Data centres are at risk of destabilising the electricity grid, which could cause blackouts. Here’s why.
Is the issue that data centres are using too much electricity?
That’s usually the problem, but in this case it’s because they sometimes use too little. It’s the suddenness of their drop in usage that threatens to unbalance the grid.
When does that happen?
When there are faults on the grid. Faults usually last just milliseconds before being rectified or compensated for by other parts of the grid, so most electricity users never know these have happened.
But data centres are very sensitive to changes and when any fault is detected, no matter how fleeting, most instantly disconnect from the grid and switch to their own backup generators.
How does that affect the grid?
Data centres use 22 per cent of all the electricity in the country and that’s forecast to rise to 30 per cent in the next five years.
So, huge volumes of electricity are continually hurtling in their direction in a few heavily concentrated locations.
If there is suddenly no use for it, it creates an imbalance nationally and an unbalanced or destabilised grid can result in blackouts.
What’s being done about it?
Eirgrid, the national grid operator, says it has managed the risk to date, but as the data-centre sector and its electricity use grows, so does the risk.
Eirgrid has devised a “fault ride-through” code that would require data centres to remain connected to the national grid whatever glitches might arise.
How often do faults happen?
Eirgrid says these are a normal part of any transmission system and can happen with bad weather, damaged overhead lines, a circuit failure or generator malfunction.
On an average day these are rare enough, but over a year not uncommon.
Is this issue specific to Ireland?
No. The European Network of Transmission System Operators for Electricity has advised all national grid operators to step up their safeguards.
Australia is also addressing the same concerns and North American operators are taking steps, too.
How are data centres here responding?
Eirgrid concedes data centres would rather not have to adjust the way they operate as it entails a change of procedures and is technically complex.
The fact Eirgrid says it has engaged extensively with the sector for a number of years and the code still hasn’t been finalised or adopted says something.
However, some data centres have signalled they expect to comply later this year.
What happens next?
The code has gone to the energy regulator, the Commission for Regulation of Utilities (CRU), which is the body that can issue directions to energy users.
Eirgrid has asked the CRU to approve it in a timely manner – in other words, without delay.