Introduction
I’ve decided to try to make my contribution to DK essays focusing on climate issues, sustainability and renewable energy. I want to write about the effort to transform our world, from blue sky daydreams to projects being built right now, in the hope that doing so informs, inspires and perhaps even offers a little grain of optimism here and there.
This is my first article on this subject. I’ll write a longer introduction at the end of this piece for anyone who is interested…but spoiler alert, that will be the most boring thing in this entire piece.
California - The Current Energy Picture
- CA carbon goals: reduce emissions to 40% below 1990 levels by 2030; 80% below 1990 levels by 2050. Achieve 100% carbon-free electricity and economy-wide carbon neutrality by 2045.
- 2020 renewable energy mix: 33% statewide totals (~90,200 gWh) + 12.2% (33,275 gWh) large hydro.1
- 2020 estimated solar capacity: 27,400 MW (approx. the same generation capacity as the entire state of either Michigan or Georgia)
- Estimated solar capacity in planning and development for deployment through 2025: 19,000 MW
- CA renewables record: On April 24, 2021, for four seconds 95% of all of CA’s electricity needs were being powered by renewables.
1The California Energy Commissions classifies hydro facilities larger than 30 MW as non-renewable sources of electricity, owing to environmental impact, although greenhouse gas emissions would still be minimal. Therefore, I think it’s safe to say we’re at ~45% carbon-friendly energy.
The Canals of California
The landscape of California is criss-crossed by a vast network of canals, which serve to move water throughout the state. Spanning over 4,000 miles (6,350 km), California’s canal network is the largest conveyance system on the planet, providing water – and hydro electricity – to one of the world’s largest economies and the world’s fifth largest supplier of food, cotton fiber and other agricultural commodities.
A recent study published in the journal Nature Sustainability discusses an exciting prospect for the future of California - what if we covered these canals with solar PV panels?
First, let’s elaborate on the concept to help paint a picture of the idea. Most canals are approx. 30 feet wide (although it varies), with concrete embankments on either side. The researchers looked at placing solar PV directly over the canals, typically stretching the entire distance from one side to the other, shading most of the waterway. There are currently two techniques for doing so, steel truss and suspension cable. I considered detailing these, but at this stage the distinction is pretty irrelevant – either way you get a canal with solar PV directly over it. All in all, we’re talking about covering concrete ditches with roofs that look a bit like solar carports.
The study examined eight sites in California that represent the geographic/climate diversity, and to run simulations on hypothetical PV installations. The team attempted to quantify the power generation potential, effects on evaporation, effects on water cost, etc. To be clear, this study is not feasibility or impact research. The team didn’t delve into the exact costs of such an endeavor, and weren’t looking at any specific plan or proposal. Rather, this should be thought of as a “first look” at this idea, where the researchers attempt to ascertain if this is worth pursuing (it is).
As it turns out, there are some tremendous synergistic effects of putting solar PV over the canals, as opposed to standard practices with either waterways or PV installations, the waterways being left open and the PV usually being built on flat, open land.
The list of benefits is long…and complex. For the purpose of this piece, I felt the best strategy was to break them out independently and explain them. The importance and impact of each varies. I’ll also discuss some of the potential drawbacks, because in the real world those are always at play.
Benefit: A massive amount of clean solar power.
Category: Renewable energy
The researchers determined that such a system could provide 13,000 MW of generation capacity. To put this in perspective, California currently has 27,400 MW total solar capacity, which includes residential panels. This generates ~20% of the state’s power. So there’s a lot of potential here - 13,000 MW is about half the solar we need to reach our next carbon cap milestone in 2030.
We should note that this is a broad estimate – the potential for even greater solar electricity generation is possible. The study examines PV only over the width of the canals. It’s likely that in many areas, especially close to towns or urban areas, wider PV arrays might be deployed as part of the same installation – rather than extending 30-40 feet, the widths might be expanded with conventional land-based PV.
Benefit: Photovoltaic panels over water will work better than land PVs.
Category: Conservation and efficiency
As solar PV panels pass a certain temperature, their efficiency drops and they produce less electricity. By placing them over waterways, a cooler microclimate is created directly underneath.
This is a key benefit to the concept – cheaper energy is better. Canal PVs also reduce the cost of water (discussed in a moment.) The economic impact of all of the benefits working together is part of what makes this such an exciting idea.
Benefit: Can help mitigate “too much” solar electricity issues.
Category: Renewable energy
A challenge with renewables is that we typically have to oversupply capacity to account for production fluctuations. In California, we’re moving into the next phase of challenges in this regard - at times we're producing too much electricity. This can wreck the grid and cause catastrophe if we don’t plan for it, the power has to go somewhere.
Right now, we’re able to sell off excess solar power to other states. However, as our neighbors ramp up their own renewable energy facilities, this won’t last forever. (Also, Arizona charges us to take our excess power. Side note: screw you, Arizona. Lol).
So how can putting in even more solar PV help? It can help because an estimated 12% of all of California’s annual electricity usage involves moving, storing and heating water. The powered systems that move our water are currently designed to expend a little energy all day long moving it. That was ideal on the old grid, it spread the tremendous energy needs around the clock.
A canal-based PV system would be theoretically located close to the water we’re moving around. An intelligent grid would start to foresee supply and demand spikes and turn these systems on during peak production hours, putting excess electricity to better use.
The potential here extends beyond getting water where it needs to go, this sort of system could also use excess solar electricity for hydro-storage, which is a fancy way of saying we use the extra power to pump water back up and over hydro dams, where it can be then be used to generate electricity at night. There are many hydro storage solutions in development here in California, and I will look at that topic for a future article - truly exciting stuff going on in this field!
Benefit: Turn off the damn diesel!!
Category: Decarbonization and pollution
Throughout California’s farmland, water is frequently moved using power supplied by massive diesel engines. These pollute the air and land with CO2 and other crap. The canals criss-cross these same farmlands, so putting solar PV over them has a proximity benefit. We can use that electricity to move the ag water and retire some of the dirtiest power left in California.
The research doesn’t measure this benefit in detail, but the team did suggest that every MW of solar PV capacity in this system could retire 15-20 of these diesel engines…and remember, we’re talking 13,000 MW of electricity.
Benefit: Land use and conservation
Category: Conservation and efficiency
As we construct renewable energy facilities, where we put them will become increasingly important, and increasingly challenging.
The Department of Energy has a 2010 road map to 80% renewable energy. A couple of years ago, on a lark (like you do), I wondered what sort of footprint we were talking for the projected industrial scale PV. So I took the PV capacity outlined in the road map, and wanted to estimate how much land that would require. I didn’t want to use watt per ft2 of panel, because that just tells us the footprint of the panels, not the facilities. So my methodology was to take ten large PV plants, average out their land requirements and power produced, then expand that to the total in the road map.
It turns out we just need to build one small PV facility roughly the size of…uh…the entire state of Georgia. Ha.
Clearly, our move to renewables will require us to look for dual-use spaces as a better option than paving over farmland or forests. (This is another area where California has a lot of exciting research underway, which will certainly come up in future articles.)
In regard to canal PVs, the awesome news is that we aren’t consuming much new land for this, just converting land already used for waterways. Another very helpful consideration is that generally we won’t have to go through the laborious challenge of acquiring new land…in most cases that state already has control to one degree or another.
Benefit: Evaporation mitigation
Category: Conservation and efficiency
Now that we’ve detailed many of the benefits of the electricity itself, let’s discuss the potential effects on California’s precious water supply.
The canals are currently left open for various reasons, so over the 4,000 miles of waterways we lose quite a bit to evaporation. This wastes water, and increases the cost of what’s delivered. The shade provided by the canals mitigates this…hugely.
The study acknowledges that calculating the effects of solar PV shading on evaporation is a herculean task – the savings depends on where the panels are installed, and the weather in any given season/year. However, their simulation was designed to try, and came up with a staggering result - a canal PV system could reduce evaporation by 45-80%, and save over 63 billion gallons of water per year.
Let’s put that into perspective. How much water is that, really? That’s a savings roughly equivalent to 1/6th the entire volume of Lake Ontario. It’s also about 0.5% of California’s total annual water consumption. A half a percent doesn’t sound like a lot, but in the world of conservation if one solution saves that much it needs to be examined seriously.
Of note, the study found that the monetary value of the water saved is so high that it offsets the cost of the solar PVs by 20-50%.
Benefit: Farmer (conservative) buy-in
Category: Eff off, GOP
California Democrats have enough political power to pursue such a proposal on their own, but California Republicans have enough political power to be obnoxious. If a canal project moved forward, I envision Larry Elder running up and down a Central Valley aqueduct in his Speedo screaming about his freedom to sunbathe. Now you’re envisioning that too…so there. Ha.
If the plan drops the cost of water for famers and provides them a source of cheap energy for moving that water, we could get enough support to dampen the conservatroll army. They’ll try, to be sure, but we can sell it the same way we sold the American Rescue Plan – shut up, this benefits you.
Benefit: Aquatic weed mitigation
Category: Conservation and efficiency
The canals are out in the open in the sun, and a lot of weeds end up taking root. These have to be continuously dealt with, and this adds up to a huge expense across 4,000 miles of canal. The shade provided by the PV hinders weed growth, reducing another expense and adding another pile of cash into the “pro” column for the idea.
I don’t want to spend too much time discussing aquatic weeds (go figure…do we assume there has EVER been a kid that said “when I grow up, I want to be a waterway aquatic weed mitigation expert??) But I don’t want to understate the beneficial impact either.
It might seem surprising, but the simulation found that the economic impact of weed mitigation was roughly the same as the economic impact of saving 63 billion gallons of water. So…a lot.
Drawback: PV over large distances
Now let’s briefly cover some challenges with the idea. First, such a project would spread the solar PV out over a huge area, wherever there are canals, and this might not be the best possible place for generation facilities (they may be way the eff out in the boonies, away from towns).
To maximize benefits of a canal PV system, the researchers point out that we might need to invest in low-loss transmission lines, which they didn’t consider. And we might need to get creative with planning how to use the power generated, as discussed some above.
Drawback: Humidity
The cooler microclimate created under the panels would increase humidity. Solar PV installations are relatively new, and there are some unknowns as to how this environment might affect their longevity. Internal components could corrode.
A canal project would therefore need to look into this in further detail, to ensure the appropriate equipment is available and deployed.
Conclusions
This summer has felt like a torrent of non-stop depressing news. On issues of climate, we’ve seen fires, floods…and should expect famine to drop in any day now for cakes and tea. Well…I suppose Famine would be on Keto and opt for just the tea. Effing keto.
Anyways - there is hope, and there are serious people utilizing their knowledge and skill to explore the solutions that will transform and save our world. And there are progressives and liberals hard at work making those solutions a reality.
Over the past decade, California went from running the world’s eight largest economy on 1% electricity from the sun, to running the world’s FIFTH largest economy on 20% sun. The idea to start putting solar PV over our network of canals promises tremendous benefits for the state and nation. It is one of the next frontiers here – transforming our canal network, a marvel of 20th century technology and ingenuity into a canal/electricity network, a marvel of 21st century technology and ingenuity.
Where do we go from here? The faster we get people thinking about these ideas, the faster we can realize them. After this posts, I’m going to email my Congresswoman and state reps with a message telling them about this study, and providing a link to this piece. If you think the benefits of solar PV canal sound like something government should be researching, I invite you to do the same. Who knows what staffer or volunteer might see the email and start thinking about this further.
Further Reading
“Energy and water co-benefits from covering canals with solar panels.” Nature Sustainability, March 2021.
“Why Covering Canals with Solar Panels is a Power Move.” Wired, 3/21
“Installing Solar Panels Over California’s Canals Could Yield Water, Land, Air and Climate Payoffs.” The Conversation 4/21
About Me
I use the handle Rory_PNG. PNG stands for “progressive new guard,” a concept an author once made the case for that resonated with me. We are “rational progressives,” looking to use reason, science and technology to foster social justice and equality. We are largely the younger generations, who recognize we have inherited a mess. We also recognize the work and accomplishments of those who came before, because there was a time when we didn’t have Medicare, and a time when we didn’t have Social Security, and a time when “We the People” meant only like 20% of the people. We recognize the gravity of the moment and we are here to help, not to add to the noise. We know that the democracy only stands if we can keep it, and we are here to do what needs to be done to keep it.
Ideologically, I’m a progressive. But I want everyone to have a seat at the table, and I want to listen to ideas with an open mind. That’s what democracy is about, really — let’s get together, talk, then take a vote. That vote has value, the mandate has meaning. It’s the will of the people, and I’m determined to have as much respect for that when I disagree with the outcome as when I agree. That doesn’t mean I won’t fight to change minds, but I see our work as that — changing minds. When the electorate disagrees with us, maybe the electorate made a dumb or bad decision...but it also means we didn’t do our jobs well enough and need to fight harder. Tomorrow is another day.
I used to comment on news sites and social media in the afternoons, while watching Rachel Maddow and other shows. For a long time, I felt there was value in offering a progressive voice in forums where there is a lot of conservative nonsense. If a conservative wrote a lie about the ACA, I knew it was pointless to fight, but thought that a mature, calm dissent with cited sources would be helpful.
I still wonder if it might be. Regardless, inspired by MANY conversations on Pod Save America on this exact topic, I realized that if there are warriors out there who want to dissent, I’m not one of them. I don’t need the emotional impact of hearing what evil, stupid people have to say about their evil, stupid value systems. I am done. I’m tired of the guy who steps in to pooh pooh windmills as bird-killers, and the guy that steps in to always point out how he likes Black women, just not “THAT” black woman, and the guys who can’t imagine how a 6 week abortion ban or voter ID could ever negatively affect anyone, because they would DEFINITELY soldier up if they had to live with such a restriction. I’m just so over it.
So I decided to leave HuffPost, which has become a bottom-dwelling trash heap of listicles and hidden ads. Politico has been crap for a while, and now it seems to be destined to become yet another hard right outlet. Places like Fox and Town Hall and Redstate and Breitbard and blah blah blah are already there, and I used to comment there very respectfully and ignore the ensuing blowback. But I've retired from that because it feels like a waste of time.
But I’m still inspired to express my opinion. I’m inspired by the many places I get my info from — Maddow, Crooked Media, various podcasts. When someone gives me info that expands my world view and makes me think, it lifts my spirits. So when I dumped the other sites and stopped going there, I wondered if I might spend that time writing the sort of stuff that would make me happy to see come across my own screen. Writing is part of my living...but I wanted to make political writing a casual thing. Maybe I’ll write an article every couple of weeks, or maybe one a month. I might also get depressed and wander away. Not because of the audience here, just if some other huge new horrible thing happens out in the world.
In the meantime, I love learning and talking about sustainability and renewable energy. It’s the fight of our lives, and all future lives. I joined DK, and read for a while, and decided that it might be interesting to supplement some of the great articles about the day-to-day climate politics with a deeper dive into the technologies and proposals behind them. I had a lot of fund writing this first piece, and I feel like I learned a ton. So we’ll see how that goes and look to future topics. Any requests — I’m open.