Hydrogen from Algae
Technology Review is reporting some interesting work going on at UC Berkeley attempting to make hydrogen from algae. The 3rd grade explaination is that they are creating mutant strains of algae that produce more or less chlorphyl during the photosynthesis process. Reducing the chlorphyl levels increases the amoung of hydrogen that algae naturally give off during photosynthesis.
Here’s an exceprt:
The researchers manipulate the genes that control the amount of chlorophyll
in the algae’s chloroplasts, the cellular organs that are the centers for
photosynthesis. Each chloroplast naturally has 600 chlorophyll molecules. So
far, the researchers have reduced this number by half. They plan to reduce the
size further, to 130 chlorophyll molecules. At that point, dense cultures of
algae in big bioreactors would make three times as much hydrogen as they make
now, Melis says.
This sounds like a compelling process, but it’s still a little foggy for me in terms of the assumed application. Producing hydrogen in bioreactors sounds okay, but it’s the capture and refinement that is always the hard part. This could ultimately determine how effective this process could be in terms of commercialization. Or in other words, it has to scale beyond what their current assumptions are before commercialization becomes viable. But that’s a little way off at the moment. They’re doing some good science for now.
The article goes on to say:
Switching 100 percent of the algae’s photosynthesis to hydrogen might not be
possible. “The rule of thumb is, if we bring that up to 50 percent, it would be
economically viable,” Melis says. With 50 percent capacity, one acre of algae
could produce 40 kilograms of hydrogen per day. That would bring the cost of
producing hydrogen to $2.80 a kilogram. At this price, hydrogen could compete
with gasoline, since a kilogram of hydrogen is equivalent in energy to a gallon
of gasoline.
These numbers don’t quite sound right to me. While I’m sure his comparison of energy with a gallon of gas is correct, it doesn’t seem to match consumption to me.
The 2006 Honda FCX fuel cell prototype (2008 will be a production model) could go 210 miles on 3.75 kg of hydrogen. If 1 gallon of gas = 1 Kg of hydrogen, then the range of the FCX (let’s assume 35 mpg - around what a Civic gets) should be around 131 miles. So obviously, comparing energy equvalence isn’t a good evaluation. This should be evidence given that we’re also comparing two different drive trains as well (fuel cell vs ICE) - that matters in comparing the economics.
Let’s think of it another way. A 35 MPG car will use 6 gallons of gas to travel 210 miles. That’s around $18 worth of gasoline (at $3/gallon). The FCX will use 3.75 kg of hydrogen to travel 210 miles. At a price of $18 for 3.75 kg of hydrogen (a service equivalent given , the price (not the cost mind you) for hydrogen would be around $4.80/kg of hydrogen. This would be an equivalence point that hydrogen production would need to beat in order to be economically viable with respect to gasoline. If the stated $2.80 / kg of hydrogen is bottoms-up cost of production for this process, then it might be way ahead of where it needs to be (if it’s an energy comparison then I’d be skeptical of it). That’s a great sign and offers high hopes for hydrogen.
