US: High oil prices along with environmental and economic security concerns have triggered interest in using algae-derived oils as an alternative to fossil fuels. A new study claimed that being smart about where we grow algae can drastically reduce how much water is needed for algal biofuel.
To embody the idea of algal biofuel production, researchers at the Department of Energy’s Pacific Northwest National Laboratory developed a comprehensive national geographic information system database. It evaluated topography, population, land use and other information about the contiguous US. This database contained information spaced every 100 feet throughout the US. It allowed researchers to identify available areas that are better suited for algae growth.
In addition, the researchers gathered 30 years of meteorological information. That helped them determine the amount of sunlight that algae could realistically photosynthesise and how warm the ponds would become. Combined with a mathematical model on how much typical algae could grow under those specific conditions, the weather data allowed researchers to calculate the amount of algae that could realistically be produced hourly at each specific site.
The researchers found that 21 billion gallons of algal oil, equal to the 2022 advanced biofuels goal set out by the Energy Independence and Security Act, can be produced with American-grown algae. That is 17 percent of the petroleum that the US imported in 2008 for transportation fuels, and it could be grown on land roughly the size of South Carolina. They showed that up to 48 percent of the current transportation oil imports could be replaced with algae. However, researchers also found that 350 gallons of water per gallon of oil — or a quarter of what the country currently uses for irrigated agriculture — would be needed to produce that much algal biofuel.
Looking beyond freshwater, the researchers noted algae has several advantages over other biofuel sources. For example, algae can produce more than 80 times more oil than corn per hectare a year. And unlike corn and soybeans, algae aren’t a widespread food source that many people depend on for nutrition. As carbon dioxide-consuming organisms, algae are considered a carbon-neutral energy source.