5 Steps In Evaluating UPS For Power Protection

By Todd Kiehn

During a new building construction project or a retrofit, there are many factors to consider. While architects will design the structure itself, facility executives often make decisions on everything inside the building. Every brick, light switch, and floor panel must be picked out and accounted for in the budget. However, there is one important decision that might be overlooked in that process: whether or not a backup power solution is needed.

For mission critical applications, where electrical interruption is not an option, uninterruptible power supply (UPS) systems and on-site backup generators are essential, as they prevent downtime caused by power disturbances and outages.

UPS systems serve two specific purposes. They condition incoming utility power and bridge the gap between utility failure and generator startup. Products can vary in a number of ways including energy storage technology, system design, operational efficiency, size, and power density. Because each facility has a distinct set of needs, they require different solutions.

If you believe that your facility could benefit from a UPS, but aren’t sure how to choose the best one for your needs, these five factors may help you make an informed decision.

1. System Performance

The first step in determining which UPS product is best suited for your facility is to perform an extensive analysis of UPS systems’ features, topology and power protection performance. In addition to thoroughly reviewing product spec sheets, be sure to also research the product’s capabilities to handle overloads and steps loads, which are common in manufacturing and industrial applications due to load profiles.

With growing concerns over global warming and pollution, it’s also important to consider the sustainability aspects when selecting a UPS. Traditional battery-based systems have strict cooling requirements and waste electricity. However, newer alternatives, such as UPS solutions with integrated flywheel energy storage technology, operate with higher energy efficiencies and can significantly reduce a facility’s carbon footprint. In fact, some flywheel UPS systems produce nine times less carbon emissions than equivalent battery UPS products. This is especially important to consider if your company is one of the many that have recently instituted internal carbon pricing or other sustainability programs in an effort to reduce environmental impact.

2. Total Cost of Ownership

While system performance is an important factor to consider, many purchasing decisions ultimately come down to one simple question: How much is this going to cost me? When selecting a UPS, it’s important to not only research the initial expenditure, but also future operating expenses. Remember the product with the lowest upfront cost may be much more expensive to maintain over its lifespan. For example, traditional battery UPS systems require frequent maintenance, battery replacements every four to six years and cooling to operate at maximum efficiency, which can all be very costly.

Flywheel UPS systems can offer up to 40% lower total cost of ownership due to higher operating efficiencies, lower maintenance and cooling requirements and no battery replacement expenses. This can equate to millions of dollars in savings depending on the size of the deployment. These products also consume less space and can be installed directly near the mission critical equipment — on a factory floor, for example — due to their wide operating temperature range.

backup power
Flywheel systems store kinetic energy (energy of mass in motion) by constantly spinning a compact rotor in a low-friction environment. A flywheel’s stored kinetic energy is proportional to the mass of its rotor (seen here), the square of its radius, and the square of its rotational speed (RPM). (Photo: Active Power)

3. Runtime

For decades, the industry standard for UPS runtime was minutes, not seconds, but technological advancements have led to faster startup times for on-site generators, with most being able to fully support a load within 15 seconds. Despite this, most facilities still overprovision UPS with minutes of runtime via batteries. This is no longer a logical or necessary expense. With the latest technology, seconds count and minutes don’t matter. Despite flywheel UPS systems’ shorter runtimes, operators can decrease operating and maintenance costs and minimize system footprint while still maintaining reliability and availability by selecting this type of solution.

4. Reliability

Reliability, in engineering terms, is the likelihood that a system or component will function properly under stated conditions for a specified period of time. With UPS equipment, reliability is measured by its likelihood of failure. It’s important to keep in mind that high reliability is not achieved through the selection of one piece of equipment, but through overall electrical system design.

The problem with battery UPS systems is, much like TV remotes and car batteries, you cannot tell if the battery will fail until you need to use it. When the TV remote doesn’t work, it’s an inconvenience, but when a UPS system fails in a mission critical setting, the consequences can be detrimental and extremely costly. A recent study shows bad batteries were responsible for 27 percent of all UPS failures worldwide. Conversely, flywheel UPS systems are easy to test – when the flywheel is spinning, backup power is available to support your load. In fact, flywheel UPS systems have been proven 12 times less likely to fail according to risk assessment firm MTechnology, Inc.(1)

Don’t just take a vendor’s word about their product’s reliability – ask for scientific research, case studies or whitepapers that support their claims. Request customer testimonials from those with similar needs and applications.

5. Maintenance

As their name implies, conventional battery UPS systems store energy in strings of valve-regulated lead acid (VRLA) batteries until needed to support a load. For these systems, it is recommended batteries be maintained quarterly and replaced every four to six years. While these preventative measures ensure the UPS and batteries are functioning properly, they can also be counterproductive – as human error is the cause of many site failures. Conversely, flywheel UPS systems use kinetic energy to provide short term power that require less maintenance and don’t require replacement over their 20-year design life. Flywheel UPS systems don’t degrade over time unlike batteries and provide the same level of service on day one as they do throughout their useful life.

While I have outlined the many advantages of flywheel UPS systems over battery based units, batteries are still the industry standard. This is because facility executives tend to be risk averse, and would prefer to continue doing things the way they’ve always been done. Widespread adoption of cost efficient, sustainable technologies like flywheels has been slow, but will likely increase in the years to come as we continue to operate in a cost and environmentally-conscious environment.backup power

When selecting a UPS, take your time in determining which solution is right for your facility. It’s an expensive purchase, but choosing the wrong one could make the cost exponentially greater.

(1) Active Power Whitepaper 115, “Mitigating Risk of UPS System Failure,”

Kiehn is vice president of marketing and modular solutions for Active Power, a global provider of flywheel energy and power technology for mission critical applications.