A Synergistic Approach to the California Drought Situation that Also Provides Clean Energy

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I just learned, via a recent Reuters article, of a new California experiment that will install solar panels over an approximate 2-mile portion of its aqueduct. I got excited because it sems to make perfect sense on several levels.

First, a little background on the California aqueduct: As part of California’s very diverse climate, the northern part of the state gets much more rain than Sothern California, yet most of the population resides in the southern 2/3 of the state (includes San Diego, Los Angeles, and San Francisco). For example, the Northern California mountains usually get 60-125” of annual rainfall/snowfall whereas Los Angeles receives only 12-13” on average (much less during the current multi-year drought). Significant portions of the Southern California desert get only approximately 5” per year. In addition, the mountain soils are shallow and unstable, so most of the rain and snow melt run off, and much of the water ends up in the ocean. In response, the California Aqueduct was constructed as a series of large, open canals that transport water from Northern California to Southern California. The aqueduct is over 400 miles long in total. It was constructed in phases that started in 1968, and I believe the most recent phase was completed in 2012.

Now, just imagine how much water evaporates each year from an over 100-foot wide canal running through the hot, sunny desert for several hundred miles. And then, think about how much less evaporation there would be if most of the exposed water is in the shade. I’m sure no one really needs to quantify it for us to be able visualize with our “mind’s eye” and conclude that it’s “a lot”.

However, reducing water loss to evaporation would not be the only advantage. The land is already state-owned, so no need to purchase real estate nor invoke eminent domain, and no need to tie up real estate that could be used for agriculture and other good purposes. Another positive would be less algae growth, as algae grows the most in direct sunlight. Having less algae to remove would lower the aqueduct maintenance costs in this one area.

Meanwhile, I believe the big question relates to the business case. Although the energy itself is free, there would still be considerable infrastructure NRE and maintenance costs that us consumers would have to pay for via our electric rates. Hence, I believe the main questions going forward are:

How do these costs compare with those of burning fossil fuels (natural gas, oil, coal, etc.)?
How long would it take to recoup the NRE required to purchase and install the solar panels and related infrastructure?
How much upward/downward pressure would it put on retail electric rates?

It appears that the answers to these questions are currently unknown until the 2-mile pilot is completed. Hence, I very much agree with the overall approach of first trying it on a small via a “beta test”.

And, in closing, I don’t care whose idea it is (Democratic/Newsom, Republican/Trump, etc.). A good idea is a good idea, and I believe this is one worth pursuing. Hence, as with many other engineering/scientific matters, we really need to put politics aside and focus on the situation itself as we assess the forthcoming results of this experiment.

Photo CTTO: ASCE | Solar AquaGrid LLC