Environmentalists are waging an ever-more-ambitious war on natural gas and, so far, national Democrats are following their lead. Activists aren’t stopping there, however, and are planning to expand their campaign to include all forms of natural gas usage, including the home appliances consumers love.

Since 2016, Democratic officials have become more aggressive while pushing energy and environment issues. By last count, six Democratic candidates for president support a nationwide ban on fracking and seven would limit or better regulate it—a clear change from 2016 when Hillary Clinton rejected a national fracking ban. Meanwhile, Berkeley, Santa Monica, and 11 other cities in California have passed zoning codes banning natural gas appliances.

In Colorado, the Boulder-based Rocky Mountain Institute helped to promote the municipalities’ bans this year and intends to push for more in 2020. In a fundraising webcast, RMI Managing Director Jon Creyts called the bans a “first push” away from fossil fuels and said that the group was committed to expanding the policy on a national and eventually global scale.

Residential natural gas use contributed less than four percent of total U.S. greenhouse gas emissions in 2016, Energy Information Administration (EIA) statistics show.

Creyts’ remarks echoed the conclusion of a major report the RMI released earlier this year, which rejected the idea that natural gas generation was needed for grid reliability and security. According to RMI, 90% of new gas-fired power plants “could be cost-effectively replaced with clean energy portfolios” and clean energy portfolios could undercut the go-forward operating costs of 90% of natural gas plants by 2035.

In a recent report, the RMI argued that change was inevitable since, “the question is no longer if but when renewable generation will outcompete coal, natural gas, and other traditional means of power generation.”

In practice, such a transition would almost certainly raise costs for consumers. In Colorado, seven out of ten houses use natural gas as their primary heating source. The decarbonization plans promoted by environmentalists would require these homes to switch to electric heat and would require replacing natural gas generators with an equivalent amount of renewable generation.

Renewables comprise only 20 percent of electricity generation and natural gas is used for 35 percent. While wind and solar production is expanding in the West, new installations are dependent on a variety of subsidies at the state and federal level.

Meanwhile, consumers continue to resist giving up their natural gas appliances. Natural gas stoves, furnaces, and other appliances remain consumer favorites. According to the American Gas Association, in 2017, natural gas had 49 percent marketshare for both cooktop ranges and water heaters.

By pushing for more extreme positions against natural gas, nonprofits like the RMI are following where its donors lead. In May, the RMI received a $2.3 million grant from Bloomberg Philanthropy to “evaluate and analyze current U.S. greenhouse gas emissions reductions” as part of a push toward a clean energy future. The philanthropic foundation was started by Michael Bloomberg, the latest entrant into the Democratic race for president.

This is not new for RMI, which has extensive ties to anti-fossil fuel organizations.