A team of General Electric engineers in Schenectady and Niskayuna has helped develop a new wind turbine that’s 30 percent larger than GE’s biggest land-based model.
The 4.8-megawatt giant, with its 158-meter rotor diameter, will reach as much as 780 feet in the air and offer utilities another option for producing clean energy under circumstances that might limit the effectiveness of smaller turbines
The project was a global one for the multinational company, but much of the technical leadership and product development was done locally by Product Breakout Lab at GE Global Research in Niskayuna and GE Renewable Energy, whose onshore wind business is based in Schenectady. The project took about nine months from start to finish, and not quite a year total from conception to completion. The input of more than 30 customers worldwide was factored into the process.
Electrical engineer Kiersten Ralston, innovation adoption leader at Global Research, said the process was much more than supersizing GE’s previous size leader, a 3.6-megawatt wind turbine with 137-meter rotor diameter. Much of the new turbine was designed from scratch.
“It wasn’t just an evolutionary step in what we’ve been doing,” she said.
Additionally, the project was pursued with the goal in mind — a 30 percent increase in power output — rather than with a particular design in mind. So the engineers picked and designed components to meet a goal for the finished product, rather than designing a finished product and tweaking its components to optimize performance.
Along with technology and the laws of physics, cost was an important consideration, said Minesh Shah, a mechanical engineer and product manager for GE Renewable Energy.
“In our world, we want to be able to bend the cost curve through technology,” he said.
A 2.85-megawatt GE wind turbine at at McLean's Mountain Wind Farm in Ontario, Canada. (John Hryniuk Photography)
It’s part of the never-ending drive to produce more electricity with each piece of equipment. Three-cent wind — wind power generated at a cost of 3 cents per kilowatt hour — is a specific focus of the Product Breakout Lab, one of four interdisciplinary labs that GE Chief Technology Officer Vic Abate created after taking over Global Research in 2015.
Mechanical engineer Mike Bowman, product breakout leader for renewables at Global Research, said part of the research and development with the new wind turbine was avoiding the diminishing point of returns that can come through supersizing: Blades can become so long that they are impossible to transport; moving components become heavy to the point of needing reinforcement at heavy cost in money and space; torque grows exponentially until it is difficult to manage.
“Those are some of the design challenges we come up against,” Bowman said. “We’ve figured out ways to address all the pinch points. Both mechanical pinch points and cost.”
There were design challenges in each of the five major systems in the turbine — rotor, tower, electrical, control and machine head — Bowman added.
Shah said the first prototype will be built in 2018. It will go into production at a GE factory in Germany, then later at GE factories in Florida and China.
GE Renewables has one of its wind remote operations centers in Schenectady, monitoring thousands of wind turbines in dozens of countries around the clock.
A 2.5-megawatt GE wind turbine is shown on a wind farm in Romania. (Provided)
It will stand atop a tower of 101, 121, 149 or 161 meters, depending on the regulations and circumstances affecting the site on which it is installed. On the 161-meter tower, the new turbine will reach up to 780 feet above ground level with the tip of its blades. That compares to 589 feet for the landmark Corning Tower in Albany, and 625 feet for the WGY radio tower in Rotterdam.
The carbon blades, each 77 meters long, will be the longest ever produced by LM Wind Power, which GE acquired last year.
GE isn’t divulging the expected price tag of its new wind turbine.
Shah said cost and value are determined by many variables. It might cost less to erect two 2.4 megawatt turbines than one 4.8 megawatt turbine, for example, but if the site is limited in space, there wouldn’t be room to double the number of towers. Or perhaps local ordinances specify a noise limit that rules out one model of turbine.
“It also depends on the wind conditions on the site,” Shah said.
“We have to be cognizant of wind speed, variation of wind speed across the rotor, turbulence, the loading of the machine.
“A multitude of factors determines what makes the most sense for that site.”
The new 4.8 megawatt onshore turbine is designed for low- to moderate-wind areas. A comparable offshore model produces 20 percent more electricity even though it is a bit smaller, because it is optimized for the much higher wind speeds found at the edge of the ocean.
Politics and policy also are in the background of the design process. The federal Renewable Energy Production Tax Credit, which has helped the wind industry expand greatly in the United States, is phasing out over the next four years.
So the more cost-effective wind turbines can be made, the better they will be positioned to operate without subsidies.
“We want a product that can compete with all power sources economically,” Bowman said.