Hawaiian Electric Companies say it expects bills to be reduced by 20 percent by 2030.
HECO released its energy plan filing before the state's Public Utilities Commission deadline.
Some of the highlights of the plan to be achieved by 2030 include more than 65 percent renewable energy, electric bills reduced by 20 percent and nearly triple the amount of distributed solar.
But, the head of an environmental watchdog group and frequent critic of HECO had a preliminary look at the documents and questions its solar implementation plan.
"They have not wanted to make a wholesale shift to new realities," said Henry Curtis of Life of the Land. "Right now, rooftop solar is doubling every year up until last September. They're projecting 7 percent growth rate over the next 15 years which seems very low."
Back in April, the PUC rejected the HECO's initial plan and ordered it to develop a plan to accommodate greater amounts of renewable energy to improve the process for customers installing solar photovoltaic systems and show how customers will connect to the grid in the future.
HECO says part of the overall plan is to use less expensive liquefied natural gas in the future and convert their existing oil-fired generating units to run on LNG.