Fossil fuel power station is also beneficial to the environment. In some instances, torrefaction of biomass may be needed if biomass is the material the converted fossil fuel power plant will be using. Improving energy efficiency of a coal-fired power plant also reduces emissions. For example, emissions can be reduced by upgrading existing plants or building new high-efficiency, low-emissions plants. Such plants emit almost 20% less CO than a subcritical unit operating at a similar load. Over the longer term, HELE plants can further facilitate emission reductions because coal-fired plants operating at the highest efficiencies are also the most appropriate option for carbon capture
Fuel gas. Biofuel can be broadly defined as solid, liquid, or gas fuel consisting of, or derived from biomass. Biomass can also be used directly for heating or power—known as "biomass fuel". Biofuel can be produced from any carbon source that can be replenished rapidly e.g. plants. Many different plants and plant-derived materials are used for biofuel manufacture. Perhaps the earliest fuel employed by humans is wood. Evidence shows controlled fire was used up to 1.5 million years ago at Swartkrans, South Africa. It is unknown which hominid species first used fire, as both "Australopithecus" and an early species of "Homo"