Signaling the early stages of a historic transition, WEC Energy Group, the parent company of We Energies and Wisconsin Public Service, last month announced its first large investment in solar power.

Once the darlings only of the green-energy crowd, solar and wind projects now have become the least expensive way for utilities to add new power generation. As a result, they’re changing how utilities plan to operate in the coming decade.

“The technology keeps getting better and better — and, the most important thing, cheaper,” said Gary Radloff, who retired this year as director of energy policy analysis for the Midwest at the Wisconsin Energy Institute, a research center at the University of Wisconsin-Madison.

Wisconsin Public Service, the subsidiary of WEC Energy Group that operates in northeastern Wisconsin, and Madison Gas and Electric plan to invest a total of $390 million to buy 300 megawatts of generating capacity — enough electricity for more than 70,000 residential customers — in two solar power projects. Read the full story here.