| "The company has deals to plant 250,000 acres of jatropha in Brazil, India and other countries expected to eventually produce about 70 million gallons of fuel a year." This does not sound promising. Scaled linearly to the current level of oil production, this would cover more land area than Brazil and India put together. (Current production is 90 million oil barrels/day [0] or 1.4 trillion gallons/year. If this biofuel yields 70 million gallons/year out of 250,000 acres, that's 280 gallons/year / acre; dividing out that's about 5 billion acres, or 18 million km^2. Brazil and India put together are 12 million km^2 [1]). Perspective on the 280 gallons/acre figure [2]: "Estimates of Jatropha seed yield vary widely, due to a lack of research data, the genetic diversity of the crop, the range of environments in which it is grown, and Jatropha's perennial life cycle. Seed yields under cultivation can range from 1,500 to 2,000 kilograms per hectare, corresponding to extractable oil yields of 540 to 680 litres per hectare (58 to 73 US gallons per acre).[17] Time magazine recently cited the potential for as much as 1,600 gallons of diesel fuel per acre per year.[18] The plant may yield more than four times as much fuel per hectare as soybean, and more than ten times that of maize (corn)." Also: [3] [0] https://en.wikipedia.org/wiki/Petroleum [1] https://en.wikipedia.org/wiki/List_of_countries_and_dependen... [2] https://en.wikipedia.org/wiki/Jatropha_curcas#Biofuel [3] https://en.wikipedia.org/wiki/Biodiesel#Yield |
All biofuel options have this limitation. Peak production for canola oil is around 100 gallons/acre. Yields for algae are higher, around 5,000 - 10,000 gallons (120-240 bbl) /acre for open-air operations (some greenhouse-based operations claim higher productivity though there's a great deal of skepticism over these), but scaling algae biofuel productions up has been extremely problematic to date. All values on an annual basis.
At present rates of consumption in the US (20 million bbl/day, or 7.3 billion annually), you'd need 30 - 75 million acres devoted to fuel production, if I'm getting my math right. Yield claimed here are for 280 gal/acre, or 6.7 bbl/acre.
The vast majority of oil goes to transportation (where it provides 95%+ of the energy used). In some cases (rail, urban/metro private vehicles, transit, canal traffic) electricity or batteries can be substituted. For others (shipping, and especially air traffic) there are few alternatives to liquid fuels, though ships could move on pelletized biomass and/or wind.
Cutting transportation energy requirements would help, but the expectation of much of the world that it will have access to Western levels of per-capita resource utilization would put a huge burden on biological productivity. I don't see the expectations being fulfilled.
Other alternatives include synthesis of hydrocarbons using electricity. The US Navy is researching such methods, which might be able to synthesize aviation fuel using surplus generating capacity from nuclear-powered aircraft carriers (aviation fuel effectively limits cruise duration as it must be frequently resupplied, cost is another factor), and the ability to obtain both carbon and hydrogen from seawater is a benefit, but the process requires _billions_ of gallons of water to be processed. Again, scale of operations is a significant constraint.