Explaining The Master+ Model

This video explains all about Master+, our innovative smart grid solution with RWE that helps data centres play their part in the energy transition.

Master+ is our pioneering project developed in partnership with energy trading experts RWE.

It combines a highly-efficient UPS system with expanded battery capacity and sophisticated monitoring, along with risk-free access to energy trading markets thanks to RWE’s expertise.

The smart grid-ready solution aims to encourage intensive energy users such as data centres to play an active role in the energy transition towards a smarter electricity grid.

It delivers operators enhanced system reliability at the same time as cutting their capital and day-to-day costs. In other words, a win-win scenario.

In this video presentation, Riello UPS Technical Services Manager Jason Yates provides background to the concept of Master+, explains the technology behind the system and how it integrates into data centre infrastructure, and shares how it interacts with the electricity grid.

He also reveals several examples where the solution is already in situ and fully operational, including commercial installations in major data centres.

Master+ Video Transcript

Hi, I’m Jason Yates and I’m Technical Services Manager for Riello UPS. Firstly, welcome to this presentation in which we’re going to be discussing the Master+ series of UPS system.

Now the Master+ is basically a UPS system that has been specifically developed in order for data centres to become partners in the energy transition.

As the electrical systems across the world continue to evolve, with greater demands placed on the need for renewable energy, in addition to the implementation of a smart grid technology, the priority is to make the transition to a decentralised, zero carbon system.

Master+ by Riello UPS & RWE – slide explaining how electricity generation is transitioning to zero carbon sources

Obviously, this requires greater flexibility from the demand and generation perspective, whilst at the same time providing frequency regulation to compensate for lower synchronous generation.

Now data centres, being large consumers of electrical energy, can effectively contribute to the energy transition as prosumers.

The Master+ was specifically developed as a UPS-battery solution designed to profit from the energy market without taking on any of the energy market risks, whilst at the same time increasing the reliability thanks to 24/7 monitoring and typically extended backup times.

An Innovative UPS-Battery System

The Master+ system is an innovative UPS-battery solution comprising of four key components. These are: a highly-efficient UPS; cycle-proof premium batteries; an integrated and secure control system; and a route to market.

Now the primary purpose of the UPS system is to provide reliable and secure power to the IT load whilst at the same time generating revenue from the energy markets without compromising the reliability of the IT load.

Characteristics Of The Master+ UPS

The UPS we developed for this specific project had to meet certain criteria. Firstly, the system had to be smart grid-ready, which essentially means the UPS can be installed and operate in a smart grid environment.

The system had to operate in true online mode with a high efficiency of 95.5%.

The output power of the UPS needed to be unity, meaning that the output kVA rating of the UPS matched the kW rating even at low or high operating temperatures.

Master+ by Riello UPS & RWE – slide listing the key features of the Master+ smart grid-ready UPS and battery system

The system had to be comprised of full IGBT and DSP-based technology. It had to provide a high fault and short-circuit capacity. There had to be multiple power options for flexibility and parallel mode for resilience.

It had to be built upon proven and resilient technology. It had to provide full galvanic isolation. And it had to come with a five-year warranty.

Now, the image on the right-hand side is of a pair of 200 kW Master+’s from one of the pilot projects at RWE’s headquarters in Essen, Germany.

Explaining The Battery System

As with all UPS solution, the battery storage is critical. For this particular project, we specifically chose cycle-proof premium lead-acid batteries from a well-established producer.

This, in conjunction with a compact battery arrangement, enabled the system to provide up to 4 times the useable capacity but with only a 20% increase in surface area requirement.

Now, the primary purpose of the battery is obviously to provide sufficient battery capacity for critical equipment support, along with the commercialisation aspect of the project.

So all of these, in conjunction with the real-time battery monitoring for the predictive maintenance, the intelligent battery charge/discharge control, and the five-year warranty ensured that the battery system chosen was suitable for this project.

The image on the left-hand side is one of the battery solutions we installed as part of the pilot project at the RWE headquarters in Essen in Germany.

Splitting The Battery Into Segments

The battery storage system is virtually split into a backup and commercial segment. The backup segment represents, in general, roughly 30% of the total usable capacity.

Now this capacity is configured and controlled by the UPS and therefore it cannot be accessed by RWE at any time. The backup segment is preserved only for the IT load.

During normal operation, the state of charge will oscillate somewhere between the 60 and 70% marker. The reason for this is, depending on the frequency of the electrical system, should the frequency increase, then the system can apply a load onto the grid and therefore attempt to pull the frequency down by storing that energy into the battery system.

However, should the frequency fall then capacity can be taken from the battery system and pushed back into the grid with the primary purpose of being able to stabilise the grid frequency.

Obviously, should a mains supply failure occur, then the data centre will typically have access to the full extended backup autonomy.

Battery Monitoring And Sophisticated System Control

The UPS controller and the battery monitoring system are connected to the RWE control centre via a highly-secure and integrated control network.

This connection enables RWE to control and monitor the system and primarily monetise the solution within the energy markets.

However, the priority of the UPS is obviously to protect the critical infrastructure and the load. Therefore should a grid interruption or a mains failure occur, the system will turn into protection mode and not accept any commands from the outside.

Outlining The Route To Market

If we now take a look at the financial aspects, and the route to market contract, the primary purpose of the system is to enable the data centre owner or operator to participate in the energy markets without taking any of the energy market risks, as these would be absorbed by RWE.

The markets involved are: Frequency Response; and Grid Cost Avoidance.

So exactly how much would it cost?

Well if we look at a typical comparison of eight 400 kVA UPSs, basically 50% of the cost is for hardware and the remaining 50% is for batteries and installation.

Master+ by Riello UPS & RWE – slide showing the route to energy market plus potential cost savings

With the RWE-Riello UPS Master+ concept, the hardware costs would remain the same.

However, the battery is significantly discounted upfront, and would therefore result in a typical cost reduction in the region of 50%. Now obviously, this would provide significant savings.

So for the data centre, effectively they get an upfront discounted battery, extended warranty for the main components, full control and 24/7 remote monitoring, preventive maintenance, extended backup time, and reduced grid charges.

In return, RWE simply gets usage rights for the commercial segment of the batteries.

Frequency Response And Peak Shaving

So how exactly does the system operate?

Well if we look at the frequency response and peak shaving aspect of the system, we know that the power grid typically operates at 50 Hz. However, that frequency is constantly changing.

Now the Master+ helps to stabilise the frequency at 50 Hz. Therefore, if the frequency falls below 50 Hz the Master+ battery is discharged and vice versa.

The extent of the frequency deviation defines the charging and discharging volumes of the system.

Master+ by Riello UPS & RWE – slide showing how solution interacts with frequency response mechanism

Now the benefit of batteries is that they are perfect for providing frequency response as they can deliver power instantly in full capacity in both directions, meaning they can profit from this market.

Depending on the location, grid charges can be reduced via peak shaving.

Now if we look at the image on the left-hand side, we can see that the blue line represents the grid frequency, the red line represents the power requested, and the yellow line represents the power provided. Obviously, this operates in two directions.

So as the blue line increases, demand on the system decreases, therefore we pull power from the grid and push it into the connected batteries.

Should the frequency decrease, we then push energy from the batteries back into the grid to stabilise the frequency.

Effectively the system is continuously taking power from the grid, where necessary, and feeding power back into the grid, when required so that the grid maintains a stable frequency.

Integrating Master+ Into Existing Data Centre Setups

One of the key benefits of the Master+ solution is that it can be integrated into an existing infrastructure.

The Master+ can effectively utilise the redundant power connection capacity in most data centres. The Master+ installation effectively doesn’t differ from any other standard UPS system.

The benefit of this is that RWE invests in a large premium battery with the virtual split, and shared infrastructure reduces the cost for both parties.

As you can see from the image on the right there, that is a typical dual stream data centre where we have two 1 MW UPS systems, with the virtually split battery system and the relevant controls.

The system does not differ too much from a standard UPS and can be integrated into most infrastructures.

Putting The Concept Into Practice

The Master+ solution is not just a concept; this is a live and operational system.

There are two pilot projects running. The first was commissioned in September 2018 at the RWE headquarters in Germany. This comprises of two 200 kVA UPSs.

The second is in Southampton, the RWE Hythe power plant, which was commissioned in December 2019 and comprises a 200 kVA UPS. These can be seen in the images on the right-hand side.

In addition to the pilot projects, there are already fully commercial installations. In the images you can see on the right-hand side, you can see the system, which is installed in a data centre in Germany and was commissioned in December 2019.

Master+ by Riello UPS & RWE – slide offering examples of pilot and fully-operational commercial Master+ installation

Since installation, this system has been helping to save costs by balancing the grid, and hence, benefiting from those markets, in addition to providing higher energy storage capacity and additional resilience in terms of a system that’s fully monitored 24/7.

The system comprises of two 250 kW UPS systems with an additional 1.1 MW of emergency generation. Now this system will continue to be expanded year-on-year up to 2024, at which point they’ll have 8 250 kW UPSs plus additional power generation onsite.

Well I do hope you found this presentation in relation to the Master+ interesting, if you do have any questions please do ask, but in the meantime, thank you very much and goodbye. 

Find out more about the Master+ solution by reading our special case study. It outlines the concept and explains the many benefits on offer to data centre operators