SolaRoof | Biomass Production

Phyto Technology? for Mass Algae Culture

Sola Roof is an approach to building a distributed solar energy system based on vegetable oil production, which would be most economically valuable when this renewable oil production process is building integrated and thus use urban land; and more specifically, the roofs of buildings. This is in contrast to Biomass Crops that are agricultural and forestry based and compete with other land uses.

Individual buildings, whether they are large or small (in individual homes) can get bottled liquid CO 2 delivered as we do now with propane for example. The CO 2 can bleed off at normal pressure into the culture tanks. This assures that the enriched CO 2 environment is maintained for maximum metabolization by the algae. Whether the project is integrated with a single family home or a large multi-residence community development (Eco Sphere is an example) one can get the liquid CO 2 delivered to various size on-site pressure tanks. Remember that it is a penalty of centralized power plants and other industrial process that produce CO 2 and must find a way of mitigating vast quantities of GHG. They may pay for Sola Roof veggie oil producers to take their quota for sequestration. In other words we are recycling a waste product - a GHG.

Think of the culture tanks as the primary unit of biomass production. These tanks have a certain practical size and will probably be scaled up by having farms of tanks. Each tank has a certain liquid volume and a biomass loading rate - which is the % by weight of the algae. You would be able to skim off the algae at a certain rate while the "bloom" is in progress. This would be during the daylight hours. No doubt the rate of harvest would be proportionate the amount of sunlight. Now you need to expose the mass of algae in a tank to the sunlight every ten minutes. This is the time line for cell division and multiplication following sunlight exposure. The cells store radiative energy that can be metabolized later and passed on to the daughter cells. A thick layer of water containing algae will not assure adequate exposure because only algae very near the surface will get a sufficient exposure to the light. A thin faster moving water layer will do the job very well.

In our Sola Roof system we are circulating water in any case to provide climate control in the fashion that I have just described - where the water film is the absorber of the solar radiant energy that has been absorbed by the higher plants growing under the Sola Roof envelope. The roof cover is already there and paid for as is the pumping energy. So the harvest of algae is a bonus that we get by setting up the tank and culture/harvest. Even the tank itself would otherwise still be there so I don't think it should be charged as an incremental cost against the total capital cost of the algae system. If we have a certain size tank producing a know rate of harvest and therefore oil as one of the products, and we know we have to circulate the entire volume of that tank to the roof every ten minutes then we would experimentally determine the area of Sola Roof system needed for an optimum flow rate per area (and get the optimum water film thickness). This could be played with until we get the best productivity out of one tank. Then a farm of tanks would need N x more roof area in a modular design. Or a roof of a certain area would be set up with a certain number of tanks.

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From: fred mcgalliard <fbmcgalliard@hotmail.com> To: <ae@listproc.sjsu.edu> Sent: Friday, November 30, 2001 10:19 AM Subject: Re: net energy/ was - plants to the rescue - CO 2 as "plant food"

I think that right now there is no problem obtaining enough CO 2 to run a CO 2 enhanced solar oil plant. The real problem is that the scale of the CO 2 sources is so large that plants smaller than a few square miles would hardly even be of interest to the sources. A mostly self sustaining small community is a pretty good idea, but you should remember that our idea of a small community is several thousand families, tens of thousands of individuals. But right, you start small and demonstrate that it works well before you commit your larger community.

I like the way you think Fred. I am also mainly thinking of distributed, community integrated systems. Let’s say sustainable communities of a couple hundred people have their own Mirco Turbine? combined heat and power (electrical generator) systems that are producing CO 2. As well as this you may have aerobic composting of garden wastes and perhaps some chickens and other livestock - all of which are sources of CO 2 that can be segregated and directed into the Sola Roof garden and algae and plant production systems.

Additionally, the large producers of CO 2 are going to be capturing and liquefying their CO 2 and as Mike was saying these produces will pay others to take the CO 2 off their hands and sequester it back into the biosphere somehow. There is I believe more practical progress and knowledge of how to get the CO 2 than there is about practical solutions to sequester it again. The biosphere of forests etc cannot be isolated to feed on the CO 2 and in any case the rates of sequestration by the photosynthesis of the higher plants, including trees (even so call fast growing tree plantations) are now where near to being able to metabolize the CO 2 that is coming down the pipe so to speak. Only algae can, with the benefit of closed atmosphere hydroponic cultivation, achieve a greatly enhanced rate of growth and conversion that would be in step with our rate of combustion of energy fuels.

I would like to see a revival of the "village" pattern of community development with distributed power systems, district heating and cooling (using the Blue Green solution: ambient solar and Ambient Cold Water systems for climate control in buildings), and a mix of alternate energy technologies that would supplement energy from a clean hydrocarbon cycle. If we look at the roof area of our homes and communities we can see that a very large potential for closed cycle ECOLOGICAL energy system to become our primary energy source. I have heard of a projection that states that more homes will be built in the next 20 years than have been built since the beginning of history through to today. California expects housing to expand by 40% in the next ten years. So if a fraction of this growth could be in the form of sustainable communities then we would reduce the rate of resource depletion and soft land the world economy on an ALTERNATIVE track to a sustainable future.

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Original Message From: fred mcgalliard <fbmcgalliard@hotmail.com> To: <ae@listproc.sjsu.edu> Sent: Thursday, November 29, 2001 6:11 PM Subject: Re: net energy/ was - plants to the rescue - CO 2 as "plant food"

If I have been following this thread correctly, the plan is to use "captured CO 2" to enrich the air in a greenhouse-like setting to grow algae for the production of energy either through production of oils or direct pyrolysis.

Bob, the purpose of the CO 2 is not just to enhance the growth rate, but in this case to dramatically increase the proportion of oil produced, so I do not have to pyrolyze the dry algae to obtain it. For this purpose I might even consider it a pay off to burn the crop leavings from my garden and feed the CO 2 into our culture. The overall cost/benefit of this process is going to include a lot of other issues I don't feel like I have any good handle on. Given the number of different ways I can get CO 2 from the air, from aerobic digestion of compost, from combustion of any of the organic byproducts, I think that is not my first worry. Getting a high enough yield of oil per square foot of algae tank, and establishing a more or less continuous process, that is my first and biggest problem. All the rest is, I think, (as the physicists always say) just a problem of engineering.

 From: Bob Allen <bob.allen@atu.edu>