Try as he might, Vlatko Vlatkovic won’t make the sun shine brighter. So when he wanted to make a more efficient solar farm, he and his team had to go for the next best thing: a gray plastic box the size of a small hut called the inverter. “It takes direct current from the PV panels and turns it into alternating current that you can use,” says Vlatkovic, chief engineering officer at GE Power Conversion. “Since the inverter system also represents as much as 20 percent of the capital costs of the farm, you could make a huge impact if you made it more efficient.”
That’s what Vlatkovic and his team just did. Using new power electronics, they increased their inverter’s power output by 50 percent by raising the voltage it can handle by half – from 1,000 volts to 1,500 - compared to the industry standard. The result is one of the most efficient utility-scale inverters in the world.
The inverter can also process power from solar installations generating 4 megawatts, instead of the typical 1-megawatt market offering. As a result, solar farms can replace four inverters with one and save an estimated $6 million in capital expenditures for a 200-megawatt farm. “The new design allows us to send much more power through the same amount of copper and get big economies of scale,” Vlatkovic says. “You won’t need as many fans, filters, concrete pads and other components for the farm infrastructure. You can change the farm’s architecture.”
America’s NextEra Energy Resources LLC just announced that it would use the inverters at its solar farms located across the U.S. “In making our choice, we insisted on having a technology that would not only be dependable and reliable, but that would also help make our offering increasingly cost competitive while yielding optimized productivity,” said Armando Pimentel, President and CEO of NextEra Energy Resources. The forecast for solar power looks bright. According to industry studies, the global installed photovoltaic capacity will grow by more than 200 gigawatts over the next three years. North America alone will add 11 gigawatts. (By comparison, the world’s 438 nuclear power plants have net installed capacity of 379 gigawatts.)
Vlatkovic and his team originally developed the inverter - GE calls it LV5 1500V - for Alstom’s offshore wind farms. But the team soon realized that the device could be also useful to solar farm operators.
But this synergy is just the beginning. Next versions of the inverter will likely include chips from a hardy but tough to manufacture material called silicon carbide (SiC). SiC chips could boost the device’s efficiency by 1 to 2 percent. Utilities spend billions to get that much gain from a new gas turbine,” Vlatkovic says. (A smaller, 1-megawatt SiC inverter from GE is already working in Germany.)
SiC takes the best features from diamond, one of the toughest materials in the world, and combines them with the properties of silicon, which is inside every computer and every smart phone. However, making a SiC chip involves up to 300 discrete steps in a clean room. “When I started it wasn’t ready, but today SiC chips can have applications just about anywhere,” Vlatkovic says.
Vlatkovic is one of GE’s silicon carbide mavens. A decade ago, he helped launch SiC research program at GE Global Research in New York, before moving to design power electronics at GE Oil & Gas and GE Energy Connections. He has seen the technology mature from lab to products. SiC chips could make everything from locomotives, planes and wind turbines much more efficient.
GE calls this transfer of people, knowledge and technology between businesses the “GE Store.” Such sharing involves many combinations of products and businesses: gas turbines benefit from jet engine know-how while medical scanners can inspect oilfield equipment.
“The technology has evolved,” Vlatkovic says about the new inverter. “This is the next generation.”