Public Service Electric & Gas yesterday began building a 10.14-megawatt solar farm at the closed Parklands Landfill in Bordentown, which will be the biggest system of solar arrays yet to be built in New Jersey by the utility.

The solar system at the capped former garbage dump complies with an initiative that aims to shift large grid-supply projects, which deliver power directly to the grid, to landfills and brownfields. The latter are unused manufacturing sites that remain idle, in some cases because the expense of cleaning up pollution on the property.

The new policy, established under a revised Energy Master Plan adopted by the Christie administration, steers this type of project away from being built on farmland and other open space in a state rapidly losing both. Beyond preserving open space, large grid-supply projects typically produce power at lower costs than smaller solar systems on homes and businesses.

PSE&G has been the most aggressive of the state’s utilities in trying to redevelop brownfields and landfills, having done so even before its Solar 4 All program was approved by the New Jersey Board of Public Utilities in May 2013. The utility will invest $247 million in the projects, most of which will be spent on landfill and brownfield systems.

The Parklands project will utilize 40 acres of landfill to build a solar farm capable of powering 2,000 homes annually. It is the biggest solar farm yet undertaken by PSE&G in the state, but that distinction may not last long. The utility also is planning to build a 11.8-megawatt solar system on the former Kinsley garbage dump, once a national superfund site.

“Landfills like Parklands offer prime opportunities for large-scale solar development that benefits New Jersey and our customers,” said Joe Forline, vice president of customers solutions for PSE&G. “We can convert this property into a productive asset that adds to New Jersey’s inventory of renewable-energy resources without reducing the state’s open space.”

So far, PSE&G has developed solar systems on four former brownfields in Trenton, Edison, Linden, and Hackensack under a previous settlement with the BPU, as well as a landfill in the Meadowlands in Kearny.

Once the Parklands Service Farm is up and running, it will mark the sixth brownfield or former dump to be utilized for solar projects capable of generating more than 20 megawatts of electricity, enough to power about 3,000 homes annually.

Eventually, the utility will end up converting four or five former landfills into solar systems, according to Fran Sullivan, a spokesman for PSE&G. All told, with projects planned for brownfield sites, the solar farms would produce about 42 megawatts of capacity, he said. According to the settlement with the BPU, the projects are to be in service sometime in 2016.

Prior to the settlement with the BPU on the program, the Division of Rate Counsel and business interests questioned whether ratepayers, who end up paying for the projects, could afford it given other large utility projects either pending or approved by the regulatory agency.

In May, the BPU approved a $1.2 billion program by PSE&G to harden its power grid and reduce outages that occur during extreme storms, such as Hurricane Sandy. Later in the summer, the utility filed a petition with the agency seeking to spend $110 million on energy-efficiency projects that would enable hospitals, multifamily housing units, and governmental agencies to cut their bills by reducing energy consumption.

But the BPU staff minimized the cost of the large grid-supply projects, estimating it would add only $4.50 to the average residential customer’s bill. Business interests, representing manufacturers who require large amounts of energy to maintain operations, argued the costs would be much higher for them.