percent net efficiency and FP30, 57+ percent net efficiency). These designs also allow for extremely flexible operation depending on how the plant is called upon.
PE: The new rush will also demand that gas units be more flexible than their predecessors, meaning they will be called upon for a wide range of cycling capability as well as baseload and peaking. How are your new gas turbines being designed to meet such flexibility requirements?
Fukumoto: GE is an industry leader in developing fuel and operating flexibility for our gas turbines. For example, in December 2007 we announced 10-minute start capability for our 7FA gas turbine. We’ll roll out simple cycle capabilities first, then combined cycle. With a start-up NO under
X
9 ppm, this turbine will be well suited to cycling and peaking service.
We’re also focused on increasing turndown capabilities. We recognize that a growing number of power providers are faced with decisions about the financial and
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