Project Nexus: The First Ever Solar Canal in the United States
Rendering of the installation of solar panels above canals across California in the United States’ first solar canal under Project Nexus. (Source: Solar AquaGrid)
As global temperature rises and weather patterns become more severe as a result of climate change, California and other states in the western coast are beginning to face increasing pressure from the issue of water scarcity. Studies indicate that the western United States is facing the worst megadrought in more than 1,200 years. So far, this dilemma has manifested in the form of increasing dryness, ground water supplies being over pumped, forest fires, and shrinking water supplies for millions across the country. The severe droughts that have plagued western states in recent years have exacerbated the issue, causing policymakers to scramble to find solutions.
In the midst of this turmoil, the United States is experimenting with a new strategy that may tackle the issue of water scarcity while bolstering the generation of renewable energy: solar-canals. By installing solar panels over water canals in this innovative project, California may be able to preserve its water supply by counteracting the force of evaporation while contributing an impressive volume of electricity to its power grid. If successful, this project could solve a myriad of issues related to water conservation, energy generation, power grid stability, and environmental harm. In fact, a study by a key contributor to the project, the University of California, Merced estimates that covering California’s 6,437 kilometers of canals could preserve 63 billion gallons of water and could generate 13 gigawatts of power - enough to power the entire city of Los Angeles for ten months.
The Rising Threat of Water Scarcity
Riddled with the concern of overuse and exacerbated by severe droughts over the past 10 to 30 years, California has struggled with maintaining a secure supply of water. The droughts, accompanied by rising temperatures and drier climates caused by climate change, have caused California's central valley groundwater wells to dry out. In response, Gov. Gavin Newsom called upon the California Natural Resources Agency in October 2020 to lead efforts to conserve 30% of land and coastal waters by 2030. In addition, the state mandated the reduction of groundwater pumping while maintaining adequate supplies to farms, cities, wildlife and ecosystems.
The Colorado River is an essential supply water for irrigation and drinking for millions of Americans.
Changes in weather patterns aside, the recent shrinkage of the Colorado River is a leading cause for alarm. The Colorado River supplies drinking water to 40 million Americans and provides irrigation for 5.5 million agricultural acres. Dams on the river’s two main reservoirs, Lake Mead and Lake Powell, generate electricity that powers millions of homes and businesses across the country. However, the river’s flows have recently fallen by one-third of historical averages, leading the Biden administration to consider reducing the allotment of water to western states. In this historically unprecedented move, the Interior Department, which manages the river, is considering the reduction of water allotment evenly across the states by 13 percent beyond what the states have already agreed to. The other option is to determine the reductions according to the seniority of water rights, which would spare California as it is the largest and oldest user of Colorado water, but would have devastating effects for Nevada and Arizona by depleting water aqueducts that create drinking water to nearly zero.
Aerial shot of the Imperial Dam and Reservoir on the California-Arizona border. 90% of the volume of the Colorado river is diverted at this point into the All-American Canal to irrigate California's Imperial Valley.
Project Nexus: Water Conservation and Energy Generation
With water conservation as a critical priority, California is pioneering a pilot program that utilizes solar-canals, which are solar panels installed over the state’s canals and aqueducts, to both limit evaporation and generate electricity. The California Department of Water Resources has committed $20 million to test the effectiveness of solar-canals in Stanislaus County and determine the most efficient locations for their installation along the state’s canals which stretch over 4,000 miles, making it one of the largest water conveyance systems in the world. The project, called Project Nexus, is a collaboration between the state, Solar AquaGrid, the Turlock Irrigation District, and researchers from the University of California, Merced who will track and analyze the finding and is expected to launch in the fall. The team expects to install 8,500 feet of solar panels over three sections of water canals in central California to determine the feasibility of installing more solar canals across the state.
If successfully completed, Project Nexus will be the first solar canal created in the United States, but are the costs and resources worth the risk of the endeavor? Covering California’s long system of canals can lead to a wide variety of benefits. To start, the state-wide adoption of solar canals could provide up to 13 gigawatts of clean energy per year, which is over 50 percent of the new renewable sources that California needs to add to meet their clean electricity goals: 60% from carbon-free sources by 2030 and 100% renewable by 2045. The addition of solar canals would address the energy needs of the canal system itself as well, as the state currently spends an enormous amount of electricity pumping water across vast distances. The California Department of Water Resources reported that water activities make up 12 percent of total energy consumption across the state.
Solar panels that act as canopies for the canals can contribute to water conservation by mitigating the effect of evaporation. Feasibility studies for the project estimate that solar canals could save California 63 billion gallons of water annually - enough to cover the residential needs of 2 million people for a year. Lastly, combining solar panels with channels of water can produce mutually beneficial effects to both systems such as increasing the efficiency of the panels themselves and preserving the health of the canals. Cooler panels generate more electricity and the cooling effect of water under the panels can reduce their temperature by 10 degrees Fahrenheit, boosting production of electricity by up to 3%. The shade provided by the panels can also prevent toxic algae blooms caused by exposure to sunlight, an issue that cost California nearly $53 million to address between 2010 and 2020.
The California Aqueduct in the Mojave Desert near Palmdale CA.
Another aspect of Project Nexus that could benefit California’s green transition is the transfer and storage of electricity generated from the solar panels into the electric grid. By testing the incorporation of battery storage alongside the solar canals, the system could help reduce demand on the power grid, bolstering grid security during extreme weather events and preventing blackouts. Building up local storage networks can cut both costs and transmission losses by reducing long-distance energy transfer. These changes can further efforts towards energy equity and accessibility for low-income families that are most likely to be affected by high electricity costs and less energy-efficient homes according to the American Council for an Energy-Efficient Economy. As such, combining solar power generation with battery storage can help establish microgrids in rural areas and benefit underserved communities by making their power systems more effective and resilient.
Preserving the Land
While solar panels can be effective tools for generating green electricity, the installation of large solar farms that require vast plots of land have been a point of contention for farmers, conservationists, and renewable energy developers. For example, the buzz surrounding the potential installation of more solar panels in California’s Mojave Desert underscores how controversial these projects can be. According to the Great Plains Institute, a conventional solar farm requires up to 10 acres of land to produce one megawatt of electricity - enough to power the average U.S. household for 1.2 months. According to this measurement, the United States would require 10 million acres of land to meet solar demand (a landmass larger than the state of Maryland which is just shy of 8 million acres in size).
Traditional solar farms require vast, open plots of land in sunny environments and can threaten desert ecosystems.
For this reason, the land conservation component of solar canals is a crucial element that cannot be overlooked. By being positioned over existing systems of water, solar canals can provide all the benefits of large solar farms without the demand for large plots of land. In addition, solar farms are most effective when installed in sunny, remote locations without trees or high buildings that can obstruct sunlight. However, the construction process can be very disruptive to delicate desert ecosystems and the lasting presence of solar panels can create barriers of movement for endangered species. Studies indicate that solar panels can affect the temperature and humidity underneath them, putting pressure on micro-habitats as well. In contrast, solar canals can avoid the high environmental cost introduced by traditional solar farms while conserving land and having complementary effects on the system of water underneath them as well. Therefore, if successfully adopted, solar canals can reduce tensions between renewable energy developers and communities, agricultural stakeholders, and conservationists.
References:
https://www.nytimes.com/2023/04/11/climate/colorado-river-water-cuts-drought.html
https://www.nytimes.com/2023/04/13/us/california-solar-panels-canals.html
https://www.eesi.org/articles/view/the-promise-and-potential-of-solar-canals
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