TABLE OF CONTENTS He had been eight years upon a project for extracting sun-beams out of cucumbers, which were to be put into vials hermetically sealed, and let out to warm the air in raw inclement summers.
Jonathan Swift, Gulliver's Travels : A Voyage to Laputa, 1726.
Any plant species has the potential to be an energy crop, whether it be an undomesticated species, an agricultural waste or a crop grown specifically for energy use. The principle underlying energy generation from crops is that, during photosynthesis, the plant harvests a proportion of the radiant energy incident on it and stores this energy as fixed carbon (mainly in sugars, oils or ligno-cellulose). Thermochemical conversion (with or without an intermediate preparatory stage) releases this stored energy into a form that can be used as heat, power or electricity.
An energy crop can be either one that yields a specific product with a high energy content, for example ethanol from sugarcane (Saccharum) or rape methyl ester from oilseed rape ( Brassica napus) these are the so-called liquid biofuels or one that yields a non-specific product, ligno-cellulosic material these are the so-called solid biofuels. The latter can be either above-ground ligno-cellulosic material such as that harvested from Salix, Eucalyptus or Miscanthus, or below-ground material from root fuels such as Cucurbita foetidissima. The waste product from a liquid biofuel can in itself form a solid biofuel ( e.g.
