Study Note - Energy Crops

If a plant is grown with the sole purpose of being used as a biofuel, or to be combusted to provide energy or heat, it is known as an energy crop. These plants are generally woody or grassy, and are low cost and low maintenance. Different types of energy crops are used in different situations: solid biomass, gas biomass, liquid biomass and green waste (by-products).

Solid Biomass

This is the simplest use of plants as biofuel, burning plants that have been grown especially for the purpose, and usually after they have been dried and turned into pellets.

Gas Biomass

By using anaerobic digesters, i.e. microorganisms that break down biodegradable material without the use of oxygen, methane can be produced, which can then be used to provide energy and burned for heating. This method is particularly popular in Germany.

Liquid Biomass

This is split into two categories – biodiesel and bioethanol. Biodiesel uses the oil extracted from plants such as rapeseed, copra (dried coconut flesh), castor seed and sunflowers in order to provide energy, or for use in converted biodiesel cars. Bioethanol uses grains such as maize to make ethanol through fermentation, which can then be added to regular diesel to provide better vehicle emissions, and is particularly popular in Brazil.

Green Waste

This involves the use of the by-products of food and non-food crops as biofuels. One example is the burning of woodchip in a biofuel factory in Vienna.