New turbine design proposes to capture more of Tehachapi's wind

Nov. 23—It's a simple idea: Fill in the wasted space between towering wind turbines in eastern Kern with shorter ones designed to be placed closer together — and ideally, produce additional energy.

The turbines Wind Harvest International Inc. wants to build in the Tehachapi area may be better positioned to catch breezes existing machines can't reach, hopefully increasing the renewable electricity California generates after the sun goes down, and maybe give large turbines a break during damagingly high winds.

Naturally, there's a catch. The Davis-based company acknowledges it lacks data and a real-life test case. It must also persuade owners of larger turbines nearby that its smaller ones won't interfere with their wind flow — or fly apart during heavy gusts and put their investments at risk.

The innovation is not entirely new, in that other companies have proposed what are called vertical-axis wind turbines, distinct from the propeller-looking, horizontal-axis machines common locally. Wind Harvest says its turbines have a unique design with patented, bolted hinges that extend the unit's lifespan longer than simple welds.

Wind Harvest doesn't operate commercially at this point, though it has produced test results co-founder and CEO Kevin Wolf deems promising. The company is trying to raise money through crowdfunding for the technology's certification and commercial trials.

Wolf said Wind Harvesters will cost about twice as much to build as conventional turbines, per unit of energy produced, but that the company ultimately wins on price "because we can come into the existing wind farms — and they have to build new wind farms."

Any attempt to alter the renewable energy landscape in Tehachapi could face stiff headwinds, people familiar with the area's wind power industry said. The area is not the hotbed of experimentation it was in the 1980s, they said, and unconventional newcomers could become a liability to existing infrastructure.

Wind Harvest does appear to have a "great concept" for tapping an otherwise wasted resource, said Senior Director Ed Duggan of La Jolla-based wind developer IOWN Renewable Energy Inc., who has worked on projects in Tehachapi since 1984.

But Wolf and his company need to prove the technology is "bona fide," including by answering questions about whether its machines will throw off parts in high winds — and whether owners of existing, multimillion-dollar turbines above "are going to be comfortable with these (new) turbines underneath them."

"Until they can actually deploy a real commercial case, they're going to have a tough time getting their approach to catch on," Duggan said.

Local energy consultant Linda Parker was somewhat familiar with Wind Harvest's proposal. If it's a viable technology, she said, "certainly I think someone will want to fund it." But she said it probably won't be easy completing necessary research and development and finding investors.

"I get all kinds of folks who have very great ideas," Parker said. "Some work and some won't. It's just extremely difficult."

She added the company might be wise to look ahead to the project's reception.

"My thoughts are always, you have to think of the local community," she said. "Are they going to want it?"

Wind Harvest says recent modeling suggests that by capturing wind 15 to 100 feet above the ground, instead of hundreds, it may be able to nearly triple the power output of the Tehachapi Wind Resource Area. It also says it can deliver a 10% to 25% boost in capacity factor, which is a wind farm measure stating a system's average output divided by its total capacity for generation.

The company received a $50,000 modeling grant from the California Energy Commission that verified the high efficiencies VAWTs can realize when placed very close together.

More recently, he said, Wind Harvest was turned down for a different grant when the U.S. Department of Energy challenged the notion of aiming for lower winds rather than higher ones. He said that analysis overlooked California's wind atlas showing strong potential for generation near the ground.

Despite the challenges, Wolf said the company invested $2.5 million to test a new prototype and validate its findings regarding how well its turbines work in turbulence.

The company's system wouldn't require expanding Tehachapi's transmission capacity, he said, because its greatest contribution would come after sunset, when the area's photovoltaic solar arrays stop generating.

Wolf said Wind Harvesters would fit well with existing, larger turbines that already pitch the angle of their rotor blades as a protection against shuddering during strong winds. Smaller, more resilient turbines below would allow their taller neighbors to pitch their blades earlier, he said, while keeping substations at full capacity.

The next step is for the company to raise money to build two turbines for certification of its technology, then 10 more to show final readiness, Wolf said. Meanwhile, he expects to produce data for convincing large turbine operators that new neighbors won't create undue turbulence or dangerously self-destruct. If all goes well, Wind Harvest intends to start building large projects in 2027.

Another question relates to what effect the small, vertical-axis wind turbines fare with condors flying around. Wolf said the only study comparing VAWTs with horizontal-axis machines found the former killed half as many birds. His explanation was that animals are more accustomed to focusing on objects close to the ground than those high in the air.

He said even if it's not Wind Harvest that ends up expanding wind energy generation in the Tehachapi area by using smaller turbines, then there will be another company that will come along to do it.

"There will be," he said. "It's just too valuable of a resource."

(Editor's note: This story has been modified to clarify the prototype investment and the modeling grant results.)