Joe Biden , the presumptive Democratic presidential nominee, laid out a new proposal Tuesday to transition the nations electricity grid off gas and coal by 2035 and spend $2 trillion over four years creating millions of jobs deploying renewable energy and upgrading old buildings.

The plan fell short of the sweeping climate visions on which the former vice presidents erstwhile primary opponents campaigned, leaving the door open to a continued expansion of fossil fuel production. But the new campaign pledge the second plank of his so-called Build Back Better agenda marked a significant shift in that direction as Biden seeks to unite his party and offered a stark contrast with President Donald Trump, whom he hopes to unseat in November.

The proposal comes less than a week after the Biden campaign released the 110-page recommendations of a task force of officials from the camps of Biden and Sen. Bernie Sanders (I-Vt.), the former vice presidents second-place rival for the nomination. The new campaign plank is largely in line with the advice from the committee co-chaired by former Secretary of State John Kerry and Rep. Alexandria Ocasio-Cortez (D-N.Y.).

The task force memo called for installing 500 million solar panels and 60,000 American-made wind turbines over the next five years. The new Biden plan promises the deployment of millions of solar panels and tens of thousands of wind turbines as part of a shift to completely carbon-free electricity in just 15 years. The United States generated close to 63% of its electricity from fossil fuels last year, including 38% from natural gas and nearly 24% from coal, according to Energy Information Agency data . Nuclear provided nearly 20% of the countrys power, while wind made up over 7% and solar fell just shy of 2%.