ORIGINAL REPORTING: Solar boom raises questions about coal in utility power mixes
Co-op solar boom raises questions about coal in utility power mixes; One of the largest power co-ops in the U.S. gets half its power from coal, but a new study finds it could save money by procuring more renewables.
Herman K. Trabish, Sept. 6, 2018 (Utility Dive)
Editor’s note: Since this story ran, more evidence has emerged that the low cost of renewables makes further spending on fossil fuel generation wasteful.
A boom in solar at electric cooperatives is forcing one of the biggest such power providers in the U.S. to answer some hard questions about its power mix. Tri-State Generation and Transmission still gets half its power from coal, even as co-op owned and purchased solar is reaching nine times what it was in 2013. But a new report shows Tri-State, already the biggest supplier of solar among U.S. generation and transmission (G&T) co-ops, can lower customer bills by increasing its procurement of wind and solar, despite its existing coal investments. RMI found the costs of utility-scale solar and wind are so low that acquiring them can save Tri-State customers as much as $600 million through 2030 even if it continues paying for and running the coal plants.
Tri-State does not doubt the importance of adding more solar and other renewables to its power mix. It does, however, question the accuracy and value of RMI's conclusions. But if the think tank is right, the remarkable boom in solar for co-ops, their power providers and other load serving entities may be just getting started. Less than 1% of co-ops had solar arrays bigger than 250 kW in 2014, but by mid-2018 the average co-op solar project is over 1 MW, half of U.S. co-ops have solar offerings, and cumulative co-op installed capacity will be over 1 GW by the end of 2018, according to the National Rural Electric Cooperative Association. Early deployed projects tested equipment and designs at a cost of $4.50 per peak watt DC, but recent projects came in at $1.30 per peak watt DC. The early growth driver was member demand for solar, but most co-ops now see it as cost-effective generation, but some co-ops now understand solar’s value for meeting challenges like peak load costs or resiliency needs… click here for more