Monday, May 05, 2014

Greenhouses Are Not the Next Green Revolution

Before I explain why greenhouses are not the next green revolution, let me tell you about the next green revolution.

Why am I doing it in this order? 

Because whenever I tell people about the next green revolution, there is always some militant ignoramus who pipes up with something about "vertical gardening" or some other greenhouse based technology and they absolutely refuse to sit down with me and run through the basic arithmetic. That is why I'm writing this.

The Next Green Revolution: The Algae6 Photobioreactor

The next green revolution will reduce agriculture’s footprint by a factor of 10 while increasing protein yields to the point that the entire planet’s population can have a diet as high in calories and protein as the US diet (even going through trophic loss in aquaculture food chains), decreasing fresh water usage by a factor of 10, decreasing greenhouse gas emissions and rewilding the Amazon basin’s soybean fields and other rainforests now being denuded for palm oil. That revolution is here: The Alga6 photobioreactor from Algasol, LLC brings the cost per insolated area below that for open ponds while yielding areal productivity at an annualized rate exceeding 35g/m^2/day using natural algae strains in high insolation desert areas, with a dry-biomass concentration greater than 12g/liter (critical for operational expense).

You haven’t heard of this because although Algasol sold thousands of its PBRs, it had to shut down production due to the strict labor laws in Spain coincident with the financial crisis, and is just now restarting a showcase under the auspices of the University of Majorca, which has the requisite labor relations.

The ideal environment for this PBR is floating on saline water. Deployment in the equatorial ocean desert doldrums is its ultimate destination — a location with much higher insolation and therefore much higher areal productivity potential, bringing the potential agricultural foot print of civilization to arbitrarily low levels.

When agriculture relocates to the ocean deserts, it makes sense to relocate population there as well — particularly if it is feasible to provide beach-front property via artificial floating atolls -- circular islands with interior lagoons.  The lagoons would have low enough sea state to provide an ideal environment for floating photobioreactors, rendering the atolls food exporters as well as population centers.  The demand for beach-front property is well established at thousands of dollars per ocean-facing foot.  Even so, the production of the atolls with beaches requires advances in energy technology that may be uniquely available in the tropical oceans.  See my prior blog entry on the Atmospheric Vortex Engine which is particularly well suited for the tropical doldrums.  In combination with the Calera process (requring 3.3GJ/tonne concrete*), the AVE can produce very inexpensive concrete from the heat collected by the photobioreactors, converted to electricity that is applied to elements available in sea water (calcium) and air (CO2).  With such technology beachfront property on artificial floating atolls could be manufactured for a small fraction of its real estate value.  With industrial learning curve, the cost of beachfront property may become affordable for virtually the entire population of the developed world.   These calculations will appear in a future article.**

An Interim Message To Aspiring Environmentalists

Rational environmental concern must favor technologies that out-compete existing technologies that have a larger ecological footprint. Any rational measure of ecological footprint must take into account the amount of biodiversity that is disrupted — not just physical size. For example, if a technology existed that would allow one to cultivate soybeans more profitably on the same amount of land in a desert as in a cleared portion of the Amazon rainforest, opposing it out of environmental concern would be irrational.

The tragedy befalling the environmental movement is that the majority of self-proclaimed “environmentalists” don’t care about the environment in this rational way.

The open ocean has places with far lower biodiversity than coastal ecosystems. If, for example, an open ocean aquaculture technology pollutes to the same degree as current aquaculture techniques that utilize coastal areas, but is more profitable, then it should be seen as an environmental good.

One would prefer to move these aquaculture operations to the so-called “ocean deserts”. If there were a technology that attracted them to that location, then that, too, would be an environmental good — all else being equal. That's where the Alga6 PBR comes in;  but do keep in mind that all else is not equal with the Alga6:

The Alga6 dramatically reduces the amount of area required for primary protein and oils production compared to the Amazon soybean fields or palm oil fields of Indonesia.

Truly those successfully opposing such technologies are doing more harm to the environment than the big corporations they decry.

Some Basic Arithmetic For Greenhouse Advocates

Dutch greenhouse technology has the highest productivity per area of any greenhouse technology, at 90lbs of tomatoes per square meter per year.  This is so far beyond the productivity of ordinary agriculture that it is easy to see why people would believe this to be the next green revolution.

In our arithmetic demonstrating the Alga6 beats Dutch greenhouse technology, we will ignore the cost of constructing the Dutch greenhouse as well as the electrical cost of artificial light and other operational expenses.

Fair enough?  You do understand, don't you, that by ignoring these costs we are giving greenhouses a running head start -- placing a handicap on the Alga6 in this comparison  (because the Alga6 has a much lower cost of construction and uses natural light)?

Now, the first thing you have to understand about agriculture is that the primary need for food is energy.  The vast majority of food mass you eat is either discarded or burned up to power the body.  Average humans burn energy at about the same rate as a 100W lightbulb.  That's even if they don't lead a particularly active life.  The brain alone burns about 20W without straining itself.  

That means people need to eat food at a rate of about 100W of power.

Now let's calculate how much power, in food watts, is produced per square meter of an artificially lighted Dutch greenhouse:

([{90 * poundm} / {meter^2}] / year) * ([22 * {kilo*calorie}] / [123 * gramm]) ? watt / (meter^2)
= 0.96939567 W/m^2

or about 1 watt of food power per square meter of greenhouse technology.

What did I just do there?  

Its pretty simple when you use the Unicalc calculator, as I did:

Dutch greenhouse technology produces about 90lbs of tomatoes per square meter in one year.  Tomatoes have an energy content of about 22 food calories (or 22 "kilocalories") per 123g.  Unicalc has the conversion factors and knows how to multiply and divide quantities given their units.  It makes doing calculations like this a snap and through the miracle of arithmetic we can discover wonderful things like what will work, what won't and even what is best.

Now lets look at the Alga6's production of food power per square meter:

([{35 * gramm} / {meter^2}] / day) * ([410 * {kilo*calorie}] / [100 * gramm]) ? watt / (meter^2)
= 6.9537708 W/m^2

or about 7 watts per square meter of food power.

Now let me make this as plain as I can:

The Algae6 does 7 times better than the best greenhouse technology!

The difference is in the energy content of algae as food.  In this case we're using the food energy for chlorella -- a widely consumed health food -- which is 410 food calories per 100g.  Chlorella just happened to have been the first algae species test-grown by Algasol, so these are verified production numbers.

Another thing to note here is that comparing tomatoes to algae isn't really fair to algae because algae possesses high concentrations of protein and omega-3 oils.

Now, one might object that people aren't going to eat algae directly whereas they will eat tomatoes directly, and this is true.  Not everyone is a healthfood nut and furthermore you don't want to make algae a primary component of your diet due to its high DNA (nucleic acid) content, which can cause gout.  Algae is best thought of as a foundation for agriculture:  It will feed the base of the agricultural food chain, just as do corn and soybeans now.  But if one looks at the energy losses in the food chain for, say, sockeye salmon -- a fish that eats algae and gets its "fish oil" directly from algae's oils -- the loss is about a factor of 2.  So that brings us down to a mere 3.5 to 1 advantage of Algae6 PBR over Dutch greenhouse production.  Ah... but now the shoe is on the other foot!  Everyone likes tomatoes, of course, but what about fresh sockeye salmon?  Moreover, with aquaponic technology coupled with aquaculture, the waste from from the fish is nutrient input to vegetable production.  So you can have your tomatoes and eat them with your salmon, too!

*The chemical formulas for the Calera process:

2NaCl+2H2O =>2NaOH + Cl2 + H2
CO2+2NaOH+CaCl2 => CaCO3+2NaCl+H2O

Combined with Calera's claimed reduction of energy usage by 60% with their “Alkalinity Based on Low Energy” (ABLE) process, yields the following energy/mass balance for CaCO3:

0.4*2*411.12kJ/mol;100.0869 g/mol?GJ/tonne
([{0.4 * 2} * {411.12 * (kilo*joule)}] / mole) * ([100.0869 * gramm] / mole)^-1 ? (giga*joule) / ton_metric
= 3.2861044 GJ/tonne

** Not that it is very important in this scenario but, yes, it does turn out that levelized algae oil costs for the Algae6 bring it into competition with crude oil — particularly when coupled with hydrothermal processes that have now been demonstrated.