Tag Archive for: photovoltaics

By Stephanie Hince, AES

Although Grafton, Massachusetts, is just an hour west of Boston, life there is very different. Grafton is a friendly country town with a lovely historical feel. It has been a farming community for centuries, where thriving cotton, grist, and paper mills once dotted the landscape.

Whereas the Quinsigamond River once powered numerous mills, a newly constructed solar farm owned by AES is incorporating two Grafton traditions: clean energy and agricultural production. Let’s explore how our solar project brings together key stakeholders to help protect farmland in Grafton and beyond.

Grafton Solar’s On-site Agricultural Production

This solar installation is located on Knowlton Farm, a family farm operating for over 150 years. Instead of merely leasing fallow farmland for the project, the solar farm was designed with on-site agricultural production and research in mind from the start.

Grafton Solar is a 2-megawatt community solar farm with a 1.4-megawatt battery energy storage system. Many stakeholders have come together with a shared vision of clean energy, food production, and learning, which is making this endeavor a success.

Our current and prospective project partners include the U.S. Department of Energy, Massachusetts Department of Energy Resources, Massachusetts Department of Agricultural Resources, UMass Amherst, American Farmland Trust, and Cornell University. In December 2020, AES acquired the Grafton Solar project from BlueWave.

What Made This Solar Farm Unique from Day 1

An agricultural plan was created early in the design phase as a collaboration between Paul Knowlton, a fifth-generation farmer and current operator of Knowlton Farms, Iain Ward of Solar Agricultural Services, and BlueWave Solar. Today, that plan has come to fruition. With a keen eye, passersby will notice something very different at our project site.

Borrego, the construction contractor, elevated the solar modules to a height of 8 to 14 feet and created large inter-row spacing to allow cattle grazing and access for farm equipment. The agricultural integration component of the project began last May with the planting of squash and lettuce, as well as cattle grazing.

There is still much to be learned. Solar developers and farmers need a greater understanding of how to make widespread use of agrivoltaics cost-effective and practical. Thus, Grafton Solar provides opportunities to advance its application on other project sites and by other solar developers across the U.S.

All photos courtesy of the AgriSolar Clearinghouse

Grafton Solar is Now a Living Laboratory

We intentionally reserved a section of the project area for new and existing research partnerships – Grafton Solar is an official hub of activity for learning about agrivoltaics. Research partners, UMass Amherst and the American Farmland Trust, are working to establish site trials to assess crop productivity, soil health, and micro-climatic conditions, thanks to a grant from the U.S. Department of Energy Solar Energy Technology Office (SETO). Once available, research information will be made publicly available so that others in the solar and agricultural industries can learn and benefit from their findings.

Solar Incentives Helped Make This Innovative Project Possible

In Massachusetts, revenue for solar projects is provided through the SMART program, which starts with a fixed compensation rate for projects. A project can obtain different adders based on project attributes, which increases the rate and therefore the benefits to the project developer and landowner. Some of these adders include making a project a community solar farm, adding battery storage, or having a dual-use agricultural component. Grafton Solar does all three.

Community solar projects expand access to renewable energy and allow subscribers like households, businesses, educational institutions, municipalities, and others to experience the same benefits of solar power without having to install a solar array on their own property. Battery storage helps to mitigate the intermittent nature of solar energy by storing solar energy when production is high and electricity demand is low and promotes reliable, carbon-free power by making solar energy available when utility companies need it most. Thus, it reduces the need to use more polluting power plants when power demand is high.

Grafton Solar is built around the community solar model, incorporates battery storage, and is supporting a legacy of agricultural production at Knowlton Farm – a win-win-win. By leveraging Massachusetts’ innovative state-level solar incentives (which includes the only rate-adder for agrivoltaics in the U.S.), Grafton Solar is delivering multiple co-benefits to the community and showcasing that solar projects can do much more than produce power on site.

Protecting Farmland When Developing Solar Energy Projects

Grafton Solar is AES’ first agrivoltaic site in the Northeast and is consistent with our vision to provide the smarter, greener energy solutions the world needs. According to a report by the American Farmland Trust, the U.S. lost or compromised 2,000 acres of farmland and ranchland every day from 2001 to 2016.

If this trend continues, an area nearly the size of South Carolina will be lost between 2016 and 2040, which could be detrimental to food security. Many farmers across the U.S., like Paul Knowlton, are looking for new revenue streams and ways to keep family farms operating for future generations. In addition to producing food, family farms are also about preserving a way of life.

At AES, we understand the importance of protecting farmland when integrating renewable energy projects into the landscape. Solar energy development and farm viability can go hand-in-hand when taking a thoughtful, dual-use approach.

Using Partnerships to Maximize Opportunities

We understand the importance of land and are actively working to create synergies between renewable energy development and agricultural land use. In addition to successfully co-locating crop growth and grazing at Grafton Solar, we have implemented active sheep grazing on thousands of acres of land at utility-scale solar sites, and we are participating in research partnerships in various regions across the U.S. to better understand how we can harvest clean energy and food from the same land.

We know that the success of our company is only as strong as the partnerships within the communities where we operate, so we develop, build, and manage projects that maximize value to a variety of stakeholders. Ultimately, we need both clean energy and productive farmland, not just one or the other.

Grafton Solar provides an excellent opportunity to collaborate with the research community and the Knowlton family to further our understanding of how to make agrivoltaics practical and more widespread. The project symbolizes preserving a way of life that spans many generations while embracing innovative clean energy technologies that promote food security, reliable energy, and a cleaner environment.

By 2035, Egypt pursues to generate 22% of the total electricity from photovoltaic power plants to meet the national spreading demand for electricity. The Egyptian government has implemented feed-in tariffs (FiT) support program to provide the economic incentives to invest in the PV power plants. The present study is carried out to evaluate the techno-economic feasibility of a largescale grid-connected photovoltaic (LS GCPV) of the Benban Solar Park with a total capacity of 1600 MW AC producing annual electricity of 3.8 TWh. The characteristics of PV panels considering the meteorological data of Benban Solar Park are evaluated. Additionally, the reduction of greenhouse gas (GHG) emissions due to constructing Benban Solar Park is assessed. As well, the influences of annual operation and maintenance cost and the interest rate on the electricity cost and the payback period are evaluated. The results indicate that the electricity cost is about 8.1¢US/kWh with 10.1 years payback period, which is indeed economically feasible with an interest rate of 12%. Furthermore, the Benban Solar Park will avoid annually almost 1.2 million tons of greenhouse gas. The working conditions of the previous study which aimed to improve the performance of solar panels using cooling water are similar to the Benban solar Park. This study showed that utilizing of water cooling for solar panels leads to an increase in the electrical energy output by 8.2%. This attributed to maximizing the benefit when cultivating the vast land area on which the station is built, and using the irrigation water to cool the PV panels, and then for the irrigation process. Thus, a double advantage can be achieved; first, an increase in the electrical energy output by 8.2% in the summer months where the panel surface temperature is high. Second, the agricultural crops as an economic value, as the solar panels are located at a height of 1.5m from the surface of the earth. The PV solar panels are installed above the existing cultivated areas while the maintained spaces among rows of PV modules provide the necessary solar radiation for crops.



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This report discusses the main principles of different tuning approaches in customizable photovoltaic designs and provides an overview of relevant concepts of tunable SC technologies. The report provides a systematic analysis addressing photovoltaic materials, electrode layers, optical structures, substrates and encapsulates. Also included is a summary of integrations of cutting-edge tunable PV adapted to versatile applications, current challenges, and insightful perspectives into potential future opportunities for tunable PV systems.

This report discusses the synthesis of four new symmetrical UV-absorbing diimides organic dyes for potential cosensitization process in greenhouse-integrated dye-sensitized solar cells (DSCs). Molecular cosensitization is favorable for manipulating solar radiation through the judicious choice of cosensitizers having complementary absorption spectra. For greenhouse-integrated dye-sensitized solar cells (DSCs), the manipulation of solar radiation is crucial in order to maximize the flow of photosynthetically active radiation (PAR) for the effectual photosynthetic activity of plants; meanwhile, non-PAR is utilized in agrivoltaics for generating electricity.

This report discusses the effects of solar radiation and total system head on techno-economics of a PV groundwater pumping irrigation system designed for sustainable agricultural production. The materials and methods of the study include crop water requirements, estimated pumping rates, estimations of PV-array ratings and solar charge controllers, and economic estimations of PV-pumping system(s). The results of the study also include an environmental impact analysis.

This research presents a highly transparent concentrator photovoltaic system with solar spectral splitting for dual land use applications. The system includes a freeform lens array and a planar waveguide. Sunlight is first concentrated by the lens array and then reaches a flat waveguide. The dichroic mirror with coated prisms is located at each focused area at the bottom of a planar waveguide to split the sunlight spectrum into two spectral bands. The red and blue light, in which photosynthesis occurs at its maximum, passes through the dichroic mirror and is used for agriculture. The remaining spectrums are reflected at the dichroic mirror with coated prisms and collected by the long solar cell attached at one end of the planar waveguide by total internal reflection. Meanwhile, most of the diffused sunlight is transmitted through the system to the ground for agriculture. The system was designed using the commercial optic simulation software LightTools™ (Synopsys Inc., Mountain View, CA, USA). The results show that the proposed system with 200× concentration can achieve optical efficiency above 82.1% for the transmission of blue and red light, 94.5% for diffused sunlight, which is used for agricultural, and 81.5% optical efficiency for planar waveguides used for power generation. This system is suitable for both high Direct Normal Irradiance (DNI) and low DNI areas to provide light for agriculture and electricity generation at the same time on the same land with high efficiency.

Colloidal quantum dots (QDs) are nanometer-sized semiconductor crystals grown via low-cost solution processing routes for a wide array of applications encompassing photovoltaics, light-emitting diodes (LEDs), electronics, photodetectors, photocatalysis, lasers, drug delivery, and agriculture. A comprehensive technoeconomic cost analysis of perovskite quantum dot optoelectronics is reported. Using economies-of-scale considerations based on price data from prominent materials suppliers, we have highlighted that increased QD synthesis yield, solvent recycling, and synthesis automation are critical to market adoption of this technology and driving quantum dot film fabrication costs down from >$50/m^2 to ∼$2−3/m^2

Sunnyside neighborhood in Houston, Texas, has been approved to develop the Sunnyside Solar Project, a 50-MW solar operation that will be built on a former landfill abandoned for 50 years. The project, set to be completed by the end of 2022, will be the largest urban solar project in the country, covering a total of 240 acres. Plans are also in place to include sheep grazing under the solar panels once the project is completed.  

According to a media report by PV Magazine, the mayor’s office expects that a community solar installation will be part of the project, but exactly how much is not yet defined.

The project is being developed by Sunnyside Energy LLC. The company will train and employ local workers for the project’s construction, as well as provide discounts to low-income residents in the Sunnyside neighborhood as part of its agreement with the city of Houston, according to the media report.

The project will also be the largest brownfield solar installation in the United States. A brownfield installation means the project has been developed on previously contaminated land. Transforming an abandoned landfill into a productive and clean energy farm demonstrates how degraded lands can be used to address land-use and energy issues. For more information on the Sunnyside Solar Project, read the original article on PV Magazine’s website.