PROVIDENCE — Progress is being made on building solar arrays in places that don’t require clear-cutting trees.

A study commissioned by Rhode Island’s Office of Energy Resources (OER) is underway to find brownfields, parking lots, landfills, quarries, and rooftops that are suitable for solar panels.

The study, being conducted by Synapse Energy Economics Inc. of Cambridge, Mass., will aid developers in considering these already-disturbed locations. It’s also in response to communities, especially rural towns, that are struggling with the loss of tracts of open space and woodlands to utility-scale solar facilities.

The study is running simultaneously with an analysis of a statewide carbon-fee program. The carbon-fee study is underway and being conducted by Waltham, Mass.-based Cadmus.

The solar study was authorized after bills stalled in the General Assembly that offered statewide incentives for renewable-energy development in already-built areas. The failed bills also required municipalities to pass their own regulations for solar development.

Bills submitted in recent years for a statewide carbon fee and dividend program also died in committee. But in 2017, the General Assembly authorized a study (H6305) of a so-called “carbon tax.” Money for the study wasn’t earmarked until this year, when $250,000 was made available from the attorney general’s office. Settlement money the state received from the Volkswagen emissions scandal will pay for this study.

Cadmus was chosen among five bidders for the carbon-fee study. An informational meeting is expected to be scheduled in October. The final carbon-fee study is expected during the first quarter of next year.

A draft of the non-greenfield solar-siting study is expected in January. The final report is expected in March, followed by a presentation to stakeholders and the General Assembly.

The $83,0000 study, funded through OER, isn’t expected to lead to direct legislation, but, according to Chris Kearns, the agency’s independent project manager, the report will “influence policy discussions.” Those discussions will likely include incentives for building solar arrays in these select locations, as other states, such as Vermont, have done.

The solar study was mostly met with questions during a Sept. 24 “kickoff meeting.” Many of the 20 attendees were members of OER’s solar-siting advisory group that represented solar developers, energy-policy organizations, and state and municipal planners. After more than a year of meetings, the group drafted a bill that limited solar facilities to a capacity of 10 megawatts in residential zones. Forests and areas of environmental concern were limited to 4-megawatt projects. Financial incentives were offered for building solar on brownfields, landfills, commercial land, and gravel pits.

Environmental groups were divided, however, on the legislation. Save The Bay and Grow Smart Rhode Island wanted incentives curtailed that allowed solar projects to be built in natural habitat.

Late in the 2019 General Assembly session, the Senate version of the bill was whittled down to simply requiring cities and towns to develop their own solar-siting rules. That bill passed the Senate but never received a hearing in the House. The House bill died in committee.

At the recent kickoff meeting, Fred Unger, of the Providence-based energy developer Heartwood Group Inc., offered the only opposition to the solar study. Unger favors the report by OER’s solar-siting advisory group. He criticized the premise of the Synapse study, because, he said, it may favor development of non-traditional solar projects and limit inducements for standard ground-mounted solar arrays. Unger said large solar arrays built on open space are less expensive and claimed better for the environment even if they require removing trees.

Unger likes to refer to the Environmental Protection Agency statistic that notes emission reductions from an acre of solar energy are 200 times greater than carbon sequestered within an acre of forestland. That statistic alone, however, fails to consider the other ecosystem services provided by an acre of forest, according to local environmental groups.

The Synapse study won’t compare the environmental benefits of open-field solar facilities with non-greenfield sites such as parking lots. But Kearns noted that the report may help expand other incentive programs such as the new community, or shared-solar, program, which has already reached its cap of 30 megawatts of power for new projects.

The Synapse study will analyze the potential greenhouse gas reductions of solar arrays built on these alternative sites. It will also include the potential costs for the five solar categories. Satellite and census data will determine the availability and suitability for installations at these already-developed sites.

Rooftops include schools, government buildings, single- and multi-family homes, and commercial and industrial buildings. If the data is available, the report will screen for the age of the roof and age of the building. Slope, orientation to the sun, and shading will also be analyzed. The report will use household income data to determine the percent of residential building likely to install solar.

Landfills include five potential sites in the state, but more are expected. The report will examine the capping status, size, slope, and type of waste in each landfill.

Brownfield sites, about 320, will be reviewed for solar-siting potential. Federal Superfund sites will not be included, nor will former military sites.

Gravel pit size and slope will be catalogued. Rhode Island has 13 known gravel, sand, and stone quarries.

Parking lot size and shading and the potential for solar carports will be studied.

The report will not recommend incentives for building in these locations but it will include incentives offered, if any, by 10 states and the District of Columbia. The Solar Massachusetts Renewable Target (SMART) program, for example, pays 3 cents per kilowatt-hour for electricity received from brownfields. It pays 4 cents for power from landfill arrays and 6 cents for electricity from solar canopies.

New York and New Jersey also offer guidance and incentives for building solar arrays on brownfields.

Synapse conducted a similar review of solar potential for rooftops and parking lots in Washington, D.C.