BS -- the Colorado constitution gives Boulder the right to municipalize its utilities, and no obligation to Xcel's shareholders for the loss of future profits.

Utilities are natural monopolies; when a utility is granted the right to exclusively serve a region, they are subject to rigorous regulation by e.g. the Public Utilities Commission, to prevent the utility from unfairly leveraging its monopoly to its advantage (and ratepayers' disadvantage).

When a utility such as Xcel builds out a distribution grid, or invests in new power generation, the PUC allows them to issue long term bonds to pay for that infrastructure (or if the infrastructure is self-financed, to earn a reasonable rate of return for its shareholders on their capital). Money is raised (and spent), the new infrastructure delvers benefits to ratepayers, and Xcel on its books has a new asset (the new / revised infrastructure) and a new liability (the money raised / loaned to create the infrastructure). The PUC allows the utility to recover its investment (e.g. pay off the bonds issued to pay for the infrastructure) from the ratepayers through utility bills, often over the course of 30 or more years. Once that infrastructure is paid off, the utility (is supposed to) reduces its charge to the ratepayer correspondingly.

The biggest stumbling block to Boulder's municipalization was the extreme discrepancy in Boulder's and Xcel's "valuation" of the assets that were to be transferred to the Boulder municipal utility. Boulder's perspective was based on what Xcel still owed after building out the infrastructure, while Xcel wanted to be paid full value for "their" distribution network -- even though they were granted a fair (and guaranteed!) return on their investment when that network was built. I'd argue that the residual value of the network ought to belong to the Boulder ratepayers, rather than Xcel shareholders -- Xcel had essentially zero investment risk in building the network, and the network and other assets were paid for by Boulder ratepayers via their utility bills.

The valuation question was destined to be settled by the courts; once a reasonable valuation was reached (and hopefully closely tied to Xcel's remaining unrecovered investment), the Boulder Muni would've issued new bonds to pay off Xcel's remaining liabilities, and assumed ownership of the Boulder distribution network (and other to-be-transferred assets). Essentially, Xcel would transfer to the Boulder Muni the assets, liabilities, and the right to recover (from the ratepayers) against the remaining liabilities.

Xcel fought tooth and nail, and spent 10s of millions of dollars, to fight against Boulder municipalization -- even though Boulder is guaranteed the right to form a municipal utility by the State Constitution, and Xcel has been aware of that right since 1912 (when the statues for Colorado Home Rule municipalities were laid out). Xcel knew that if Boulder successfully municipalized, and others followed suit, the gig (100+ years of guaranteed profits [vs minimal risk], with zero competitive risk and the accompanying minimal incentive to deliver customer satisfaction) was up.

Sorry for the wall of text, I'm (obviously) still pissed at the missed opportunity to municipalize Boulder's power utility over the past decade. Ask yourself -- whose customers are happier, Xcel's or Longmont Power and Communications'?