Renewable Energy storage using Urine?

Storing surplus energy generated by renewables when there is excess supply and low demand is a pressing problem. A problem that is undeniably holding back the widespread use of renewable energy technology.

pee power for the people

Current storage systems include various types of chemical batteries, water and air pressure, flywheels and conversion to hydrogen. Of these systems, hydrogen is sometimes seen as the most promising to provide long term and flexible storage.

The hydrogen for energy storage is generally created from a renewable electricity source electrolysing water to produce hydrogen and oxygen. The hydrogen is stored, to be later either burned in a engine or fed to a fuel cell to produce electricity. The oxygen is generally vented to the atmosphere due to it's limited economic value.

The process of converting the initial electricity source to hydrogen and then back to electricity is low compared with some other technologies, but the gas can be stored for a much longer time than batteries or flywheels, and is more transportable than water or air pressure systems. The use of hydrogen in transport is seen as a possible alternative to fossil fuels.

So what has this got to do with pee? Researchers at Ohio University, recently developed the GreenBox, a device that electrolyses urine to produce hydrogen and nitrogen. The hydrogen can be stored and used to generate electricity and nitrogen is a valuable resource used in fertilizers. This system was primarily created as a way to harvest energy whist cleaning waste water.

Electrolysing urine takes just 30% of the voltage required to electrolyse water. Therefore traditional hydrogen production facilities could benefit from increased efficiency by switching to urine. The nitrogen could be chemically captured and sold, and the clean waste water could be recycled or returned to water courses.

Could this be a new way to produce hydrogen for storage from renewable energy technology whilst also producing a economically valuable by-product and helping to produce clean water?