BURRILLVILLE, R.I. — The Clear River Energy Center is still in the approval process, but National Grid and Invenergy Thermal Development are expected to begin preliminary work next month on connecting the proposed fossil fuel power plant to the electric grid.

A decision on the $1 billion energy project is months away and the interconnection project still requires several permits, but preparing the 6.8-mile route through rural Burrillville is scheduled to commence in a few weeks.

Soil testing and sampling will start in August in preparation for widening an existing power-line route from 300 to 500 feet. The entire project, including the interconnection work, is expected to require the clear-cutting of some 64 acres of forestland, including disrupting 10 wetland acres.

Rick Enser, an ecologist who spent 28 years as coordinator of the Rhode Island Department of Environmental Management’s Natural Heritage Program, wants National Grid to use a biologist during the survey to ensure protection of rare species, such as turtles and plants.

“If they are using heavy equipment then there will be a noticeable impact, even using best practices,” Enser said.

This power-system buildout will connect the nearly 1,000-meagwatt Clear River Energy Center with National Grid’s Sherman Road switching station. It was originally expected to be completed by the winter of 2018-19. Steel, H-shaped towers and monopoles with a height of up to 110 feet will be erected to accommodate high-voltage transmission lines.

Invenergy said it wouldn’t bury the power line because underground construction typically costs three to 10 times more than overhead power lines. Maintenance and fixing power outages is also more time-consuming with underground systems, according to the Chicago-based developer.

Abutters along the power-line route have been notified of the work, which can take place between 7 a.m. and 7 p.m. Monday through Friday and until 5 p.m. on Saturdays. Invenergy will seek approval from the town if work is necessary on Sundays or holidays.

Last year, Invenergy failed to have ratepayers subsidize the $47.2 million interconnection costs. The energy company eventually dropped the effort, after the state Energy Facility Siting Board (EFSB) suggested that doing so might invalidate the application for the power plant by violating Invenergy’s pledge to not charge ratepayers for the power plant.

“All costs related to the interconnection facilities and any required network upgrades will be paid for directly by Invenergy, the power plant’s proponent. National Grid ratepayers will not be responsible for these costs,” according to Invenergy.

The Federal Energy Regulator Commission approved the interconnection agreement between National Grid and Invenergy. But permits and reviews are still required from the Burrillville Zoning Board of Review, Burrillville Planning Board, Burrillville building inspector, the Rhode Island Department of Transportation, the state Department of Environmental Management, and the Army Corps of Engineers. The Army Corps of Engineers has issued a permit to conduct pre-engineering surveys.

Invenergy and National Grid say all of the work complies with environmental regulations.

Invenergy says that only “minimal” brush clearing will occur during the survey work. Timber swamp mats will be installed to protect wetlands, and silt fences and staked straw bales will control water and sediment runoff, according to Invenergy.

Abutters will be allowed to keep any wood from trees along the route. Questions about the wood and clearing can be answered at [email protected] or by calling 844-344-1900.

National Grid says modeling for the 345-kilovolt transmission system shows that the electronic and magnetic fields (EMF) are below risk levels. Studies have found mixed to no association between cancer and exposure to power lines, but the World Health Organization maintains there is a risk of nuisance shocks and nerve stimulation from high-voltage power lines. National Grid will conduct EMF surveys for abutters by request.

The power lines can also emit a low-level noise akin to a faint sizzling, popping, or humming sound. A corona effect occurs when moisture causes the air around a power line to break down electrically, a process called ionizing. National Grid will install corona rings to reduce noise and coronas.

The state Department of Health said the transmission line will pose negligible or no impact on public health. A portion of the project exceeds international risk thresholds for radiation but will not pose a health threat if public access to the area is limited.

In a press release about the survey work, Invenergy noted that the natural-gas/diesel-fueled power plant will be the most efficient energy facility in the region. Carbon emissions savings are equal to taking 100,000 cars off the road, according to Invenergy.

The survey work is expected to last four to six weeks.

The final hearings for the Clear River Energy Center are scheduled to resume July 19 at 9:30 a.m. at the state Public Utilities Commission, 89 Jefferson Blvd. in Warwick. Invenergy will offer testimony from Mark Wiitanen of the engineering firm HDR Inc. Michael Sabitoni of the Rhode Island Building and Construction Trades Council, a supporter of the proposed power plant, is scheduled to testify about job benefits. Ryan Hardy of PA Consulting Group Inc. and Robert Smith of McMahon Associates will also tout the employment benefits of the proposed power plant.