Vinod Khosla on Affordable Biomass, Feedstocks, More

For the regressives who project fixed land use and biomass production capacity based on yesterday’s technology, un-optimized yields and practices, I just beg to differ. Many people simply refuse to accept that the future can be different from the past and yet extrapolating an unsustainable present is a bankrupt strategy by which to reach a sustainable future. Much research remains to be done but the potential clearly exists for significant jumps in our biomass capacity. With proof of this biomass as a source of liquid fuel, this research will accelerate. _GTM

Greentech Media continues its Khosla series with a look at biofuels feedstocks and how they compare:

There is a surprising amount of forest waste available; a good example would be hardwood waste, which can reach up to 30 percent or more of the harvest: southeast timber has roughly 18 to 22 percent waste by mass, whereas the Northeast and Alaska have as much as 30 percent. Ultimately, scaling fuels will depend upon exploiting these near-term available non-food feedstocks. In the mid-term (5 to 10 years) winter cover crops (where appropriate) and energy crops planted in crop rotations or on marginal land (over one billion acres of marginal land worldwide has been put out of production due to degradation)[1].

The appropriate perennial, polyculture biomass production approaches, (which can restore degraded lands) will come into play in addition to continued wood, agricultural waste and bagasse use. Long term (10 to 15 years), dramatically improved energy crops, new cropping practices and new chemical fertilizer reduction strategies (such as polycultures) could yield well over a billion tons of biomass in the United States alone, if not substantially more, without significant land impact.

...Use of bark, waste and mixed feedstocks will lower costs and be a significant competitive advantage for any process. Accepting mixed feedstocks will be a major advantage for any conversion process. Such technologies, in my estimation, should yield more than 2000 gallons of fuel per acre (ethanol equivalent) in the long term (versus 400 to 500 gallons per acre today with corn ethanol) to provide material biomass fuels scalability without significant land use impact.

At a high level, at 2000 gallons per acre, to reach 36 billion gallons, we need 18 million acres of land (which need not be farmland), compared to 309 million acres of cropland currently in production (of 406 million acres of total cropland). If one displaces corn ethanol and recovers that land, the numbers for land usage could be substantially lower to meet our 36 billion gallon goal (though corn does co-produce animal feed). In the last 10 years alone, more than 30 million acres went out of production due to degradation, crop yield improvements and conservation.[2] The issue is further complicated by the recovery of land that takes place (covered in more detail in my previous papers) as diets shift from red meat (beef) to white meats (chicken), which take less than 5% of the land beef requires for corn cultivation for animal feed. _Greentechmedia

Khosla then moves from biomass feedstocks to oils:

, technologies that focus on specialty oils like jatropha, rape seed (used extensively in Europe for biodiesel), palm oil and the similar are less attractive because their gallon per acre yields are far lower (40 to 50 gallons per acre for jatropha, up to 600 gallons per acre with palm oil), and we don’t expect these oil yields to increase substantially over the next decade. Not only that, jatropha in particular is toxic to animals. Additionally, used restaurant grease, oil from old tires and animal waste, are largely irrelevant as feedstocks at the global scale, though they can be used to produce cost effective fuels where available. As a result, we are not considering them here in detail because in my view, they are not likely to achieve relevant scale, regardless of profitability. _GTM

Khosla similarly discards algal feedstocks as being too expensive for near term utilisation. He feels that 2,000 gallons per acre yield will be the minimum which can possibly impact global fuel needs. As a result, Khosla feels that both maize and sugar cane ethanol will be superceded by more prolific biomass crops.

...A few years ago, I forecast that as processes mature, one ton of cellulosic biomass will yield 110 gallons of ethanol equivalent, approaching our target of 2000 gallons of ethanol equivalent per acre as yields approach 18 to 20 dry tons per acre. If Kior, for example, is able to reach 2 barrels per ton of production (equivalent to 140 gallon ethanol equivalent per ton) in the next five years, then it will only take 14 tons per acre to reach this 2000 gallon per acre goal; such adjustments to estimates will continue to happen. If these process improvements prove out, we will need smaller yield improvements than I forecast only a few years ago. Encouragingly, Ceres and Mendel, two energy crop companies, forecast biomass crop yields at roughly 15 to 20 tons per acre, depending upon the region, rain and soil.

Again, for comparison, though corn is currently one of the most efficiently grown agricultural products in the world, it only produces 400 to 500 gallons of ethanol from an acre of corn (though animal feed byproducts do increase the effective yield equivalent per acre), with an additional ~300 gallons of ethanol equivalent cellulosic biofuel theoretically possible from the stover. Corn requires prime crop land, which stokes “food versus fuel” politics (perception is important), requires fertilizer, herbicides and pesticides,...

...The beauty of cellulosic processes is the flexibility of biomass feedstock, which allows the use of short and long rotations (up to 10 year rotations), agroforestry (interplanted rows of trees and row crops), and polycultures. Technologies that can use mixed feedstocks will have much lower long-term costs and less price volatility. By using feedstock flexible technologies we have an opportunity to increase biodiversity and symbiotic production of nutrients, which improves soil quality and yields, while not adversely affecting fuel output. Technologies like enzymatic hydrolysis, besides higher early costs, will likely be more feedstock specific and feel less likely to succeed in my opinion.

One option I have previously proposed is the usage of a 10 year x 10 year energy and row crop rotation. As row crops are grown in the usual corn/soy rotation, lands lose topsoil and get degraded, need increased fertilizer and water inputs and decline in biodiversity. By growing no-till, deep rooted perennial energy crops (like miscanthus or switchgrass - see below) for ten years following a ten year row crop (i.e. - corn/soy) cycle, the carbon content of the soil and its biodiversity can be improved and the needs for inputs like fertilizer decreased. _GTM

Biomass crops can even be engineered specifically to add value to the topsoil over time.

Perennial polycultures, drought and salt tolerant plants (a huge upside for humanity), long term crop rotations, winter cover crops and innovative low input (water and fertilizer) techniques are very powerful tools in improving agronomy, environmental impact, yields and biodiversity while potentially recovering even non-arable land. Meanwhile, some companies are aiming at dramatically reducing fertilizer and pesticide demand, by developing creative new approaches and technologies. These techniques will shape the ultimate level of impact. In many scenarios, a little imagination, a lot of research and a continued focus on biofuels could actually increase available land by creating incentives to recover degraded lands.

...At least half a dozen technologies will be competitive with oil, with some more profitable than others. The critical point is that for the next 10 years at least, there will be an unbounded demand for biofuels, the quantities required by the current mandates both in the US and in many other countries will be an achievable stretch with all the technological innovation. US and worldwide demand of oil will be such that biofuels will not compete with each other, they all compete far more with oil. Each technology is suited to particular local conditions, and with the expected demand, there is lots of room for all these and even more technologies. Within a decade after beginning to scale (2012?), advanced biofuels will become material in the oil supply equation, and will be a significant market force within twenty years. I firmly believe that in 30 years, the price of oil will be more dependent on the marginal cost of land than anything to do with exploration, drilling, OPEC, or Middle East instability.

To those who accuse me of believing because I’ve invested in these technologies; I continue to invest because I continue to believe. _GTM

In an attempt to prove Khosla wrong in his negative attitude toward algal fuels, Origin Oil is cooperating with an Australian company to prove its extraction technology.

SG Biofuels is attempting to prove its approach to fuels from the oilseed tree jatropha -- in tropical Brazil.

Most analysts predict liquid fuels to continue to rule over the highway for at least 20 more years.

Biofuels will be competing not only with conventional crude oil, but with unconventionals such as Canada's new in situ oil sands technologies, GTL, CTL, and in situ coal gasification to liquid fuels.

As long as oil prices stay above $70 a barrel, investment into advanced biofuels, unconventionals, and other alternative liquid fuels will continue.