President Donald Trump has pledged to turn around the fortunes of America's largely bankrupt coal industry and shred Obama administration efforts at combatting climate change. But state lawmakers around the country are pushing back, boosting their green energy bonafides by upping the ante on commitments to transition their states away from fossil fuels and toward cleaner forms of energy, like wind and solar.

Legislatures in Massachusetts and California have proposed bills that would accelerate — and increase — previous commitments to expand the amount of energy sourced from renewables. California Senate leader Kevin de Leon, a Democrat from Los Angeles, has proposed legislation that would require the state to obtain 100 percent of its electricity from renewable sources by the end of 2045 — up from 50 percent by 2030. Lawmakers in both chambers of Massachusetts's legislature introduced efforts at obtaining 100 percent of the state's electricity from renewables by 2035 — and to completely decarbonize its economy, including transportation, by 2050. The state previously pledged 15 percent renewables by 2020, increasing 1 percent each year after.

Nevada is also looking to boost its renewable energy use to 80 percent by 2050.

So-called renewable portfolio standards are nothing new in the United States. In 2015, Hawaii committed to 100 percent renewables by 2045, and 26 other states, the District of Columbia, and three U.S. territories have adopted mandatory renewable energy goals. Another eight states and Guam have voluntary targets.

While efforts at boosting state-level renewable pledges could help to make up for lost ground under Trump, ramping up production reveals underlying problems, said Adam Reed, a researcher at the Renewable and Sustainable Energy Institute at the University of Colorado in Boulder.

"People always think of the state having its own kind of self-enclosed grid that has wind turbines and solar panels everywhere and nothing else," he said. "Actually, it's a bit more messy."

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Lawmakers in California and Massachusetts propose 100-percent renewable energy use, which is different than production, since neither state actually generates all its own power. Instead, the two states purchase some renewable energy from their neighbors — wind from Idaho, solar from Nevada, hydropower from Canada, for example.

In other words: State efforts at boosting renewables might succeed or fail based upon factors beyond their borders — namely, the interconnectedness of the nation's energy infrastructure.

The nation's power is distributed along one of three huge, independent electrical grids. Most renewable sources — namely wind and solar — are beholden to weather and time. The sun goes down at night; sometimes the wind doesn't blow in Texas.

If you want 100-percent renewable energy powering lights at the same time that it is being produced, you either have to store it for later use, or expand the range in which you collect it. Recent advances in battery storage offer some promise, but remain insufficient economy-wise.

Reed sees an efficient, interconnected power grid as one key part of powering not just California and Massachusetts — but the whole nation. By improving and connecting the current grids, the differences in time zones would allow power producers to match peak production, a sunny afternoon in Nevada, for example, with peak demand during evening times on the East Coast.

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Reed points to research indicating that the country could dramatically reduce carbon emissions by 2020 using renewables and improved power distribution.

"But the challenges of going to a high-renewables grid nationwide are significantly larger than going 100-percent renewable from the perspective of a single state," he said.

The problem lies in the complexity of the current grids, which are transnational (one includes parts of Canada) and incorporate more than 500 power companies and other entities.

"If we were ever to turn it off," Reed joked, "I don't think we'd get it started again."

But, he added, failure at ramping up renewable energy solutions is no laughing matter.

"If we're not largely decarbonized by 2050," he said, "really, really bad stuff starts to happen climate-wise."

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