Tesla battery packs power the Hawaiian island of Kauai after dark

While investors on Wall Street debate whether Tesla’s ambitious transformation from electric car maker to sustainable energy company will pay off, its industrial power packs are already having an impact on at least one US state.

In Hawaii, the Kauai Island Utility Cooperative (KIUC) is now drawing energy from 272 Tesla power packs to provide electricity after dark. While the island previously relied on solar and other renewable energy during the day, it had no way to store the sun’s power after it went down.

Using stored energy from Tesla’s power packs is expected to save KIUC 1.6 million gallons of diesel fuel annually, which has traditionally been the way the utility generates power after dark.

Tesla says the power packs will cut KIUC costs per kilowatt hour from 15.5 cents down to 13.9 cents. The 13.9 cents is a fixed price for the next 20 years.

For Kauai, the chance to cut the use and fluctuating costs of diesel fuel is what makes Tesla’s energy storage system so attractive. Yet for Wall Street analysts, it isn’t enough to convince them that the Tesla’s energy initiatives will be enough to move the needle.

“At this time, we ascribe zero value to Tesla shares from this business,” Morgan Stanley analyst Adam Jonas told investors. “We take this view due to the uncertain economic and regulatory forces facing the energy business, particularly the solar business.”

Tesla Chief Technical Officer JB Straubel attributed analyst scepticism to the fact that solar and energy storage form a new market.