What are Ethanol Feedstocks
Feedstock such as soybeans, palm, canola and rapeseed are considered first generation feedstock for biodiesel production, as they were the first crops to be experimented for biodiesel extraction. Most first generation biodiesel feedstock could be used alternatively to make food for humans as well.
While first generation feedstocks helped kick start the biodiesel industry, they posed some serious challenges.
- Threat to human food chain – Most of the first generation feedstocks have been used as food sources by humans. For instance, palm and soy oils have been used as edible oils since time immemorial. This gave rise to a food vs. fuel crisis emerged as these edible crops were used in the production of biodiesel.
- Threat to the environment – Owing to the high yield of oil, first generation feedstocks required cultivation in vast areas of land. Such a necessity resulted in countries around the world cutting down forests, creating serious ecological imbalances.
Second generation biodiesel are obtained from non-food bio-feedstocks. Typically, energy crops such as Jatropha represent the second generation biodiesel feedstock. With the use of technologies such as the Biomass to Liquid (BTL), many other non-food crops could be converted to biodiesel. These feedstocks have the advantage of not affecting the human food chain and can be grown in marginal and wastelands.
While feedstocks belonging to the second generation do not typically affect the human food chain, they may not have the ability to replace more than 20-25% of our total transportation fuels.
Algae are considered to belong to the third generation of biodiesel feedstock. These feedstock offer superior yields when compared to second generation feedstock and do not have an effect on the human food chain. In addition, crops such as algae can be grown in places that are not suitable for agriculture, thus providing superior ecological performances as well.
First and Second Generation Ethanol Feedstock
The first generation ethanol feedstock comprises corn, sugarcane, maize etc. To a large extent, these feedstocks are still in use in many countries. These feedstocks however present the problems of adversely affecting food prices (as these are also used as food) and an inability to scale owing to constraints on land areas available for cultivation. Ethanol derived from these feedstocks typically use the starch component present in them.
The second generation ethanol feedstocks primarily comprise feedstocks called cellulosic feedstocks. In the case of these feedstocks, ethanol is derived from the lignocellulosic component of the feedstock instead of the starch component. A large number of non-food wild plants that grow in non-cultivated and non-arable lands, and plant waste, contain lignocellulose; as a result, the second generation ethanol feedstocks overcome the two main bottlenecks of the first generation feedstock: adverse effects on food prices, and inability to scale.
Low-cost crop and forest residues, wood process wastes, and the organic fraction of municipal solid wastes can all be used as ligno-cellulosic feedstocks. It should be possible to produce biofuels with virtually no additional land requirements or impacts on food and fibre crop production, where ever these materials are available.
However, in many regions, these residue and waste feedstocks may have limited supplies, so the growth of vegetative grasses or short rotation forest crops will be necessary as supplements. Where potential energy crops can be grown on marginal and degraded land, these would not compete directly with growing food and fibre crops which require better quality arable land.
Relatively high annual energy yields from dedicated energy crops can be achieved from these crops when compared with many of the traditional food crops currently grown for first-generation biofuels. In addition, their yields could increase significantly over time as breeding research (including research into genetic modification) is at an early stage compared with research for the breeding of varieties of food crops.
New varieties of energy crops may lead to increased yields, reduced water demand, and lower dependency on agrichemical inputs. In some regions where low intensity farming is currently practiced, improved management of existing crops grown on arable land could result in higher yields per hectare. This would enable energy crops to also be grown without the need for increased deforestation or reduction in food and fiber supplies.
- Ethanol as Biofuels
- What are feedstocks?
- Properties of Feedstocks for ethanol production
- Yield of Biomass for Various Feedstocks
- Feedstocks used by Various Companies
- Why Cellulosic Ethanol?
- Cellulosic Ethanol Production
- Cellulosic Ethanol Production Value Chain
- Ethanol production methods
- Biochemical Conversion Process
- Thermochemical Conversion process
- Latest Discoveries and Breakthroughs
- R & D Roadmap in Cellulosic Ethanol
- Future projections
- Companies Involved in Producing Cellulosic Ethanol
- Investments & Funding
- Challenges & Barriers in the commercialization process