Thursday, April 17, 2008

Biofuel from Algae: Vertical Reactors (HDVB).

I am indebted to a reader for bringing a new technology to my attention, namely the "High Density Vertical Bioreactor", or HDVB in contrast to open-pond systems, as alluded to in my recent posting, "Biofuel from Algae: Photosynthetic Efficiencies." The HDVB system is marketed by Valcent Products Inc. and consists of growing plants or algae in plastic pockets on clear vertical panels that move on a conveyor-belt arrangement. The strategy is designed to maximise the amount of sunlight and provide an ideal balance of nutrients to achieve optimum growth. It is proposed that such vertical growth systems might provide a solution to the problem of feeding urban populations so that urban living becomes sustainable.

Now, I like the sound of this, as it fits with my notion that once transportation begins to fail in consequence of cheap oil supplies waning in 5 - 10 years, humanity will relocalise into relatively small communities far less dependent on transport. The lack of urban growing space is counteracted by the very high efficiency of crop production in HDVB reactors. This form of agriculture as also soil-free, and uses perhaps 5% of the amount of water that is required to grow crops by conventional means, since the whole constitutes a closed-system with far less evaporation. Since these reactors can be placed anywhere (as can open-ponds) there is no necessity to compromise arable land which can still be used for standard agriculture.

However, the HDVB offers the potential of producing fuel as well as food, since algae can be grown in these systems too, and it is claimed in higher yield than in open-ponds. Thus in principle, food is grown locally, thus eliminating much of the fuel-costs borne in the carriage of crops from one part of the country to another or even across the world, by air or by ship, and also biodiesel can be made from oil extracted from algae grown using the technology, by transesterification with methanol or ethanol, as is done with plant-derived oils. Growing food both efficiently and locally also averts much of the spoilage that occurs on long hauls, during which as much as 50% of it is thus rendered inedible.

It is claimed that 100,000 gallons (US) of diesel can be produced per acre of HDVB area, which does seem very high. I commented in my article on photosynthetic efficiencies that the figure of 20,000 gallons/acre quoted in the wikipedia entry on "permaculture" looks to be well above the theoretical efficiency for a horizontal open-pond/algal system, but higher surface areas could be attained using vertical reactor arrangements; however, to install this paraphernalia on the very large scale is going to take a lot of plastic (derived from oil) and a lot of engineering, especially since the HDVB systems are more intricate than the basis I have indicated. Irrespective of whether the algae are grown in open-ponds or HDVB systems, there will also need to be a massive construction of transesterification plants and a source of methanol or ethanol must be found, in an amount equal to perhaps 10% of the diesel that is produced.

It sounds like a great idea and sits comfortably with most of my values and projections as to what precisely we need to achieve in order to form a stable, sustainable society. However, the scale-up will be a gargantuan task. If we can cut our fuel use to say 25% in relocalised communities, we still need to produce around 700 million tonnes of biodiesel annually (15 million tonnes just for the UK and 175 million tonnes for the US) and convert most vehicles to run on diesel-engines; but can this be done quickly enough to breach the demand/supply gap facing conventional oil production?

Related Reading.


Anonymous said...

yes, a gargantuan task indeed. Then I don't know if the system proposed by Valcent really works of if they were just trying to sponsor their own system. I truly am no expert, so a question comes to mind, that maybe has already been discussed in this blog. Is there a smart solution to the problem? Isn't there a new technology on its way that will enable us to live pretty much with the same level of comfort as we have today? As far as you as a scientist can see.

Professor Chris Rhodes said...

Well, my own opinion is that we can't carry on at the levels of comfort/energy we are used to and so big changes are necessary - either through design or default. Design would be a lot less painful, but the world seems to be in denial of the coming energy crunch!

Relocalising society and acting at a more local and less transport intensive level is the best way forward I can see.

Using less, but applying more ingenuity makes sense. I don't believe we have any new technology, e.g. hydrogen, just around the corner. If the world had forged-ahead with its "alternative to oil" projects 30 or so years back, we might be closer to having a solution now. But I suspect we've left it too late!

No, I don't know if this technology works either, but the general idea of algae-to-oil looks like the best option yet if it can be made a success. It would also mean that we could more or less use our existing fuel-distribution network rather than a completely new one to handle hydrogen, say.

Meanwhile, I am trying to be optimistic!


Anonymous said...

So why is everything moving calmly with no worries, with that "everything is fine" attitude. I think actually this is the whole point of your blog, to try and make aware of the problem, and surely in this blog it has been mentioned already countless times. I don't see any sign of warning from institutions, governments or oil multinationals. In fact, which institution should be in charge of announcing that the oil is going to finish and we might be in big trouble I don't know. It just seems strange that nothing is being said, and there's a business as usual attitude. either there is a solution or not or we are just worrying for no reason.
I have been following your blog for two years now, since I saw it mentioned on the New Scientist website (I'm not even graduated from university though). I agree with you on most things, but the fact that we shall be living in local small communities. Although I cannot provide you with data to support my idea, it would seem like a jump back to the middle ages to have to do that. I still see as a great achievement the existence of means of transport (cars, trucks, trains, planes, etc.) not only for leisure but because they are vital to the survival of our community. I think of it as a human being. If the blood wouldn't be allowed to flow the body would die. Not long ago there was a strike of lorry drivers in Italy, and the whole country was nearly grounded to a halt. No food delivered to supermarkets, no fuel delivered to petrol stations.
In any case, sorry for ranting, I am not providing you with any data here. I am not trying to be pessimistic here, but I agree with you that there might be no easy solution.

Professor Chris Rhodes said...

I sincerely hope we are worrying for no reason! I sat at this screen transfixed about 2 1/2 years ago when I first read about peak-oil. I remember as a kid being told that oil would run-out eventually, but while there are decades worth of it left, the price will go ever higher and take the world economies with it.

Ultimately we shall have to live "oil-free" but the prospect would cause mass panic, in all likelihood, and it is in nobody's interests to voice the matter publicly. Yet, I think that thinking on the local level might prove the better way in all respects.

The issue needs to be handled delicately and I think that much that is spoken of cutting fossil-fuel use to "avert climate change" has as much to do with preserving oil and natural gas as cutting CO2 emissions, since both causes are served by the same set of actions.

I like my life, quite frankly, and I am not a gung-ho survivalist who wants us all to return to the stone-age. Writers like Kunstler predict doom and gloom and they may well be right, but I am trying to keep alive the embers of optimism.

Then there are the extremists, mostly in the US, who think that the Western way of life (using-up oil and gas, polluting the atmosphere etc.) is simply serving the coming of the "end-times" as prophesied in the Bible.

I am hoping for a better outcome than that!



Anonymous said...

Well said, I always thought that the Kyoto Protocol and that stuff was just a lie told to the masses to try and hide the fact that the oil is getting to an end and we have to start saving it. Cut emissions should then be translated into "cut consumption", which is alarming because is a form of disinformation I don't like. Yet as you said consuming less is already on your recipe for hope of "surviving". Less feasible I think the small community part.

Professor Chris Rhodes said...

Only time will tell! Although given the economic insecurity around the world I fear we are beginning to see the start of this great social change. I hope not, but that's how it looks to me. The inextricable dependence of society on oil/cars must be the first string to break in our world fabric if the peak oil notion is true, and I don't see how it can be otherwise.

Even the CEO of Shell has written that there will be a gap between supply and demand for oil by 2015. Other analysts reckon it will come by 2011 - 2012.

As I say, only time will tell.


Beth said...

RE: "and convert most vehicles to run on diesel-engines"

Considering the relative thermal efficiencies of utility electric power production (when hydrocarbon fuel is the energy source) compared to internal combustion and the overall "well to wheel" efficiency of electric power generation and utilization, electric is not only preferable for locomotion because of lower emissions, but even in the USA, it's a lot less expensive (1/3) per mile than any kind of fuel.

PlugIn Hybrid Electric Vehicle autos will be available starting in 2010. These recharge onboard batteries capable of going 40 miles overnight using reduced rate power. (In the US there is sufficient idle generation capacity to convert 83% auto fleet to PHEV.) Most people would make most trips using electric power only and save 2/3 per mile. When the battery runs low, an onboard generator pack cuts in powered by a highly tuned fuel engine that is capable of charging the battery while going 70mph on the highway extending the range to over 600 miles.

This is a game changer because when we reach 83% conversion, there will be no need for imported oil, the foreign trade deficit will be erased, and there will be no further dependence on rogue producer states. And, of course, total emissions will go down 50% in the US even before carbon sequestration and increased renewable generation enters the calculation.

One of the beauties of micro algae cultivation is that it wants a 13% CO2 feed that can be had at a power plant or a refinery. The algae will recycle as much as 1/2 the CO2 as lipids that are readily processed into biodiesel. This can be burned along with coal or natural gas by the power producers to reduce the amount of fossil fuel needed for power generation by 1/2 and the emissions go through the floor.

Though it is readily used for glycerin or high protein animal food, there is a tantalizing possibility for using the biomass that remains after oil is squeezed from an algae harvest: Using pyrolisys and by recycling the syngas effluent, it is possible to produce a charcoal based "terra preta" fertilizer that will sequester the remaining CO2 captured from utility emissions in the soil when it is applied. This product has the property of providing a carbon matrix that protects the nutrients from washout and nitrogen fixing soil bacteria from pesticides.

Excess fertilizer runoff is causing wild algal blooms all over the world that endanger lake and bay aquaculture. It's a bit ironic that if this algae based product was widely used in the Chesapeake Bay watershed, for instance, it would end the pollution of the bay that is choking the crab and mollusk population, ruining the historic seafood harvest.

Professor Chris Rhodes said...

Hi Beth.

Thanks for your very interesting comments. I can see you are a fan of potential algae too. Regarding PHEV's I worked out that if lithium batteries are used, even if the whole of the world's present output of lithium were doubled and used to make them, it would take 50 years to "convert" 10% of the world's car fleet to this kind of technology.

Hence either way, we are all going to travel less in the foreseeable future. So, I think they are a great idea especially as you point out, recharging them with the excess electricity capacity there is.

Meanwhile I am looking toward liquid fuels - e.g. algal biofuel, although making enough of it will be a monumental task.

I don't see an easy or single solution to the impending depletion of oil, but less transport seems to crop-up as the conclusion from most arguments I can find.


Unknown said...

As long as the oil companies have a monopoly it is not in their interest to invest in any new technology. They do not care if oil prices go up because at least right now we have to go to them for the energy we use each and everyday, and because oil is used for so many products! It would be crazy to them to make an opening for a new fuel source that would take money out of their pockets!

As long as you have the Republicans in office we will not be moving in the right direction anyway. They only seem to want to enrich their corporate buddies because it aids them in the political realm as we have seemed over the past few years.

We have the technology right now to become energy independent but everyone is playing it safe, because they want to be reelected to office, otherwise why would politicians support and subsides corn ethanol which will drive up the cost of so many of the food and other products that we use each and everyday, when they know that they are clearly not viable!

Professor Chris Rhodes said...

Hi Purnell,

there is indeed an advantage in the status quo for some. Oil producers are doing very well out of the high oil prices and I think their shareholders would not thank them for cutting profits.

I am interested in your comment that "We have the technology right now to become energy independent". Do you think so. How might the oil be replaced (i) for fuel and (ii) as a chemical feedstock e.g. making plastics etc.

I ask because the British government has just announced a scheme to make a lot of renewable electricity (wind-farms, solar etc.), but I don't see how that can be used to replace oil-fuelled transportation?



glenn said...

Wouldn't the algal productivity per acre be limited by the available insolation regardless of the vertical growing area?

Can you ever extract more energy in fuel than strikes the area in sunlight?


Professor Chris Rhodes said...

Hi Glenn,

no the amount of energy from the sun is the absolute maximum and you only get a few percent of that in actual yield.

Yes, the amount of sunlight depends on the latitude. So, northern Europe is about 2 kWh/day but Arizona, say 5 kWh/day. It depends on the seasonal cycles too, and so these are just average figures.



Unknown said...

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Crystal Coleman said...
This comment has been removed by the author.
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