EPA Proposes Solution for Renewable Energy Storage
Although it is by far the most abundant element in the universe, not all hydrogen is created equal. A recent proposal by the U.S. EPA aims to establish a distinct category: renewable hydrogen, also called low-GHG hydrogen. This initiative tackles one of the biggest challenges in renewable energy—storage.
Some sources of renewable energy aren’t fully reliable. For example, windmills can only generate electricity when the wind is blowing, and photovoltaic power plants aren’t practical at night. A stable electric grid needs a certain amount of dependable base-load power, a role that old coal-fired power plants used to perform, and natural gas-fired power plants fulfill today. But for renewable energy plants, battery storage comes with detrimental limitations and a hefty price tag.
That’s where low-GHG hydrogen comes in. From an environmental perspective, it’s an ideal fuel. It burns clean and doesn’t emit any greenhouse gases. The rub: most of the world’s hydrogen starts out as natural gas, and the process of converting natural gas to hydrogen does release a lot of greenhouse gases, chiefly carbon dioxide. The fix: a traditional method of producing hydrogen—electrolysis. In this process, electricity is passed through ordinary water, releasing hydrogen and oxygen, the elemental components of water. The hydrogen can then be collected, stored, and used for fuel.
Hydrogen production via electrolysis is limited today because it costs more than hydrogen produced from natural gas. However, the EPA proposes a solution to require natural gas fired electric-generating stations to co-fire a minimum amount of hydrogen to reduce carbon dioxide emissions. The catch: this hydrogen must be produced via electrolysis, using electricity from renewable or nuclear sources. The proposed standard aims to limit greenhouse gas emissions to 0.45 kilograms of carbon dioxide equivalent per kilogram of hydrogen produced, achievable only through renewable or nuclear energy technologies.
There are a lot of questions and opinions about this outside-the-box approach, mostly involving the cost, safety, and practicality of refitting turbines and boilers to co-fire hydrogen. If and when these proposed rules will be put into effect has not yet been determined.