Google is renowned (and sometimes ridiculed) for its willingness to allow a vast herd of esoteric projects to roam its offices, but inevitably there is a culling. Among several victims announced today: Renewable Energy Cheaper than Coal (RE<C), a project largely focused on advancing a type of concentrating solar power technology known as power tower.
On its blog and in a longer post on its website, Google more or less said it had taken the work, which began in 2007, as far as it could. “We’ve reached a point in our engineering projects where we’re facing new challenges related to our solar receiver design,” the company wrote. “At this point, other institutions seem better positioned than Google to take this work to the next level. Therefore, we’ve retired our engineering work on RE<C and are sharing our key findings.”
Power tower systems work by assembling an array of mirrors (heliostats) around a tower receiver, where water (or some liquid) is heated, ultimately creating steam to drive a turbine. Plants along these lines are operating in Spain, and BrightSource Energy’s Ivanpah plant now under construction in the California desert – with $168 million in backing from Google – will be the world’s largest when it begins operations in a couple of years.
Google acknowledged that a sharp decline in the installed cost for solar photovoltaic (PV) systems, which has made PV “a compelling choice for consumers,” was a factor in its decision. “We’re excited that some technologies are so quickly approach cost competitiveness with traditional forms of energy,” the company wrote.
In addition to passing along its research, the company listed a trio of lessons learned through RE<C: first, that “using lower cost materials and smarter software controls can generate better performance at lower cost” than making strong heliostat structures; two, “that using a ‘Brayton engine’ – a jet engine that uses solar energy to heat air and does not require spray cooling with water – significantly reduces water use and may reduce operating costs as well”; and, lastly, that “focusing on the cost and quality of the system as a whole … rather than attempting to optimize each individual component,” is a better approach to take.