considerations when purchasing, to ensure the continual
rightsizing of the UPS.
Most UPS systems can operate in an ambient temperature
of 400°C without de-rating, however, VLRA (lead-acid)
batteries used in UPS start to degrade at above 200°C.
For every 100°C above 200°C, the useful working life of
the battery is halved. So, a VRLA battery with a 10-year
design life working at 200°C will last five years at 300°C,
and just over two years at 400°C. In addition to the
battery replacement costs and/or the requirement for air
conditioning, there’s the environmental cost of replacing
many tonnes of batteries that current legislation classifies
as special waste.
An alternative is Li-ion battery technology. Li-ion has
a higher purchase price, but because Li-ion batteries can
operate at higher ambient temperatures without degrading,
the need for air-conditioning is significantly reduced. In
Northern European locations such as the UK, this means UPS
cooling could be provided by the natural air temperature
resulting in significant savings on data centre running costs
and, equally importantly, reducing its carbon footprint.
Li-ion batteries also have a much longer useful working life.
Five-year design life VRLA batteries operated at 200C are
normally replaced every 3-4 years. With Li-ion, this is a more
significant 13-15 years.
When it comes to UPS purchases, there are usually two
budgets: one for the capital expenditure and one for
maintenance. Traditionally, the employee selecting
the cheapest UPS were misguidedly praised for saving
money, but the cheapest UPS are invariably built with the
cheapest components which have much higher repair and
maintenance costs and are therefore actually ‘costing
money’. A top-quality UPS using Li-ion batteries will need
only one capacitor change 15 years, whereas an inferior
solution will typically need three capacitor changes plus
three sets of replacement VLRA batteries in 15 years.
Commercial UPS installations can learn from Industrial
UPS installations where up to 25 years working life is
normal. It’s true that IT technology is changing rapidly,
but the same 230V/50Hz being used 20 years ago will be
the same in 20 years. So, by using UPS that are engineered
to last, commercial organisations can contribute positively
to environmental impact by reducing the need for
maintenance, replacement parts and scrappage.
Correct decision making
The increase in UPS efficiency from 85% in the 1980s
to 97% today is a 12% improvement that reduces the
UPS’ carbon footprint, but purchase decision makers
are often still focused only on the bottom line, missing
the bigger environmental picture. Of course, increased
efficiency and lower total cost of ownership are closely
linked, and the most environmentally friendly systems
enjoy ongoing operating cost savings. However, given a
choice, decision makers still take an ill-informed short-term
view and purchase the lowest cost system thinking they’re
saving money for their company and often contrary to
the company’s environmental and sustainability policies.
While this behaviour is understandable, it’s old school
and needs to change from the top down. Employees need
to be incentivised and educated help the make the right
environmental choices for all our sakes. n