New types of biofuels being researched could provide sustainable alternatives to fossil fuels.
Current biofuel tech (a topic we covered here) helps reduce emissions, but critics say it’s grown at the expense of food production, both taking up arable land and water and driving up food prices.
A second generation of biofuels that’s under development could solve this problem, however.
Although there is no strict technical definition of “second generation biofuels,” according to (pdf) the World Bank, it’s generally used to refer to biofuels created from non-food biomass.
This includes residues from agriculture and forestry, as well as plants grown specifically for creating biofuels, according to the International Energy Agency.
Fuel is created either by breaking the cellulose in the biomass down to liquids, then fermenting it into fuel-ready ethanol, or by heating up the feedstock, turning it into either a gaseous or a liquid fuel like diesel.
There are several types of second generation biofuels currently under development:
Crop and forestry residues
Currently, agriculture produces a large amount of non-edible residue, such as corn cobs, rice husks, and stems from gains, that are not being utilized. This falloff can be collected and broken down into liquids and be made into ethanol fuel.
Similarly, forestry produces a large amount of runoff such as sawdust and wood chips, which can be gathered and either burned as a carbon-neutral fuel, or turned into a liquid fuel like diesel.
Wood diesel has been in development since 2003 at the University of Georgia, which specializes in sustainable biofuels.
Both of these methods have the advantage of using existing production systems, meaning their associated carbon emissions, costs and land use are minimal.
However, as always, there’s a balance to be struck: removing too much residue could have an adverse effect on crops and forests, according to the World Bank.
Dedicated energy crops
More similar to first-generation biofuels, this method involves growing crops dedicated to producing biofuels.
However, the crops are not food such as the corn and grains used in current biofuels, but non-food plants such as switchgrass, miscanthus and alfalfa.
These plants require relatively little water, land, and work, making them more sustainable than regular agriculture.
In order to avoid competing with food resources, though, they would have to be grown on land where food crop production and grazing pastures are not viable.
Using rapidly growing microalgae, scientists have been able to cultivate large amounts of biomass usable for bio-diesel.
This is a form of synthetic biology, a potentially revolutionary field of science we covered here.
It’s considered one of the most efficient methods of producing biomass, taking up little space relative to the volume produced.
Algae can also be cultivated on saline water and non-arable land, reducing or eliminating its competition with traditional agriculture, and opening up economic opportunities in arid areas, the World Bank report states.
Current systems for producing this algae are costly, however, so extensive research and investment is required before microalgae-based fuel can be an economically viable alternative to regular fuel.
Fuel of the future?
Successfully deploying second generation technologies is going to require “intensive” research and development efforts over the next 10-15 years, according to the International Energy Agency.
But even if only 10% of the world’s agricultural and forestry residues were available by 2013, the IEA estimates, 5% of the world’s transportation fuel demand could be met.
For that to happen, however, costs have to go down significantly: second generation biofuels currently cost several times as much as fossil fuels, according to the World Bank.
Originally published on February 4, 2014.