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Power management specialist Riello UPS has teamed up with energy trading experts RWE Supply & Trading to offer data centre operators the opportunity to turn their UPS systems into a ‘virtual power plant’ capable of demand side response – providing a lower upfront and operational cost for a more reliable UPS system.

The UK’s energy mix is going through what most experts agree is a necessary transition away from fossil fuel-generated electricity to a low-carbon future powered by renewable sources like wind, tidal, and solar. These cleaner, greener sources already contribute 33% of the nation’s energy, with this trend on a steadily upwards curve.

In fact, the recent Easter weekend saw the UK break its record for the longest continuous period of coal-free electricity generation, with the 90-plus hours smashing the previous best of 76 hours 10 minutes set last April. 

However, this growing reliance on more unpredictable low-carbon energy poses serious challenges to National Grid in terms of balancing supply with demand to ensure a stable, consistent grid frequency. 

Diverse smart grids of interconnected power generators, using battery storage to harness the potential of renewables and on-site generation offer an obvious solution, particularly with the price of large-scale premium lithium-ion batteries plummeting 76% since 2012 and likely to continue to fall in the coming years.

New partnership powering change 

Up to now, mission-critical sites such as data centres have been slow to join the party, with their persistent concerns over availability and uptime still outweighing the supposed benefits of reduced energy bills and improved efficiency. 

A new partnership is dismissing these doubts by arguing operators can tap into the environmental and economic benefits of battery storage without compromising on overall system resilience.

With energy costs accounting for up to 60% of a data centre’s running costs, Leo Craig, general manager of Riello UPS, says that now is the perfect time for operators to rethink the role of their uninterruptible power supplies.

“UPS systems are an essential insurance policy for mission-critical sites in case of any failures with the mains power. But in developed societies such as the UK, such major power outages or network crashes are extremely rare, so how often is that UPS actually called upon? More often than not, it’s an underutilised asset – one that can be pretty expensive too. 

“Recent developments in rectifier technology, along with the increased commercial viability of lithium-ion batteries, mean there’s now an alternative to the status quo – something that enhances the security of supply while at the same time offering significant cost savings.”

Virtual reality

To deliver those dual benefits, Riello UPS has joined forces with energy company RWE, one of the largest electricity producers in Germany. Through its RWE Supply & Trading division, it is also one of the biggest energy traders in Europe. 

Their ‘virtual power plant’ concept is based on an adapted Riello UPS fitted with a special rectifier that enables the bi-directional flow of electricity to and from the grid network. 

This modern, energy efficient UPS system is backed by either premium lead-acid or lithium-ion batteries – the cost of which is partially covered by RWE – equipped with sophisticated monitoring software and communications technologies that enable it to interact with the grid in real-time. The 24/7 mandatory monitoring also helps improve battery reliability through predictive maintenance, and offers greater reassurance that the batteries will work when called upon compared to traditional sealed lead-acid cells, which are much more difficult to monitor. 

The batteries are divided into two sections, the first of which is only used to provide backup power in case of emergency. The second ‘commercial’ element can be used for various demand side response (DSR) mechanisms or to store electricity at cheaper times avoiding peak charges. 

In the event of a power failure, any energy left in the ‘commercial’ part of the battery can be activated to complement the primary backup, providing a boost to overall runtime.

Dario Hernandez, product manager for RWE Supply & Trading GmbH, explains, “For data centre operators, there are two major benefits. Firstly, we will look to subsidise the more expensive premium batteries; this reduces significantly the upfront and operational costs and increases the system reliability compared to installing a conventional UPS system. 

“Secondly, RWE also takes on any associated risk with trading on the energy market. We can help operators reduce standard grid operating costs. Depending on where the project is connected, operators could save up to £6,000 per MW a year. Data centres also have the opportunity to tap into the wide range of financial incentives that National Grid offers to help balance the electricity network.”

One such mechanism is dynamic Firm Frequency Response (FFR), which rewards companies that can quickly – within a matter of seconds – reduce their consumption or feed energy back into the network to ensure a consistent grid frequency within 1% of 50Hz. 

According to National Grid’s latest Power Responsive annual report, FFR provision from DSR providers rocketed from 392 MW in 2017 to 2,720 MW in 2018, a clear demonstration of the market potential for data centres and other facilities with similar on-site energy generation and storage capabilities such as hospitals, utilities, and councils. 

Putting theory into practice

Riello UPS and RWE have been successfully piloting their ‘virtual power plant’ solution since September 2018 at RWE’s global headquarters in Essen, Germany, at a site carrying a secured load of 100 kW. 

The project has already been shortlisted in the ‘Data Centre for Smart City’ category of the 12th annual Datacloud Global Awards 2019, with the winners set to be announced in Monaco on 4 June. A follow-up pilot plant in the UK is scheduled to go online later this year. 

A typical 1 MW load plus batteries installed to offer 10 minutes runtime and 1 MWh of FFR, the cost of installing a modified UPS is roughly a fifth lower than standard UPS systems. 

Because the advanced battery and system monitoring capabilities reduce the need for manual maintenance, annual operating costs can be cut in half too, saving tens of thousands of pounds over the 10 to 15-year lifespan of a UPS system.

Add in grid tariff savings and the option to even generate additional revenues from schemes such as FFR, and it makes a compelling case for data centre operators to ditch their doubts and transform their UPS systems from a reactive insurance policy into something that’s working – and earning – 24 hours a day, 365 days a year. 


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