Solar power delivered low bids to Indiana’s second-largest electric utility in July, now it looks like the utility will be retiring at least 1.35 GW of coal by 2023 plus another 400 MW by 2028. The coal will be replaced by 1 GW of solar and solar+storage, 150 MW of wind, 125 MW of demand side management and buying 50 MW from the MISO marketplace in 2023, with another 500 MW of solar, solar+storage by 2028.

On Wednesday, NIPSCO said it is finalizing a submission to close its remaining coal-burning power plants within 10 years, some more than 15 years early. Specifically, the four units at the Schahfer Generating Station in Wheatfield by 2023, and the Michigan City Generating Station by 2028. NIPSCO says the retirements are not yet final but are “the most viable option for customers” under a plan to be submitted to the Indiana Utility Regulatory Commission by November 1.

The utility said the plan would save customers $4.3 billion versus running those plants through 2035. The utility retired two coal-fired units at its Bailly Generating Station along Lake Michigan earlier this year.

If you want a deeper look and Monte Carlo Engines running power prices in weighted scenarios incorporating daily and hourly volatility is your thing, enjoy the NIPSCO Integrated Resource Plan – 2018 Update.

The original bidding provided far greater volumes than needed. Developers submitted 90 unique bids, totaling just under 15 GW of capacity.

Solar power and solar+storage bids were submitted in two formats – “asset sale or option,” meaning building a project and then selling it to the utility to own (as shown in the top section of the above table), and a power purchase agreement (PPA) (the bottom half of the table). And these prices showed the increasingly small delta in prices between solar and solar + storage projects.

The solar power asset sales, for 1.3 GW-AC worth of projects, were priced at $1.15/watt. The solar+storage project asset sales, 705 MW-AC worth, were bid at $1.18/W.

The solar PPAs, 26 of which that totaled almost 3.6 GW-AC of capacity, were averaged to 3.57¢/kWh. Solar+storage projects, just over 1 GW-AC, included the standard PPA price above and added a $5.90/kW per month capacity payment.

No specifics were noted in the most recent presentations for which projects were chosen or additional pricing information.