As the country looks to grow its green energy portfolio, there are instances where existing renewable fuels have led to development of new energy sources, improving the efficiency of resource utilization for energy production. Such is the case with the race for transition to cleaner and greener natural gas power plants, which is getting a healthy leg up from what some might say is an unlikely source -- solar energy.
To learn how these two unlikely partners spawned a new energy source, take a look at the Energy Department's Pacific Northwest National Laboratory (PNNL) project that has developed a new system for converting natural gas and light from the sun into an even more energy-rich fuel labeled "syngas," which will allow hybrid solar-gas power plants to produce the same amount of electricity with 20 percent less natural gas while still lowering the plant's greenhouse gas emissions.
Large Magnifying Glass
How does it work? The system involves concentrating solar power, which uses a reflective surface to concentrate the sun's rays, much like a magnifying glass can, but on a larger scale. In the case of the new system from the lab, a mirrored parabolic dish serves as the "magnifying glass" and directs sunbeams to a central point. There, a device absorbs the solar heat to product the energy source, syngas.
The device is 4-feet long and 2-feet wide, a rather sizable magnifying glass. It contains a chemical reactor and a number of heat exchangers. The concentrated sunlight heats up the natural gas flowing through the reactor's channels. Then, a catalyst helps convert the natural gas into syngas. The heat exchangers recycle the leftover heat from the chemical reaction gas, which increases the efficiency of the system. Efficiency is fairly high. The Energy Department says tests on an early prototype of the device showed that more than 60 percent of the sunlight hitting the parabolic dish was successfully converted into chemical energy that can be contained in the syngas.
Bringing It Up to Scale
One of the biggest hurdles for many types of alternative energy is the point when it becomes necessary to bring a technology up to scale. With syngas production, the promising part is that the system is adaptable to the size of a given natural gas power plant with the number of devices needed for the process dependent upon the size of the power plant. And what happens on days when solar energy is a bit more scarce? In case of thick cloud cover, the process can be bypassed to burn natural gas directly.
There's another common challenge in alternative energy development: competing effectively on a cost basis with The Energy Department says the team's goal is to keep the system's overall price tag low enough to ensure that by 2020, these potential hybrid solar-gas power plants can be cost competitive with conventional, fossil fuel-burning power plants. The lab is refining its early prototype to increase its efficiency and cost competitiveness. At the same time, more cost effective manufacturing techniques for mass production are under development and expected to be rolled out in the future.
Because of its use of solar energy, the project is funded by a combined $4.3 million from the Energy Department's Sunshot Initiative along with funding from private partner SolarThermoChemical LLC. Under the agreement, SolarThermoChemical will be allowed to manufacture and sell the system after the project ends.