The completion this week of a 420.75-kilowatt solar project brings Delta Diablo Sanitation District (DDSD) closer to achieving its goal of energy-neutral operation. The system comprises five fixed canopies over an existing parking lot, which will offset a large portion of retail energy at lower cost for the main Plant Operations Center.

In its first year, the project is expected to produce 683,087 kilowatt-hours (kWh) – the equivalent of annual electricity use in 58 homes – which will offset 471 metric tons of CO2 and take 92 passenger vehicles off the road each year.

Wastewater treatment is one of the most energy-intensive utility processes, as it requires the pumping and moving of domestic waste on a continuous basis to ensure public health. As future energy costs are expected to rise, the introduction of a range of resource recovery options allows DDSD more certainty when forecasting operating costs.

Examples of current resource recovery options include recycled water, engine co-generation for wastewater treatment and solar-energy generation. Meanwhile, the capture of energy from biosolids and grease-to-energy is being explored.

According to Irene O’Sullivan, DDSD associate engineer and project manager for the solar initiative, “Creating a diverse portfolio of alternative-energy-producing options allows DDSD to fully utilize resource recovery methods, which help protect the environment and reduce ratepayer exposure to variable external energy costs.”

The resource-recovery approach by DDSD supports greenhouse gas reduction guidelines set by the State of California, which is moving toward implementation of 33-percent renewable energy by the year 2020. The DDSD solar project was made possible through a funding reservation from the California Solar Initiative Program with an expected amount of $650,000 payable to the district over the next five years.

– Contributed by Angela Lowrey