GE’s New Power Technology Combines Conventional Efficiency with Renewables

Today, GE unveiled their new combined cycle FlexEfficiency 50 power plant, a dramatic new power generation technology that is intended to create a bridge to the future. This technology will use natural gas to form a smooth transition from today’s coal plants to tomorrow’s renewables while allowing for the continuous uptake of a growing number of renewable sources and at the same time, providing breakthrough levels of efficiency.

Company officers said at the announcement that they expect to see abundant natural gas play a major role in energy production over the next 25 years. GE technology currently powers approximately 25% of all electricity generated worldwide.

There are two important things to understand about this technology:

1. It has the highest efficiency of any natural gas fired power plant, 61%, as compared to the current state-of-the-art peaker plants which run at 46%.


2. It has the flexibility to change its output quickly, making it highly compatible with renewable resources like solar and wind, which tend to be intermittent in their output.

GE has been able to achieve these independent objectives by leveraging the technology from their aircraft engine division. Aircraft engines are designed specifically to be able to change their power output levels quickly, which has not been the case for conventional power plants until now. These new turbines can ramp up at a rate of 50MW per minute, which is twice the current industry benchmark. This capability, along with the advanced control systems that have been incorporated, will enable the generators to respond rapidly to real-time fluctuations in both supply and demand as more and more renewables like solar and wind, which are inherently unsteady in their output, come online. This substantial efficiency improvement comes largely from the utilization of a nickel-based super alloy which allows the turbines to run at higher temperatures where they can operate more efficiently. Previous generations of gas turbines were temperature-limited by the best available steel components.

At this level of efficiency, the natural gas savings from each of these plants would be enough to power 4000 European homes. When renewable generation is added to the mix, these 510MW power systems can achieve combined efficiencies in excess of 70%.

The term combined cycle refers to the fact the both gas and steam turbines are used in tandem, the steam turbines running off the lower temperature discharge of the gas turbine in a cascading manner. This is not new, combined cycle plants have been around for a while and may have been the last big jump in power plant efficiency before this one.

The new FlexEfficiency 50 is the first combined-cycle power plant designed from the ground up to operate in a world in which renewable sources play an increasingly significant role. It will be initially made available in a 50 Hertz configuration, suitable for the European market, which is why the announcement was made in Paris. The first units will ship in 2014 and should be operational the following year. Sixty Hertz units, suitable for North American operation should become available sometime after that. No doubt, GE made that decision, after a $500 million R&D investment, based on the Europeans’ higher level of commitment to taking action against climate change, though the 50 cycle market is the larger of the two as well.

This is a significant announcement. These plants will operate very effectively in conjunction with renewable sources while providing substantially improved efficiency themselves. Opponents of renewables have previously argued that renewables, because of their intermittent nature would be disruptive to the grid and would save little energy, because peaker plants would have to be kept running as “spinning reserves,” in order to respond quickly enough to changes in power availability. Both of these arguments are eliminated with this technology.

GE is to be commended for this advance and maybe we can all feel at least a little bit better about the fact that we continue to pay their taxes for them. Okay, maybe not…but at least for today, we should give credit where it's due.

RP Siegel, PE, is the co-author of the eco-thriller Vapor Trails, the first in a series covering the human side of various sustainability issues including energy, food, and water.  Like airplanes, we all leave behind a vapor trail. And though we can easily see others’, we rarely see our own.

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