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Unlimited oil from sunlight and slime changes the energy game

Unlimited oil from sunlight and slime changes the energy game Anthony Harrington

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It is ironic that, just as we are finally saying goodnight and farewell to Peak Oil theory, scientists are poised to bring unlimited quantities of the finest sweet crude oil to market, courtesy of algae and sunlight. Moreover, the algae route to creating oil is said to generate 95% fewer greenhouse gasses than the conventional route of drilling for oil, so, even if climate change activists would rather that we stopped using oil altogether, "green oil" goes a long way towards meeting most of their objections.

The technology is not new. Research has been going on for at least the last 30 years, but for much of that time, scientists found that they were having to put more energy into the process to grow the algae and extract the oil, than was contained in the oil - not exactly a winning proposition. However, 2013 saw breakthroughs coming thick and fast from a number of university laboratories and from commercial companies focused on developing large scale oil-from-algae production capabilities. One of the most exciting breakthroughs comes from the US Department of Energy's Pacific Northwest National Laboratory (PNNL), where scientists are claiming to have perfected a process that transforms a solution of algae and water, in a rough 20 : 80 ratio, into crude oil in 30 minutes.

Named hydrothermal liquefaction, the process mimics the natural processes, such as the application of intense heat and pressure, that turned vast seas of algae into reservoirs of crude oil over millions of years. The headline for PNNL's statement on the breakthrough reads, Million year natural process takes minutes in a lab, which says it all, really. The process has a slurry of wet algae pumped into the front end of a chemical reactor:

Once the system is up and running (at the required temperature and pressure), out comes crude oil in less than an hour, along with water and a by-product stream of material containing phosphorus that can be recycled to grow more algae. With additional conventional refining the crude algae oil is converted into aviation fuel, gasoline or diesel fuel. And the waste water is processed further, yielding burnable gas and substances like potassium and nitrogen which, along with the cleansed water, can also be recycled to grow more algae."

What is so astonishing about the PNNL process is not only the speed with which the transformation of algae into oil takes place, but the number of efficiency gains that PNNL's approach generates. Project lead Douglas Elliott points out that cost has been the major roadblock keeping algae fuel production out of the mainstream. A huge part of the cost in previous production processes has been the need to dry the algae before processing, which was very energy intensive. The high water content of PNNL's process - between 80% and 90% - completely does away with this area of cost. Furthermore, the PNNL process is a continuous process, with algae being constantly fed in at the front end and oil (and waste water) coming out the other end. Its demonstration scale chemical reactor only processes about 1.5 liters of algae slurry an hour, but there are no technical barriers to scaling it up to produce commercial quantities.

A third major benefit of the PNNL process is that it does not require complex processing of the algae soup using solvents like hexane to extract the oils from the algae slime. A combination of extremely hot water (the system runs at 350 degrees centigrade) and high pressures (3000 PSI) break the algae apart, converting the bulk of the biomass into liquid and gas fuels, PNNL says. As Elliott notes:

It's a bit like using a pressure cooker, only the pressures and temperatures we use are much higher. In a sense, we are duplicating the process in the Earth that converted algae into oil over the course of millions of years. We're just doing it much, much faster."

PNNL is working with long time commercial partner Genifuel Corp, which has worked with Elliott's team since 2008, and which is carrying out a full commercial assessment of the technology. The whole project shows the importance of government funding in enabling radically new solutions to the world's energy problems to make the transition from the laboratory to the real world. PNNL's work on algae fuels is part of the DoE's National Alliance for Advanced Biofuels & Bioproducts, which in turn is funded by funds from the DoE's Office of Energy Efficiency and Renewable Energy.

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Further reading on oil and global warming:

Tags: biofuels , Douglas Elliott , energy , Genifuel Corp , greenhouse gasses , Hydrothermal liquefaction , Office of Energy Efficiency and Renewable Energy , oil , oil from algae , Pacific Northwest National Laboratory , Peak Oil , PNNL , renewable energy , US Department of Energy
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