Going Net-Zero in California with the Help of Geothermal

When it was time to build its Americas headquarters in California to LEED Platinum and net-zero standards, power management solutions provider Delta looked to a geothermal exchange system for the building’s heating and cooling functions.

As the first of the company’s global facilities to use the ground-source technology, the new headquarters in Fremont, Calif., represents a step into the future for Delta. The new building, which opened last fall, also features solar PV generation and energy efficiency solutions that are helping reduce — and will ultimately eliminate — the energy load required from the local utility.


Image: Solar panels on the rooftop of the Delta Americas Fremont headquarters. Credit: Delta.

Projects like Delta’s Fremont headquarters are effectively demonstrating the value of geothermal exchange technology, which is gaining more widespread acceptance as a clean resource with the support of incentives, standards and installer knowledge.

Success in Fremont

Delta’s ability to successfully install a geothermal exchange system at its new Americas headquarters is due directly to general contractor Vance Brown Builders’ ability to access installer knowledge about how this technology can be applied across locations with varied geological foundations.

According to Bill Russell, director of preconstruction for Vance Brown, the initial plan for the geothermal project was to drill vertical wells in the ground under the building for a closed-loop system — a traditional approach for ground-source installations at commercial properties. The water district that oversees the Freemont area, however, initially turned down Delta’s request for a permit to drill the approximately 200 vertical wells at depths of 200 to 300 feet that were required for the system.

The City of Fremont, as it turned out, was concerned about the effect the vertical wells would have on aquifers in the area, which had been contaminated by saltwater from the San Francisco Bay after decades of commercial well drilling. Russell said that Fremont has been working for years to push the saltwater back into the bay, and Delta’s plan to drill vertical bore holes through at least two aquifers would undo that work.


Image: Delta Americas headquarters in Fremont, Calif. Credit: Delta.

“Luckily we found geothermal consultant John Geyer,” Russell said. “He helps people with their ground-loop heat exchange projects, and he was working on a couple of projects on the West Coast that used a horizontal drilling approach using technology called directional drilling.”

Directional drilling is commonly used to install utility infrastructure under existing streets without tearing up the asphalt.

Geyer conducted testing at Delta’s 15-acre site, and determined that by using directional drilling and placing the bores for the project horizontally with one layer at 15 feet underground and another at 30 feet, the project would achieve the same results as the vertical approach. In addition to avoiding the aquifers, the directional drilling approach also turned out to be less expensive than vertical drilling, Russell said.

Because geothermal exchange systems have not been widely installed in central California, there are few if any drillers in the area experienced in the technology. Russell said Delta would have had to bring in a driller from outside the area, which would have been costlier than hiring a local company with experience in directional drilling for local utility companies.

System Performance

The geothermal exchange system at Delta’s Fremont facility is performing “as expected,” according to Ruth Chao, general affairs manager for Delta. Chao was involved with the development of the geothermal project from its inception, and says Delta chose geothermal because it was founder Bruce Cheng’s longtime goal to use the technology in one of the company’s new facilities.

“The system is so efficient that it brings our energy bill way down,” Chao said, adding that, while the goal for the building is to reach a net-zero standard (i.e., all heating, cooling and power needs are met by energy conservation and on-site generation), Delta still is buying some power from the local utility.


Image: The mechanical room at Delta Americas Fremont headquarters. Credit: Delta.

“We’re in the process of tweaking the system and reducing our load, because the facility is new,” Chao said. “We keep the building efficient in energy use, and generate power with a 618-kW solar PV system on the rooftop.”

Delta also is evaluating adding 30 percent more solar capacity through parking lot car ports, she said.

Mike Gazzano, marketing manager for Delta, said the company used some of its own products to support efficient operations in the building.

“We installed our own industrial automation variable frequency drives, or VFD, that help drive the motors and the pumps for the geothermal system and circulate the water throughout the building,” he said. “The VFDs are highly efficient.”

The VFDs also were used in conjunction with Delta’s active front end controllable rectifiers that provide bidirectional power exchange for the building’s elevators.

“They act much like a hybrid car with regenerative braking,” Gazzano said. “They harness and pull some power out of the [elevator] braking mechanisms.”

What’s Next?

Ongoing growth in the coming years for the commercial and residential geothermal exchange industry in the U.S. is all about securing federal tax credits now, according to Douglas Dougherty, president and CEO of the Geothermal Exchange Organization (GEO).

Geothermal exchange installations currently have a 10 percent investment tax credit for commercial applications and 30-percent income tax credit for residential installations through the end of the year.

Geothermal, along with some other renewable technologies, such as small-scale wind, were left out of the tax credit extensions package passed by the U.S. Congress last December for solar and utility-scale wind resources. Congressional leadership has since looked for ways to correct that oversight. Dougherty said that GEO has been advocating for extension of geothermal tax credits, nearly securing that extension as an amendment to the Federal Aviation Authorization bill in April. The amendment, however, ultimately was left out of the aviation bill.

Now, GEO is looking for support for a stand-alone bill to amend the existing law that grants a five-year tax credit extension for solar and wind, and to ensure equal benefits for renewables.

Dougherty said that Congress should not support benefits for some renewables over others.

“Either they grant the extension to all renewable technologies, or they take away the extension from solar and wind,” he said.

The pending expiration of those federal tax credits is having a negative effect on the industry, according to Dougherty. He said the GEO is already seeing a reduction in planned installations.

The GEO also expects the U.S. geothermal exchange industry to benefit from the release earlier this year of a North American standard for ground-source systems. Independent standards organization CSA Group released the bi-national 2016 edition of its C448 standard governing the design and installation of residential and commercial ground-source heat pumps.

Dougherty said that the standard, which is the first edition to be released for the U.S., will help local governments in their efforts to understand and define the technology in reference to their ordinances.

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