Proposed in 2001, and funded by hundreds of millions of dollars from one of the largest private energy investment firms in the country, the plant was to be among the biggest new electricity projects in New England, costing nearly $1 billion.
Construction workers had to move 1.6 million yards of rock and earth to claw out a 137-acre site for the plant on land owned by Middletown trash czar Phil Armetta. Armetta is a former partner in the project who withdrew after he was convicted in a federal crackdown on the trash industry.
William Corvo, a former Middletown councilman who is a principal partner in the project, said from the chaotic scene Sunday that the plant was 96 percent complete.
He said a test of the natural gas-fired turbines "was being lined up." Middletown fire officials said the explosion involved natural gas.
The Kleen Energy plant would burn a huge amount of natural gas piped to the site, and, to a lesser extent, low-sulfur oil.
The proposal for the plant was controversial in Middletown because it involved drawing hundreds of thousands of gallons of water from the Connecticut River to cool the turbines, and because the project was awarded tax breaks by the common council during the administration of former Mayor Domenique Thornton.
But Corvo fired back with studies showing that the water draw would not affect the flow of the river, and said the project would be one of Middletown's largest taxpayers, even with tax abatements.
He said the plant would provide much needed electrical capacity to the power grid feeding southern New England.
To make the plant's application to divert water from the river more palatable, Corvo became partners with the city of Middletown on a joint application to the state Department of Environmental Protection.
When Mayor Sebastian Giuliano took office in 2005, he was less inclined to play ball with Corvo, canceling a deal in which the power plant partnership was paying the city's legal bills for project-related issues.
But the plant stayed on track, receiving Connecticut Siting Council and DEP permits.
Energy Investors Funds, with a multibillion-dollar power generation portfolio stretching across the country, acquired 80 percent of Kleen Energy in 2008 by pulling together $985 million in construction financing.
The project was underwritten by Goldman Sachs, and ProjectFinance magazine named it "The Deal of the Year" in 2008.
Corvo and a partner, David Oneglia, held onto the remaining 20 percent and have positions on the board, offices at the plant and roles as local representatives of the project.
After Enron collapsed and banks stopped financing power plants, Corvo lobbied state regulators, newspaper editors, politicians and anyone else who would listen about something called "capacity contracts" — 15-year agreements that pay plants just to exist and act as incentives to developers to build them.
The deals, between the power plants and utility companies, have their critics because the payments are for capacity, not for production of electricity. The state Department of Public Utility Control issued four of the contracts in 2007 in a fiercely competitive bid that drew some of the largest operators in the country. Kleen Energy bagged the biggest share of the capacity payments. The four commitments will cost ratepayers $340 million, but save them $552 million in electricity generation costs over the 15 years, in part by bringing new plants online, state energy officials have said.
Kleen Energy Systems LLC first proposed building the plant in 2001 in Middletown's Maromas section, bordered on the north by the Connecticut River. Just west of the plant is vacant residential land, to the south is Bow Lane and to the east is land owned by Connecticut Light & Power for a 345 kilowatt transmission line, according to a 2006 report by the Connecticut Office of Legislative Research.
The plant primarily uses natural gas in making power, but can also burn oil with a very low sulphur content. The legislative report said, "The proposed plant would operate on natural gas using a combined cycle turbine, which reuses the waste heat produced in generating power and thus increases the plant's efficiency."
Kleen Energy Systems received approval to generate 520 megawatts — enough electricity for 364,000 to 520,000 households — in November of 2002 from the Connecticut Siting Council. As of 2006, the company was petitioning the Siting Council to be able to produce 620 megawatts. A megawatt can serve 700 to 1,000 homes.
Courant Staff Writer Matthew Sturdevant contributed to this story.