Datacenters selling power back to the grid? Don’t bet on it, say operators
- Reference: 1744889651
- News link: https://www.theregister.co.uk/2025/04/17/datacenters_feed_energy_back_unrealistic/
- Source link:
So-called "grid-interactive" datacenters use battery energy storage systems (BESS), typically part of uninterruptible power supplies (UPS), to supply electricity back to the grid during peak demand periods.
The goal is to help stabilize power grids that are increasingly reliant on variable renewable energy, like wind and solar, which can cause fluctuations in supply.
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Notably, Microsoft and Digital Realty have conducted trials of this technology at their facilities near Dublin, Ireland.
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In Microsoft's case, it [4]teamed up with power management specialist Eaton to deliver this capability back in 2022, while Digital Realty was [5]implementing its scheme last year. Both were working via [6]Enel X , an energy services provider acting as an aggregator to sell energy from various sources back to Ireland's electricity operator, EirGrid.
Focusing on Dublin was not a coincidence: Ireland has a lot of bit barns for a relatively small country, many of which cluster around the capital, and these [7]accounted for 21 percent of the nation's total metered electricity consumption during 2023.
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At the same time, renewables provide a large amount of the country's energy - over 35 percent of the electricity supply comes from wind farms – and this calls for grid stabilization services from any energy source that can deliver a minimum base load to the network.
The idea behind "grid-interactive" facilities is that they would be able to provide at least some of that energy from their battery backup systems. For a fee, of course – this was very much pitched as a way for operators to make money from underutilized assets in their data centers.
But according to Fabrice Coquio, Digital Realty's SVP and Managing Director for France, feeding energy back to the grid is not easy, as few datacenters are designed with the power infrastructure to be able to accomplish this.
It is important to highlight reliability, and the main function of the UPS and BESS is to protect the mission critical equipment, with the required runtime in case of a power failure
"It requires different equipment and different investments to be done up front," he told The Register .
Moises Levy, former principal analyst for Datacenter Physical Infrastructure at Omdia, highlighted this some time ago: "The concept for smart grid ready UPS is simple, but we need to keep in mind that it has to satisfy stringent technical requirements with bidirectional flow of energy depending on the applications."
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He added, "It is important to highlight reliability, and the main function of the UPS and BESS is to protect the mission critical equipment, with the required runtime in case of a power failure. So, we must maintain a BESS capacity to satisfy datacenter requirements if needed."
Ireland was a unique example that may not easily be transferrable elsewhere, Coquio explained.
"So we had a specific initiative, because there in Ireland and Dublin is a very particular market because of the limited size of the island, limited size of the grid, and the complete lack of capacity because of what was consumed for datacenters, representing some people say close to 30 percent of the total capacity in Ireland," he said.
In France, the amount of energy consumed by bit barns is less than 4 percent, while in Germany it is 6 percent, and the UK is likely in a similar position, Coquio claimed.
IDC Senior Research Director Andrew Buss also expressed skepticism about any wider adoption of grid-interactive schemes.
For many datacenters, building excess power capacity is a high cost burden, so they would not even be considering this
"For many datacenters, building excess power capacity is a high cost burden, so they would not even be considering this," he said.
"It makes far more sense for the power generation companies and the grid to build an optimized battery-based storage and buffer system to bolster grid capacity than to try and get that capacity through a greater number of small and independent entities attached to the grid."
We asked Microsoft if it was persevering with feeding back energy to the grid from its Dublin campus, and what happened to its plans to [10]duplicate the scheme in other regions.
A spokesperson at Microsoft told us: "The GUPS system in Dublin is still in operation." Asked if this model is to be expanded to other datacenters its operates, Microsoft said:
"The feasibility of this model is highly dependent on the right electricity market conditions, meaning that the project cannot be replicated everywhere. We continue to explore other locations where this could make sense."
In addition, it turns out that the electrical grid, straining under current demand, is part of the problem, said Coquio at Digital Realty.
"Even in France, where we've got excess of power production for the coming 15 to 20 years, which is also a unique situation in Europe, everywhere we've got the same problem. It's not the power production, it's the grid distribution, which is a bottleneck, and it's the reason why, in the last five, six years, it became much more expensive and took much longer in terms of waiting for getting the connection to the grid."
It's not the power production, it's the grid distribution, which is a bottleneck
There are two solutions to this, he claimed: Either bring power to your datacenter, or you put your datacenter where the power is.
"That's the reason why the French government has launched a plan further to the AI summit in early February, that [power company] EDF will provide some piece of land they've got close to some nuclear plants or other electrical plants to provide direct capacity," Coquio said.
"The problem is that they [nuclear plants] are not located where we need them. In France, we need them in Paris and Marseille, and instead they are in the countryside, not exactly where we need them. So either you do that, or you try to manage to produce your own electricity, which would mean that we would become an energy company. It's not normally our job, but if we have to do it, we'll do it," he added.
[11]Why wait to build a datacenter when you can just unpack one?
[12]Dot com era crash on the cards for AI datacenter spending? It's a 'risk'
[13]Microsoft walking away from datacenter leases (probably) isn't a sign the AI bubble is bursting
[14]Global datacenter electricity use to double by 2030, say policy wonks. Yup, it's AI
Grid connection difficulties have been noted before. Last year, David Sleath, CEO of Segro – one of the UK's major commercial property developers – said his company would be investing "hundreds of millions [of pounds] and more" in building new bit barns. However, he noted that some existing projects had [15]faced years of delays in getting wired up to power from the grid.
Others are attempting to work around the grid problem entirely. In the UK, a datacenter startup is putting AI servers and infrastructure into modules similar to shipping containers that can be [16]colocated at biogas generator facilities , drawing power directly from them instead of the grid.
And in the US, tech giants like Microsoft, Amazon, and Oracle are increasingly trying to build or repurpose dedicated nuclear facilities for their data centers, although these may take a [17]decade or longer to get up and running . ®
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[4] https://www.theregister.com/2022/07/08/microsoft_grid_interactive_ups_dublin/
[5] https://www.theregister.com/2024/04/23/digital_realty_irish_grid/
[6] https://www.enelx.com/n-a/en/home
[7] https://www.theregister.com/2024/07/25/ireland_datacenter_power_consumption/
[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/cxo&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aAElq57sa6JUvdGChK1U6gAAAEk&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
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[10] https://www.theregister.com/2023/02/24/microsoft_wants_to_export_grid_interactive/
[11] https://www.theregister.com/2025/04/15/prefab_datacenters/
[12] https://www.theregister.com/2025/04/14/datacenter_spending_ai/
[13] https://www.theregister.com/2025/03/26/microsoft_ai_apocalypse/
[14] https://www.theregister.com/2025/04/12/ai_double_datacenter_energy/
[15] https://www.theregister.com/2024/10/29/datacenter_developer_says_power_issues/
[16] https://www.theregister.com/2025/01/30/startup_datacenter_biogas/
[17] https://www.theregister.com/2025/03/31/nuclear_no_panacea_ai/
[18] https://whitepapers.theregister.com/
Re: Virtue
> from emergency batteries meant to keep themselves alive
There is a certain amount of greenwashing PR bullshit here.
Datacentres would never start discharging their batteries to the grid until they have completed the transfer to Diesel or Gas power. So pretending that it is somehow "green" because it is "from batteries", is bollocks really.
There are already DCs (e.g. Microsoft) which overprovision backup generation by a factor of two or more (Diesel and OCGT, each able to supply the full load of the datacentre, plus batteries for the changeover time) and they intend to run both Diesel and OCGT so that they can export power to the grid when it is profitable to do so.
The bottleneck is the grid connection itself, and they are trying to optimise the use of that by running it both ways (instead of simply disconnecting and falling back to backup generation when the grid pays them to do so, they put their generators into overdrive and their substation into full reverse, because the grid i.e. the tax/bill payer, are paying them top dollar)
The main reasons that this is needed profitable, are 1) because NIMBYs object to pylons, so there are transmission constraints, and the UK is considering having 'locational pricing' instead of improving infrastructure, 2) because the distribution networks are decrepit and there is not enough capacity in dense urban areas like West London, and 3) because datacentre builders refuse to build in places like Scotland where they would reduce grid constraints rather than exacerbate them.
Re: Virtue
1) because NIMBYs object to pylons, so there are transmission constraints, and the UK is considering having 'locational pricing' instead of improving infrastructure
Ok I might be talking bollocks here, but wasn't there an assessment that underground cabling would be cheaper and less disruptive long term? Seems like the whole idea of pylons makes no sense, unless you are a manufacturer of pylons.
And with conspiracy tinfoil hat on, pylons serve another role - strong local resistance, so they give ministers opportunity to have someone to blame when project is not delivered.
Re: Virtue
Er, unfortunately no, not really!
Underground cables only make sense for short distances due to the capacitance of the cable (not to mention the expense) see: https://xcancel.com/EngineerLondon/status/1791012963945488815#m
The capacitance (due to the close proximity of the 400kV live conductor to earth) causes excess current in the cable and a phase shift, which also needs expensive equipment (static VAR compensators) to correct.
HVDC is not affected by this (and that is why all long underground cables are HVDC) but HVDC has its own problems - it is not "synchronous" with the AC frequency and makes the grid more vulnerable to "islanding" where one part of the grid ends up out of phase with the other - a headache for transmission operators. It's also very expensive (requiring big, power electronic convertor stations) and tends to be point-to-point only, not in a network.
I'd say that the opposite is true: Pylons are cheap - underground cables only make sense if you are a manufacturer of cables and HV power electronics
But do link to the assessment that you mention
Grid batteries?
I don’t know about them but there is a considerable energy cost / loss associated with using batteries to store energy. How exactly is this good for the environment?
Re: Grid batteries?
Er, it isn't...
Batteries can't be used to plug wind lulls (dunkelflaute) because we simply can't make enough of them - we'd need almost 1TWh to power the UK for a day, and the entire global supply of batteries is 3TWh/year, and we can't scale up production by an order of magnitude or three, because the production of batteries is already causing massive (and unacceptable in my view) environmental loss/damage, and they also have a serious waste/recycling problem.
Grid batteries are only used to make money by arbitrage (like with interconnectors) and to keep the grid frequency stable during sudden changes in supply/demand, while we warm up or cool down some gas plants (the combined cycle part of a CCGT is a steam turbine, and it takes a while to ramp up and down) - batteries can plug that half-hour gap, but they can't cover weather-induced gaps without gas.
The cycle round-trip efficiency of battery storage system is 90-92%, so 8-10% is lost.
They work on a small scale (rooftop solar etc) but at grid scale, it's daft IMO. If we're to have any hope of decarbonisation (and have a chance of survival past the last drop of oil), we need to loosen the regulatory stranglehold on Nuclear. (and stop wasting electrons on bullshit machines)
Datacenters as dispatchable load curtailment may make sense. That would work on a facebook or Google scale. The way it could work is if a grid operator sees that an area is overloaded they request the big data center to shed load by transferring workloads to other regions.
Datacenters could be good for the grid, at least locally. I live in a fairly rural area. Electricity should probably cost me at least 20% more per kWh than it does, based on the distribution infrastructure required to feed power to us. Fortunately for me, we have large mines and paper mills around here. The local power utility is built to serve them. Commercial and residential users are small potatoes, so our costs are relatively cheap. I could see datacenters having a similar effect.
Except that telling a datacentre to reduce its consumption actually means telling it to start its Diesel generators - hardly 'green'.. They aren't going to be shutting down or throttling any of their customers when they could just burn some oil instead.
They are NOT good for the grid (if anything, they are quite [1]destabilising ) and thanks to soon-to-be-introduced locational pricing, high-demand areas will pay more, so you will be paying that 20% sooner or later.
(didn't downvote you though)
[1] https://forums.theregister.com/forum/all/2025/04/10/uk_ai_energy_council_meets/#c_5053224
"It requires different equipment and different investments to be done up front,"
"It requires different equipment and different investments to be done up front,"
A bit like the London Sewage system then.
From Wikipedia, "During the early 19th century the River Thames was an open sewer, with disastrous consequences for public health in London, including cholera epidemics. These were caused by enterotoxin-producing strains of the bacterium Vibrio cholerae. Although the contamination of the water supply was correctly diagnosed by Dr John Snow in 1849 as the method of communication, up to the outbreak of 1866 it was believed that miasma, or bad air, was responsible.
Proposals to modernise the sewerage system had been made in the early 1700s but the costs of such a project deterred progress.
Further proposals followed in 1856, but were again neglected due to the costs.
However, after the Great Stink of 1858, Parliament realised the urgency of the problem and resolved to create a modern sewerage system."
Everything costs more initially than throwing your shit out of the window or burning the planet, doesn't mean it shouldn't be done.
LOL wut?
Datacenters bringing benefit to the community?
Absurd on the face of it.
Virtue
Datacentres, having strained the grid to breaking point, now float the idea of heroically feeding energy back - from emergency batteries meant to keep themselves alive. The scheme? Buy low, sell high - by charging batteries off-peak and dumping the juice back during shortages, like some kind of ESG-approved scalper.
But the whole thing hinges on a tariff system the grid operator can rewrite with a keystroke. One clause change, one regulation tweak, and the grand plan turns into a glorified UPS test. It’s not a solution - it’s virtue signalling so daft, it needs its own backup power.