One of the most important sectors over human history has been energy. Energy has always been equivalent to power and wars for control have mostly been wars over energy. Woodstock and flowing water were the sole energy source for centuries. Next came fossil fuels, petroleum, natural gas, alternate sources such as solar, wind and geothermal power, nuclear energy, and biofuels, in very much this order itself.
There has always been a long gap, usually a few decades, from when an energy source becomes theoretically viable to when it becomes commercially viable. The delay is majorly due to two reasons. First, the energy source must give other by-products for it to be considered for exploitation. Second, the new energy often requires very different infrastructure to utilize it than the former. The time taken to implement the shift – for example from steam engines to electric engines – is long enough to question its viability.
Oil imports have played a major role in the world in the later half of the previous century. Developing countries, led by Brazil, have experimented with biofuels to reduce their dependence on oil imports and to enable their agricultural communities. Most of the above 7 billion people in the world are looking forward to a more comfortable life in the next decade or two. As of 2006, energy equivalent to 3 cubic miles of oil (CMO) was consumed globally per year. Energy requirement is sure to soar above levels which won’t be fulfilled by the conventional resources – renewable and non-renewable combined. Biofuels are, thus, heralded a major industry in the making of the 21st century. But, the population needs to fed as well. Here comes the question of food or fuel?
Biofuels being currently explored
- Bioethanol – Produced from fermentation of sugars obtained through beet, sugarcane, wheat, corn, potato etc. These are blended with gasoline/petrol in various ratios.
- Biodiesel – These are vegetable oil methyl esters (VOME) obtained from transesterification of rapeseed or sunflower oil. These are blended with diesel.
- Ethanol from lignocellulosic biomass – Lignocellulosic biomass comprises of cellulose, hemicellulose and lignin. These are broken down using cellulase complex and other enzymes. This approach overcomes two limitations of biofuels by avoiding competition with food and improving the carbon dioxide balance.
Biofuels would not be commercially more viable than the petroleum industry despite all their obvious advantages as long as we do not find multiple products from the biomass and a way to produce them simultaneously.
Biorefineries, analogous to petroleum refineries, are the solution.
A biorefinery is a facility that makes it possible to integrate –
- thermochemical and biochemical processes involved, and
- biofuels production with biomass transformations involving production of sugars, pulp, paper etc.
Current biofuel production systems involve production of a single biofuel in a stadalone unit from a single feedstock. On the contrary, biorefineries will make it possible to produce a wide range of fuels and by-products from diverse feedstocks. Also, advances in synthetic biology and metabolic engineering would allow us to devise production systems with specific metabolite fluxes of the products involved.