An electrolyser is a device that uses electricity to split water (H2O) into hydrogen (H2) and oxygen (O2). This process has been known about for more than 200 years. In 1800 the worlds first electrical battery, the voltaic pile, was used by Nicholson & Carlise to decompose water into its constituent parts. These days electrolysers come in many shapes and sizes, from the industrial megawatt scale to the demonstration watt scale. There are also several types of electrolyser, for example Alkaline and Proton Exchange Membrane electrolysers.
The electrolyser which was part of The Hydrogen Office Project (2008-2014) was a 30kW Alkaline model built by Erre Due and installed by Pure Energy Centre. This kind of electrolyser has a potassium hydroxide electrolyte, two electrodes (one positive, one negative) and a diaphram that allows the reacting ions to pass through but not the formed gases. The electrolyser produces hydrogen at around 99.5% purity up to 12 bar of pressure. The hydrogen was then put through a purifier to increase the purity up to 99.995% before it entered the stainless steel storage tank.
This electrolyser has now been replaced with a 25okW PEM, and 60kW PEM and a 60kW Alkaline electrolyser as part of the Levenmouth Community Energy Project.