Sunday, June 05, 2005

Am I missing something?

The plan in Japan according to this article in the Times Online is to raise giant, fast-growing seaweed in the ocean to absorb carbon dioxide from the atmosphere and then convert the seaweed to a biofuel that can be burned. Such a scheme would supposedly be carbon dioxide neutral since it would release no more carbon dioxide into the air than the seaweed had already absorbed. I don't see how that would do anything to fight global warming unless this biofuel energy takes the place of energy currently generated by fossil fuels. Besides this, the processing of the seaweed involves "superheated steam." Where are they getting the energy to create the steam? From fossil fuels? How will they tend and harvest the seaweed? In boats run on diesel fuel?

My point is that it pays to look at the entire process. Both the reporter and the researcher interviewed seem to be confused, and we can't afford that kind of confusion when it comes to evaluating alternative energy sources.

(Via Energy Bulletin.)

(Comments are open to all. See the list of environmental blogs on my sidebar.)


Big Gav said...

No - you aren't missing anything - no one seems to have looked at the full cycle EROEI.

But its still an intriguing idea. Maybe it won't turn out to be of any use at all - then again, maybe it will.

Do you think it would cause any problems if they were to at least do a small scale prototype ?

It seems to me that trying these sorts of ideas out while energy is relatively cheap is worth the effort.

Kurt Cobb said...

Big Gav is right. We do need to experiment with alternatives while energy is cheap. I hope that a standard part of evaluating these experiments will be a thoroughgoing EROEI study. Mostly what I'm complaining about is the ignorance of the both the reporter and the research scientist who don't even seem to know that EROEI is a critical issue for alternative fuels.

lee said...

hi... longtime lurket first time poster...

1) the times and japan aren't the only ones.... check out the NREL's work: ((apparently you can buy the patents from them and stort it on your own) they were getting great results (90% emission reductions from coal plants) and turning the algae into biodiesel.... i have heard of japanese pyramids growing algaes as wlel (that are supposed to be better at creating hydrogen than fatty lipds for the biodiesel)

one interesting thing is that it doesnt all turn into fuel... something like 60% the other 40% can be composted an dturned into soil.

there have been small scale prototypes... and in a perfect place for slimy green creatures... in Roswell NM of all places.... something liek a 1 acre pond that sucked CO2 from coal plants.... by the time they scooped up all the algae, there woudl already be a new layer... its something like 1500 times faster at photosynthesis than redwoods..... worth a shot if you ask me, which you didnt, thanks for the great blog!

Anonymous said...

If you're seriously looking at biodiesel, ocean crops like algae are probably the way to go. And energy is required for the conversion, not only for the steam but for heating the raw matter. How much net energy you get depends on the yield.

And if you ever going to do anything like this, you better start it while the investment costs are still doable.

cameron said...

I'd like us to "step back" a level and look at the underlying question: Can Earth sustain the current (and growing) human population, and the degradation of ecosystems and fresh water supplies EVEN IF we could replace petroleum with seaweed biodeisel, etc?

How many people are hoping that we can continue on our constant growth curve (population and resource consumption) by just replacing fossil fuels with with 'clean' energy?

In my view, the built-in logic and momentum of our current economic system is that --regardless of how 'clean' it were to become-- we would not stop until we completely consumed every last bit of Brazilian rain forest, ocean fisheries, etc. (through all the rest of the geoglobal ecosystem).

WHT said...

One of my favorite boondoggles is the attempt at farming California Giant Kelp. I blogged about it

That's got an old link though, an archived account is here.

Whatever could go wrong went wrong. It also looks a bit like herding cats.

Anonymous said...

Look at EROEI - Yup.

I've seen a waste of photons talk about making Hydrogen from Algae. Great. 'Cept it was using a 1% sunlight energy into Hydrogen as a target.

I can take a 15% pv panel 'waste' 50% by converting it into Hydrogen.

The hydrogen->Algae dud ignored the energy neeed to contain the Algae and Hydrogen, the processing of the hydrogen, water vapor and other stuff from the algae->hydrogen process, and the CO2 injection into the process.

Can Earth sustain the current (and growing) human population,

From an energy POV, it is possible. From a 'changing behavior' POV - such is up for grabs. If every human building in the US was covered in PV panels, the US would have 4X the energy than presently consumed. (per a quote I've never been able to verify)

The answer to the 'can it be done' is to calculate the photons put out by the sun VS the photons that are useable on earth VS a conversion to the use of mankind. Balance VS the effects of capturing these photons by man. Can it be done doesn't address the 'will it work' question, as much of the US is all about the cheap energy and keeping the cheap energy lifestyle.