From The Pueblo Chieftain (Matt Hildner):
In Alamosa County, where three plants have secured power purchase agreements with Xcel Energy since 2009, companies have chosen to use photovoltaic technology largely because of its low water requirements. “The water has been one of the main determining factors to go with photovoltaic over some other types of solar plants,” said Craig Cotten, the division engineer in the valley for the Colorado Division of Water Resources…
The water needs for the photovoltaic plants have been met by the San Luis Valley Water Conservancy District, which normally provides augmentation water for business and residential developments. The augmentation water is used to replace the depletions to the system caused by the new uses and ensure senior users are not injured. Mike Gibson, the district’s manager, said supplying the photovoltaic plants was no different than how it supplies its other clients, with the exception that additional agreements were needed with ditch companies to move the water to the plants. Moreover, the district also struck agreements with neighboring landowners to build recharge pits, where the replacement water filters back into the aquifer.
When solar companies began flooding the San Luis Valley with proposals that never made it off the drawing board, a number of them called for utilizing concentrated solar power, also known as solar thermal technology. Those types of plants gather the heat from the sun and use it to heat water to power a turbine. In the cases where those plants deploy a water cooling system, the need for water is large. And in the valley where all the water is already tied up, local water managers were uneasy with the proposals…
California-based SolarReserve had submitted a proposal to Saguache County that had originally called for their plant near Center to use up to 1,200 acre-feet per year. The company told the county in October that it would switch to a dry-cooling system, although it would still require up to 300 acre-feet per year. It has yet to offer details to the county on how it will get that amount of water.