Fewer freckles improve turbine blades

General Electric has made what they believe is a major breakthrough in the manufacture of turbine blades. The discovery could ultimately lead to lower electricity costs and drastically reduce greenhouse gas emissions.

General Electric Corporation has developed a process to produce turbine blades capable of withstanding temperatures up to 2,600 degrees Fahrenheit, a necessity for fossil-fuel power plants to reach efficiencies of 60 percent and higher.

Existing coal and gas fired plants reach efficiencies of 33 to 45 percent respectively. Achieving higher efficiencies will, says GE, result in less fuel being used and fewer emissions, including carbon dioxide, being produced.

The high-performance turbine blades are made of single-crystal, nickel-based superalloys.

Key to GE’s method of manufacturing the turbine blades is that they are less likely to contain defects known as ‘freckles.’ The defects are freckle-like spots, usually in a line, that indicate a blade’s weaknesses.

The breakthrough technique can produce single-crystal blades in less time than other processes, leading to a considerable decrease in manufacturing costs.

The GE blades have been used successfully in a 400-megawatt demonstration unit, but the costs have to be further optimised before the blades can be tested in large-scale applications.

The breakthrough is the result of work carried out by the US Energy Department’s Advanced Turbine Systems and Vision 21 programs, both of which are managed by the US National Energy Technology Laboratory (NETL).