Dominion Energy’s investment in Virginia solar power has topped $800 million and headed to $1 billion, the utility revealed Tuesday.

Nearly 400 MW of solar generation is either completed or under development throughout the state, enough to power 100,000 homes, the utility noted. Most of the costs are being borne by specific large business and government customers under contract, according to the release.

“Our company has made a major commitment to develop significant blocks of solar generation to meet customers’ energy needs going forward,” said Paul Koonce, CEO of power generation at Dominion Energy, in a statement. “Our goal is to have a balanced generating portfolio that is highly reliable, cost effective and environmentally responsible. The cost of energy powered by the sun is coming down and we are working hard to develop projects in new and economical ways for our customers.”

In February 2015, Dominion committed to developing 400 MW of large-scale solar generation facilities in Virginia and placing them in service by 2020. Additionally, legislation passed by the Virginia General Assembly in 2015 found that development by Virginia utilities of up to 500 MW of solar projects in the state was “in the public interest.”

In addition to building larger solar-powered units, Dominion’s Solar Partnership Program has placed company-owned solar panels on leased rooftops and grounds of government and business properties throughout its Virginia service area. Ten of these facilities have been installed at sites including Canon in Gloucester, Old Dominion University in Norfolk and Capital One in Chester.

The commonwealth’s commitment to 500 MW of large-scale solar development by 2020 was included in Senate Bill 1349, passed by the General Assembly in February 2015. SB 1349 froze the company’s base rates – making up about 60 percent of the typical residential bill – at 2015 levels for five years. This helped provide price stability for customers as the company deals with complex federal air quality regulations, including those limiting power station carbon dioxide emissions.

Virginia traditionally has ranked in the bottom rung of states by installed solar capacity, according to reports. The moves by Dominion could lift the state into the top half nationally.

“We are well ahead of schedule on the solar expansion and what we have added so far will have a very minimal impact on the price of electricity for the 2.5 million regulated customers we serve in Virginia,” Koonce said.

More than 80 percent of the cost of the facilities is being covered by large business and government customers, including the Commonwealth of Virginia and the University of Virginia, who signed long-term contracts with Dominion to develop the generation.