by Bob Shively, Enerdynamics President and Lead Instructor
“Technology is no silver bullet, yet it’s an essential part of the de-carbonization equation.” ~ April Reese, Discovermagazine.com
In recent years, the energy industry has made significant strides in moving toward technology that helps reduce greenhouse gas emissions including developments in wind, solar, biofuels, and electric vehicles. But as Dan Arvizu, Director of the U.S. National Renewable Energy Lab, recently stated at the IEEE Power and Energy Society conference, the technology that got us to the gigawatt scale in clean energy will not get us to the terawatt scale. And this matters in a world that in 2014 consumed more than 20,000 terawatt-hours of electricity.
So what new technologies might help society get to terawatt-hours of clean energy? Much research is being done by highly skilled and intelligent people, and, as Arivizu noted, progress in the lab is absolutely phenomenal. It is impossible to know what might become the technology of the future, but here are some interesting ones to ponder:
Solar arrays in space are not hampered by many of the realities of land-based solar. Space arrays can receive sunlight almost all hours of the year and can take advantage of intense solar rays. It’s estimated that a photovoltaic (PV) cell in space can deliver up to 40 times more energy that the same cell would generate on earth. But how does the energy get back to earth? The energy would be converted to either laser beams or microwaves, sent to a receiving terminal on earth, and then converted back to electricity. Various entrepreneurial companies have attempted to develop a successful space energy business model, and ideas continue to be batted around in the world of venture capital.
The same process that heats the sun might be harnessed as a high-powered source of energy. Fusion reactions occur when nuclei from two fuel atoms fuse under high temperature, resulting in a heavier nucleus. As the atoms fuse, high amounts of energy are released. The technology has been held back by the difficulties of containing the fuel plasma and making the process efficient enough given the large energy input required to start the reaction. But researchers in various countries continue development of viable concepts.
Small modular nuclear reactors (SMR)
Nuclear power is carbon free, but it has been held back in some countries due to safety concerns and the high initial cost of constructing nuclear reactors typically over 1,000 MW in size. Development work is now proceeding in multiple countries to adapt the nuclear fission process to smaller generators that can be manufactured in a factory and shipped to location in modules on the order of 200 MW. These units could be designed for passive safety, meaning the nuclear fission would automatically shut down if safety issues occurred. Smaller units are attractive since they can fit demand needs more precisely and can be more viable for utilities to purchase.
Photoelectrocatalytic (PEC) water splitting
Clean hydrogen fuel has been created for years using water-splitting processes. The problem? Energy input into the process is too high to create a viable industry. But certain metal alloys with semiconductor properties are capable of absorbing sunlight to separate charges that can be used to split water. In the lab, it has been shown that these materials can convert sunlight to hydrogen fuel. Researchers are now working on extending the concept to a workable technology.
These are just a few of many interesting concepts in R&D. Others include advanced biofuels, ocean thermal energy conservation (OTEC), green buildings that generate more power than they consume, and new generation PV materials. Will any of them come to fruition? All could be long shots, but so were many of the technologies we now take for granted.