ADVOCATES FOR a “green new deal” in Massachusetts gained another major backer on Thursday, as Democratic gubernatorial candidate Sonia Chang-Diaz came out in support of fare-free public transit and rapid deployment of offshore wind, solar, and electricity storage to make the regional power grid run on 100 percent renewable energy by 2030.

The positions of Chang-Diaz, a state senator from Jamaica Plain, are similar to those of Ben Downing, a former senator and another progressive in the Democratic race for governor who similarly is calling for fare free transit and a quick shift to all renewable energy. Both favor policies that are far more aggressive than what the administration of Republican Gov. Charlie Baker is pursuing.

Chang-Diaz and Downing both call for eliminating fares on buses across the state in their first year in office. Both also favor eliminating fares across the MBTA, with Downing promising to get the job done by the end of his first term. Both candidates also back East-West rail service and regional rail, a concept that favors commuter rail trains running every 15 to 30 minutes across the entire day. Most commuter rail trains currently run on the hour.

Both Democrats favor electrification of buses and commuter rail. Their timetables are similar, although Downing seeks full electrification of the commuter rail system by 2030 while Chang-Diaz sets a 2040 target date.

Reducing greenhouse gas emissions is a top priority of both candidates. Both promise the power grid will run on 100 percent clean energy by 2030. Downing says he will transition all current non-electricity sectors (transportation, heating, and cooling) to renewable energy by 2040.

The policy outlines of the two candidates are big on ambitious goals but skimpy on details about how to reach them. They portray the shift to clean energy and fare-free transit as transitions with environmental and economic benefits for society at large and particularly for low-income communities of color.

“A combination of onshore and offshore wind and large- and small-scale solar, together with energy storage, is capable of meeting all of our energy needs in the Commonwealth and then some: indeed, estimates suggest that offshore wind alone could generate more than 19 times as much electricity as Massachusetts currently consumes on an annual basis. Massachusetts has all the natural resources it needs to power our future with clean, renewable power,” says Chang-Diaz’s green new deal outline,

But Chang-Diaz’s plan to move the power grid to 100 percent clean energy by 2030 would be an incredible challenge. Vineyard Wind, the nation’s first industrial-size offshore wind farm, began construction this year and is not scheduled to start producing power until 2023. The state’s second wind farm — Mayflower Wind — hasn’t even won final regulatory approval yet.

Chang-Diaz indicated she favors a home-grown energy industry and wouldn’t pursue imports of Canadian hydroelectricity, as the Baker administration is doing. “We don’t have to depend on energy generated in another country,” she said in an interview.

Chang-Diaz said the experts she has consulted insist Massachusetts can meet the timetables she is setting. “We need to walk and chew gum at the same time,” she said. “We have the technology for this. We have the know-how. The missing piece on all of this is not the technology but the political will.”

She said she has helped lead reforms on Beacon Hill of the criminal justice and education systems, and is prepared to do the same for transportation and energy.

“I’m convinced it’s possible, but it’s not going to be easy,” she said.

Reaching her transportation and energy goals would require massive investments. Her plan doesn’t spell out where all the money would come from, although she said she would help replace fare revenue at the MBTA with tax revenue gained by cracking down on companies evading taxes by shifting income abroad. A policy paper issued in February 2020 by the left-leaning Massachusetts Budget and Policy Center said such a crackdown could generate $450 million a year.