One sign of urban growth around the world is the proliferation of urban lights. But, what happens if many American cities are at risk for blackouts?

Electricity blackouts will become more common as surging power demand outpaces public and private utilities’ abilities to provide a continuous and reliable flow of power to customers, a new research paper asserts.

The problem, while global in scope, could be especially pronounced in urban areas where old and often fragile power distribution systems are being tested in ways not conceived of a generation ago, states the research paper that examined the causes behind 50 blackout events in 26 countries since 2003, including several major U.S. outages.

“Understanding the nature of blackouts is more than just a record of past failures,” researchers Hugh Byrd and Steve Matthewman write in the Journal of Urban Technology. “[B]lackouts are dress rehearsals for the future in which they will appear with greater frequency and severity, and as urban areas become more compact, with greater consequences.”

Their research paper, titled “Energy and the City: The Technology and Sociology of Power (Failure),” is the latest in a series of studies examining grid failures and warning that the world should “prepare for the prospect of coping without electricity as instances of complete power failure become increasingly common.”…

The paper estimates the economic damage caused by power outages in the United States alone at $25 billion to $180 billion annually, although the indirect costs of such disruptions could be up to five times greater.

It is a little difficult to operate a world-class city when the power is out or if there are consistent threats of blackouts. As this paper suggests, such incidents could be crippling given the amount of critical infrastructure and day-to-day necessities are dependent on electricity.

If this is the case, what are cities doing about it? Not having enough electricity is a fundamental issue that requires large-scale attention. Building power plants, transmission lines, and resilient systems are not sexy but they are critical.