Posted by: Deirdre Des Jardins | April 29, 2019

California’s water resiliency strategy should reduce GHG emissions

On Monday, April 29, Governor Gavin Newsom issued Executive Order N-10-19, “directing the secretaries of the California Natural Resources Agency, California Environmental Protection Agency and the California Department of Food and Agriculture to identify and assess a suite of complementary actions to ensure safe and resilient water supplies, flood protection and healthy waterways for the state’s communities, economy and environment.”   The executive order also states that “climate change is having a profound impact on water and other resources.”

Governor Newsom’s order doesn’t mention reducing greenhouse gas (GHG) emissions from the state’s water sector.   But this is an important part of achieving our state’s goal to reduce greenhouse gas emissions by 100% by 2045.

In particular, California’s State Water Project is the single biggest user of electricity in the state.   It takes enormous amounts of energy to ship water hundreds of miles south and up 2,000 feet over the Tehachapi mountains to the Los Angeles basin. While the State Water Project has eight hydroelectric powerplants, they produce only about two thirds of the electricity needed for the project.   As a result, the State Water Project uses electricity from fossil fuel based power plants to ship water south, including the Lodi Energy Center natural gas fired power plant, shown below.

Lodi

Lodi Energy Center Natural Gas Power Plant

Using fossil fuels to ship water hundreds of miles to water lawns and grow low value field crops is a concept from the 1950s and 1960s. For a 21st century water strategy, greenhouse gas footprints must be considered.

Some detailed recent case studies of GHG footprints are available in “Energy and emissions footprint of water supply for Southern California” by Fang, Newell, and Cousins.  (2015 Environ. Res. Lett.)  The table below shows the authors’ calculations of greenhouse gas footprints for water sources for the Los Angeles Department of Water and Power.   As LADWP switches to cleaner sources of power in 2020 and 2030, using local sources of water, including recycled water, groundwater, and the Los Angeles Aqueduct, results in substantially lower greenhouse gas emissions.

Fang et al LADWP

Urban water conservation provides even greater greenhouse gas emission reductions, because it also results in savings for water treatment, residential water heating, and sewage treatment.   A  California Energy Commission study found that in 2001, 19% of the electricity and 32% of the natural gas use in California was for water conveyance, groundwater pumping and water treatment and wastewater treatment.

By 2030, the Department of Finance has projected there will be 44 million Californians.  To achieve sustainability and resiliency, we can and must reduce our individual water footprints.  We can do so by adapting our urban landscaping to California’s variable, Mediterranean climate, and fully implementing indoor water conservation.


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