One of the many impacts of the ongoing lava eruption on the Big Island is on the supply of electricity. There is less power, but the Hawaiian Electric Light Company has also lost customers. So far, there’s been no obvious impact to remaining consumers — at least in terms of turning on their lights.

Hawai'i Electric Light Company provides most of the Big Island’s electricity. Lava has overrun more than 760 power poles and a switching station in lower Puna. Customers with rooftop solar supply about half the island’s power, but there’s a complication from the volcano. We spoke with HELCO President Jay Ignacio on a very sunny day.

“We believe vog has an impact on the solar output from rooftop solar systems. We’ve placed photovoltaic sensors at our substations to monitor sunlight intensity. We have a total 91 Megawatts interconnected to our system, but the output today was 41 Megawatts. We had more PV output from the east side, than the west side, which is intuitively contrary. We believe the vog has something to do with it.”

HELCO’s peak demand before losing customers because of the lava was around 170 Megawatts. Surprisingly, demand has not decreased.

“I would have anticipated, with the loss of approximately a thousand customers in lower Puna, in combination with the slowdown in the visitor industry, I thought we would have lower loads. But the loads are comparable to what we saw in the last two years. People may be running their air conditioners more because of the vog in West Hawai'i, and large volumes of purchases of air purifiers, so that could be adding load.”

Before the plant shut down, Puna Geothermal Venture supplied roughly a quarter of the island’s power. Replacement electricity does not come from renewable sources.

“We’re using more generators that use fossil fuel, unfortunately.”

One lingering question: the impact on rates. Ignacio estimates the increase might be around $1.70 per month, for now. The company is asking for proposals for more renewable energy, but as with power restoration in lower Puna, the timeline is uncertain.