Related by context. Frequent words. (Click for all words.) 89 fossil fuels 66 renewables 64 biofuels 64 renewable energy 63 coal 61 renewable 61 greenhouse gases 61 biomass 60 biofuel 59 coal fired 58 energy 58 carbon dioxide emissions 58 carbon emissions 58 alternative fuels 57 renewable fuels 57 ethanol 57 CO2 56 natural gas 56 greenhouse gas emissions 56 carbon dioxide 56 tar sands 55 greenhouse gas 55 carbon 55 greenhouse emissions 53 biodiesel 53 reduce carbon emissions 53 CO2 emissions 52 petroleum 52 cellulosic ethanol 51 emissions 51 carbon capture 51 GHG emissions 51 polluting 51 feedstock 51 fuels 50 electricity 50 diesel 50 gas 50 internal combustion engine 49 fuel 49 global warming 49 oil 49 climate change 48 hydrogen 48 bio diesel 48 LNG 48 gasoline 47 Ethanol 47 feedstocks 47 emission reduction 47 oil sands 47 oilsands 46 liquefied natural gas 46 hydropower 46 reduce greenhouse gas 45 diesel fuel 45 hydro 44 desalination 44 incineration 44 geothermal 44 pollution 44 IEA 44 emission 44 wind farms 44 methane 44 wood chips 43 fossil 43 Energy Agency 43 hydrogen fuel 43 gas guzzlers 43 Clean Energy 43 Hydrogen 43 crude oil 43 zero emission 43 hydrocarbons 43 hydrocarbon 43 kilowatt hour 43 Biodiesel 43 hydroelectric 42 Biofuels 42 biogas 42 Emissions 42 rare earths 42 environmentalism 42 megawatts 42 combustion 42 reducing greenhouse gas 42 EVs 42 thermal coal 41 carbon neutral 41 solar 41 carbon credits 41 kWh 41 methanol 41 nuclear 41 environmentally sound 41 deforestation 41 shale gas 40 pollute 40 carbon footprint 40 gasification