It seems like only yesterday that the only game in town when it came to biofuels was corn ethanol. When it was first introduced to the U.S. market, it was widely touted as the future of renewable fuels -- an alternative to gasoline that would help us move closer to energy independence. Despite its obvious disadvantages, corn ethanol was quickly embraced by the federal government, businesses and even some environmentalists. When an acute food crisis gripped the world earlier this year -- finally laying bare the folly of using food-based crops as fuel -- a backlash had already begun against corn ethanol.
Far from nipping the growing biofuel industry in the bud, as some had feared, the backlash helped pave the way for a new generation of advanced biofuel feedstocks and start-ups eager to develop the first viable alternative to gasoline. While there are too many to mention all of them, we'll focus on 6 of what we consider to be some the most promising feedstocks.
Kudzu, European Milfoil and other invasive species
One of the latest entries into the field is kudzu, an invasive Asian vine found in many parts of the southern United States, which some believe could make an ideal feedstock for ethanol. (One company has been busy trying to trademark the term "kudzunol.") According to a study published in Biomass and Bioenergy, the vine could generate up to 270 gallons of ethanol per acre -- as much, or more, as can be produced from corn though not nearly as much as can be made from rapeseed or palm oil.
Another late entry is Eurasian Milfoil, an invasive water plant that has been wreaking havoc in rivers and lakes for the past three decades. A couple in Washington is now investigating the biofuel potential of this plant, armed with a $8,000 grant from the state's Department of Ecology and a team of high school volunteers (obviously, we're talking low-tech here).
The obvious problem is that, being invasive species, they will be hard to harvest in the wild and most likely will not be amenable to domestication. Sure, it'd be great to find a constructive use for all that excess biomass but, since we're not in the business of helping invasives spread, it may have more potential as a local biofuel source. Since we've been reading quite a few stories about states struggling to eliminate kudzu, converting it into ethanol could kill two birds with one stone. The same could go with Eurasian Milfoil and other appropriate invasive species, including Miscanthus (which I describe in more detail below) and camelina.
The new big kahuna among biofuel hopefuls, algal biodiesel start-ups like Sapphire Energy, PetroSun (which got its first commercial-scale facility up and running a few months ago) and Solazyme have attracted millions in investment from high profile venture capital and private equity firms, including Bill Gates' Cascade Investment, because of their high energy content and wide availability. We're probably still several years off from seeing commercial-scale production, but, given the level of interest in the fuel, it could come sooner rather than later. Sapphire Energy believes it will be able to sell algal biofuel in 3-5 years for $50 to $80 a barrel and claims its product is chemically identical to crude oil.