Commonwealth Edison (ComEd), the largest electrical utility in the city of Chicago, has introduced new rules requiring large-load energy users.

The new rules will require large-load users to make financial commitments for future large-scale projects to shield ratepayers from footing the bill for the transmission infrastructure needed to power facilities such as data centers.

First reported by Bloomberg, the utility, which is part of the Exelon Group, will require “firm financial commitments” from developers of projects of at least 50MW. In addition, the customers will have to provide a letter of credit for ten years of transmission service revenues.

So far, the utility has signed agreements with eight of the 11 firms it presented the deal to. The eight customers are currently seeking a combined load of more than 6.5GW of power.

According to the utility’s CEO Gil Quiniones, the agreements will allow ComEd to “better ensure that the customers who impose very large demands on the system are paying their fair share.”

ComEd had previously sought tariff amendments from the Illinois state regulator to require data centers to post larger deposits for data center projects, in an effort to shield ratepayers from speculative applications that have blighted several utilities across the country.

According to a company statement, the new rules “reduce speculative projects, which will also help ensure that ComEd makes the right levels of investment needed to serve new large loads while upholding system reliability.”

ComEd is following AEP Ohio's lead. Last year, the utility reported that it had cut its data center demand in half due to a new data center tariff introduced in July that required data centers to pay for a portion of their energy requests, even if the electricity is not ultimately needed.