Expect PNM's solar ambitions to be scaled back when it submits its renewable energy plan to the New Mexico Public Regulation Commission at the end of June.

In the meantime, according to Nelson, the cost of photovoltaic panels has dropped considerably. That changes the economic equation, in part because you can start small with PV panels and scale up over time, something that is not really feasible with thermal plants.

Nelson said final decisions have not been made. We'll have a clearer picture at the end of the month, when the company submits its renewable energy plans to the PRC.