Harnessing The Power Of Pond Scum

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A new study from Pacific Northwest National Laboratory (PNNL) estimates that the US could support the production of up to 25 billion gallons of algae biofuel annually. That accounts for a whopping one-twelfth of the nation’s current needs and it could prove even more significant if electric vehicles replace liquid-fuel vehicles in greater numbers, which seems likely.

As always, though, there’s a catch. Although the PNNL estimate is based on available land and water resources, the booming natural gas industry is already sucking water from critical areas at an increasing rate. If you’ve ever seen the animated short Bambi Meets Godzilla, you’ll have some idea of what the nascent algae biofuel industry is up against.

new pnnl algae biofuel study
Pond scum by STC4blues.

PNNL Algae Biofuel Study: The Good News

The new PNNL algae biofuel study focused primarily on the potential for growing algae in large-scale, shallow ponds in the open air, with the most promising areas being mainly along the Gulf Coast and the Southeastern Seaboard.

These areas already have a built-in fuel processing infrastructure, along with relatively abundant water resources and a warm, humid climate that mitigates water loss through evaporation.

Water resources in these areas, by the way, also include seawater as well as salty groundwater, which could help solve part of the water scarcity issue. Aside from salt-friendly strains of algae, solar powered desalination technology is beginning to make seawater-to-freshwater conversion a more cost effective option.

As PNNL sees it, the typical large-scale algae farm would consist of large numbers of shallow ponds, ranging in depth from about six to 15 inches.

More Good News For Algae Biofuel

Since PNNL is focused on regions ideally suited for open-pond algae farming, it’s also worth taking a look at broader opportunities.

UC-Davis, which has emerged as a hotbed of algae biofuel research, works from the estimate of a US annual liquid fuel consumption of 140 billion gallons per year to conclude that algae has the potential to fill 100 percent of the nation’s liquid fuel needs.

Based on a rule of thumb yield of about 3,000 gallons of liquid fuel per acre of algae per year, that translates into a need for about 45 million acres dedicated to algae production.

That’s a pretty daunting prospect, though if you factor in the potential to farm algae on brownfields and other unproductive lands, or within existing infrastructure such as wastewater treatment plants, that doesn’t necessarily mean replacing 45 million acres of active farmland with algae ponds.

And Now For The Bad News!

One reason for PNNL’s optimistic outlook is the involvement of ExxonMobil in algae biofuel research leading to commercial development. Just four years ago, ExxonMobil invested a whopping $600 million in a company called Synthetic Genomics Inc.(SGI), about half of which was dedicated to algae biofuel research.

However, while PNNL mentioned the investment in a press release earlier this week, apparently the release was prepared before May 16, when SGI announced that it had entered into a new agreement with ExxonMobil that severs its involvement in the commercial development aspect of the project, leaving SGI to focus on foundational research.

According to these tea leaves, it looks like ExxonMobil is backing off its interest in bringing algae biofuel to market any time soon, especially when you add in the company’s interests in natural gas and its involvement in natural gas-to-gasoline conversion technology.

Also weighing in on the Debbie Downer side is the sustainable business group Ceres, which recently issued a study on the impact of fracking on water resources (for those of you new to the topic, hydrofracturing or fracking is an oil and gas drilling method that involves copious amounts of water).

Of the 25,450 oil and gas wells included in the report, almost half were located in areas with “high and extremely high water stress.”

To be clear, most of the highly stressed areas identified in the report do not overlap with PNNL’s target areas for algae farm development, except for the Gulf Coast area of Texas. However, the report does suggest that if large scale algae farming is going to be national in scope, the ongoing battle between the agriculture and fossil fuel industries for water resources is going to escalate exponentially.

As for national policy, although the Obama Administration has been aggressively pursuing algae biofuel commercialization, for now that pesky “all of the above” energy strategy has included a healthy dose of support for the gas industry, most recently in the form of opening up new natural gas export markets and providing new funding for research leading to the development of commercial gas-to-gasoline conversion technology.

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Tina Casey

Tina specializes in advanced energy technology, military sustainability, emerging materials, biofuels, ESG and related policy and political matters. Views expressed are her own. Follow her on LinkedIn, Threads, or Bluesky.

Tina Casey has 3330 posts and counting. See all posts by Tina Casey