Joe Biden has raised the ambitions of his climate plan, in a clear sign his campaign is responding to demands for greater action among the progressive flank of his party.

In a speech on Tuesday, the presumptive Democratic nominee for president announced proposals to spend $2 trillion on clean-energy projects and eliminate carbon emissions from the electricity sector by 2035, stepping up his primary targets in an effort to revive the economy and combat climate change.

Biden also trumpeted plans to retrofit millions of homes and buildings to make them more energy efficient; create a Civilian Climate Corps that would put people to work on environmental restoration projects; install 500,000 charging outlets for electric vehicles; establish a cash-for-clunkers program to replace gas-guzzling cars and trucks with hybrids and EVs; and spark a “second great railroad revolution.”

The plan on Biden’s campaign page specifies that it would implement an “energy efficiency and clean electricity standard” to achieve the 2035 power sector goal, a policy instrument that requires utilities and grid operators to gradually reduce the share of electricity coming from carbon-emitting sources. It’s a technology-neutral standard, meaning it could allow for generation from solar, wind, geothermal, or nuclear sources, or even fossil-fuel plants with effective carbon capture systems.

Tuesday’s news comes on the heels of Biden’s “Build Back Better” announcement last week, in which he committed to spend $400 billion to boost US manufacturing and $300 billion in research and development funds for electric vehicles, artificial intelligence, and other areas.

The new plan is far more aggressive than Biden’s earlier campaign proposal. It called for  investing $1.7 trillion into clean energy and achieving “net zero” emissions across the economy by 2050. The earlier plan had no specific timeline for cleaning up the electricity sector, beyond a mention of unspecified 2025 “milestone targets.”

The raised ambitions follow a set of climate policy recommendations issued earlier this month by a “unity task force,” created this spring with Biden’s primary rival, Senator Bernie Sanders. It had recommended the 2035 power sector target, among other goals.

But even Biden’s new targets still fall short of the demands of many climate activists as well as the goals of Sanders’s original plans, which included $16 trillion in clean-energy spending, all-renewable electricity generation by 2030, and an immediate ban on fracking, a drilling method used for natural-gas and oil extraction.

Biden’s sprawling climate plan had already called for new fuel economy standards, support for advanced biofuels, climate adaptation projects, and a restored commitment to the Paris climate agreement. He also pledged early on to spend $400 billion on clean-energy research over the next 10 years and set up a new agency, ARPA-C, to accelerate research on small modular nuclear reactors, carbon capture, grid-scale energy storage, carbon-free hydrogen, and lower-emissions methods for producing steel, cement, hydrogen, and food.

The campaign said at the time the plan would be paid for by reversing the Trump tax cuts for corporations, ending subsidies for fossil fuels, and introducing additional tax reforms.

Biden’s campaign also previously told the Washington Post he supports setting a price on carbon, either through a tax or a cap-and-trade program, though there’s no specific mention of it in his previous or newest climate plan.

Biden is trying to walk a delicate line, appealing to the progressive voters demanding sweeping climate polices without turning off more conservative working-class voters in key swing states where coal and natural gas are still large contributors to the economy.  He stressed near the start of his speech that the plan will create “good-paying union jobs that will put America to work.”

Laying out an ambitious climate plan is the easy part, however. For any of this to matter, Biden first needs to clinch the election. And then he’d have to win over the next Congress, where Democrats may or may not seize control of the Senate, but where there’s been little appetite historically for such aggressive climate and spending proposals.

Finally, the funding and policies would actually have to achieve their stated goals, and begin rapidly driving down the nation’s emissions.

The trillions in spending coupled with a federal clean-energy standard would certainly help to spur the development of renewables and other clean-energy and climate projects. But the campaign has provided fewer details on the sorts of planning reforms that would be necessary to build a huge number of projects in the next 15 years, given the dragged-out approval process for any major developments in the US. And those hefty R&D investments will need to deliver some real breakthroughs to begin affordably cleaning up the trickier parts of the economy, like agriculture, aviation, steel, and cement.