Increased oil prices and air pollution concerns have prompted automakers to develop vehicles that use less fuel, such as hybrids that combine traditional gas engines with electric motors for efficient energy use. One popular energy-saving vehicle choice is the Prius hybrid, with both its traditional gas engine and electric motor working together for maximum efficiency.
Sustainable car fuel alternatives include biofuels like ethanol and biodiesel that don’t compete with food production as well as carbon-capturing e-fuels. Below are nine promising green car fuels of tomorrow.
Biofuels
Biofuel production and use have many potential environmental advantages: reduced GHG emissions, lessened petroleum imports and relief on natural resources that are increasingly threatened. Unfortunately, they may also increase food prices, require significant land area for cultivation and irrigation purposes and contribute to environmental degradation.
Biofuels come in both liquid and gaseous forms, and can be produced from agricultural products, organic waste materials, or dedicated energy crops. Liquid biofuels include ethanol, biomass diesel fuel (biodiesel and renewable diesel), sustainable aviation fuel and sustainable aviation fuel, while gaseous versions include compressed biomethane or renewable natural gas as renewable natural gas alternatives.
Many biofuels are produced on traditional agricultural crops like corn, soybeans and sugarcane; an alternative may involve cultivating high-diversity biomass like North American tallgrass prairie grass for growing biofuels. Such high-diversity cropping systems can increase wildlife habitat while simultaneously decreasing soil erosion, cleansing waterborne pollutants from entering groundwater supplies and storing carbon in the soil – not to mention providing protection to abandoned or degraded farmlands.
Electric Vehicles
Traditional engines use gasoline or diesel fuel, but electric vehicles (EVs) draw their power from an external source. Although EVs do not produce emissions at their tailpipe, they require regular recharge – sometimes taking anywhere between 3-12 hours depending on your model – in order to function.
Electric vehicles (EVs) tend to produce far fewer emissions over their lifetime than hybrid and conventional cars when charged with electricity from renewable sources; however, batteries themselves do produce carbon emissions due to being manufactured using fossil fuels; however EVs equipped with high-efficiency motors and longer battery lifespan may help mitigate some of this concern.
Hydrogen can also provide an attractive option, being utilized by both fuel cells and internal combustion engines to generate electricity and burnt as an internal combustion fuel source respectively. Hydrogen’s benefits include no tailpipe emissions if produced using renewable energy sources – Toyota already demonstrated their GR86 racing car powered by synthetic fuel while McLaren has expressed interest in using this technology as well.
Fuel Cell Vehicles
Hydrogen fuel cell vehicles (HFCVs) use hydrogen gas combined with oxygen from the air in a fuel cell to produce electricity, which then powers an electric motor. As water vapor emissions are all that remain from this process, HFCVs are considered zero emission vehicles.
Regenerative braking technology in these cars recaptures wasted energy to maximize efficiency, but one major barrier is limited access to hydrogen refueling stations – especially for commuters with long journeys or those living far from an automotive dealership.
UT-ORNL scientists are making strides toward solving this challenge. Ferguson Faculty Fellow Cong Trinh is using bacterial cells to convert biomass into hydrogen-based fuels derived from hydrogenous sources – potentially creating a low-carbon alternative that’s both renewable and domestically produced, providing fuel for freight vehicles like port drayage trucks, yard tractors and cargo handlers/switcher locomotives.
Hybrid Vehicles
Hybrid vehicles combine internal combustion with an electric motor for greater fuel efficiency and lower emissions, protecting both human health and climate change by decreasing pollution in the environment while simultaneously helping address carbon dioxide levels.
Sustainable fuels such as bioethanol can be combined to make advanced biogasoline, an environmentally-friendly replacement for fossil gasoline that can be used in existing cars. F1 plans on switching over from high-octane E10 fuel in 2025, to one produced under laboratory conditions from various potential sources.
E-fuels like hydrogen are increasingly being considered as viable alternatives to traditional gasoline, yet their production requires substantial amounts of energy sourced primarily from natural gas; however, some manufacturers have started using renewable electricity as the source for their e-fuel production – thus making these carbon neutral. Though exactly where that energy source may lie is yet uncertain.