AS TEMPERATURES APPROACH 90 degrees in Boston that will send electricity demand higher in the coming days, two large renewable energy projects serving Massachusetts are not providing the jolt of power they promised.

The New England Clean Energy Connect project (NECEC), a 145-mile transmission line bringing hydropower from Canada into Massachusetts, was completed in January after a decade-long topsy-turvy political and legal process. Yet the project had not delivered any power into New England for two weeks before it flickered back to life on Tuesday, according to data from ISO New England, the regional grid operator.

And while state leaders have cheered the completion of Vineyard Wind in the face of unprecedented attacks from the Trump administration, the wind farm off the coast of Martha’s Vineyard is producing power at less than half of its expected capacity as it remains mired in litigation with its Massachusetts-based turbine supplier GE Vernova.

The two setbacks are coming as summertime heat is expected across the region later this week that could deepen dependence on natural gas. And they signal the continued challenges ahead for how to bring on new clean energy sources to move off fossil fuels and meet growing power needs while maintaining reliability as Gov. Maura Healey confronts complicated energy politics in pursuit of her “all of the above” approach.

In the case of NECEC, a project that is forecasted to account for 20 percent of Massachusetts’s electricity consumption, no power had been delivered through the transmission line between May 26 and June 8, ISO New England data show, despite no formal announcement from Hydro-Québec, the government-owned utility. Lynn St-Laurent, a spokesperson for Hydro-Québec, told CommonWealth Beacon in a statement on Friday that NECEC had been “offline” due to “technical issues” but that “repairs are currently underway and should conclude shortly.”

“With any new transmission infrastructure, a period of optimization and fine-tuning is to be expected,” she said.

This pause is in some ways more notable than a week-long one during frigid conditions that occurred not long after Healey celebrated the completion of the project this past winter. In January, high energy demand and spiking natural gas prices, coupled with decreased electricity from Canada, led the New England region to rely on oil for 40 percent of its power during peak periods and caused a spike in greenhouse gas emissions.

It was somewhat understandable that Hydro-Québec would export little or no power over a brand-new transmission line for a short period of time to ensure residents north of the border had enough capacity to heat their homes, said Joseph LaRusso, senior advocate at environmental nonprofit Acadia Center.

This time, however, a pause in electricity transmission on the NECEC line has not only dragged on substantially longer, but it has come when the region needs that power most. Energy demand in New England peaks during the summer, when homes and businesses turn on their air conditioners to cool off during warm temperatures, whereas Québec’s system reaches its highest demand in the winter months as it relies more on electricity for heating.

The province has also been dealing with a record drought that has dwindled its water supplies and forced it to recalibrate how much hydropower it’s able to share. New England’s imports of Canadian hydropower through an older transmission line waned significantly between 2022 and 2024, and hydropower plans across Canada have had to be scaled back because of the drought.

On Monday, Québec municipalities and environmentalists called on province officials to consider stricter water regulations as the drought persists.

Even without contributions from the NECEC, there’s no indication at this point that New England won’t have the supplies that it needs to meet electricity demand this summer. Matt Kakley, a spokesperson for ISO New England, said that the system has remained reliable over the past few weeks and the grid operator isn’t expecting any issues in the near future.

But LaRusso said the region would likely be forced to rely more on natural gas because of this NECEC suspension and any future ones that may occur. As of Monday afternoon, a comfortable and sunny day in Boston, 60 percent of the region’s power came from gas, according to ISO, up slightly from 55 percent last year.

“I’m sure that the Healey administration would find it disappointing, if Hydro-Québec is not able to send power, that the overall reduction in emissions that it hoped to achieve would be frustrated, but that’s another story,” he said. “In terms of resource adequacy, we won’t be put on the back foot because NECEC is not delivering full power.”

Another key difference: During NECEC’s January suspension of power deliveries, the Healey administration made it clear that Hydro-Québec would be “facing steep penalties for each day they are not providing power to Massachusetts” under the contract, and that those penalties would be returned to ratepayers, Maria Hardiman, a spokesperson for the Executive Office of Energy and Environmental Affairs, said in a statement at the time.

Whether the Bay State will be collecting such penalties this time, for a much longer outage, isn’t as straightforward. Lauren Diggin, a spokesperson for the Department of Energy Resources, said in a statement that the state is “aware of a technical issue on the NECEC line and we are in communication with the company,” but didn’t directly respond to questions about whether Hydro-Québec would be penalized.

St-Laurent, the Hydro-Québec spokesperson, said that contract provisions “are designed to reflect a range of possible circumstances when deliveries are suspended.” That means sometimes deliveries can be rescheduled at a later date, sometimes “compensation mechanisms” apply, and sometimes, “non-delivery may be permitted.”

Asked about which one of those scenarios applies to Hydro-Québec’s two-week pause, she said that is being “addressed through confidential discussions between the parties” and would not provide additional details.

More broadly, net imports from Hydro-Québec through the first half of this year are on par with this time last year — before NECEC was operational, said Dan Dolan, president of the New England Power Generators Association.

“Fundamentally, we don’t see in the market any meaningful increase in energy supply from NECEC,” Dolan said. “They’re not doing anything legally wrong. They are abiding by the flexibility and the open-ended elements of this contract. The challenge here is more of a political one, where the political expectation is one of reliability and energy security, and that’s not what this is.”

Vineyard Wind’s struggles to produce power through all 62 turbines in the Atlantic Ocean is not tied to unpredictable boom-and-bust cycles of drought like NECEC. Vineyard Wind is instead facing political and legal hurdles that will eventually likely work themselves out, LaRusso said.

Plus, offshore wind generally produces more of its power during winter months — including peaks in its production during this season’s cold snap.

“Vineyard Wind is going to be producing power for a long time, so we need to take the long view and anticipate that it’s going to be there when we need it, primarily in the wintertime, when it’s going to displace oil production,” LaRusso said.

Still, the challenges on display now are risking Massachusetts’s ability to bring in more power quickly that can cut emissions, meet rising demand from artificial intelligence and electrified vehicles and heating sources, and lower residents’ soaring utility bills.

“If we think back over the major energy policy choices that Massachusetts and many other New England states have taken in the past decade-plus, it has been fundamentally about reliance on the state-mandated long-term contracts making really big bets on really big projects,” Dolan said. “There has to be a pretty sober assessment on whether these policies work.”