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Energy experts discuss grid resiliency, redesign against external threats

KAILUA-KONA — Since its conception, the “R” in renewable energy has stood for reliability.

In the aftermath of a violent volcanic eruption and close calls with multiple tropical storm systems this year, energy leaders in Hawaii are more frequently uttering another “R” word they say is just as critical — resiliency.

The components of the concept were part of a panel discussion Wednesday during a conference on energy storage trends and opportunities convened by the Natural Energy Laboratory of Hawaii Authority and hosted at the Sheraton Kona Resort and Spa at Keauhou Bay.

“This issue of resiliency will largely define the future trajectory of renewable energy because of how the change in climate … is going to impact that,” said Kyle Datta of New Energy Partners.

Resilience is the ability of an energy system to promptly rebound in the face of low-probability, high-impact events such as lava flows and hurricanes.

Beyond rapid recovery, its elements include adaptability, quality site selection and robustness, or the ability to withstand forces of nature absent failure. Hardening, or reinforcing, system infrastructure also is integral.

According to Datta, building out an appropriately resilient system in Hawaii also would mean a design overhaul on transmission and distribution systems, relying instead on isolated microgrids functioning as part of mini-grids that comprise the main grid.

“We fundamentally have to rethink the grid architecture before we run down the path of modernizing it,” Datta said.

Research conducted in the wakes of Hurricanes Sandy and Maria indicates it takes only three days without power before cracks in social framework become evident. After a week, serious and myriad public health issues ensue.

Jay Ignacio, president of Hawaii Electric Light Co., detailed resiliency within the county’s power grid. Strengths of the system include diversity, as generation happens in West Hawaii, East Hawaii and Hamakua tied together with four transmission lines, he said. Also, none of the county’s power plants are coastal, isolating them from tsunami threats.

The entire island nearly lost power in 2006 following an earthquake when the shaking impacted older protected relays tasked with monitoring the system. But that near disaster actually improved infrastructure. Since then, HELCO has conducted relay replacements, locked down fuses on transformers, as well as anchored transformers, and made other structural improvements.

A 6.9-magnitude earthquake that coincided with Kilauea’s most recent eruptive activity and mirrored the 2006 event didn’t create nearly the same consequences, Ignacio said.

The eruption did affect 935 customers, claimed 835 poles and knocked out 229 transformers. The Pohoiki switching station also was destroyed and Puna Geothermal Venture, which generated 38 megawatts a year, was isolated.

Confident in the system’s resilience aside from direct lava flows, Ignacio said the county’s greatest vulnerability is the threat the combination of high winds and tall, frail albizia trees pose to power lines.

“We need to do more,” Ignacio said. “It can’t just be the utility. It’s got to be every neighborhood. It’s got to be state. It’s got to be the county to jump on board to manage these trees.”

As for PGV, Ignacio said the company expressed desire to come back online. Currently, the greatest challenges are access to the facility and loss of the switching station. Ignacio thinks most of PGV’s infrastructure remains unscathed save for a well or two.

The next steps to resuming operations at PGV are getting power to its station to test the equipment then checking the quality of the wells. After that, permitting at the county and state levels would be required.

Ignacio said the grid’s capacity was 270 MW before losing the 38 MW at PGV. The island currently eats up about 180 MW annually. The smaller margin, however, has limited planned maintenance, rendering it more difficult.

Site selection, an important element of resiliency, is trickier with geothermal power. HELCO put out a request for proposals in recent years for another geothermal project, wanting to locate it in West Hawaii for diversification purposes.

However, Ignacio said every bid that came in wanted to locate in the East Rift Zone of Kilauea volcano, where heat is closest to the surface, despite the potential peril.

Datta spent his portion of the panel discussion pitching what he thinks is the future of grid design, a cellular structure of microgrids with their own power supplies and the capability to isolate themselves from the main grid.

The reconfiguration would be a move away from central power plants energizing the entire grid. Hawaii County is set up fairly well for the transition because power is generated at different points around the island, he said.

Mini-grid systems split by districts would include microgrids within them, all of which would be part of the main system.

“The microgrids, if they stay on after the storm, they can help re-energize the mini-grids,” Datta said. “The mini-grids then help re-energize the main grid. So it’s sort of a cascading up (effect).”

The state Public Utilities Commission would decide on the viability of such plans. Datta added the process already began, with the PUC announcing last week its intention to include resiliency in the metrics for how utilities are financially rewarded.

The next step is figuring out the cost of redesign and how to socialize that cost, Datta said.

Ignacio said mini-grids are part of HELCO’s strategy moving forward but that it doesn’t have the equipment necessary.

“We’re looking at a system where we can actually put in equipment so that (the) re-establishment of the entire grid from mini-grids can be done autonomously,” Ignacio said.

He added that HELCO supports microgrids in certain applications, for instance in North Kohala, where the utility has only one, 60-year-old transmission line. Creation of a microgrid there so HELCO can complete construction on the line is under consideration.