At the end of the first song, the centre of the stage went dark, though there was still light in the wings and the auditorium. The cast ad-libbed about not being able to see each other. I thought nothing of it. Years ago, I worked in theatre lighting myself, and I learnt that there are many reasons why part of a stage can lose light: a blown fuse, the mechanical failure of a single light, an operator error. After a minute of gloom, the curtains closed, the house lights came up, and the stage manager emerged to apologise for the power cut, and ask for our patience while the theatre staff sorted it out and restarted the show.
The second time, the whole place went dark. The only illumination was the eerie glow of emergency lighting. Once again, the curtains closed, and the stage manager begged for our patience. After a couple of minutes, the house lights returned, but the hiatus dragged on until the final, apologetic, announcement that, after a total of three power cuts, the show couldn’t go on. Like the cast and crew, front-of-house staff coped perfectly, and as promised our tickets were refunded within hours.
Resorting to a local pub, our party discovered that the theatre over the road had cancelled their show before curtain up — again, because of power cuts. I later discovered that half a dozen West End shows had experienced power cuts that night. One of our group had recently been at Glyndebourne, which also had to cancel a performance because of power outages, prompting some snide commentary about that opera house’s lone wind turbine.
Ironically, the report into March’s power outage that closed Heathrow Airport for a day had been published that very morning. So I became curious: was Glyndebourne’s often-mocked wind turbine unfairly blamed for the power cut that hit the opening night of Saul? Was our power outage a fluke, driven perhaps by the heatwave making unreasonable demands on the grid? Are theatres, with their energy-hungry lighting and special effects, particularly susceptible?
Or is this a wider problem? Is the UK’s electricity supply becoming less reliable? That is a question which, it turns out, is hard to answer. Anecdotally, stories of power cuts lasting from a minute to a week seem to be more and more frequent. Small outages don’t even make the news: hardly anyone reported the show cancellations we experienced. But power suppliers give only generic answers, and theatre managers don’t want to comment at all.
“Anecdotally, stories of power cuts lasting from a minute to a week seem to be more and more frequent. Small outages don’t even make the news.”
We can piece things together, though. First, Glyndebourne. The opera house was not relying on its solitary wind turbine when it fell prey to power outages. Instead, said UK Power Networks, which maintains electricity networks across much of England, the outages were the result of a local fault. The half-dozen West End shows affected by power cuts the same night as ours were all in the same electricity distribution area, and that outage was down to a cable fault — rather than being weather-related. So the heatwave is off the hook.
But do theatres still — as they did back when I wielded a spanner and could tell you the catalogue numbers of my favourite coloured gels — draw so much power from the grid that a poorly designed lighting rig can unbalance the substation?
The answer to that one is more complicated.
Lighting technology has transformed in recent decades. LEDs have replaced most of the incandescent bulbs that would put out enough heat to burn a careless technician’s fingers. Rob Halliday, a stage lighting designer, calculated that the change could reduce the total energy demand for one performance by more than a quarter. The lighting for one musical could be done for less than 90 kilowatt-hours per performance — about the same wattage that Transport for London uses to transport 600 people for one kilometre. So it takes more electricity to get us all home than to entertain us.
Perhaps more importantly for electricity suppliers, the energy demand has evened out, as peak power requirements have fallen to less than half the pre-LED levels. Curtain calls, when all the lights are blazing, are the moment of highest electricity use — but even if all West End shows had their curtain calls simultaneously, the local substations should be able to cope better than twenty years ago.
On the other hand, Halliday pointed out to me, as theatre productions become more spectacular, with more special effects and dynamic staging, other energy-hungry equipment like winches and motors may be eating up the spare power. Then you have to add the ordinary building lighting, heating, bar and ice cream fridges, possibly air conditioning, and stage lighting starts to fade into insignificance.
It nevertheless seems unlikely that theatres, compared to other public buildings, transport systems, and street lighting, are especially demanding of electricity suppliers. The latter are responsible for more than a quarter of local authority energy bills, which explains those authorities’ willingness to follow theatres in replacing older street lights with LEDs.
Which leaves me with my final question: was my party just unlucky, or is the UK experiencing more power outages?
In the West End alone, Halliday tells me, “there have been a number of occasions I know about where there have been genuine power problems”. London is, after all, a tangle of tunnels, wires and pipes snaking around cellars and basements, with no definitive guide to what goes where. This is a tall order for anyone trying to maintain critical energy infrastructure, let alone repair it in a hurry. Many of the buildings are also old, with idiosyncratic wiring, though theatre wiring may be refurbished more regularly than, say, that of the Houses of Parliament.
But on the other hand, it’s always easy to blame power when a problem is a technical one that’s specific to the building. Halliday tells me a story from decades ago: a failing show was closed shortly after opening for extensive rewrites and re-rehearsal, and “the excuse they gave to the public on that occasion was power problems”. A few days later, there were actual power problems in the building. “So we ended up with a generator parked outside, and the electricity board said, ‘Well, I’m sorry, we’re not covering the cost of this, because we read in the press that there were power problems, and you didn’t tell us.’”
UK Power Networks reassured me that “the electricity network is 99.99% reliable” — but that would leave a one-in-10,000 chance of failure at any time. And with millions of customers, that means plenty of room for problems. Halliday, like me, has the impression that UK power infrastructure is struggling to keep up with changing patterns of supply and demand.
Decades of under-investment and planning delays have left the UK power grid out of date and sometimes struggling to cope. Old electricity power plants are shutting down faster than they can be replaced by new ones, leaving us regularly reliant on imported energy. Supply from intermittent renewable sources, requires different distribution infrastructure to keep the electricity flowing steadily when demand also fluctuates. Failure to regulate the frequency and voltage of power supply caused the massive Iberian Peninsula power outage earlier this year, according to a Spanish government report.
May 2025 saw another power outage that hit multiple London Underground lines, on this occasion a National Grid cable fault that caused a fire at a substation. And of course the March substation fire caused Heathrow Airport to close for a day, with enormous impact on airlines and travellers, though no casualties. That catastrophic failure was traced to a known fault that went unrepaired for nearly seven years, compounded by the age of the substation and Heathrow’s assumption that such an event was a low-probability.
Are electricity suppliers complacent about the reliability of their systems? They maintain otherwise. UK Power Networks recently upgraded the Leicester Square substation to increase current reliability and future capacity. They’ve also adopted a “new technology” to reduce power cuts — consisting of steel support trusses for the poles carrying overhead power lines. You may giggle, but the power failure that hit Glyndebourne could perhaps have been prevented by such reinforcement. In general, suppliers are trying to anticipate and prevent unplanned power outages.
Nor are theatres content to relegate power outages to “low-probability events”. They don’t want to lose a single performance, says Halliday, so insurers insist on building redundancy into technical systems: sending the audience home, and refunding tickets, is the last thing they want. For every West End show’s lighting desk, “there’ll be a backup one sitting under the table, live, tracking along, ready to go. And other departments do that as well.”
Some theatres have back-up power supplies. Glyndebourne switched to battery storage when power outage hit Saul’s opening night, but in the absence of wind to turn the turbine, it wasn’t quite sufficient to finish the show. One newly-built London theatre has a generator on the roof, in case of power failure: clearly already enough of a problem in 2022 to merit an entire back up power system.
For Halliday, the question is why more venues don’t couple battery storage with solar panels, as festivals are starting to do. “I’ve become a bit obsessed with solar power,” he says. “It baffles me every time I walk past the National Theatre, for example, which is a big giant expanse of space that’s beautifully lit by the sunshine all day long. Why is that not covered in solar panels?”
So perhaps the unfairly maligned Glyndebourne windmill is not such a terrible idea. If the electricity distribution system fails, venues with their own generation and storage capacity will be able to say, “the show must go on”. Whether the transport system will still get us home afterwards is another question.
