Climate change and extreme weather affect tea growing. A competitive tea market needs quick, short-term solutions. This study evaluates the effects of various shade nets under mild and extreme cold stress on tea leaf physiology, photosynthetic alterations, antioxidant activities, and physiochemical characteristics. Tea plants were treated with SD0 (0% non-shading), SD1 (30% shading), SD2 (60% shading), and SD3 (75% shading). The 30%, 60%, and 75% shade nets shielded tea leaves from cold damage and reduced leaf injury during mild and extreme cold conditions compared with SD0% non-shading. Shading regulates photochemical capacity and efficiency and optimizes chlorophyll a and b, chlorophyll, and carotenoid contents. Moreover, carbon and nitrogen increased during mild cold and decreased in extreme cold conditions. Shading promoted antioxidant activity and physiochemical attributes. In fact, under 60% of shade, superoxide dismutase, peroxidase, catalase, and omega-3 alpha-linolenic acid were improved compared with SD0% non-shading during both mild and extreme cold conditions. From these findings, we hypothesized that the effect of different shades played an important role in the protection of tea leaves and alleviated the defense mechanism for “Zhong Cha 102” during exposure to a cold environment.
Tag Archive for: Agrivoltaics
Agrivoltaic systems have an increasing interest. Realizing this upcoming technology raises still many challenges at design, policy and economic level. This study addresses a geospatial methodology to quantify the important design and policy questions across Europe. An elevated agrivoltaic system on arable land is evaluated: three crop light requirements (shade-loving, shade-tolerant and shade-intolerant) are simulated at a spatial resolution of 25 km across the European Union (EU). As a result, this study gives insight into the needed optimal ground coverage ratio (GCR) of the agrivoltaic system for a specific place. Additionally, estimations of the energy production, levelized cost of energy (LCOE) and land equivalent ratio (LER) are performed in comparison with a separated system. The results of the study show that the location-dependent solar insolation and crop shade tolerance have a major influence on the financial competitiveness and usefulness of these systems, where a proper European policy system and implementation strategy is required. Finally, a technical study shows an increase in PV power of 1290 GWp (almost × 10 of the current EU’s PV capacity) if potato cultivation alone (1% of the total arable agricultural area) is converted into agrivoltaic systems.
The push toward carbon-free and renewable energy sources has precipitated a nationwide (United States) trend to increase solar generation via ground-mounted photovoltaic (PV) arrays. Beyond carbon benefits, one possible way to provide additional ecological value of solar PV projects is to co-locate pollinator habitat when site conditions permit. Around 2015, the concept of a “scorecard” emerged that could assess the value of a solar project to pollinator species. The development and application of these scorecards, to date, has not been controlled by any central organization. Scorecards are being developed on a state-by-state basis using various processes, by a variety of subject matter experts, and using a range of oversight and review approaches. As such, there is variation between different state scorecard programs and divergent opinions regarding the scorecards themselves. Given that developing state and local laws and incentive programs are linked to the pollinator-friendly solar scorecards, it is important to consider the basis of the scorecards themselves. With interest in co-location of solar with pollinator habitat, this comprehensive study of existing pollinator solar scorecards considers the level of consistency across the scorecards, analyzes the specific scorable elements and their relative weighting, and investigates the factors that influenced scorecard development. A total of 15 state scorecards and one nonspecific scorecard available as of April 2021 were reviewed to identify common and differentiating features. A categorization system for individual scoring elements was created to facilitate numeric assessment across the available scorecards. Further, in order to understand the unique motivations and processes that influenced the design of the scorecards, interviews were conducted with 34 experts involved in scorecard design, policy development, and use, including university professors, state agency staff, and solar project developers, owners, and operators. Research uncovered a general lack of rigor, consistency, and oversight for scorecard design methodology, version control, and use. However, if the scorecards can be predictive of ecological outcomes – healthy pollinator habitat – then they may still be meeting their primary purpose. Field-based research is necessary to determine if there is a correlation between the points received on a pollinator-friendly scorecard and the actual solar PV site habitat conditions.
AgriSolar Shown to be Ideal for Various Crops and Livestock
“Agrivoltaics, the practice of producing food in the shade of solar panels, is an innovative strategy that combines the generation of photovoltaic electricity with agricultural land use. The outcome is an optimized relationship between food production, water, and energy – the so-called Food-Energy-Water Nexus.
According to research by Prof. Greg Barron-Gafford (University of Arizona), potential crops include hog peanut, alfalfa, yam, taro, cassava, sweet potato, and lettuce. In a 2019 study, he analyzed cherry tomatoes, chiltepin peppers, and jalapeno production in combination with solar production. Cherry tomato production doubled under solar panels, while chiltepin pepper production tripled.
Sheep seem to be the best livestock for agrivoltaics. They do an excellent job of keeping vegetation down, which lowers maintenance and long-term operational costs. According to research by Cornell University, sheep grazing resulted in “2.5 times fewer labor hours than mechanical and pesticide management on-site.” – HDI
AgriSolar Adds Value to Low-Yield Crops
“A group of 35 French agricultural entrepreneurs decided to change their agricultural practices to adapt to the low quality of their groundwater and chose agrivoltaics as a way to compensate for crop yield losses.
In May, we experienced an episode of high heat and drought. Under the panels, which retained the evapotranspiration of the plants, we found that the plants were greener and better developed than between the rows. So, we think the return will be higher than what we originally estimated,” Jean-Michel Lamothe, a farmer in France’s Lands department and vice president of the French Federation of agrivoltaic producers (FFPA), told PV Magazine.
“We decided to grow plants rich in omega-3s, which respond well to our water quality problem and the climate of the region: flax, chia, camelina, rapeseed, and sunflower,’ he further explained. ‘And we will compensate for the drop in productivity with revenues from photovoltaics.’” – PV Magazine
AgriSolar Benefits Crops in Water-Stressed Regions of Brazil
“Brazil’s first agrivoltaic system is called Ecolume. It was developed by a network of more than 40 Brazilian researchers and funded by CNPq, the National Council for Scientific and Technological Development.
The Ecolume Agrivoltaic System (SAVE) makes the most of the scant local water resources by reusing water and collecting rainwater. It consists of 10 photovoltaic panels that cover 24 square meters (258 square feet), installed at a height of 2 meters (6 feet) above the ground.
In simulations carried out by Ecolume researchers, the agrivoltaic system produced up to 70% more vegetables and lowered the need for water, depending on the crop and environment. A study carried out at the University of Arizona, in the southwestern U.S. — a region that also experiences water scarcity — showed yields two to three times higher for some fruits and vegetables planted under solar panels. The SAVE water recycling and treatment systems also showed a 90% savings in water used for irrigation.” – Mongabay
New Study Shows Broccoli as Ideal Crop for AgriSolar Farms
According to a new study by researchers of South Korea’s Chonnam National University, broccoli has shown to be an ideal crop to be grown under solar panels.
“As per the study, the shade offered by the solar panels helps the broccoli get a deeper shade of green, which makes it look more appealing and it does so without a major loss of crop size or nutritional value. However, financial benefits for farmers producing solar energy are considerably more compared to the income generated by growing broccoli — nearly ten times more. Essentially, farmers are missing out on an opportunity by not having solar panels installed on the field.” – IT Technology
Cattle Graze Under Solar Panels in Minnesota
Cattle grazing under solar panels along U.S. Highway 59 in Morris, Minnesota, are under the direction of Bradley Heins, Ph.D., University of Minnesota. The cattle use the panels for shade and shelter, while other aspects of the operation are being studied further, such as water-runoff usage, pollinator habitat, and various potential crops to be grown.
“Studying both the theoretical and the practical applications of agrivoltaics is James McCall, a researcher in mechanical engineering with the National Renewable Energy Laboratory (NREL). NREL is funded by the U.S. Department of Energy.
‘To achieve the current administration’s decarbonization goals, we are going to need 10.3 million acres of land (by 2050) to achieve a high decarbonization and electrification scenario,’ said McCall. ‘We see a lot of pushback from local communities who don’t really want these projects on their land or in their community, a solution that has popped up is agrivoltaics.’
It’s possible that agrivoltaics could help develop a more pastoral environment for communities, and additional revenue streams for developers and farmers.” – Farm Ranch Guide
U.S. Army Launches Floating Solar Farm
Last month, a ribbon cutting took place for a U.S. Army floating solar farm, sited on Big Muddy Lake at Camp Mackall on Fort Bragg, North Carolina.
“Fort Bragg is the largest military installation by population in the Army, with around 49,000 military personnel, 11,000 civilian employees, and 23,000 family members. The 1.1-megawatt (MW) floating solar farm includes 2 MW/2 megawatt-hour of battery energy storage.
The floating solar farm is a collaboration between Fort Bragg, utility Duke Energy, and Framingham, Massachusetts-based renewable energy company Ameresco. The U.S. Army’s announcement explains: This utility energy service contract project will provide carbon-free onsite generation, supplement power to the local grid, and provide backup power for Camp Mackall during electricity outages.
The U.S. Army has a goal of slashing its emissions 50% by 2030 and achieving net zero by 2050. It also wants to proactively consider the security implications of climate change in strategy, planning, acquisition, supply chain, and programming documents and processes.” – Electrek
This resource guide discusses strategies for decommissioning solar energy operations. The guide includes details on extending performance periods, planning for decommissioning, cost examples and financial assurance mechanisms.
AgriSolar Clearinghouse partner Rob Davis has generously offered a full Solar Farm Lego set as a prize for the winner of the competition for best photo taken at one of the Follow the Sun tour field trips.
This set is priceless and can not be purchased. If you support the idea of a real-life Lego set being commercially available, vote here: LEGO IDEAS – Solar Farm. For a great background on the kit, see this NREL blog.
Please post your Follow the Sun photos to our forum here, or tag us on social media by using the hashtag #AgriSolar.
Solar Farm Lego Set. Photo: Rob Davis
The Follow the Sun Tour launched in Arizona, at Biosphere 2 and the Manzo Elementary agrivoltaic research site, and it was a great educational, inspirational, and networking event. Next up, we will travel to Minnesota on August 4 to tour Enel North America’s Lake Pulaski agrisolar site, US Solar’s Big Lake agrisolar site, and Connexus Energy’s agrisolar site in Ramsey. We’ll end the day on a sweet note with an Enel-sponsored Solar Farm to Table™ event featuring foods grown or pollinated at agrisolar sites. Get your free tickets here: Events – AgriSolar Clearinghouse.
The next week, we’ll travel to Massachusetts for a tour of the University of Massachusetts South Deerfield agrisolar research site and then the Million Little Sunbeams solar and hay farm, capping off the day at Knowlton Farms. Get your free tickets here: Events – AgriSolar Clearinghouse
In September, we will join forces with Jack’s Solar Garden, Sprout City Farms, and our partners at NREL and University of Arizona to tour Jack’s Solar Garden during its annual Night on the Farm. Stay tuned for details.
Over the next year, we’re planning more field trips to central California, Texas, Oregon, Virginia, Idaho, New York, and many more sites. If you have a site you’d like to highlight with an AgriSolar Clearinghouse fieldtrip, we’d love to hear from you. We’re looking forward to seeing you on the road!
GivePower Desalinates Water Overseas Using Aquavoltaics
“Austin, Texas-based GivePower started by installing solar panels for schools, community centers or other projects in communities in need. But GivePower founder Hayes Bernard realized that people, especially women and girls, would not attend school if they had to walk 8 miles to get water every day. That’s when the idea to include water pumps and desalination came to mind.
GivePower has seven operational desalination sites in countries like Haiti, Kenya, and Colombia. Four additional solar water farms are expected to become operational by the end of this year. GivePower has different sized desalination sites and setups. The largest one, the Solar Water Farm Max, produces up to 18,500 gallons of water daily — enough to support 35,000 people. It has a solar structure that acts like a roof over the water tanks and the twenty-foot equivalent unit shipping containers that house the desalination technology.” – American Shipper
Resource Guide for Decommissioning Solar Energy Systems
A new resource guide on decommissioning solar energy systems, written by AgriSolar Clearinghouse partner Heidi Kolbeck-Urlacher, offers resources for understanding solar project end-of-lifecycle management and recommendations for local governments to consider when drafting decommissioning ordinances. The report is now available through the Center for Rural Affairs here.
“Solar projects are often located in rural areas and can provide numerous benefits to nearby communities, including lease payments to landowners, tax revenue to fund infrastructure and services, and the creation of both permanent and temporary jobs. County officials are typically responsible for enacting siting or zoning standards to help ensure solar development is supported by local residents. This can include planning for the eventual decommissioning of energy projects that have reached the end of their life cycles.” – Center for Rural Affairs
The guide includes examples of decommissioning costs, extending performance periods of solar systems, recycling and disposal of solar panels, sample task lists associated with decommissioning solar systems, and recommendations for plans that define obligations of developers during the decommissioning process.
Chinese Fishery Deploys 70MW Solar Plant
“Farms where fish and algae thrive under solar panels might have secured their place in a future powered by renewable energy. Concord New Energy, a Chinese company that specializes in wind and solar power project development and operation, has installed a 70 MW solar plant atop a fishpond in an industrial park in Cangzhou, China’s Hebei region. The hybrid system integrates solar power generation with fishery in a unique way that not only saves land but also produces clean energy. This hybrid system is straightforward: a solar array is installed above the fish pond’s water surface, and the water area beneath the solar array is used for fish and shrimp farming.
The fishery-solar hybrid system is a type of floating solar farm that has grown in popularity over the years as solar power has evolved to meet the needs of our increasingly climactic times. For example, the United States has just begun construction of the country’s biggest floating solar farm in New Jersey.” – Interesting Engineering
Valley Irrigation Develops Solar Irrigation Site in Nebraska
Valley Irrigation has announced the completion of its first North American agrisolar installation in Nebraska through its partnership with Farmers National Company.
“The installation is located near Davenport, Nebraska, and will provide solar power to a Valley center pivot by offsetting energy consumption used to irrigate the field. Farmers National Company’s landowner client invested in Tier 1 solar panels, which are the highest-quality panels and are also used on major utility-sized installations. They are built to withstand the often-harsh conditions of Nebraska weather, including strong winds and hail.” – Valmont
“Matt Gunderson is with Farmers National Company and says it helps producers become more sustainable and increase return on investment. “We create some on farm generation not only to power a farm, but how do we tie it back into the grid system to support the electricity needs that are out there? And, along the way with it, sell that electricity back for some excess needs and create some investment opportunities and income generation for producers.” – Brownfield
By Emma Kampherbeek
Land is limited. Agriculture, electricity production, housing, nature, etc. all compete for the same plot of land. In some areas more than in others, but the competition is everywhere. On top of that, greenhouse gas emissions keep increasing and the global temperature keeps rising, leading to more frequent natural disasters and parts of the earth becoming uninhabitable. We shouldn’t only focus on stopping the global temperature from rising, but also on climate change adaptation and multifunctional land use now that ‘good’ land is getting scarcer.
It makes sense to have at least dual land use, but preferably use land for three, four or even more purposes. Agriculture and electricity production are a really good fit that can create win-win situations. That’s why I researched what I like to call ‘Solar Sheep’ – sheep that perform vegetation management on solar farms.
A lot of research is currently being done on the impacts of solar farms on soil health and biodiversity of flora and fauna. But what about sheep? Sheep are very effective grazers, which means that they are perfect for vegetation management on solar farms. Unlike goats, sheep don’t jump on the panels and don’t chew the wires. Unlike cattle, they are not heavy and large, which means that they can easily graze under the panels. They are also great with different types of terrain, like steep, rocky hills, which are hard to navigate for (robotic) mowers. These are a few of the advantages of sheep for solar farm owners.
Gold Tree Solar Farm Sheep Grazing. Photo: Emma Kampherbeek
How about advantages for the sheep? Is it also a positive experience for them to graze under solar panels? As many farmers who use their sheep for vegetation management on solar farms can tell you, sheep really don’t seem to mind grazing under and between the solar panels. This is also what my research showed, which was conducted on Gold Tree Solar Farm in San Luis Obispo, CA, in January 2021. Sheep on the solar farm grazed more than sheep in the natural rangeland without solar panels (see Figure 1). The solar panels provide shade and protection to the sheep. This prevents them from experiencing heat stress and protects them from harsh weather conditions, which will happen more frequently in the face of climate change. I live in the Netherlands, so heat stress didn’t use to be a big issue here, but in the last decade cases and mortality of heat stress have increased significantly.
Figure 1 Bar graphs showing the mean (± SEM) of the total percentage of time spent grazing during the Main study over the total period of sixteen days of both treatment groups (NR & S) and both management types (R & IR).
* P < 0.0001, ** P = 0.0015, *** P = 0.031. (S = Solar; NR = Native Rangeland; R = Rotational; IR = Intensive Rotational).
The article is now under peer review but will hopefully be published later this year in the Journal of Applied Animal Behaviour Science as an open-access article.
Aquavoltaics to be Developed in Taiwan by 2023
“UK solar specialist Lightsource is developing a 150 MW solar park at a fishery in Budai, in Taiwan’s Chiayi County. Construction is expected to commence in June 2023. The company is co-developing the project with Germany’s Green Rock Energy. They plan to start construction on the facility in June 2023. Lightsource said the project will be one of the largest fishery solar farms in Taiwan and will be able to generate 210,000 MWh per year.” – PV Magazine Global
Farmers Could Become Energy Exporters in Italy
“Italy wants the European Union to allow farmers to sell surplus electricity they generate on their land, a measure that could help soften a bloc-wide energy crunch. “Italian agricultural companies have huge surfaces available that should be filled with solar panels,” Agriculture Minister Stefano Patuanelli said in an interview Monday, referring to the roofs of stables, granaries and sheds.
Solar sharing – which involves using farmland for producing crops as well as generating power – has gained traction in recent years, as farmers have sought to cash in on a renewable project boom. It is also not uncommon for them to lease their land and be paid indirectly, without owning the project.” – Bloomberg
National Pollinator Week Recognized
“Agriculture Secretary Tom Vilsack issued a United States Department of Agriculture (USDA) proclamation in recognition and support of National Pollinator Week (June 20-26, 2022). Pollinator species, such as bees, other insects, birds, and bats play a critical role in producing more than 100 crops grown in the United States. Honeybee pollination alone adds more than $18 billion in value to agricultural crops annually. USDA recognizes the critical role pollinators play in agriculture and supports pollinator health through research, data collection, diagnostic services, monitoring, pollinator habitat enhancement programs and pollinator health investments.” – USDA
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