ETH- Caltech Solar Reactor: World’s Cheapest Source Of Energy?

Imagine waking up late on Monday morning and having an important meeting in few hours. You gather yourself fast; get ready in a jiffy and whoops! Your car is dry because last night, you went longer than anticipated to relish your favorite cuisine with your friends… Now what would you do? What if you had petrol/ gasoline/H2 pump at your own house? You think I’m a weirdo right? But the scientists at California Institute of Technology (CIT) are working on a device which surely will catch you off the guard.

#-Link-Snipped-#We can call it our residential energy refueling station/pump, but Sossina Haile and William Chueh at CIT gave their creation the name of “Solar Reactor”. Now let’s see what they got up to… it is a common knowledge that water (H2O) and carbon di oxide (CO2) into hydrogen (H2) and carbon monoxide (CO). Hydrogen can be directly used to power the cars and if mixed with carbon monoxide, it makes for an exciting energy resource in the form of liquid fuel. To add more, H2 and CO can be used to make methane. According to Sossina Haile, professor of Science and of Chemical Engineering at CIT in Pasadena, methane thus obtained can be utilized to power the gas fired electricity generator. Now you can catch your meeting if your car runs on H2, electricity or methane! For petrol and diesel lovers, don’t be disheartened as we can expect someone else to come up with a surprise invention. (P.S. My bike runs on petrol, so do let me know!)

Well it was not difficult to get H2 and Co from H2O and CO2, so what exactly have the scientists at CIT done different? To understand that, it should be known that converting H2O and CO2 into H2 and CO on a wider scale with efficient and cheaper methods created some problems. One of them was the requirement of expensive and rare elements such as platinum or iridium which acts as a catalyst and helps in the conversion. Scientists at CIT used Cerium (IV) oxide or Ceria (Ceo2) which is stable at room temperature and hygroscopic. The use of ceria in the self cleaning ovens reduced the cost of production for H2 and CO to a large extent.

The “extraction” of H2 and CO from H2O and CO2 is achieved in two steps. The first step is carried out at high temperatures (about 3,000 deg. F.). In this step, the ceria is heated due to which it release some oxygen from its structure. If the same ceria is cooled back, the oxygen vacancies will try to get filled. The next step is operates at room temperature. Here, H2O and CO2 are brought in contact with the ceria from the previous process. Now the ceria will try to get back its lost oxygen and in the process, snatches it from H2O and CO2 molecules. The resultant product is H2 and CO with oxygen re-enriched ceria.

The scientists have already tried this out in laboratory. The setup consists of two pieces: reactor and solar concentrator. The reactor is a cylindrical container lined with ceria that has input and output lines for the gases. A set of giant curved mirrors that gather sunlight from wide area make up the second piece, the solar concentrator. Haile and Chueh were supported by Aldo Steinfeld, a renewable energy technology professor at the Swiss Federal Institute of Technology, also called ETH Zürich, in Switzerland. Steinfeld also leads the Solar Technology Laboratory at the Paul Scherer Institute in Switzerland.

The question which crops up in your mind is how feasible are these devices and will it replace conventional sources oil, gas or coal? The answer to the latter question is NO. It is still a distinct possibility that such type of technology will be replacing the conventional sources for energy in near future. But the answer to the first question is a big YES.

According to Haile, “The abundance of cerium means that this approach could have a significant impact on our national energy budget,". As cerium is readily available than platinum about 100,000 times, it will surely reduce the cost. In the experiment carried out, the efficiency of the reactor at converting sunlight to usable energy measured just less than one percent, which is as good as other methods. "As a second step, it will be important to develop materials with even better characteristics than ceria," she stressed.

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