Saturday, April 21, 2007

Curb Pollution with a Rain Garden: Singing in the Runoff
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You can single-handedly curb your city's pollution by building a lovely, native rain garden.
Published: February 21, 2007 @ 11:30 AM CST from the March/April 2007 issue of Natural Home.
By: Misty McNally
Booming urban growth, and the concrete that comes with it, has pushed storm drainage to its limits. Most cities channel rain overflow to holding ponds via drains and culverts, which then empty into fresh-water supplies. These manmade systems are designed to move water quickly, but several factors make all this drainage a problem. First, our urban areas produce a lot of runoff: An impervious surface such as a parking lot or rooftop generates nine times more runoff than a wooded area of the same size, according to the Environmental Protection Agency. Second, pollutants such as motor oil, fertilizers, pesticides and debris also are washed down storm drains, accumulating and becoming more concentrated as they enter streams and ponds. This poisonous runoff pollutes drinking water supplies, harms fish and wildlife, kills native vegetation, and makes recreational areas unsafe.

Stop the cycle
In an effort to restore natural drainage patterns to cities across the country, many people are planting rain gardens. Planted in depressions in yards and along roadsides, rain gardens (also called “bioretention” areas) are designed to catch and divert runoff into the ground before it reaches storm drains. Rain gardens include plants, usually natives, that help percolate rain back through the soil. By doing so, they also filter many contaminants.Municipalities and watertreatment districts nationwide are promoting or subsidizing rain gardens. In Kansas City, where violent storms and flash floods are the norm, city organizers recently launched the 10,000 Rain Gardens project to address storm-drainage issues. This volunteer initiative includes an educational website and how-to classes, links with landscape professionals and hundreds of official participants (www.RainKC.com).

Scott Cahail, environmental manager of Kansas City’s Water Services, believes the initiative does more than prevent flooding. “We should value water as a resource, not see it as a nuisance,” he says. When people add rain gardens to their landscapes, they see the cycle of water conservation. Plus, native plants or flowers attract bees, birds and butterflies. “And on the practical side, it eliminates a patch of grass that needs mowing!” Cahail says. He estimates the cost of building a rain garden at $10 per square foot or even less-the environmental benefit is priceless.

BUILD A RAIN GARDEN IN 10 STEPS
Materials

o Shovel
o Ruler, stick or scrap wood (12 inches or longer)
o Pencil or marker
o Peat or compost
o Moisture-loving native plants (see"Selecting Native Plants")
o Shredded mulch
o Decorative rock

Step 1
Call before you dig. Contact your local utilities providers (electricity, gas, phone) to have them mark the location of underground wires or cables.

Step 2
Pick a location. A rain garden should be at least 10 feet from foundations, septic systems, utility lines and fence posts. You may wish to extend the length
of a downspout to reach the rain garden.
Step 3
Measure drainage rate. Dig a hole about the size of a large coffee can. Insert a ruler or stick into the hole. Fill the hole with water from a hose and mark the water level on the ruler. Wait four hours, then measure and mark the water level again. To determine the daily percolation, take the amount that has drained in four hours and multiply that by six. (Follow this formula: __ inches every 4 hours x 6 = __ inches every 24 hours)

Your rain garden should empty within 24 hours, so if you can drain 6 inches in that much time, dig 6 inches down. If the water in your test hole doesn’t drain well, consider different placement, or add gravel, compost, sand or peat (see Step 7).

Step 4
Determine the garden’s depth. It should be no more than 6 to 8 inches deeper than the surrounding soil, but you can place it in the bottom of a larger landscape depression or slope.

Step 5
Outline the garden location. Use string and wooden stakes or a garden hose to mark the general placement. Think about the land’s slope and where heavy rain may come in and flow out; don’t orient the garden so that overflow runs into your foundation or septic system.

Step 6
Dig in. The depression should be within your marked outline and to the depth you determined in the previous steps.
Step 7
Check the drainage rate again. Fill the depression with water, then measure the rate as in Step 3. If the drainage is poor, remove 3 to 4 more inches of soil and till in some sand, gravel, peat or compost to a depth of 1 foot, then check drainage again.

Step 8
Add vegetation. Put plants that can tolerate “wet feet” in the lowest places. Lightly cover with additional soil if necessary, but don’t fill the depression completely.

Step 9
Mulch to keep the weeds out.
Step 10
Water. Until the plants are established-especially if rain is scarce-it is beneficial to water to 1 inch at least once a week.If there’s regular overflow from the depression, you may wish to enlarge it or build a series of rain gardens with connecting drainage notches.

↓ Continue reading this article
Selecting Native Plants
The plants best adapted to your region will thrive in a rain garden. Look for flowers, shrubs and grasses that are not invasive or spreading, that thrive in damp conditions, and that are adapted to wet and dry cycles. For the deepest points in your rain garden, choose plants that can tolerate “wet feet”-that is, their roots enjoy boggy conditions. For suggestions, consult your local Cooperative Extension office, botanical garden or a nursery that sells native plants.

Resources
Cooperative Extension office locator
www.CSREES.USDA.gov/Extension
native plants
Lady Bird Johnson Wildflower Center
Native Plant Information Network/Native
Plants Database
(512) 292-4100
www.Wildflower2.org
native plants
Further Reading
10,000 Rain Gardens
http://www.rainkc.com/PDF/house%20and%20garden%20article.pdf
Rain Gardens of West Michigan www.raingardens.org
Rain Gardens: A How-To Manual for Homeowners
from the University of Wisconsin Cooperative Extension (www.LearningStore.uwex.edu)
Rain Garden Design for Home Owners
from the Alabama Cooperative Extension
(www.ACES.edu)
Harvesting Rainwater for Landscape Use
by Patricia H. Waterfall
(University of Arizona Cooperative, http://Ag.Arizona.edu/pubs/water/az1052/harvest.html)
Composters.com
(800) 233-8438
www.Composters.com
Gardener’s Supply Company
(888) 833-1412
www.Gardeners.com
Master Garden Products
(800) 574-7248
www.MasterGardenProducts.com

Harvesting Rainwater for Landscape Use
by Patricia H. Waterfall
(University of Arizona Cooperative, http://Ag.Arizona.edu/pubs/water/az1052/harvest.html)
Diverse Crops to Grow Biofuel
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originally posted at
http://www.washingtonpost.com/wp-dyn/content/article/2007/03/23/AR2007032301625_pf.html

Corn Can't Solve Our Problem

By David Tilman and Jason Hill
Sunday, March 25, 2007; B01

The world has come full circle. A century ago our first transportation biofuels -- the hay and oats fed to our horses -- were replaced by gasoline. Today, ethanol from corn and biodiesel from soybeans have begun edging out gasoline and diesel.

This has been hailed as an overwhelmingly positive development that will help us reduce the threat of climate change and ease our dependence on foreign oil. In political circles, ethanol is the flavor of the day, and presidential candidates have been cycling through Iowa extolling its benefits. Lost in the ethanol-induced euphoria, however, is the fact that three of our most fundamental needs -- food, energy, and a livable and sustainable environment -- are now in direct conflict. Moreover, our recent analyses of the full costs and benefits of various biofuels, performed at the University of Minnesota, present a markedly different and more nuanced picture than has been heard on the campaign trail.

Some biofuels, if properly produced, do have the potential to provide climate-friendly energy, but where and how can we grow them? Our most fertile lands are already dedicated to food production. As demand for both food and energy increases, competition for fertile lands could raise food prices enough to drive the poorer third of the globe into malnourishment. The destruction of rainforests and other ecosystems to make new farmland would threaten the continued existence of countless animal and plant species and would increase the amount of climate-changing carbon dioxide in the atmosphere.

Finding and implementing solutions to the food, fuel and environment conflict is one of the greatest challenges facing humanity. But solutions will be neither adopted nor sought until we understand the interlinked problems we face.

Fossil fuel use has pushed atmospheric carbon dioxide higher than at any time during the past half-million years. The global population has increased threefold in the past century and will increase by half again, to 9 billion people, by 2050. Global food and fossil energy consumption are on trajectories to double by 2050.

Biofuels, such as ethanol made from corn, have the potential to provide us with cleaner energy. But because of how corn ethanol currently is made, only about 20 percent of each gallon is "new" energy. That is because it takes a lot of "old" fossil energy to make it: diesel to run tractors, natural gas to make fertilizer and, of course, fuel to run the refineries that convert corn to ethanol.

If every one of the 70 million acres on which corn was grown in 2006 was used for ethanol, the amount produced would displace only 12 percent of the U.S. gasoline market. Moreover, the "new" (non-fossil) energy gained would be very small -- just 2.4 percent of the market. Car tune-ups and proper tire air pressure would save more energy.

There is another problem with relying on a food-based biofuel, such as corn ethanol, as the poor of Mexico can attest. In recent months, soaring corn prices, sparked by demand from ethanol plants, have doubled the price of tortillas, a staple food. Tens of thousands of Mexico City's poor recently protested this "ethanol tax" in the streets.

In the United States, the protests have also begun -- in Congress. Representatives of the dairy, poultry and livestock industries, which rely on corn as a principal animal feed, are seeking an end to subsidies for corn ethanol in the hope of stabilizing corn prices. (It takes about three pounds of corn to produce a pound of chicken, and seven or eight pounds to grow a pound of beef.) Profit margins are being squeezed, and meat prices are rising.

U.S. soybeans, which are used to make biodiesel, may be about to follow corn's trajectory, escalating the food vs. fuel conflict. The National Biodiesel Board recently reported that 77 biodiesel production plants are under construction and that eight established plants are expanding capacity.

In terms of environmental impact, all biofuels are not created equal. Ethanol is the same chemical product no matter what its source. But ethanol made from prairie grasses, from corn grown in Illinois and from sugar cane grown on newly cleared land in Brazil have radically different impacts on greenhouse gases.

Corn, like all plants, is a natural part of the global carbon cycle. The growing crop absorbs carbon dioxide from the atmosphere, so burning corn ethanol does not directly create any additional carbon. But that is only part of the story. All of the fossil fuels used to grow corn and change it into ethanol release new carbon dioxide and other greenhouse gases. The net effect is that ethanol from corn grown in the Corn Belt does increase atmospheric greenhouse gases, and this increase is only about 15 percent less than the increase caused by an equivalent amount of gasoline. Soybean biodiesel does better, causing a greenhouse gas increase that is about 40 percent less than that from petroleum diesel.

In Brazil, ethanol made from sugar cane produces about twice as much ethanol per acre as corn. Brazilian ethanol refineries get much of their power from burning cane residue, in effect recycling carbon from the atmosphere. The environmental benefit is large. Sugar-cane ethanol grown on established soils releases 80 percent less greenhouse gases than gasoline.

But that isn't the case for sugar-cane ethanol or soybean biodiesel from Brazil's newly cleared lands, including tropical forests and savannas. Clearing land releases immense amounts of greenhouse gases into the air, because much of the material in the plants and soil is broken down into carbon dioxide.

Plants and soil contain three times more carbon than the atmosphere. The trees and soil of an acre of rainforest -- which, once cleared, is suitable for growing soybeans -- contain about 120 tons of organic carbon. An acre of tropical woodland or savanna, suitable for sugar cane, contains about half this amount. About a fourth of the carbon in an ecosystem is released to the atmosphere as carbon dioxide when trees are clear-cut, brush and branches are burned or rot, and roots decay. Even more is lost during the first 20 to 50 years of farming, as soil carbon decomposes into carbon dioxide and as wood products are burned or decay.

This means that when tropical woodland is cleared to produce sugar cane for ethanol, the greenhouse gas released is about 50 percent greater than what occurs from the production and use of the same amount of gasoline. And that statistic holds for at least two decades.

Simply being "renewable" does not automatically make a fuel better for the atmosphere than the fossil fuel it replaces, nor guarantee that society gains any new energy by its production. The European Union was recently shocked to learn that some of its imported biodiesel, derived from palm trees planted on rain-forest lands, was more than twice as bad for climate warming as petroleum diesel. So much for the "benefits" of that form of biodiesel.

Although current Brazilian ethanol is environmentally friendly, the long-term environmental implications of buying more ethanol and biodiesel from Brazil, a possibility raised recently during President Bush's trip to that country, are cloudy. It could be harmful to both the climate and the preservation of tropical plant and animal species if it involved, directly or indirectly, additional clearing of native ecosystems.

Concerns about the environmental effects of ethanol production are starting to be felt in the United States as well. It appears that American farmers may add 10 million acres of corn this year to meet booming demand for ethanol. Some of this land could come from millions of acres now set aside nationwide for conservation under a government-subsidized program. Those uncultivated acres absorb atmospheric carbon, so farming them and converting the corn into ethanol could release more carbon dioxide into the air than would burning gasoline.

There are biofuel crops that can be grown with much less energy and chemicals than the food crops we currently use for biofuels. And they can be grown on our less fertile land, especially land that has been degraded by farming. This would decrease competition between food and biofuel. The United States has about 60 million acres of such land -- in the Conservation Reserve Program, road edge rights-of-way and abandoned farmlands.

In a 10-year experiment reported in Science magazine in December, we explored how much bioenergy could be produced by 18 different native prairie plant species grown on highly degraded and infertile soil. We planted 172 plots in central Minnesota with various combinations of these species, randomly chosen. We found, on this highly degraded land, that the plots planted with mixtures of many native prairie perennial species yielded 238 percent more bioenergy than those planted with single species. High plant diversity led to high productivity, and little fertilizer or chemical weed or pest killers was required.

The prairie "hay" harvested from these plots can be used to create high-value energy sources. For instance, it can be mixed with coal and burned for electricity generation. It can be "gasified," then chemically combined to make ethanol or synthetic gasoline. Or it can be burned in a turbine engine to make electricity. A technique that is undergoing rapid development involves bioengineering enzymes that digest parts of plants (the cellulose) into sugars that are then fermented into ethanol.

Whether converted into electricity, ethanol or synthetic gasoline, the high-diversity hay from infertile land produced as much or more new usable energy per acre as corn for ethanol on fertile land. And it could be harvested year after year.

Even more surprising were the greenhouse gas benefits. When high-diversity mixtures of native plants are grown on degraded soils, they remove carbon dioxide from the air. Much of this carbon ends up stored in the soil. In essence, mixtures of native plants gradually restore the carbon levels that degraded soils had before being cleared and farmed. This benefit lasts for about a century.

Across the full process of growing high-diversity prairie hay, converting it into an energy source and using that energy, we found a net removal and storage of about a ton and a half of atmospheric carbon dioxide per acre. The net effect is that ethanol or synthetic gasoline produced from this grass on degraded land can provide energy that actually reduces atmospheric levels of carbon dioxide.

When one of these carbon-negative biofuels is mixed with gasoline, the resulting blend releases less carbon dioxide than traditional gasoline.

Biofuels, if used properly, can help us balance our need for food, energy and a habitable and sustainable environment. To help this happen, though, we need a national biofuels policy that favors our best options. We must determine the carbon impacts of each method of making these fuels, then mandate fuel blending that achieves a prescribed greenhouse gas reduction. We have the knowledge and technology to start solving these problems.

tilman@umn.edu; hill0408@umn.edu

David Tilman is an ecologist at the University of Minnesota and a member of the National Academy of Sciences. Jason Hill is a research associate in the Department of Applied Economics at the University of Minnesota.
Thermodynamics of Biofuel by Dr. Krassen Dimitrov
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originally posted at http://algae-thermodynamics.blogspot.com/

Wednesday, March 21, 2007

How can one not like GreenFuel Technologies? These people say they can convert emissions from power plants into biofuels using algae in proprietary photobioreactors, which has so far resulted in tons of positive press, awards and accolades. And why wouldn’t it? You take CO2-containing pollutants and turn them into valuable, clean-burning fuels, just when we are running out of oil? Could there BE a better idea than that?

Actually, I for one do have a better business idea. Why not just skip the algae altogether, take water and CO2, put them in some Magic-o-Matic reactor and Voila! get oil out of it?

There is just one slight problem with mine and GreenFuel’s ideas: they break the Law. Now, events from the past few years suggest that anytime the end result is something that looks like oil… well… breaking laws is sort of OK. The problem with this Law is that nobody has succeeded in breaking it, and boy, have people tried?! It has the pretentious name of First Law of Thermodynamics, and basically says that when you convert energy from one kind into another you cannot gain energy, you can only lose it.

In other words, if we picture different types of energy as rectangles, where the height is the amount of energy, then an energy conversion chain can only look like a telescope, where every rectangle is narrower than the previous one.



Now let’s look at what GreenFuel is trying to accomplish in each square meter of their reactors. First, they take solar energy and convert it into algal biomass via photosynthesis. Not all of the solar energy is suitable for photosynthesis, the part that can be used is called photosynthetically active radiation (PAR). You want to know how much PAR you get in your neck of the woods? Check this website, they have the best PAR maps out there.

The energy - in the form of biomass - that can be obtained via photosynthesis thus depends on the level of PAR and the efficiency of the conversion process Q.

Ebiomass = PAR x Q

Photosynthetic organisms use eight photons to capture one molecule of CO2 into carbohydrate (CH2O)n Given that one mole of CH2O has a heating value of 468kJ and that the mean energy of a mole of PAR photons is 217.4kJ, then the maximum theoretical conversion efficiency of PAR energy into carbohydrates is:

468kJ/(8 x 217.4kJ) = 27%

This is the ideal yield on PAR energy that is: (i) actually absorbed by the photosynthetic organism, (ii) in conditions where this organism operates with 100% photosynthetic efficiency (every photon that is absorbed is effectively used in photosynthetic reactions), and (iii) the organism does not waste any energy on any life-support functions, other than building biomass.

Ideally, you want your algae photobioreactor plant to be someplace sunny, and according to the maps, the sunniest place in America is in the Southwest. One little problem: algae require tons of water but in the southwest water is not that abundant and is already being used for more vital purposes, like the Bellagio fountains in Vegas, for example.

Let’s sidestep the water issue and look into a square meter of photoreactors installed in the Southwest that convert PAR into biomass. From the maps, the mean annual PAR is about 105J/s, which translates into 3.3GJ/yr (there are about 31.5 million seconds in a year). If this gets converted using the absolutely highest, super-duper, theoretical photosynthetic efficiency of 27% it will equal to 0.89GJ/yr of energy locked into biomass.




So far so good! Now this biomass has to be converted into biodiesel, which has an energy content of 126,200BTU/gal or roughly 0.133GJ/gal. A look at the last page (Examples 2 through 5) of the patent application filed by GreenFuel shows you that they plan on getting something like 342,000 bbl of biodiesel per year from a 1.3sq.km. plant built in the Southwest. By doing some simple math conversions (342,000bbl x 42gal/bbl x 0.133GJ/gal : 1.3M sq.m.) one gets to … tah-dah… 1.47GJ/yr from a square meter!

Now we’ve done it! The process gained energy out of nowhere, which is against the First Law. We can add this patent to the list of other similar claims, that have invariably failed to materialize.

So what is a more realistic outcome for the conversion of PAR into biodiesel? First of all, the maximum achievable efficiency is of course not 27%, but more like 10%. Why? Not all of the PAR gets into the reactor in the first place, there are all kinds of transmission, reflection, and shading losses. Then, not all of the light that gets in gets actually absorbed by algae. Photosynthetic organisms have no good use for the green light and don’t bother to absorb it but rather reflect it back (you wouldn’t guess that by their color, would you?). Finally, algae don’t pile up all of the converted energy in a pile of biomass; they use some for their own life’s needs (this comes especially handy at night-time).

Next we have the question of how to turn the biomass into biofuels. There are three ways to do it:

* pyrolysis: this is a process where you heat the biomass to anywhere from 300 to 800 oC to get liquid fuels, gas and char. If you ever run into somebody who’s into pyrolysis, chances are that you’ll be made to believe pyrolysis is a divine answer to everything that we’ll ever need. These people are true pyro(lys)maniacs. In reality, though there are no substantial commercial installations for pyrolysis and it is not clear how much net energy you gain after taking into account the heat that one needs to input in the process.
* fermentation: this is how the most ubiquitous biofuel – ethanol - is being made from the sugars in corn or sugarcane. In a theoretical 100% conversion from glucose, two of the six CO2 molecules that were captured by photosynthesis are released, and 118kJ per mole are lost to support the lifestyle of the fermenting microbes. That’s not so bad, but there is a better option (next).
* transesterification of lipids into biodiesel. Biodiesel is the highest-priced liquid fuel, it sells at wholesale for $2.50/gal, which translates into $18.80/GJ. The allure of biodiesel comes not only from these high selling prices, but also from its easy and efficient manufacturing by transesterification, which is becoming a well established method, with low capital costs and high efficiency.

What you need for transestrification is lipids (fats). Algae are thought capable of providing high lipid content, some species can accumulate 30-60% (mass) and in some cases higher lipid contents.

There’s a catch, though! These “fat” algae develop only in conditions of cellular stress, most notably lack of a nitrogen source needed for making proteins. Feeding algae with mostly sunshine and no nitrogen is the same as raising your kids only on sweets - they may grow fat but they are not healthy and don’t develop properly. Similarly, growing “fat” algae is not worth it as they don’t grow properly and their overall photosynthetic efficiency is poor.

A reasonable best-case estimate then, for a healthy and efficient algal culture is to put aside 50% of all captured energy into fats and the rest into other things needed for their well-being: proteins, carbohydrates, chlorophyll, etc. These can be used and sold, too, as by-products in a variety of schemes, however, they won’t be fetching the same juicy dollars per gigajoule as biodiesel does.

What we get as maximum achievable yield for our square meter in the Southwest is the following:




“OK,” one may say, “last time I checked sunshine was still free and the algae grow by themselves. You get what you can: 5%, 1%, half percent, whatever... who cares… you still make valuable biodiesel out of free stuff! You can’t beat that!”

To which someone - a little more perceptive - might reply, “The land is not free, you silly, how do you get enough land to grow enough algae to get enough lipids to turn it into enough biodiesel if one only gets so much from a square meter?”

In fact, both of these imaginary friends would be wrong. The biodiesel will be far from free, and the reason is not the cost of the land, as shocking as this may sound for anyone from the San Frascisco Bay Area. How so? We’ll let our favourite author on energy issues, Kenneth S. Deffeyes explain it:

“At typical efficiencies of 10%, a solar collector has to occupy five square miles to deliver 1,000 megawats. I can direct you to any of several Nevada basins where you can get the five square miles; your problem is the capital cost of paving five square miles with solar collectors” (from “Hubbert’s Peak”, 2001)


Building and operating the photobioreactors on significant acreage is quite expensive. How expensive? We don’t know, it is not on GreenFuel’s website and something tells us that it’s not going to be there anytime soon. Nevertheless, we can look at comparable examples of solar capture systems to get an idea.





First, here’s GreenFuel’s Photoshop idea of how their plant will look like next to a power plant:







This is something that looks somewhat similar, a nice greenhouse farm.







Finally, something that many would simply call a big field of mirrors, and in fact, it is exactly that:




These are all installations that convert sunlight into something useful. The algal photoreactors are intended to convert it into biodiesel, while the greenhouse turns it into flowers and vegetables: both systems use photosynthesis for the purpose. As for the mirrors, they are used to reflect the sunlight into a central receiver which gets heated and the heat is then turned into electricity – technology known as concentrated solar power (CSP).
Now let’s look with higher resolution at the individual elements.



Here’s what a GreenFuel reactor looks like from up-close:





Here’s a greenhouse; this is a somewhat fancy one, as it is made out of polycarbonate, the same material that GreenFuel uses for their reactors. It costs ~$200/sq.m., excluding installation.




Here’s the mirror example, which is a bit more sophisticated than what one may imagine initially, as it has a drive that shifts the mirror, so that it always faces the sun directly. Hence it is called a heliostat. Its costs in 2003 were estimated at $160/sq.m.






Which of these installations do you think would cost more to build and operate per square foot or square meter of surface coverage? The study goes into some detail about that, yet if we are talking about a ballpark figure, they probably will cost the same.

How much energy can each of these three installations capture and how much $$ can one make from them?

A report on the greenhouse industry for the state of New York in the year 2000, puts the average revenue per square meter at $161.77/sq.m./yr, with a gross margin of 24%, for gross profits of $38.82/sq.m./yr. That’s pretty typical for the industry. $161 looks like a very decent number, are greenhouses really so proficient at capturing Sun’s energy? No! The solar yield in a greenhouse is probably on the order of 0.5W/sq.m., (0.015GJ/sq.m./yr), or up to twenty times less than what we estimated for the best-case GreenFuel reactors. The key here is what this energy is being converted into. Turns out that a gigajoule of sunlight - captured into winter tomatoes or poinsettias around Christmas-time - has a very high value, which covers up the expenses for building and operating a greenhouse.

What about the CSP example? It produces electric energy, not vegetables, therefore should be a more relevant example, right? CSP power plants are not competitive at today’s prices of electricity, so there is not much hard data for analysis. However, if we look at this report, done by a respected consultancy, we will find some projections.

For the near term, a CSP power plant will break even if it could sell electricity at $0.14/kWhr ($38.89/GJ). These near-term plants are expected to convert sunlight into 46W/sq.m., or 1.46GJ/sq.m./yr of electricity. At $38.89/GJ, the dollar yield will be $56.77/sq.m./yr, which should be enough to cover the expenses to build and operate the plant.

For the medium term, CSP plants are expected to become both slightly cheaper to build and slightly more efficient in capturing sunlight. The corresponding projections are:

breakeven electricity costs of $0.08/kWh ($22.22/GJ);
solar-to-electric capture of 55W/sq.m. (1.73GJ/sq.m./yr),
resulting in breakeven cash yield of $38.15/sq.m./yr.
Remarkably similar to the greenhouse profits of $38.82/sq.m./yr!


Now let’s look at GreenFuel’s biodiesel. We saw above that the maximum achievable yield of biolipids is ~0.16GJ/sq.m./yr. If we assume that these get converted with 100% efficiency (a truly heroic assumption) into biodiesel , which currently sells at $18.80/GJ wholesale, then we get a paltry three dollars per square meter per year ($3/sq.m./yr)

Here are the results summarized in a table:






It is pretty clear from the table that we won’t be growing fuel crops in greenhouses anytime soon. Algal photobioreactors are still not worth it.

What biodiesel price would be required to achieve the same $38 /sq.m./yr cash yield as from a greenhouse, or from a projected medium-term CSP plant?

Here’s the calculation: $38/0.16GJ = $237.5/GJ,

which incidentally also equals to $31.60 per gallon of biodiesel or $1,327 per barrel. (The study uses more optimistic assumptions and arrives at ~$20/gal and ~$850/bbl).

Stunned?!

Twenty to thirty bucks per gallon?

Thousand bucks per barrel?


Well, as shocking as these prices are, they would still be lower than what you pay for soft drinks at major league ballparks, or for that most expensive fluid on the planet – ink for inkjet printers. If we are running out of oil and if the global warming is gonna get us, maybe it is worth paying up for a renewable fuel like biodiesel from algae… sigh?

Relax, folks! There are better options for both post-oil fuels and for CO2 mitigation. The study mentions some of them, and there are others that would certainly be economic at prices much lower than that.


How did we get there? How can a process and a company based on such feeble premises get funding, awards, and so much prominence in the media? Let’s again turn for explanation to Dr. Deffeyes:


“There will be numerous voices claiming to have the new, new thing to solve the energy problem. They are not necessarily con artists. Some of them convince themselves first, then they try to con the rest of us. They are their own first victims.”


In a free market world there is no Central Committee that says what makes sense and should be tried and what doesn’t and should be banned. If somebody promises to break the laws of physics and if somebody else is a GreenFool enough to invest their money there, so be it! No harm to the public, right?

Except that today many people don’t invest their own money. The contemporary world functions through a sophisticated web of financial intermediaries. When you put part of your salary into your company’s 410(k) or you make a donation to the endowment fund of your alumni college, the money flows through a chain of financial managers into mutual funds, hedge funds, venture capital funds, each with their own money managers.

These financial agents are, or course, motivated to make profits, however they are also getting paid a fixed percentage of the assets they manage. So, in other words, the upside is there for them, but there is no real downside: whether the investment fails or not, these people still get paid.

I happen to know the person responsible for the largest piece of money invested in GreenFuel - Jennifer Fonstad, who oversees the $6mln invested by Draper Fischer Jurvetson. Jennifer is a businesswoman with impeccable credentials, yet with a marked tendency to disregard the scientific reality.

Any ordinary person would be extra careful not to put their life’s savings into ventures that promise to break the laws of physics. If financial managers with Jennifer Fonstad’s high intelligence and Harvard degrees were as vigilant and careful when investing other people’s money, the world would be a much better place and no energy or environmental catastrophes would be a match to humankind.

Posted by Dr. Krassen Dimitrov at 4:12 AM 4 comments

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