The Master+ Model – Rethinking The Role Of A Data Centre UPS
Riello UPS Ltd (in partnership with RWE)
Data Centre Power Innovation of the Year
Entry Description
The Master+ model is a holistic solution developed by uninterruptible power supply manufacturer Riello UPS in partnership with power generation and energy trading company RWE.

It integrates a smart grid-ready UPS system, increased battery storage capacity, 24/7 monitoring, and risk-free access to energy markets.

The innovative solution enables data centres to transform the large energy storage capacity in their often underutilised UPS systems into proactive ‘Virtual Power Plants’ that help balance grid supply with demand and provide operators with new revenue-generating opportunities.

It combines increased reliability with lower capital and running costs for data centre operators, all while helping the grid transition to a cleaner, greener and secure future.

The Challenge – An Evolving Energy Mix

Data centres are notorious for their large-scale energy use. Industry organisation TechUK estimates the sector accounts for 2% of all UK electricity use. The biggest facilities face annual electricity bills of £3 million+ a year.

That’s the equivalent amount of energy needed to power 300,000 homes – the approximate population of Leicester, Belfast or Sunderland.

The sector faces even greater demands with the ongoing rollout of superfast 5G. All that promised low latency processing power comes at a cost – power.

All this comes at a time where the UK’s electricity network is going through a massive transformation. Last year saw more power generated from zero-carbon sources (48.5%) than fossil fuels (43%) for the first time.

With challenging zero-carbon targets to meet, this development is irreversible. But our growing reliance on unpredictable renewable sources such as wind and solar poses challenges for National Grid. How does it balance supply with demand and maintain a stable frequency?

It is increasingly turning to smart grids, energy storage and demand side response (DSR) as the answer. The latter incentivises energy users to store power and shift usage from busy to off-peak times.

This provides data centre operators with the opportunity to rethink the role of their backup power. No matter the size, all data centres deploy uninterruptible power supplies and batteries to protect against system downtime.

But in a developed society such as the UK, how often are there major power cuts? How often is a UPS really needed?

More often than not, a UPS is an essential but ultimately underutilised and expensive asset.

Working in partnership with RWE, we’ve come up with a commercial solution that transforms reactive UPS systems into ‘Virtual Power Plants’ that can play a part in DSR without impacting on resilience.

The Solution – The Master+ Model Explained

Our innovative project focuses on one of our high-efficiency Master+ UPS units fitted with a specially-designed rectifier that enables electricity to flow both to and from the grid.
The smart grid-ready UPS is backed with premium lead-acid or lithium-ion batteries. It’s also equipped with RWE’s dedicated monitoring and communications software. This allows for real-time condition analysis and two-way interaction with the grid.

The UPS’s battery capacity is divided into two distinct roles. The first part’s only function is to provide backup power in case of any disruption to the mains supply – the traditional UPS safety net.

The remaining batteries form a ‘commercial’ section which stores power and feeds it back into the grid via the DSR mechanism Firm Frequency Response.

This scheme helps maintain grid frequency within the safe range of 49.5-50.5 Hz thanks to energy-intensive organisations such as data centres either reducing demand by switching to batteries or feeding power into the network within seconds of a major grid event.

If there’s an onsite power cut, any energy still stored in the ‘commercial’ part of the batteries is automatically released to top up the primary backup and offer operators longer runtime.

The Benefits – Data Centres As Partners For Energy Transition

There are two main advantages of the Master+ model. Firstly, RWE subsidises the more expensive premium batteries, cutting the upfront investment costs. And with huge expertise in the field, RWE also takes on the risk associated with trading on the energy market.

Now some data centres are reluctant to use their UPS batteries for demand side response. Operators are in a high-pressure environment where any downtime for clients can cost thousands or even millions of pounds.

Conventional wisdom suggests that using batteries for anything other than emergency backup adds an unnecessary layer of risk.

But the Master+ model turns such thinking on its head.

Unless you’ve got hugely-expensive battery monitoring and management systems in place, it’s extremely difficult to assess the condition of the sealed lead-acid batteries typically used in data centres. Hand on heart, can you be 100% sure they’ll work when you really need them?

With our Master+ solution, however, sophisticated battery monitoring is mandatory. That means data centre operators know the exact condition of their cells in real-time. Any deterioration is identified immediately, ensuring batteries can be replaced, where necessary, before it’s too late.

So, instead of compromising system resilience, this smart grid-ready solution actually improves reliability.

Such sophisticated battery monitoring also lessens the need for time-consuming manual service visits.

The Results – Enhanced Resilience, Reduced Costs

We’ve been successfully trialling the Master+ solution initially at RWE’s headquarters in Essen, Germany, since September 2018, followed by a UK site operating from early last year.

Projecting the results onto a data centre with a typical 1 MW load and batteries to provide 10 minutes autonomy plus 1 MWh of ‘commercial’ storage, the upfront capital investment is roughly a fifth less than a standard UPS.

Ongoing operating costs are significantly lower too, as the monitoring reduces the need for manual maintenance and service visits.

Throughout the 10-15 year service life of a typical UPS, these cumulative savings would add up to tens of thousands of pounds.

The Master+ model does require slightly more floor space than a standard UPS to house the additional battery capacity. However, the many benefits outweigh this slight inconvenience:

- Highly efficient UPS system plus increased premium battery capacity
- Longer battery life and enhanced reliability because of sophisticated monitoring
- Reduced initial capital costs (CAPEX) thanks to subsidised batteries
- Lower ongoing maintenance and operating costs (OPEX)
- Reduced grid tariffs and other network charges (up to £6,000 per MW per year)
- Additional revenue streams from selling surplus power back to grid through Firm Frequency Response
- RWE takes on any risk of trading on the energy market
Supporting Documents