DOE Research Looks At Taking Solar Power To The Next Level

By Scott Kriner, Green Metal Consulting

Many of us attend webinars that tease us with an intriguing title.  One that caught my eye recently was hosted by the Department of Energy. The title was “Highly Efficient Solar Thermochemical Reaction Systems”. It sounded like a highly technical topic that someone like Bill Nye the Science Guy would just love to hear.

As the webinar started I knew instantly that this was not like the typical webinars. The summary of the project started with acknowledging that this project had won the 2014 R&D 100 Award. The work was done with Pacific Northwest National Laboratory (PNNL) from the DOE’s Fuel Cell Technologies Office, as well as the DOE’s Solar Energy Technology Office. Others from the project team included Southern California Gas Company, Oregon State University and Infinia Technology Corporation.

We have heard of co-generation where technology can create energy and heat from the same device. According to Wikipedia, co-generation or combined heat and power (CHP), is the use of a heat engine or power station to simultaneously generate electricity and useful heat. The “space age” new technology described in this webinar also combines energy generation with other outputs from one unit. But in a way that Dr. Sheldon Cooper of TV’s Big Bang Theory would drool over. In a nutshell, the new DOE technology utilizes solar energy to generate chemical energy. The benefits include reduced CO emissions, efficient conversion of solar energy to electricity and an accelerated approach to grid parity for concentrated solar power.

The technology uses preheated steam, natural gas or methane introduced into a thermochemical reaction chamber that produces electrical power and transportation fuel and hydrogen. The technology is flexible enough to generate different types of fuel gas. In one configuration, methane and water are introduced into the reactor and the results are methanol and carbon dioxide. The compact rapid heat exchangers allow for rapid mass transfer in the reactor. A parabolic dish concentrates solar energy striking the surface to achieve the 700°C temperatures in the reactor and generates electricity as well.

The prototype reactors and heat exchangers used for this technology were first developed in a DOE project for generating hydrogen, during 1997-2003.

The efficiencies are remarkable. The developmental reactor achieved a world record 70% solar-to-chemical energy efficiency. A 98% methane conversion rate was achieved as well. The electrical power generation is estimated at 6¢/kWh and the transportation fuel cost is estimated at < $2.00 /gallon of gasoline equivalent.

The goal of DOE and PNNL is to commercialize the technology by 2020. Before that happens, more field testing is planned. The testing is expected to increase the efficiencies even more and will demonstrate the ability to tap into the grid for electrical power distribution through continued improvements in the manufacturing process.

It was a challenging webinar to follow along, compared to some that are simple to understand, but the technology being described was fascinating. The advances that have been made by DOE, their national laboratories and industry partnerships are helping to reduce our reliance on conventional fuel sources and will certainly pay off in the future.

Scott Kriner is the president and founder of Green Metal Consulting Inc. He is a LEED Accredited Professional who began his career in the metal construction industry in 1981. His company is a member of the U.S. Green Building Council, the California Association of Building Energy Consultants and the Residential Energy Services Network (RESNET).

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