Algae to the rescue

Ivan Seeking

No matter how this pans out, the high energy density of biodiesel as compared to ethanol - about 1.5 times higher - and the fact that it can be used in existing diesel and [with modifications] aircraft engines, and the fact that diesel engines are more efficient than existing IC engines means that BD is needed in large quantities for many years to come.

But again, one of the huge benefits of algae is that it can be used for waste remediation [industrial, agricultural, and municipal] and then used to produce fuel. In essense we have the potential to make a profit by cleaning-up environmental disasters. For example, nitrogen from agricultural runoff kills lakes and streams, but algae loves it!

mheslep

Its not the nitrogen that kills. The N spawns accelerated plant growth that in turn takes oxygen from the water, its the lack of O2 that kills.

DrClapeyron

I am thin on why watered down diesel fuel production involves the earth sciences. Yall certainly have a wholesale issue grasp, so may I assume the earth science relationion has something to do with available water resources, which if the production plants are built close to large water reserves like say on the texas gulf coast no problem unfolds.

Ivan Seeking

The N kills the lake though the associated growth, which kills the fish.

Ivan Seeking

Could you explain what you mean by watered down fuel? It would appear that you are just taking cheap shots at something that you know nothing about.

dlgoff

Hey Ivan. I just saw little clip from the local news on the Fox network out of Kansas City about Biodiesel.

Of course you were the first person to come to mind. I was wondering if the person they interviewed was you.

Regards

_Mayday_

Am I correct in saying that algae would also take in alot of the carbon dioxide in the atmosphere? If I am correct then its like killing two birds with one stone. It would need to be grown in HUGE numbers.

mheslep

Yes all plant photosynthesis does.
Theoretically at best it would be carbon neutral - fixing carbon during growth and then liberating it again when the resulting biofuel is burned. A recent spoiler to this equation: apparently if one slashes and burns the land needed for growth of your fuel crop then the net CO2 problem becomes worse, at least for some crops. I don't know what is commonly planned for Algae farms. If its done in the ocean somehow then the CO2 would be neutral; if massive land locked algae lakes have to be made then one is back to clearing land again.

Ivan Seeking

Algae is the answer to slash and burn because unlike the alternatives, it doesn't require good farmland. Also, the yields per acre are typically ten to forty times higher than other crops, so it requires less land area [or water area] accordingly.

mheslep

Where would it typically be grown then? BTW Id favor it in any case if its economical since its better (for now) than being dependent of foreign oil.

Ivan Seeking

There are many approaches ranging from open lakes and covered ponds to high-tech bioreactors. IIRC, there was even talk of dedicating the entire Salton Sea for algae production; due to the existing levels of pollution. But in principle you can grow it anywhere that you can have water, NPK, a fairly moderate climate [for production all 12 months of the year], and sunshine.

mheslep

Does one take sugar directly from algae or is there also cellulose conversion required (via cellurase and all that)?

Ivan Seeking

Right now the shortest and most economical path is to produce biodiesel from algae. Microalgaes produce mainly sugars and long-chain hydrocarbons [plant oil for biodiesel]. I'm not sure exactly what is involved in extracting the sugar but it can constitute as much as 50% of the algae by weight. And no, we're not talking about something as inefficient as cellulosic ethanol.

There is a chemical switch that selects for either oil or sugar production. Controlling this switch is one of the goals of modern research.

Note that there is one slow growing algae - botryococcus braunii - that is known to produce as much as 80% oil by weight.

There is a group through MIT that is growing algae for hydrogen production, so in addition to providing an immediate solution to our energy problems, algae may be the key to a hydrogen economy.

mheslep

Cellulosic ethanol is inefficient in what sense? In economic terms, the Coskata article up thread said they could produce for $1/gallon from basically any organic material, and for much less heat/pressure/water than is required for corn ethanol. I don't how to calculate land use for cellulosic, since the source can be municipal waste, trash wood pulp, feedstock, whatever.


A bit of a digression - do you believe the distribution problems for H are solved? Pipelines won't work, liquification costs, etc. I see serious economic difficulties there in putting that infrastructure in place.

Ivan Seeking

I'll believe it when I see it. Sounds to me more like a ploy for funding considering that it's not being reported more generally. I've heard many claims like this before that all turned into vaporware. Generally, the best predictions for cellulosic ethanol to be competitive are ten to twenty years, and [historically] even predictions like that are often overly optimistic. And by then we will likely have solved the problem with algae.

One key concept in a H economy is local production. This eliminates many of the infrastructure problems. It also makes the energy supply more secure than it is now because it decentralizes the system. Note also that many Hydrogen fueling stations already exist and the country of Iceland is converting to H right now.

Here you can find a list of the world's H fueling stations.
http://www.physicsforums.com/showthr...59#post1306959

mheslep

This makes sense - if it can be done.

mheslep

I have to backup a bit here. After googling Iceland's H plans, there is indeed a ton of information: lots of the usual why 'H is great' for energy independence, environment, use the geothermal, etc. But after digging into it, its all the same load of hand waving when it comes to distribution and storage, in particular nobody has demonstrated an economically viable onboard automobile storage approach. 'Concept projects planned for metal hydride' storage' - yes they better do some projects because hydride storage isn't close to being economically efficient. "Well fishing boats have problems storing H for weeks at sea, project planned to 'store' the H in methanol on board instead" - which is just begging the question IMO. Nanotube storage, blah, blah. Its not there yet.
Edit: more - the buses Iceland is deploying go for $1.1M a pop (4x diesel). This is just a Disneyworld stunt, pandering to the EU for subsidies and some feel good for the voters.