The term "alternative" presupposes a set of undesirable energy technologies against which "alternative energies" are opposed. As such, the list of energy technologies excluded is an indicator of what problems that the alternative technologies are intended to address. Controversies regarding dominant forms of energy and their alternatives have a long history.

History

Historians of economies have studied the key transitions to alternative energies and regard the transitions as pivotal in bringing about significant economic change. Prior to shift to an alternative energy, supplies of the dominant energy type became erratic, accompanied by rapid increases in energy prices.

Coal as an alternative to wood

Historian Norman F. Cantor describes how in the late medieval period, coal was the new alternative fuel to save the society from overuse of the dominant fuel, wood:

"Europeans had lived in the midst of vast forests throughout the earlier medieval centuries. After 1250 they became so skilled at deforestation that by 1500 AD they were running short of wood for heating and cooking... By 1500 Europe was on the edge of a fuel and nutritional disaster, 1 which it was saved in the sixteenth century only by the burning of soft coal and the cultivation of potatoes and maize."

Petroleum as an alternative to whale oil

Whale oil was the dominant form of lubrication and fuel for lamps in the early 19th century, but by mid century and the depletion of the whale stocks, whale oil prices were skyrocketing and could not compete with the newly discovered source of cheap petroleum from Pennsylvania in 1859.

Alcohol as alternative to fossil fuels

Main: Ethanol fuel In 1917, Alexander Graham Bell advocated ethanol alcohol from corn and other foodstuffs as an alternative to coal and oil, stating that the world was in measurable distance of depleting these fuels. For Bell, the problem requiring an alternative was lack of renewability of orthodox energy sources.Since the 1970s, Brazil has had an ethanol fuel program which has allowed the country to become the world's second largest producer of ethanol (after the United States) and the world's largest exporter. Brazil's ethanol fuel program uses modern equipment and cheap sugar cane as feedstock, and the residual cane-waste (bagasse) is used to process heat and power. There are no longer light vehicles in Brazil running on pure gasoline. By the end of 2008 there were 35,000 filling stations throughout Brazil with at least one ethanol pump.

Cellulosic ethanol can be produced from a diverse array of feedstocks, and involves the use of the whole crop. This new approach should increase yields and reduce the carbon footprint because the amount of energy-intensive fertilisers and fungicides will remain the same, for a higher output of usable material.Cellulosic Ethanol: Not Just Any Liquid Fuel As of 2008, there are nine commercial cellulosic ethanol plants which are either operating, or under construction, in the United States.