Seattle weighs a moratorium on new data centres as 369 MW proposals raise concerns

Projects totalling 369 MW - almost a third of the city’s demand - are fuelling concerns about bills, the environment and infrastructure resilience

Seattle data centres: surge in proposals prompts moratorium talks

Seattle’s city administration is considering a moratorium on building additional data centres after a sharp increase in interest from developers. The discussion was triggered by approaches from several firms looking to establish large-scale data-processing facilities within the city.

According to city officials, four companies have contacted the municipal utility Seattle City Light with plans to develop five data centres with a combined peak capacity of 369 megawatts. That figure is roughly equivalent to about one third of the city’s average daily electricity consumption - a level of demand not previously contemplated for development within Seattle.

Mayor Cathy Wilson said she shares residents’ worries about the environmental and economic implications of projects on this scale. She added that the administration is already working with the city council, utility providers and other market participants on possible regulatory steps, including a temporary ban on siting new facilities.

Energy demand, tariffs and pressure on local infrastructure

Seattle currently hosts around 30 data centres, but they are substantially smaller. The proposed new facilities could draw nearly ten times as much electricity as the existing sites, raising questions about strain on infrastructure and the potential for higher tariffs for customers.

A wider US trend driven by artificial intelligence

What is happening in Seattle mirrors a broader pattern across the United States. With artificial intelligence expanding rapidly, major technology companies - including Microsoft and Amazon - are investing hundreds of billions of dollars in data-centre construction. At the same time, limited available power capacity in traditional hub regions is pushing developers to look at cities that operate their own power systems.

Project changes, developers involved, and Seattle City Light’s response

Some of the Seattle proposals are already being adjusted. Local media report that one company has withdrawn, while the remaining three - Prologis, Equinix and Sabey - are continuing to assess sites in the southern part of the city. All of the projects remain at an early stage and have not yet submitted formal applications to connect to the electricity grid.

In response, Seattle City Light is reviewing contract terms for large consumers. The plan is to require data-centre operators to secure their own electricity generation and to pay for infrastructure upgrades, so that these costs are not passed on to city residents.

Companies are expected to decide whether to file official applications within the next two to three months. Before then, Seattle’s authorities intend to determine what limits and rules will apply to such projects going forward.