The Arizona utility Salt River Project wanted to charge a fee to customers who installed solar power on their rooftops since Dec. 9, a charge that could cost them $50 a month or more. This type of fee could discourage Arizona residents from getting their own solar power systems. It could also be described as damaging to the whole solar power industry there.

SolarCity filed a lawsuit against the utility calling the fee anti-competitive behavior. The solar power company wrote this on its blog: “SRP’s stated reasons for the new plan don’t hold up. What SRP claims now is inconsistent with years of the utility’s own policies regarding the solar industry and its own investments in solar power. Just as importantly, SRP cannot justify the elimination of competition and the denial of Arizonans’ choice in electricity service. We understand that SRP does not like the choices its customers are making. SRP does not want to lose customers, and revenue to solar companies.”

The Salt River Project requested that the SolarCity lawsuit be halted, but a judge denied the request. SolarCity is arguing that the utility has acted in ways that are consistent with the behavior of a monopoly.

SRP, as a publicly owned utility, might sound like it is anti-solar but it just started constructing a 45 MW solar power plant in July. Currently, SRP appears to have about 92 MW of solar power. So, SRP does not seem to be saying, “We can have solar, but you can’t.” It seems to be more like, “We can both have solar, if you agree to pay us an unreasonable fee.”

We Energies, a utility serving Wisconsin and Upper Michigan, tried to implement a similar solar fee for its customers, but was not allowed to do so.

SRP might find itself in the same boat soon. If this does come to pass, SolarCity would have acted as an effective advocate for Arizona homeowners who want to invest in solar power.