Hi Chris et al
Useful analysis of claims including this one at http://www.theoildrum.com/node/7566#more
I am indebted to one commenter to the above (‘carnot’) for the following
“A few thermodynamics might help. Cyanobacteria is a C3 plant.
Overall 2H2O + CO2 = CH2O + O2 + H2O
Benson- Calvin cycle Z scheme 8 photons of light for each CH2O + O2 produced
Overall maximum possible thermodynamic efficiency is ~5-6% (insolation)
Incident mean PAR in US South West 100 watts/square metre.
Max Theoretical Yield is = 189 MJ carbohydrate/ m²/yr
If 50% of the net carbohydrate produced was converted to oil ( approx 28%) at no losses this would equate to around 2.5 kg oil per m² or 25mt per hectare/yr. At very best.
This oil yield is well below many claimed yields in press releases.
Of the max theoretical yiels up to half could be used in respiration. The carbohydrate has an energy value of a little under half of the oil value, and the conversion process of carbohydrate to oil would consume energy.
On an equivalent basis the Joule claim is 100+ mt approx of algae oil per hectare, assuming it is esterified. That is nearly 4 x the theoretical maximum. It would be hard to produce that even as biomass with a low oil content.
Some good reading is here from Walker.
his book Energy, Plants and Man – recommended
You can get this book in pdf for free by sending an email to Walker.
Simply Email David Walker at d.a.walker at sign sheffield.ac.uk
Joule = Total bunkum in my opinion.” END OF QUOTE
Mass. Company Making Diesel With Sun, Water, CO2
Global Processing – Thursday, March 03, 2011
A Massachusetts biotechnology company says it can produce the fuel that runs Jaguars and jet engines using the same ingredients that make grass grow, the Associated Press reports. Joule Unlimited has invented a genetically engineered organism that it says simply secretes diesel fuel or ethanol wherever it finds sunlight, water and carbon dioxide. The Cambridge, Mass.-based company says it can manipulate the organism to produce the renewable fuels on demand at unprecedented rates, and can do it in facilities large and small at costs comparable to the cheapest fossil fuels. Work to create fuel from solar energy has been done for decades, such as by making ethanol from corn or extracting fuel from algae. But Joule says they’ve ‘eliminated the middle-man’ that’s makes producing biofuels on a large scale so costly. That middleman is the “biomass,” such as the untold tons of corn or algae that must be grown, harvested and destroyed to extract a fuel that still must be treated and refined to be used. Joule says its organisms secrete a completed product, already identical to ethanol and the components of diesel fuel, and then live on to keep producing it at remarkable rates.
Joule was founded in 2007. The company worked in “stealth mode” for a couple years before it recently began revealing more about what it was doing, including with a patent last year for its production of diesel molecules from its cyanobacterium. This month, it released a peer-reviewed paper it says backs its claims. Joule claims, for instance, that its cyanobacterium can produce 15,000 gallons of diesel fuel per acre annually, over four times more than the most efficient algal process for making fuel. And they say they can do it at $30 a barrel. The organisms are engineered to take in sunlight and carbon dioxide, then produce and secrete ethanol or hydrocarbons — the basis of various fuels, such as diesel — as a byproduct of photosynthesis. The company envisions building facilities near power plants and consuming their waste carbon dioxide, so their cyanobacteria can reduce carbon emissions while they’re at it. The flat, solar-panel style “bioreactors” that house the cyanobacterium are modules, meaning they can build arrays at facilities as large or small as land allows, the company says. The thin, grooved panels are designed for maximum light absorption, and also so Joule can efficiently collect the fuel the bacteria secrete. The company plans to break ground on a 10-acre demonstration facility this year, and Sims says they could be operating commercially in less than two years.