Hurdle of renewable energy storage overcome by Siemens

Posted on 21 Mar 2013 by Tim Brown

German engineering firm Siemens has devised a new technology which allows the conversion and storage of power generated by renewable energy sources.

The new technology uses electrolysis to convert the extra power produced by wind and solar facilities, which would otherwise go to waste, into hydrogen gas, which can then be compressed and stored for conversion into electricity at a subsequent stage.

This new technology could greatly improve the versatility of renewable energy sources.

In the past, electrolysis facilities have lacked the flexibility or speed to respond to the major energy fluctuations which characterise power generation based on fickle climate phenomena.

According to a report published in Engineering Source, the new technology developed by Siemens’ Industry Sector, however, has overcome the limitations of its predecessors and is capable of responding to fluctuations in energy supply within a span of mere milliseconds.

The key to the speed of the new technology is a proton exchange membrane (PEM) which separates the electrodes on which hydrogen and oxygen form. Electrolysers equipped with the PEM are capable of far swifter reaction due to the stability of the membrane despite disparities in gas pressure.

A prototype storage facility making use of Siemens’ new PEM technology has successfully generated between two and six kilograms of hydrogen per hour, and is rated at 0.3 megawatts at peak capacity. The facility has already commenced operation at the Coal Innovation Centre of the RWE power plant in Nieder­außem, situated 18 kilometres west of Cologne in North Rhine-Westphalia.

Modular systems capable of generating up to 10 megawatts are expected to hit the market within the next several years, while in the long-term Siemens hopes that PEM electrolysis will be capable of handling megawatt loads in excess of 100 megawatts.

The new technology promises to overcome one of the most besetting dilemmas of wind and solarpower: how to best store the energy produced so that it can be used as and when required. Presently, due to the lack of reliability, wind power for instance is only used to top up power sources during peak times and is often generating power that is not added to the grid and goes to waste.

The conversion of surfeit energy into hydrogen gas also has the added bonus of providing a several usage options to power providers. In addition to compression and storage for conversion into electricity at a subsequent date, hydrogen gas can also be employed as a raw material in the chemical industry or as a zero-emissions fuel in combustion engines.