By Irina Slav
Oilprice.com recently reported on a renewable natural gas project in progress in Vermont, a rare sort of a project that collects methane from manure and other waste. Now, another similar project has been announced—this time in Colorado. Only this one does not collect methane. It produces it from renewable hydrogen.
The project is dubbed the first scalable biomethanation reactor system and is the product of a partnership between Southern California Gas Co and a German company, Electrochaea. Here’s how they describe what their facility does:
“First, renewable electricity, generated by the sun, passes through an electrolyzer where water molecules are split into hydrogen and oxygen, storing the renewable electricity as hydrogen gas. The newly-created ‘green’ hydrogen is combined with carbon dioxide and piped into the reactor where archaea microorganisms produce renewable natural gas by consuming hydrogen and carbon dioxide and emitting methane.”
This sounds quite a bit more complicated than the methane collection and processing project touted by its operator, Clean Energy Fuels, as a viable alternative to fossil fuels. It is also uncertain if the biomethanation reactor system would prove commercially viable. Essentially, however, the idea is to store the methane in pipelines to use as power generation fuel at some later point. The methanation reactor, then, is a sort of energy storage facility. When needed, the energy—the methane—is pumped “for use in homes, businesses and in transportation.”
According to the partners, who worked with the National Renewable Energy Laboratory, every 10 kWh of power produce 5 to 6 kWh of electricity equivalent in the form of methane. The efficiency rate of the system is 50-60 percent. More importantly, however, it can recycle carbon dioxide from various sources. This includes the anaerobic digesters such as the one Clean Energy Fuels operates in Vermont.
Carbon capture is one way of dealing with the emissions of this greenhouse gas. Reusing it takes the good deed a step further. Yet there is a problem: cost. Energy companies are trying to find a cheaper way of capturing and storing or reusing carbon dioxide, but we have yet to see a major breakthrough in this area. It’s no wonder SoCalGas and Electrochaea will not turn their attention to reducing the capital costs of their energy system.Related: Houthi Drone Attack Sets Saudi Oil Field On Fire
According to Electrochaea’s chief executive, the system could beat battery storage at its game. “With SoCalGas and NREL demonstrating the scalability of this technology we can soon realize safe and reliable storage of renewable energy well beyond the capacity of batteries,” Mich Hein said in the press release on the news.
Indeed, according to its authors, the project had demonstrated the renewable methane can be stored in the existing natural gas pipeline infrastructure “for periods of time ranging from seconds to months.” This implies the use of this infrastructure allows for the storage of methane for months at a time if necessary, but this is not the case across the United States. In the Northeast, for instance, there is a shortage of natural gas pipelines. In other regions, those where fossil gas production is the most intense, chances are the existing pipelines are being used to maximum capacity, leaving no room to store methane.
In other words, the methanation technology may be scalable, but its scalability is not unlimited. It needs solar power installations—though there is no reason why it couldn’t work with wind energy too—and it needs pipelines to store the methane.
What’s more, it’s not a genuine energy storage system. It does not release the energy it stores as electricity when needed. There is no mention about feeding the methane into power plants, although this may be part of the future development of the project.
Recycling carbon dioxide is certainly a positive undertaking. Using renewable energy to produce equally renewable methane is also a good thing. The high capital costs and the complexity of the system may not be so positive, though. The project has 24 months to prove commercially viable.
By Irina Slav for Oilprice.com