Renewable revolution: Rethinking the role of a UPS

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Riello UPS general manager Leo Craig explains why our increased reliance on renewable energy offers mission-critical sites the perfect opportunity to rethink the role of their uninterruptible power supplies. It’s time to turn a reactive, underutilised asset into a proactive, carbon-cutting money-maker.

Winds (and rays) of change

It was a record-breaking 2018 for renewable energy in the UK, with sources such as solar and wind contributing a third of our total electricity. Indeed, renewable generation has increased by 95 TWh since 2005. 

While these cleaner and greener power sources continue to grow, old-style coal, nuclear, and thermal power plants are slowly being phased out. Around 23 GW of thermal capacity has closed since 2010, with another 24 GW of coal and nuclear expected to go offline by 2025.

But this renewables revolution poses serious challenges for the electricity network. Compared to coal or nuclear, renewables are far more unpredictable – it goes without saying that you can’t guarantee when the wind will blow or the sun shine. Our increasing dependence on these changeable low-carbon sources means maintaining a secure, stable supply and frequency becomes a tougher task. 

The solution? A decentralised electricity grid with a wide range of power generators connected to the network, feeding in power or adjusting their energy use in real-time. 

These smart grids help harness the untapped power of renewables through mechanisms such as battery storage and demand side response (DSR), which basically involves storing cheaper off-peak electricity and using it instead of expensive mains supply during periods of peak-demand. 

And for mission-critical sites such as data centres, factories, and hospitals – often some of society’s most energy-intensive environments – this opens up the possibility of using their backup power systems for a greater good.

Ditching the doubts about energy storage

Despite its undoubted potential, battery storage is still looked upon with scepticism by such mission-critical settings. Even though if only 5% of our peak demand was met by DSR it’d be the equivalent of a costly new nuclear plant, for data centre operators, network administrators, and facilities managers big doubts still remain. 

When 100% uptime is the priority, the perception remains that using a UPS system and its batteries for anything other than emergency backup power is an unnecessary risk. 

But this simply isn’t true. Rather than undermining system resilience, in reality, battery storage enhances reliability. And it opens up a whole new world of opportunities for IT managers to take advantage of.

An uninterruptible power supply is an essential part of any mission-critical site’s infrastructure, ensuring a clean and consistent flow of electricity and preventing the potentially catastrophic fallout from any mains failure.

More often than not though, a UPS system sits quietly in the background – an indispensable safety net, but it could so easily be described as an expensive, underutilised asset. How often is that backup power ever called upon?

Capitalising on battery storage transforms a UPS from the purely reactive into something truly dynamic. A ‘virtual power plant’ reducing energy bills, improving system resilience, and opening up new revenue streams. As we head into uncertain political and economic times, why would any site manager ignore these benefits?

Working in a smart grid world

While the more common sealed lead-acid (SLA) batteries can be used to store energy, premium lithium-ion (Li-ion) blocks tend to be far more effective. This is because they provide the same power density in less than half the space and weight, they have up to 50 times the cycle life, and they recharge much quicker. 

In theory, this means more than twice the number of Li-ion cells can be installed in the same space, meaning you can retain enough autonomy for emergency backup, but also have the spare capacity for energy storage – the best of both worlds.

Admittedly Li-ion is still significantly more expensive than SLA. But the cost has fallen sharply, by 79% since 2010, and this trend is predicted to continue in the coming years.

And when you consider that Li-ion batteries will last for 10-15 years, during which time an SLA would probably need replacing three times, the total cost of ownership over a ten-year period is 10-40% less, more than balancing out the higher initial investment. 

Reaping the rewards – Firm Frequency Response (FFR)

Bear in mind that large data centres or factories typically require 30 GWh of electricity a year, which translates into a £3 million annual bill. While energy storage isn’t purely the pursuit of this top end of power-hungry users, it’s currently only commercially viable for organisations that use significant amounts of energy. 

Across the UK though, there are thousands of sites with electricity costs in the £500,000-£1 million bracket that are more than suitable – data centres, utilities, hospitals, manufacturing plants, and more.

The National Grid offers such bodies a variety of incentives and mechanisms to encourage participation in DSR. There’s something called Reserve Services, which aims to overcome any unexpected spikes in demand or drops in power generation. Short Term Operating Reserve (STOR) is probably the most common scheme. This gives guaranteed payments over two years for businesses to crank up power generation or reduce demand at 10 minutes notice, three times a week.

Another alternative is Frequency Response, which attempts to ensure a stable grid frequency within one hertz of 50Hz.

Firm Frequency Response (FFR) is only suitable for organisations that can meet the challenge of feeding in or turning down demand by 1 MW within 10 or 30 seconds of a major event, such as a power station tripping out. But their rapid response, fast ramp times, and capacity to continually generate and absorb power make Li-ion UPS batteries ideally-suited to this task. 

Reduced energy costs, enhanced reliability

Signing up to smart grids and energy storage obviously delivers a wide range of benefits, starting with lower electricity bills thanks to not having to call upon the mains supply during expensive peak times. Revenue from incentives such as FFR is welcome too.

But the rewards aren’t simply financial. Think back to earlier… What’s been the single biggest obstacle to participation in DSR? The thought that using UPS batteries for any other purpose apart from as an emergency backup would negatively impact on reliability.

In practice, one of the principal reasons why a UPS might not spring into action when required, is that there’s been a battery failure. Because a comprehensive monitoring system for SLA cells comes at significant cost, many admins choose not to take up this option. And as SLA batteries are difficult to monitor, if they haven’t been used for a while, can you truly know 100% that they’ll be up to the task, if and when required?

Whereas for lithium-ion batteries, advanced monitoring is mandatory – each individual cell is closely examined to maintain balanced states of charge. The ongoing inspection and insight from the monitoring system boosts resilience and reduces the risk of battery failure when your backup is truly needed.

Powering the renewables revolution

Our increased emphasis on solar, wave, wind and other renewable sources can only be fully harnessed by mission-critical sites embracing battery storage. It offers facilities managers the chance to use their UPS systems as something more than just an ultimate insurance policy. Something that generates additional value. 

Battery storage planning applications have soared by an incredible 1,653% in the last three years, with the UK Government’s National Infrastructure Commission predicting more than 15 GWh capacity by 2030. Smart grid-ready UPS are ready to play their part in turning these lofty ambitions into reality.