The power demands of data centers can be staggering, with larger facilities using as much electricity as tens of thousands of homes. Now, in parts of London, those energy requirements are reportedly stopping developers from building new houses because there’s simply not enough electricity to go around.

According to a report from The Financial Times, which shared letters sent to housing developers by London’s local governing body (the Greater London Authority, or GLA), the issue is affecting new developments in three west London boroughs: Ealing, Hillingdon, and Hounslow. The GLA said west London’s electricity grid was at capacity, and told one developer there may not be “sufficient electrical capacity for a new connection” until 2035.

It seems there are a few factors at play here, including the difficulty of building new infrastructure given the high value of land in London. But a significant one is the electricity demands of data centers located along the M4 corridor. This is a stretch of land adjacent to the M4 motorway that runs west of London and is home to many technology companies, including campuses for Microsoft, Oracle, LG, Huawei, Amazon, and Dell.

The GLA notes in its letter that “data canters use large quantities of electricity, the equivalent of towns or small cities, to power servers and ensure resilience in service.” It’s not clear how many housing projects have been blocked by this bottleneck, but the FT notes that the three London boroughs affected account for around 11 percent of the city’s housing supply.

The electricity demands of data centers are only likely to grow in future, as companies switch more processing and storage operations to cloud operations, and as rising temperatures caused by climate change strain facilities’ cooling systems. Earlier this month, for example, when the UK experienced a record-breaking heatwave, the rise in temperature knocked out several data centers in London operated by Oracle and Google. It also led to energy companies paying record prices to keep the lights on: a worrisome combination.

The UK has been suffering from a chronic under-supply of housing for many years now, with the problem regularly described as one of the country’s greatest challenges.