Batteries included: Deepwater Wind proposes Mass. plan that could make wind power more reliable 

PROVIDENCE, R.I. – One of the problems with wind turbines is that they’re intermittent sources of power. The wind doesn’t always blow.

Deepwater Wind, the Providence company that last year built the first offshore wind farm in the United States, may have solved that problem with its latest proposal, a 144-megawatt wind farm in the waters off Rhode Island that would be backed up with a 40-megawatt-hour battery storage system engineered by Tesla.

“There’s no reason that an offshore wind farm paired with batteries can’t be considered a baseline resource,” Deepwater CEO Jeffrey Grybowski said. “We see that pairing as a fundamental driver of new energy sources in the U.S.”

The wind farm, known as Revolution Wind, would be built far offshore between Block Island and Martha’s Vineyard in waters that the company is leasing from the federal government. It would supply power to Massachusetts, enough for about 80,000 homes.

The battery storage facility would be at either Brayton Point in Swansea or Quonset Point in North Kingstown, depending on where the transmission cable for the wind farm makes landfall.

It would be charged by the farm’s 24 or so wind turbines in the middle of the night when power demand is at its lowest and would then push that power back into the electric grid in the late afternoon or early evening when demand is at its highest.

Under one configuration being considered by Deepwater, the batteries would be drained over two hours and be able to meet the energy needs of about 24,000 homes.

Deepwater announced the proposal earlier this week after responding to a request for proposals for clean energy in Massachusetts.

It’s not news that the company wants to build a project that could supply power to Massachusetts. It’s one of three offshore wind developers – along with DONG Energy and Vineyard Wind – that have leases to federal waters off the state’s southern coast.

But Deepwater wasn’t expected to submit a project proposal until December under a Massachusetts RFP specifically looking for offshore wind proposals.

It’s surprising that the company has responded to the separate clean energy RFP because it will have to go up against renewables that are typically cheaper. They include big hydro from Canada, onshore wind from Maine and solar.

But Grybowski says that Deepwater’s price – which covers the cost of an undersea electric cable and the batteries – is competitive with hydro or onshore wind when the costs of lengthy transmission lines for those other sources of energy are factored in.

Other proposals that were submitted include Emera’s plan for a cable from New Brunswick, Canada, that would carry onshore wind and hydro power and plans from National Grid and Citizens Energy for onshore wind and solar from around New England.

Grybowski would not disclose Deepwater’s bid price or the overall price-tag of the Revolution project, which could be scaled up or down depending on the needs of Massachusetts. Deepwater’s bid includes 96- and 288-megawatt alternatives.

Construction would start in 2022, with final assembly of the turbines taking place at the New Bedford Marine Commerce Terminal. The wind farm would go into operation the following year.

The proposal is just Deepwater’s latest. The company completed the nation’s first offshore wind farm, a 30-megawatt, five-turbine project three miles southeast of Block Island, last fall.

It followed that up with a proposal for the 120-megawatt Skipjack Wind Farm off Maryland. And in January, the Long Island Power Authority agreed to buy power from the company’s proposed 90-megawatt South Fork Wind Farm.

The South Fork project would constitute the first phase of development in the federal waters off Rhode Island leased by Deepwater. The 256-square-mile lease area has room for up to 2,000 megawatts of offshore wind power, according to Deepwater’s latest estimates.

The Revolution project would be built in the second phase, if it’s selected in the Massachusetts clean energy RFP. And Deepwater still plans to submit a separate bid to the state’s offshore wind RFP, which is seeking proposals of 400 megawatts of energy but will consider bids ranging from 200 megawatts to 800 megawatts.

One of the aims of the Massachusetts solicitation for new clean energy sources is to temper reliance on natural gas for power generation on the coldest winter days when the fuel is needed for heating. New England has seen natural gas price spikes in previous winters on frigid days.

The winds offshore are generally strong on those days, but using batteries offers a guarantee that Deepwater can meet the demand for power, says Grybowski. He believes the combination of battery technology and renewable energy is the future for the industry.

“We see this as a good opportunity to push forward down that path,” he said.