New White Paper & Tradeoff Tool From Schneider Electric Compares Carbon Footprint of Batteries vs. Flywheels in UPS Systems

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Although flywheel energy storage for static UPS systems is often thought to be a green technology, a lifecycle carbon footprint analysis shows that emissions for flywheel systems can be greater in the long run than for equivalent battery-based systems, according to White Paper 209 from Schneider Electric.

Wendy Torell, Senior Research analyst, Schneider Electric, Data Center Science Center

The majority of UPS systems supporting data-centre loads today comprise a static UPS with a lead-acid battery. However, a growing interest in flywheel energy storage as a replacement for batteries has been driven by a number of benefits including a wide temperature range, a smaller physical footprint and easier maintenance leading to less frequent replacement.

These attributes have led to flywheels being presented as a greener alternative because their greater tolerance to high temperatures reduces the need for cooling, and their longer life expectancy and comparative absence of hazardous materials reduce pollution. By contrast, the discarding of expended VRLA (Valve Regulated Lead Acid) batteries has caused concern about the environmental impact of lead in landfill sites.

A new white paper from Schneider Electric, a global specialist in energy management and leading provider of data centre physical infrastructure solutions, shows that when the environmental footprint of both types of backup system are measured over the course of their operating lives, the carbon emissions from flywheel systems can be greater than for VRLA-backed UPSs. White Paper #209, entitled “Lifecycle Carbon Footprint Analysis of Batteries vs. Flywheels”, shows that the difference in operating energy is a bigger factor in calculating environmental footprint than cooling, replacement life and hazardous raw materials.

Authored by Wendy Torell, a senior research analyst at Schneider Electric, the White Paper is based on an analysis which models the life-cycle carbon footprint of both types of energy storage, based on: materials, manufacturing & packaging, delivery, installation, operational energy, cooling operational energy, maintenance and disposal.

The analysis shows that although the materials used in battery systems have a greater environmental footprint in terms of CO2 emission per MW of power, the difference is relatively insignificant when compared with that of operational energy. The analysis finds that VRLA batteries can produce 80% less carbon emissions from operational energy than flywheels over an operational life of 20 years. This is calculated from the energy lost in keeping the flywheel spinning which, although it varies from vendor to vendor, is typically around 1%. Over the operating life of a flywheel, this becomes significant.

The White Paper also discusses the use of a Carbon Tradeoff tool which allows data-centre management to make adjustments for the particular conditions of their own facilities. The biggest of these can involve: the location of the centre, which will have different carbon footprints based on the method of electricity generation used; loss data for the flywheel and loss data for batteries. Using this tool, data centre operators can make the most appropriate choices for their specific needs.

Available for free download via, White Paper #209 “Lifecycle Carbon Footprint Analysis of Batteries vs. Flywheels”, can be accessed directly by clicking the link. For more details about please visit the company’s website, or call 0870 608 8 608.

For more information, or to use Schneider Electric’s new Carbon Tradeoff tool, please visit


About Schneider Electric

As a global specialist in energy management and automation with operations in more than 100 countries, Schneider Electric offers integrated solutions across multiple market segments, including leadership positions in Non-residential & Residential Buildings, Industries & Machines Manufacturers, Utilities & Infrastructure and Data Centers & Networks. Focused on making energy safe, reliable, efficient, productive and green, the Group's 170,000 employees achieved revenues of 25 billion euros in 2014, through an active commitment to help individuals and organizations make the most of their energy.

Press Contact:
Schneider Electric
Lavina Dsouza

Phone: + 44 7887 560218

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