In the U.S., more than a dozen utilities have worked with Energy Efficiency Institute to apply PAYS to building energy upgrades. Utility regulators in New Hampshire, Kansas, Kentucky, Hawaii, and Arkansas have approved opt-in tariffs for those investment programs. See the status of these programs here.
The PAYS model has also been applied to LED lighting and other efficiency upgrades in India by Energy Efficiency Services Limited (EESL), a state-run super-Energy Service Company (ESCO) that has collaborated with utility distribution companies. See EESL PAYS business model, and a recent World Bank press release on IBRD financing for EESL.