Duke Energy Florida’s First Large-Load Tariff Covers 50 MW Customers and Sets No Rate for Them

Duke Energy Florida filed the first large-load tariff under Senate Bill 484, and the filing sets no rate for the customers it covers. The utility proposed a 20-year minimum contract term, minimum monthly bills and mandatory early-termination fees. Those terms apply to any customer that draws 50 MW or more. Duke asked the Florida Public Service Commission to defer the rate design to a later proceeding. Its current rate settlement runs through the end of 2027. The Commission took up the petition on August 25 and 26, 2026. Briefs are due September 15.

What the law actually requires

SB 484 took effect on July 1, 2026. It created section 366.043 of the Florida Statutes. The law defines a large load customer by size. The test is an anticipated monthly peak load of 50 MW or more. Utilities measure it as the highest average load over a 15-minute interval at a single location, and a customer cannot combine load across separate sites to stay under that line.

Every investor-owned electric utility in Florida must file a compliant tariff by October 1, 2026. The statute tells each utility to reasonably ensure that a large load customer bears its own full cost of service. That cost must not shift to the general body of ratepayers. The law names the categories that count. They are connection, operations and maintenance, incremental transmission, incremental generation, and other infrastructure needed to serve the customer.

The objection

Walt Trierweiler is Florida’s Public Counsel. He told the Commission that the petition does not attempt to comply with the most basic provisions of SB 484. No settlement agreement grants an exclusion or an exemption from a statutory requirement, he argued. Commissioner Mike La Rosa went further. He said the petition appears facially noncompliant with the mandatory statutory requirements.

Bradley Marshall represents Florida Rising for Earthjustice. He warned that the general body of customers will be left holding the bag for billions and billions of dollars. Duke disagrees. Company spokesperson Ana Gibbs said the existing settlement already protects customers. A large load customer could connect now and pay less than the cost to serve it. That gap would fall to shareholders rather than to existing customers, she said.

Why It Matters

Duke went first, so its outcome sets the template. Every other Florida investor-owned utility files by October 1. Each one now watches whether the Commission accepts contract terms in place of a rate. Developers siting data centers in Florida should read the same signal in reverse. The 50 MW threshold and the 20-year commitment are settled. The price is not. Anyone modeling a Florida site should treat the cost of power after 2027 as an open number, and the September 15 briefs are where it gets argued next.

Enforcement Reality

SB 484 sets a filing deadline. It does not set a penalty for filing something thin. Enforcement therefore sits with the Commission. It can accept the tariff, reject it, or order Duke to refile. Duke’s own position narrows the window further. The rate class would wait for the next rate case. That case cannot start until the current settlement expires at the end of 2027. The first binding number would then land roughly 15 months past the statutory deadline.

One detail deserves attention. The shareholder backstop Duke describes is a term of the settlement, not a term of the tariff. It expires when the settlement expires. A 50 MW customer signing a 20-year contract would spend most of that contract under a rate nobody has written yet.

Sources

• Utility Dive, Duke Energy Florida asks to punt on rate for large load customers
• Florida Senate, CS/CS/SB 484 enrolled text
• Florida Senate, SB 484 bill summary
• WFSU News and The Florida Trib, A Florida law to protect consumers from data center costs faces its first test
• WUSF, Florida utility regulators will decide if Duke Energy data center tariff protects residents

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