Energy carrier

An energy carrier is a substance or object that can be used to store energy for the production of work or heat or to power physical or chemical processes. Energy carriers include, batteries, fossil fuel (coil, oil, gas), biofuels (biodiesel, bioethanol, wood), hydrogen, etc. Springs, water in dams and pressurized gases also act as energy carriers. In terms of transport, batteries may be suitable for relatively short distance travel. Hydrogen may be a future option for transport if new technology is developed. Fossil fuels and biofuels are currently the only medium term options for long distance travel such as road freight and air travel.