Biodiesel from Algae
I had an opportunity recently to attend a presentation by Solix, a startup company located in Fort Collins, CO that is developing a method to produce biodiesel fuel from algae. I also had a chance to take a look at Solix's proof-of-concept photobioreactor.
The Solix process works by optimizing the conditions to grow a particular type of algae which is high in lipids. Lipids are fats which are relatively easily to convert to vegetable oil and thus into biodiesel. The algae are grown in water-filled raceways called photobioreactors that are sealed off from the atmosphere to avoid contamination from microorganisms and other algae species. It also helps prevent evaporation of the water which is used to grow the algae. Because of this approach, it should be possible to produce biodiesel from this method with 98% less water than it takes to produce it with more conventional crops like soybeans.
Corn ethanol, with nearly 5 billion gallons produced in the U.S. annually, can be made at the rate of approximately 450 gallons per acre of corn. Crops like soybeans and rapeseed produce between 50 to 150 gallons biodiesel an acre. According to Solix, algae-based biodiesel from their photobioreactors may be able to produce as much as 8000 gallons of biodiesel per acre.
Another advantage of algae is that it's not necessary to situate the reactors on land that is suitable for other forms of agriculture. A common criticism of biofuels today is that they raise food prices by competing for the same land as food crops. It's conceivable that the photobioreactors could be placed in a desert environment, although one of the challenges for growing algae is to keep the water at a very consistent temperature of around 70 degrees Fahrenheit so that will likely also influence optimal placement of the photobioreactors.
The primary inputs for growing algae are water, CO2, and sunlight. This activity would be best accomplished closer to the equator, where seasonal sunlight levels and temperatures don't vary as much as they do further away from the equator. Another possible method to increase production would be to put the photobioreactors near a conventional coal-burning electric plant and harvest the significant amounts of CO2 generated by the plant. As attractive as it sounds, the production of biodiesel shouldn't depend on the coal plant operating indefinitely since that wouldn't be a sustainable long term strategy. Whenever capturing CO2 from an existing process is discussed, it's not long before you'll hear it called 'carbon sequestration', but that is really not an accurate description. While capturing CO2 can reduce the amount of fossil fuel-generated CO2 released into the atmosphere by displacing an equivalent amount of oil, it's fair to expect that any CO2 captured in the form of biodiesel would be released into the atmosphere in short order, probably within weeks, so it's really not a form of carbon sequestration. It's better described as a 'carbon mitigation' strategy. There are other commercial products that can be harvested from the algae such as carbohydrates and those will have uses such as animal feed.
There are not very many examples of commercial algae cultivation today. There are some facilities producing algea for neutraceuticals and pharmaceuticals that sell for as much as $750/lb but that is a completely different economic payback scale than bio-diesel which would only bring about $.50/lb at current prices. When the techniques to produce bio-diesel from algae were first developed back in the 1990's, diesel fuel was hovering around $1/gallon and so biodiesel from algae wasn't considered economically viable. Now that diesel fuel has gone over $4/gallon in the U.S., various methods to produce biodiesel are seeing a lot of renewed interest.
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The Solix process works by optimizing the conditions to grow a particular type of algae which is high in lipids. Lipids are fats which are relatively easily to convert to vegetable oil and thus into biodiesel. The algae are grown in water-filled raceways called photobioreactors that are sealed off from the atmosphere to avoid contamination from microorganisms and other algae species. It also helps prevent evaporation of the water which is used to grow the algae. Because of this approach, it should be possible to produce biodiesel from this method with 98% less water than it takes to produce it with more conventional crops like soybeans.
Corn ethanol, with nearly 5 billion gallons produced in the U.S. annually, can be made at the rate of approximately 450 gallons per acre of corn. Crops like soybeans and rapeseed produce between 50 to 150 gallons biodiesel an acre. According to Solix, algae-based biodiesel from their photobioreactors may be able to produce as much as 8000 gallons of biodiesel per acre.
Another advantage of algae is that it's not necessary to situate the reactors on land that is suitable for other forms of agriculture. A common criticism of biofuels today is that they raise food prices by competing for the same land as food crops. It's conceivable that the photobioreactors could be placed in a desert environment, although one of the challenges for growing algae is to keep the water at a very consistent temperature of around 70 degrees Fahrenheit so that will likely also influence optimal placement of the photobioreactors.
The primary inputs for growing algae are water, CO2, and sunlight. This activity would be best accomplished closer to the equator, where seasonal sunlight levels and temperatures don't vary as much as they do further away from the equator. Another possible method to increase production would be to put the photobioreactors near a conventional coal-burning electric plant and harvest the significant amounts of CO2 generated by the plant. As attractive as it sounds, the production of biodiesel shouldn't depend on the coal plant operating indefinitely since that wouldn't be a sustainable long term strategy. Whenever capturing CO2 from an existing process is discussed, it's not long before you'll hear it called 'carbon sequestration', but that is really not an accurate description. While capturing CO2 can reduce the amount of fossil fuel-generated CO2 released into the atmosphere by displacing an equivalent amount of oil, it's fair to expect that any CO2 captured in the form of biodiesel would be released into the atmosphere in short order, probably within weeks, so it's really not a form of carbon sequestration. It's better described as a 'carbon mitigation' strategy. There are other commercial products that can be harvested from the algae such as carbohydrates and those will have uses such as animal feed.
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What is Biodiesel?
Perhaps you've seen it. Perhaps you haven't. A local gas station opens a new pump offering E85 a new, environmentally friendly and renewable fuel source! Naturally, you think of filling up at that pump instead of the usual grades of gas. Word of warning: DON'T DO IT! Unless you're one of the few people driving the right car, called a flex-fuel vehicle, that is.In addition to E85, which is a mixture of 85% ethanol and 15% gasoline, another biofuel is becoming available at some filling stations. It is called 'biodiesel'. Although both E85 and biodiesel are made from biomass, there...Headlines:
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