Algae has been making the news a lot lately, and is a fairly new topic in environmental circles. Let's take a step back for a moment and talk about why algae is interesting and important.
What is algae?
It's a big, giant, diverse set of plants. You probably know them best as seaweed. They have no leaves or roots like plants you find on land, but they perform photosynthesis all the same. Generally, algae grows in water.
What makes algae a good candidate for biofuel production?
Several things. For starters, it is the fastest growing plant in the world. That's right, bamboo has nothing on algae when conditions are right. Algae has been known to double its volume overnight.
Next, it has a significantly higher oil content than any other plant in the world. 50% of the plant is oil, vs. the next best plant, palm trees, which contain 20% oil.
If you combine both of these facts, algae has amazing potential to produce vegetable oils that can be converted into fuel. Take a look at this comparison of gallons of fuel produced per acre per year for each of these plant sources:
- Algae: 5000-20000 gpa/year
- Palm oil: 650 gpa/year
- Coconut: 230 gpa/yeer
- Rapeseed: 102 gpa/year
- Soy: 98.6 gpa/year (Soy is used in 80% of USA biodiesel)
- Peanut: 90 gpa/year
- Sunflower: 82 gpa/year
- Corn: 77 gpa/year
Yeah, that's right. Corn can only produce 77 gallons of fuel from an entire acre every year. Pathetic. That would barely run my car for a month. Algae has the potential to produce 250x that amount.
Another great thing about algae is that you can grow it anywhere. All you need is salt water, light and carbon dioxide. This eliminates the need to commandeer precious farmland to produce our fuel needs, unlike corn and soybeans.
Cool! So, why aren't we making a bunch of fuel already?
Growing algae is a bit tricky. The conditions have to be exactly right for it to grow quickly and to have the right amount of oil.
People started out trying to grow it in big ponds out under the open sky. This hasn't worked very well because the weather continually alters humidity and PH conditions.
Lately, companies have started growing algae in closed conditions, like in big tubes. But, algae needs an enormous surface area on which to grow. The light algae needs for growth only penetrates the water 3-4 inches deep, so the layer of algae harvested is usually relatively thin. Keeping an enormous shallow pool in a controlled environment is a bit tricky.
Many have pointed out that there's plenty of algae already in the oceans that we could start using. In fact, during the winter months, harmful algae blooms emerge that are so thick they strangle other sea life out of the area. In Seattle, some guys have retrofitted a boat that they think will zoom around to these algae blooms and harvest the existing algae out of the water.
Others suggest we just use the ocean to grow algae for us. Proposals range from giant tube-based algae farms floating in the seas around the equator to companies that want to throw huge quantities of iron in the ocean to force algae to spread, then harvest it.
Progress is slowly being made. In fact, the first commercial facility in the US just opened last month. But a few technical problems need to be solved before we can make full use of algae as a resource.
What's the relationship between algae and CO2?
Algae, like all plants, uses CO2 in its photosynthesis process to grow. And remember, it grows fast.
A few carbon offset companies have expressed a desire to capitalize on this fact by using iron to seed the oceans and force algae to bloom. They don't care about harvesting the algae, but would only do it to capture CO2 in the air. They theorize that once the CO2 is captured, it would then sink to the ocean's bottom, and over time we could cleanse our air this way.
Their proposals are extremely controversial. Most worry about the ecosystem impact of such a plan as large amounts of algae are dangerous to sealife. Others doubt that a carbon capture scheme ignoring natural processes will work as designed.
Another more helpful solution to capture CO2 has been proposed by Dr. Berzin at MIT, who suggests a system where each coal-fired plant feeds its CO2 to accompanying algae pools to be sucked up. In fact, these facilities can be installed directly on top of smokestacks.
What else is algae good for?
Lots of stuff:
- Once algae has been pressed for oil, the remaining algae can be fed to livestock for a nutritious, natural meal.
- Algae is a fantastic soil fertilizer
- Algae is the leading source in the hunt to produce hydrogen on the cheap. When algae is deprived of sulfur, it switches from a mode of producing oxygen to producing hydrogen. This could be the answer to cheap, clean hydrogen power!
- Algae are used in wastewater treatment facilities as a natural solution to clean up the water.
