SLO wants to use water from Nacimiento pipeline to generate electricity

A San Luis Obispo energy project would use water from the Nacimiento pipeline to generate hydroelectric power.
A San Luis Obispo energy project would use water from the Nacimiento pipeline to generate hydroelectric power.

The California Energy Commission is offering the city of San Luis Obispo a $3 million loan to build a 261-kilowatt solar photovoltaic system as well as a 264-kilowatt hydroelectric generation system — both located at the city water treatment plant on Stenner Creek Road behind Cal Poly.

By generating its own power at the treatment facility, SLO could earn savings of $266,863 annually compared to its current power bill, according to a commission report.

Furthermore the loan could be paid back in just over 11 years, while the facility generates renewable power for many more years after.

The Energy Commission is expected to approve the loan May 15. The project will go to the San Luis Obispo council July 2 for approval, Utilities Director Aaron Floyd said.

The hydroelectric portion of the project taps water from Lake Nacimiento, 45 miles away, that comes to SLO by pipeline.

The city wants to add an inline turbine-generator on the Nacimiento pipeline that delivers an allocation of 5,482 acre-feet of water a year to local taps. That would allow the water — which falls from Cuesta Ridge to the city plant — to generate electricity.

In 2017, the city spent more than $2 million on electricity. For its part, the Utilities Department spends approximately $1.2 million each year for electricity, with one of the largest users being the Water Division.

The Water Division treats and delivers an average of 4.9 million gallons of water each day at an annual electricity cost of $625,000.

The project is part of San Luis Obispo’s goal to become a “net-zero carbon city.”

It will largely meet the goal to cut greenhouse gases at the utility division, according to a 2018 report.

Extra power expected

The staff report says that the reduced energy use created by the proposed efficiencies combined with the energy generated by the identified renewable energy systems will exceed all of the city water utility’s current annual electricity consumption by nearly 775,000 kWh or 24%, meaning that the water utility will be a net exporter of electricity.

The water treatment plant is not to be confused with the city wastewater treatment plant at Highway 101 and Prado Road, itself going through a planned rebuilding to include renewable power.