PNNL researchers turn chemical energy storage into practical solutions for renewables

In Washington state, through decades of fundamental research, scientists at Pacific Northwest National Laboratory (PNNL) have contributed detailed information about how catalysts help convert energy into molecular bonds, storing the energy by making bonds and releasing it by breaking bonds. Now, a team is working to turn chemical energy storage into practical setups that could one day help power neighborhoods, infrastructure, and industry. To do that, the team is studying entire systems, from catalysts to reactors to end products—and everything in between.

The team is developing hydrogen carrier systems that harness chemical reactions to add and remove hydrogen from stable molecules on demand. An entire subfield of chemistry studies the catalysts that perform hydrogen addition and removal. PNNL researchers specialize in designing catalysts that facilitate storing hydrogen in molecules such as formic acid, methylcyclohexane, and butanediol, among others.

A PNNL chemist led work testing the suitability of hydrogen-rich ethanol, combined with an established catalyst, to cycle with ethyl acetate for long term storage. Hydrogen remains bonded to the ethanol until needed, when it can be released for use and the ethanol converted into ethyl acetate. The catalyst can add two molecules of hydrogen to a single ethyl acetate molecule, producing two stable ethanol molecules that store the hydrogens.