Duke Energy, one of the largest utilities in the US, has requested a statewide electrical rate increase in South Carolina to compensate for the investments it is making in its generation and transmission capacity.

If Duke's request is satisfied, data centers in the state will be among those most affected, as they have some of the highest power densities per square foot.

Duke has asked the South Carolina Public Service Commission, which regulates utilities in the state, to increase the rates by 15%, which would translate into a US$216m increase in revenue from energy sold there.

While not considered a hot data center market, South Carolina does have its fare share of data center users, including a large Google data center campus in Mt. Holly. States like these are usually attractive for data center operators because of low energy rates and relaxed regulations.

If approved, the rate increase will go into effect in February 2012. The increase would not be shared by all users equally.

Residential customers would see their rates go up most: 17% on average. Industrial customers (the category where most data centers would fall) would have to swallow a 13% rate jump.

Duke said it needed the extra cash to pay for a number of projects including shutting down a number of generation units, launching new ones, technology improvements at power plants and new transmission and distribution infrastructure.

Duke's service area includes parts of North and South Carolinas, Florida, Indiana, Kentucky and Ohio.