Microgrid for California wastewater treatment plant


A combined biogas cogen and solar generation powered microgrid is under development for the City of Rialto’s wastewater services.

The project, a first in California, is aimed to improve energy independence and resilience and to improve the vulnerability of the wastewater treatment plant to power outages which could cause a shutdown and spillage into neighbouring waterways.

The microgrid development is being led by water and wastewater services provider Veolia, which operates and maintains the treatment plant, in partnership with Rialto Water Services.

The first stage of the estimated $8 million microgrid, a feasibility study, has been completed and the initiative now moves into the second stage design phased.

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Alongside the biogas and solar generation, storage batteries will be incorporated to provide back-up power.

“As California and the rest of the country contend with a growing number of natural disasters linked to climate change, the resilience offered by a microgrid power source is more important than ever,” said Rialto Mayor Deborah Robertson.

“This project represents a great step forward in the way municipalities like ours can take positive steps toward a more green future.”

With the potential health and environmental consequences of a slowdown in wastewater treatment, microgrids are proving a popular option for treatment plant operators to build resilience into their operations.

The Rialto microgrid is being funded through the 30-year concession agreement for the plant’s operation.

Under the public-private partnership, initial funding enabled the city to invest in necessary capital improvements in the system while setting aside funding for deferred utility system lease payments and strategic reserve funds.

With most of those initial efforts now completed, the microgrid project represents the first of the next-generation projects supporting the city’s commitment to innovation and sustainability.

The microgrid due to be completed in 2024 is expected to save the city an estimated $355,440 per year in energy costs, with an expected return on investment in about eight years.