Ahead of DCW on 15th March, Emma Fryer muses on the barriers that prevent data centre operators from using their standby generating capacity to relieve pressure on the electricity grid at times of peak demand.
Sitting between a government keen on regulating every aspect of energy use and an energy intensive sector that is growing rapidly, I sometimes think I am on an excursion into Lewis Carroll’s Alice’s Adventures through the Looking Glass. Paradoxes abound so I will pick one that is a point of conversation at the moment within the industry and also features in our current policy dialogue with government: DSR – Demand Side Response.
DSR (see box) takes advantage of embedded generating capacity to allow National Grid to manage power shortages or surpluses without having to reduce voltage or limit supply. Power stations with additional standby can bring this online, and large electricity users with emergency standby generation can opt to come offline and onto backup to increase available supply (or supply power directly). DSR makes an important contribution to the stability and security of our power supply.
The role that data centres can play in DSR is complicated by several government policies. Data centres depend on a constant supply of electricity so operators usually install emergency standby generators in case of mains power failure (see our technical brief on emergency generation). Although rarely used other than for testing, these generators are classed as combustion plant and therefore attract various forms of regulation (See Box 2, and our roadmap has more information on generator compliance requirements: Cones of Pain.)
Compliance with the various legislative obligations is complex. For instance, retrofitting abatement measures to a single generator costs over £100,000. However, there is scope to streamline some compliance requirements for data centres, and in some cases exempt them from some of the more onerous requirements.
But there is a problem. Concessions and exemptions are currently restricted to plants that are only used for emergency generation. If data centres adopt any form of DSR they are ineligible for streamlining or exemptions, and may find it difficult to obtain an operating permit at all.
Since we need DSR at times when peak demand exceeds available generating capacity, it would be sensible to allow limited generating. DEFRA modelling suggests that impacts on air quality are only marginal if run time is below 50 hours per year and in fact its domestic proposals currently allow for limited DSR provided this threshold is not breached. techUK supports this approach, especially because the high reliability of the UK electricity grid means that it is extremely unlikely that this threshold would be reached.
However, the Environment Agency (EA) is concerned about short term impacts on local air quality and consequent effects on human health. The UK is also close to its national permitted levels of NOx. Generators fired to take facilities off grid for DSR purposes may run for longer periods at times of peak demand (4-7pm) when they will add to other local pollution sources. For data centres in Air Quality Management Areas there are further issues. The EA, who enforces the legislation and issue the relevant permits (and penalties) takes the view that any form of DSR is elective combustion and renders the site ineligible for concessions or exemptions.
In truth, DSR is not universally popular in the sector but some operators do engage in it. Larger sites are already unlikely to be allowed to adopt DSR and from December 2018, (when MCPD comes into force) this restriction will apply across the board. So the embedded capacity associated with data centres cannot be used to alleviate the grid when under stress. Ironically, this job will be done by exactly those newly built generator farms that the new domestic legislation is being drafted to prevent (see Box 2).
That’s just one issue relating to data centres and energy. While I certainly won’t be going into that level of detail in the panel discussion this month this small area is indicative of the complexity involved in balancing air quality and emissions regulation with flexible and reliable electricity supply, and the risks and contradictions that the sector faces in trying to weave a route through this compliance minefield.
Demand Side Response or DSR takes a number of different forms and different services are emerging. More familiar approaches include Short Term Operating Reserver (STOR), Demand Side Balancing Reserver (DSBR), F http://www.datacentreworld.com/irm Frequency Response (FFR) and Turn-Up (which asks operators to use more power at times of oversupply). See http://www2.nationalgrid.com/UK/Services/Balancing-services/Demand-Side-Response/
Legislation applicable to generators may be targeted at reducing carbon emissions (such as EU ETS) or controlling air pollutants like NOx, SOx and particulates, such as IED (Industrial Emissions Directive) transposed as EPR (Environmental Permitting Regulations) in the UK. In addition the sector will shortly suffer the joys of MCPD - the Medium Combustion Plant Directive (currently in transposition) that will introduce minimum emissions standards of for all plant above about 0.3MW. In addition domestic regulation specifically targeted at diesel generators is to be introduced at the same time. This latter piece has been developed purely to address a policy failure from the Contracts for Difference that resulted in large generator farms with obvious air quality impacts.
Emma Fryer is on a panel moderated by Caroline Donnelly, along with Professor Jon Summers and Rolf Brink at DataCentreWorld in the session “When the Great Powers Meet” in the Energy Efficiency & Cost Management Theatre on Weds 15th March at 13.20