Alternative energy is an umbrella term that refers to any source of usable energy intended to replace fuel sources without the undesired consequences of the replaced fuels. The Renewable Chemicals Corporation utilizes alternative energy derived from sugarcane feedstock to make renewable plastics as opposed to using petroleum. Additionally the E³ Corporation (E³), via its national footprint of certified independent distributors will offer customized alternative energy solutions to consumers, homeowners, businesses and municipalities. E³ evaluates, identifies, selects, negotiates and distributes what it deems as the “most efficient” and “best priced” from the many alternative energy manufacturers and available technologies worldwide. The product categories will include; Wind, Solar, Water, Automotive, HVAC, lighting, sustainable products, personal and home products; and items that promote and provide security, self sufficiency, independence and self-reliance. Over the years, the nature of what is regarded as alternative energy sources has changed considerably, and today because of the variety of energy choices and differing goals of their advocates, defining “alternative" is highly controversial, for example the use of nuclear energy. The term "alternative" presupposes a set of undesirable technologies against which "alternative energies" are opposed. Controversies regarding dominant forms of energy and their alternatives have a long history. For example;

Coal as an alternative to wood
In the late medieval period, coal was the new alternative fuel to save the society from overuse of the then 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 there was a shortage of wood for heating and cooking. Europe was on the edge of a fuel and nutritional disaster, from which it was saved in the sixteenth century 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 cheap newly discovered Petroleum source from Pennsylvania in 1859.

Alcohol (ethanol) as alternative to fossil fuels Petroleum as an alternative to whale oil
In 1917, Alexander Graham Bell advocated ethanol from corn and other foodstuffs as an alternative to coal and oil, stating that the world was in measurable distance of depleting them. For Bell, the problem was lack of renewability of orthodox energy sources. Brazil has an ethanol fuel program which has allowed them to become the world's second largest producer of ethanol (after the United States) and the world's largest exporter. Brazil’s uses sugarcane as feedstock, and the residual cane-waste (bagasse) is used to process heat and power. Cellulosic ethanol can be produced from a diverse array of feedstocks, and involves the use of the whole crop.

Coal gasification as alternative to expensive petroleum
In the 1970s, President Jimmy Carter's advocated coal gasification as an alternative to expensive imported oil. The program was scrapped when petroleum prices plummeted in the 1980s.

Renewable energy as alternative to non-renewable energy
Renewable energy is energy generated from natural resources such as sunlight, wind, rain, tides and geothermal heat; which are all renewable or naturally replenished. When comparing the processes for producing energy, there remain several fundamental differences between renewable energy and fossil fuels. The process of producing oil, coal, or natural gas fuel is a difficult and demanding process that requires a great deal of complex equipment, physical and chemical processes. On the other hand, alternative energy can be widely produced with basic equipment and natural basic processes. Wood the most renewable and available so called "alternative" energy, interestingly burns the same amount of carbon it would emit if it degraded naturally.