The renewed lease on the Priest Rapids complex has been formally celebrated by Grant County Public Utility District (PUD) of Washington state, US.

Grant County PUD has a new 44-year licence to operate the Priest Rapids complex – the Priest Rapids and Wanapum dams – following development work and agreement to improve fisheries, natural, cultural and recreational resources.

The original licence expired almost three years ago and in April the Federal Energy Regulatory Commission (FERC) issued a new licence. The relicensing process took more than 10 years and cost more than US$50M.

Priest Rapids has a total installed capacity of 855MW from 10 units and an annual output of almost 3900GWh. It was commissioned in 1959 and has produced commercially from 1963.

The Wanapum dam also has 10 units in its plant, which has a total installed capacity of 1038MW. Annual output is just over 4600GWh. It was commissioned in 1963.

Grant PUD is to spend more than US$1B to meet the licensing conditions over the period, including work to replace turbines, upgrade generators and increase electricity output as well as introduce a number of structures to improve fish passage.

Last year, agreement was reached with a new stakeholder, Yakama Nation, for the PUD to market a share of the output until 2015. The native people set up a utility, Yakama Power, for the initiative and it is a power purchaser along with 22 other organisations. The agreement allowed for a step-down share of the output, from 20MW to finally 10MW, and it was estimated that annual revenues could range from US$2M-US$8M.

In return, the PUD has the right to a share of the tribe’s renewable energy credits for the first 75MW of any project developed, and first refusal for involvement in such schemes, such as possibly at Cle Elum dam.