The UK has been working to significantly reduce its carbon emissions and with that effort, it hit some major green milestones this year. In April, the country went a full day without coal-generated power for the first time in 135 years. And in June, the country saw more than half of its energy being generated by renewables (i.e. solar, wind, hydropower and biomass) for the first time.

Looking back on 2017, renewable energy sources outstripped coal use in the UK quite often. Wind farms generated more electricity than coal plants for more than three-quarters of the year. Solar also did well, providing more energy than coal for more than half of the year. Taking all renewables into account, they, as a group, outperformed coal plants in energy production on 315 days of the year (as of December 12th).

However, the country didn't do quite as well when it comes to reducing its natural gas use. Wind only outperformed gas on two days in 2017 and when comparing renewables overall with fossil fuel energy production, renewables only outstripped fossil fuels during 23 days this year.

The BBC reports that Andrew Crossland, founder of MyGridGB, which provides analysis of UK carbon emissions and energy use, and a Durham Energy Institute fellow said, "The government has focused on reducing coal use which now supplies less than 7% of our electricity. However, if we continue to use gas at the rate that we do, then Britain will miss carbon targets and be dangerously exposed to supply and price risks in the international gas markets."

By 2025, the UK plans to close all of the coal plants that can't effectively capture and store their carbon emissions, and the country is well on its way towards that goal. But getting renewables to consistently outperform gas still poses a challenge. Emma Pinchbeck, executive director of RenewableUK, said, as the Guardian reports, "We want to see more boldness from the Conservative government. In 2018, the government should move to allow onshore wind, now the cheapest form of power for consumers, to be developed in parts of the UK where it is wanted, and agree an ambitious sector deal with the offshore wind industry. The new year could be the first in a golden age for UK renewables."