Hawaii has officially committed left traditional energy this week when they received their last shipment of coal.

On Wednesday, the state welcomed 15,000 tons of coal, bound for the AES Hawaii power plant. It’s the biggest power plant in Oahu and the island’s main source of energy.

Although Hawaii aims to increase reliance on renewable energy, the governor did admit that the transition would be challenging.

“Renewable energy projects to replace coal are coming online with more on the way,” the governor continued. “Even as we face challenges in making this transition, it’s the right move for our communities and planet. Most importantly, it will leave Hawaiʻi a better place for our children and grandchildren.”

Renewables are notoriously more expensive and less effective than fossil fuels. Some estimates posit it would take at least a $5 trillion dollar investment to switch the nation to renewables, and it takes a massive amount of structures to power large swaths. In California – another state that has committed to wean itself off fossil fuels – rolling blackouts and electrical grid malfunctions are common. Renewables are not t reliable source of energy yet, and massively more expensive on a mass scale.

Coal was banned in Hawaii in 2020.