For businesses in the 22 L.A. County cities and unincorporated areas that have joined the Clean Power Alliance, power bills are about to get a little more complicated.

All businesses in the alliance will continue to receive their bills from Southern California Edison, which will charge for the use of its grid to transmit the electricity to the businesses.

But for those businesses enrolled in the alliance’s energy program, the electricity rate charges for the alliance will be substituted in the portion of the Edison bill detailing power generation charges. Edison is passing on this portion of the charges to the alliance.

“This will be like choosing your content on an a-la-carte cable bill,” said Ted Bardacke, the alliance’s executive director.

And that’s not all. Businesses enrolled with the alliance will see an extra charge on their bill called PCIA. That’s intended to compensate Southern California Edison for the loss of power generation customers, according to Colin Cushnie, vice president of energy procurement and management for Southern California Edison. Cushnie said in an email that Edison had locked in power supply contracts years ago that were dependent on all the company’s customers at the time paying their bills to Edison. Without this charge, he said customers in other cities that have not joined the alliance would see their bills increase.

As for the three price tiers available to businesses enrolled with the alliance, when a business chooses to enroll at the 100 percent renewable power price tier, it is not actually receiving 100 percent renewable power, as there is no way to physically separate electrons from different power sources once they are on the grid.

Bardacke explained that the power percentages work on the aggregate level: If more businesses choose to pay the higher rate associated with the 100 percent renewable power tier, then the alliance has more money available to procure long-term renewable power supply contracts. That, in turn, boosts the overall proportion of renewable power in the portfolio.

So far, the Clean Power Alliance has signed only one long-term renewable power deal: the purchase in October of six wind turbines out of a total of 48 turbines on New York-based Terra-Gen’s Voyager Wind project site in the Tehachapi Mountains. Those six turbines can produce up to 71,500 megawatt hours per year of electricity. Financial terms of that deal were not disclosed.