The benefits of microgrids in building a new generation of sustainable and resilient data centres

There are many reasons why Ireland has become a popular location for data centres in recent years. In the first instance, its geographical location makes it an attractive destination for submarine communications cables—a fact that has been evident since the first ever transatlantic telegraph messages were sent between Newfoundland and Valentia Island, Kerry in 1858. Today’s underwater cables, now comprised of optical fibre, also provide copious direct links between the island and Great Britain, the European continent, and North America.

Added to this is the long-term industrial policy of encouraging high-technology industry clusters around pharmaceuticals, software, web development, and other digital-centric industries, both through inward investment and indigenous growth. This strategy inevitably requires the availability of resilient IT and data centres, and excellent connectivity to the cloud.

However, there is a downside to having so many large data centres in Ireland, namely the electrical power that is needed to keep them running reliably and efficiently.

The industry has also been under great scrutiny from environmental groups who have questioned their energy demand in line with the country’s environmental goals. Set also within the context of households facing higher energy bills due to a global surge in wholesale power and gas prices, there has been a growing backlash against new developments. Following a public consultation earlier this year, for example, EirGrid announced that they will no longer accept applications for new data centres in Dublin for the foreseeable future, and that any new applications for other parts of the country will be assessed on a ‘case-by case basis’.

Providing a solution

I believe that the data centre industry can play a key role in Ireland’s sustainability ambitions, using innovative technology approaches to design, build and operate sustainable digital infrastructure, enable greater resilience of the grid and generate new green, electrical energy.

For example, one such connection measure required by the Commission for Regulation of Utilities (CRU) is that new data centres must have onsite dispatchable power generation capacity equal to, or greater than their demand, to be connected. This means the ability to integrate with the grid, to store energy on site and the use of innovative technologies, such as microgrids, present key opportunities for Irish data centre operators to underpin the country’s sustainability ambitions and build greater resilience into the grid.

Microgrids are onsite networks of distributed energy generators and storage systems that are intelligently coordinated with the utility grid to optimise costs and power stability. In some circumstances they can be temporarily removed from the grid to avoid exposure to outages and disturbances, using stored energy to ensure operational continuity.

Typically, most mission-critical facilities, be they data centres, hospitals, or other critical infrastructure, will have emergency onsite backup generators that come online in the event of a prolonged grid outage. Microgrids, on the other hand, encourage the use of renewable energy sources to supplement power from the grid, both to offset the cost of the utility and provide stores of energy.

These may be called upon in an emergency but may also be used temporarily to implement cost-saving strategies such as peak shaving, which is the practice of using stored energy in place of utility power to keep within agreed usage limits and avoid cost penalties for exceeding tariffs.

Microgrid components

A true microgrid can make use of several energy-generating and storage systems. Many installations use onsite generators to produce heat. As these are based on reciprocating engines, they can also be used to generate electricity, a process known as cogeneration or combined heat and power (CHP). In the case of data centres, given the requirement to cool the IT equipment, an alternative system known as combined cooling heating and power (CCHP), or trigeneration, makes use of waste heat to produce chilled water for the cooling function.

CHP and CCHP systems are a very efficient way to combine energy required for ancillary functions like heating and cooling to produce electricity. However, they usually have a significant carbon footprint because they burn fossil fuels. A second component in a true microgrid would be some form of onsite renewable energy production. The optimal type of renewable used would depend on local conditions and might comprise a wind turbine, solar panels, biomass or hydrogen fuel cells to produce energy to supplement the grid.

Along with electrical generation, a microgrid makes use of stored energy to reduce demand on the grid. Although all critical installations will have uninterruptible power supplies (UPS) to provide immediate cover in the event of an outage, additional batteries can be used to store the excess power generated. This can then be used to supplement the UPS systems or to realise demand-management strategies such as peak shaving.

Microgrid control

Critical to any microgrid is the software that collects, coordinates and analyses its demand and generation requirements. Typically this is a three-layer architecture, the first of which comprises smart sensors based on Internet of Things (IoT) technologies, gathering data on the status of all components of the microgrid. The second layer allows localised, real-time control of the assets via software, which monitors them, makes critical decisions and takes cost-optimised actions to control both power generation and consumption to maximise resilience and efficiency.

The third and final software layer includes applications, analytics and services that enable high-level strategic decision making. This combines technical data obtained from the equipment with external information such as weather predictions, including the assessment of conditions favourable to wind or solar generation, energy market pricing or costs for grid electricity, as well as the fuel needed to drive onsite generators.

Not only does such software enable more efficient and sustainable operation of a single site, but it opens up the possibility of microgrid clusters, where several businesses can collaborate or combine their own microgrids to drive economies of scale and share power sources for even operational efficiency.

This, in turn, makes sophisticated energy-sharing programs possible, including energy as a service in which participating sites can outsource management of a microgrid cluster to third-party operators who will coordinate and arbitrate between the power generation and consumption according to demand.

A digital, electric future

The potential of microgrids to deliver more efficient use of energy, and increased use of renewable resources will be a significant tool in delivering a thriving data centre sector, while minimising the burden on the national grid.

However, the challenge of providing adequate power to all parts of an increasingly digital economy is one that requires a coordinated response from all stakeholders including government, energy suppliers, distributors, and consumers of electricity. At Schneider Electric, we believe that our vision of sustainable data centres, and of Electricity 4.0 can play a key role in helping Ireland decarbonise its digital economy. Through the convergence of digital and electric technologies we can make both data centres, and the energy grids of the future, more efficient, sustainable, and resilient.

Furthermore, through this collaborative approach we can unite key stakeholders across the industry, including governmental bodies such as the CRU, national energy grid operators such as EirGrid, and data centre operators, to deliver a green and net zero future.

Looking forward this approach will be essential to build a sustainable and resilient future, and minimise the environmental impact of data centres.