Entries by Carl Berntsen

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A Standardized Classification and Performance Indicators of Agrivoltaic Systems

The rapid increase of photovoltaic installations highlights the potential of agrivoltaic systems. These dual-land use systems mitigate land use conflicts for places with limited open space and moreover, show the potential as an added value in crop- and livestock cultivation. The many different names and interacting possibilities between agriculture and PV make it difficult and confusing for stakeholders to compare and benchmark existing installations as well as propose and set new (EU) legislation schemes. This work proposes a standardized classification (including names) of agrivoltaic systems, which is usable worldwide. The classification is based on the application, system, the farming type, PV structure and flexibility. These elements makes it possible to describe and categorize each existing agrivoltaic installation properly. This work suggests to mention each sub-category (for example: static stilted orchard agrovoltaic system) in future research papers or documents to order to better compare (rangevoltaic <=> agrovoltaic) and benchmark new installed installations. When comparing agrivoltaics, the use of the proposed seven KPIs will help to make meaningful comparisons and grounded decisions in case of possible new installations.

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Agrivoltaic Systems to Optimize Land Use for Electric Energy Production

A system combining soil grown crops with photovoltaic panels (PV) installed several meters above the ground is referred to as agrivoltaic systems. In this work a patented agrivoltaic solar tracking system named Agrovoltaico®, was examined in combination with a maize crop in a simulation study. To this purpose a software platform was developed coupling a radiation and shading model to the generic crop growth simulator GECROS. The simulation was conducted using a 40-year climate dataset from a location in North Italy, rainfed maize and different Agrovoltaico configurations (that differ according to panel density and sun-tracking set up). Control simulations for an irrigated maize crop under full light were added to results. Reduction of global radiation under the Agrovoltaico system was more affected by panel density (29.5% and 13.4% respectively for double density and single density), than by panel management (23.2% and 20.0% for suntrack and static panels, respectively). Radiation reduction, under Agrovoltaico, affected mean soil temperature, evapotranspiration and soil water balance, on average providing more favorable conditions for plant growth than in full light. As a consequence, in rainfed conditions, average grain yield was higher and more stable under agrivoltaic than under full light. The advantage of growing maize in the shade of Agrovoltaico increased proportionally to drought stress, which indicates that agrivoltaic systems could increase crop resilience to climate change. The benefit of producing renewable energy with Agrovoltaico was assessed using the Land Equivalent Ratio, comparing the electric energy produced by Agrovoltaico cultivated with biogas maize to that produced by a combination of conventional ground mounted PV systems and biogas maize in monoculture. Land Equivalent Ratio was always above 1, it increased with panel density and it was higher with sun tracking than with static panels. The best Agrivoltaico scenario produced twice as much energy, per unit area, as the combination of ground mounted PV systems and biogas maize in monoculture. For this Agrivoltaico can be considered a valuable system to produce renewable energy on farm without negatively affecting land productivity

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Agrivoltaics Provide Mutual Benefits Across the Food-Energy-Water Nexus in Drylands

Researchers present here a novel ecosystems approach—agrivoltaics—to bolster the resilience of renewable energy and food production security to a changing climate by creating a hybrid of colocated agriculture and solar PV infrastructure, where crops are grown in the partial shade of the solar infrastructure. They suggest that this energy- and food-generating ecosystem may become an important—but as yet quantitatively uninvestigated—mechanism for maximizing crop yields, efficiently delivering water to plants and generating renewable energy in dryland environments. We demonstrate proof of concept for agrivoltaics as a food–energy–water system approach in drylands by simultaneously monitoring the physical and biological dimensions of the novel ecosystem. We hypothesized that colocating solar and agricultural could yield several significant benefits to multiple ecosystem services, including (1) water: maximizing the efficiency of water used for plant irrigation by decreasing evaporation from soil and transpiration from crop canopies, and (2) food: preventing depression in photosynthesis due to heat and light stress, thus allowing for greater carbon uptake for growth and reproduction. An additional benefit might be (3) energy: transpirational cooling from the understorey crops lowering temperatures on the underside of the panels, which could improve PV efficiency. We focused on three common agricultural species that represent different adaptive niches for dryland environments: chiltepin pepper (Capsicum annuum var. glabriusculum), jalapeño (C. annuum var. annuum) and cherry tomato (Solanum lycopersicum var. cerasiforme). We created an agrivoltaic system by planting these species under a PV array—3.3m off the ground at the lowest end and at a tilt of 32°—to capture the physical and biological impacts of this approach. Throughout the average three-month summer growing season we monitored incoming light levels, air temperature and relative humidity continuously using sensors mounted 2.5m above the soil surface, and soil surface temperature and moisture at 5-cm depth. Both the traditional planting area (control) and agrivoltaic system received equal irrigation rates, and we tested two irrigation scenarios—daily irrigation and irrigation every 2d. The amount of incoming photosynthetically active radiation (PAR) was consistently greater in the traditional, open-sky planting area (control plot) than under the PV panels. This reduction in the amount of incoming energy under the PV panels yielded cooler daytime air temperatures, averaging 1.2+0.3 °C lower in the agrivoltaics system over the traditional setting. Night-time temperatures were 0.5+0.4 °C warmer in the agrivoltaics system over the traditional setting (Fig. 2b). Photosynthetic rates, and therefore growth and reproduction, are also regulated by atmospheric dryness, as represented by vapour pressure deficit (VPD) where lower VPD indicates more moisture in the air. VPD was consistently lower in the agrivoltaics system than in the traditional growing setting, averaging 0.52+0.15 kPa lower across the growing season. Having documented that an agrivoltaic installation can significantly reduce air temperatures, direct sunlight and atmospheric demand for water relative to nearby traditional agricultural settings, we address several questions regarding impacts of the food–energy–water nexus system.

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Catalyzing Community Solar: A Handbook for Municipalities

Community solar is an innovative new investment model that can provide Americans with the many benefits of solar energy even if they cannot site a system on their own property because they are renters, have roofs that are shaded or in disrepair, or they are not able to finance a solar installation. These barriers are particularly prevalent in less affluent areas, making community solar a promising way to improve access to renewable energy in low-income neighborhoods. This Handbook is intended to help municipalities clearly define and articulate the project’s objectives and understand the financial, legal, and policy issues they would need to address to initiate community solar investments in their communities and convey the resulting benefits to their constituents. The Handbook identifies three obstacles to success — access to capital, expertise, and risk-allocation — and includes suggestions on how to overcome these obstacles, including the potential use of public funds to reduce the project’s cost and public-private partnerships. This study also includes ideas gleaned from other community solar projects that appear particularly interesting or innovative. In addition, it offers five possible deployment models municipalities could use to support, finance, or build a community solar project in their jurisdictions. There are no simple, one-size-fits-all, models for a successful community solar project. However, a municipality can be a catalyst and hub for development of the necessary expertise, and it has opportunities to help reduce project costs and risks that can open the door for successful projects.

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Residential Consumer Guide to Community Solar – 2016

Deployment of solar energy systems in the U.S. has grown rapidly over the past decade. Costs have dropped, and new ownership and financing models allow more Americans than ever to choose solar. Solar is now available as a power choice in all states. The solar industry is creating even more solutions that allow all consumers to produce their own electricity by going solar. Consumers who rent their homes, live in an apartment, do not have unshaded or otherwise well-oriented roof space, or may not qualify for a lease now have the ability to choose solar in an increasing number of states. Even for consumers who have the roof and property to install a solar system, community solar offers an alternative option for going solar. Some community solar projects allow subscribers to purchase or lease as little as one panel or a small fraction of the power generated from the project. Subscribers’ interest can also typically stay with them if they move to a new address within the same utility service territory. Community solar brings more choice to consumers interested in solar. Entering into a community solar agreement is a significant decision, similar to signing up for a cell phone, and consumers should understand the basics of solar energy, where community solar is available, key terms in agreements, and the right questions to ask solar professionals.

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Long Island Solar Roadmap: Advancing Low-Impact Solar in Nassau and Suffolk Counties

Solar power offers Long Islanders a host of benefits — reductions in greenhouse gases and air pollution, healthier communities, affordable access to renewable energy, and good paying jobs. Solar can also play a significant role in helping address the climate crisis and meeting the goals of New York’s Climate Leadership and Community Protection Act (CLCPA). This nation-leading 2019 law requires 70% of the state’s electricity to be generated from renewable resources by 2030 and 100% of electricity to be generated from carbon-free sources by 2040. Many people are familiar with residential rooftop solar systems, which range in size from 3 to 10 kilowatts (kW). Larger commercial and utility-scale solar systems, which can generate hundreds to thousands of kilowatts each, offer the opportunity to realize the benefits of solar power more quickly and cost-effectively in the region. This report shows how solar power can be scaled up without impacting the natural areas that are critical for wildlife, water-quality protection, and quality of life on Long Island. Low-impact sites like rooftops, parking lots, and other land already impacted by development, such as capped landfills and remediated brownfields, are excellent locations for the development of commercial- and utility-scale arrays. Building solar on low-impact sites minimizes impacts to natural ecosystems and habitat, reduces the potential for land-use conflicts and community opposition, decreases project cost and permitting times, and avoids the harmful release of carbon pollution that results from the conversion of natural areas for development. The Nature Conservancy and Defenders of Wildlife created the Long Island Solar Roadmap (the Roadmap) with the aim of advancing deployment of mid- to-large-scale solar power on Long Island in a way that minimizes environmental impacts, maximizes benefits to the region, and expands access to solar energy, including access to benefits by underserved communities. The Roadmap’s creation was supported by a diverse group of Long Island stakeholders. Individuals from state, local, and county government; the solar industry; the farm community; environmental and community organizations; the electric utility; businesses; and academic institutions provided input and guidance on design, research, and strategies. The Roadmap identifies low-impact sites for solar arrays on Long Island and shows their energy generation potential. Key findings also highlight Long Islanders’ opinions and preferences about solar development in their communities and provide information about the costs and benefits associated with bringing more solar online. It is our hope that the cohesive set of strategies and actions provided in this report will help lower barriers to low-impact solar development that meets the needs of all Long Island communities and benefits the whole region. Together, the key findings of the Roadmap point toward a promising future for Long Island as we transition to renewable energy. Taking full advantage of Long Island’s solar potential will require the commitment and collective action of a diverse group of stakeholders, including local and state government, Long Island Power Authority (LIPA), PSEG Long Island, the solar industry, commercial and industrial property owners, farmers and farmland owners, nonprofits, and community organizations.

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Integrating Solar Energy With Agriculture: Industry Perspectives on the Market, Community, and Socio-political Dimensions of Agrivoltaics

Despite the mature and promising potential for solar photovoltaic (PV) technology to retrench global reliance on fossil fuels, large-scale PV development is experiencing complex challenges, including land use conflict and — as the scale of solar has increased — social resistance, which has previously been more commonly associated with large-scale wind farms. Growth in large-scale PV development can create land use disputes, especially in instances of competition between land for agriculture versus energy production. This history and growing concern over land use highlights the challenge of meeting the soaring demands for solar power while conserving rural and agricultural lands. It is posited that the impact of solar development on land will be diminished by siting PV in a manner that is compatible with multiple uses, suggesting changes in conventional practices will be necessary. The specific intent of this study was to draw insight about solar development from participant experience, and responses indicate that the most considerable opportunities and barriers center on social acceptance and public perception issues. Perspectives about the opportunities and barriers to agrivoltaic development were captured via interviews with solar industry professionals, and inductive analysis revealed that interviewees were most focused on opportunities and barriers that correspond with Wüstenhagen et al.’s three dimensions of social acceptance: market, community, and socio-political factors. The social acceptance of renewable energy is shaped by a complex interplay among market, community, and socio-political factors. While this framework is constructive for understanding the varying dimensions of social acceptance, Devine-Wright et al. assert that it is weak in terms of the relationships between dimensions, suggesting that further research should apply a holistic approach for discerning the interdependence among factors shaping social acceptance of renewable energy. The purpose of this study is therefore to explore the perceptions of industry professionals in the U.S. and consider the implications of the identified opportunities and barriers from a social science perspective. To address global demands for both food and energy, the relationship between critical land uses must become complementary rather than competitive. Because social acceptance of renewable energy technology is pivotal to energy transitions, this study reflects a proactive attempt to understand agrivoltaics from a solar industry professional’s perspective to better understand the significant opportunities and barriers to development. This research suggests that agrivoltaics are potentially accretive to the long-term growth of the solar industry, possessing the capacity to increase social acceptance of local solar developments. While the agrivoltaic concept is widely supported by the participants in this study, popularity of an emerging technology among industry experts may not indicate local level acceptance of a specific development. As new energy technologies such as agrivoltaics transcend niche applications to become more prevalent, localized resistance is to be anticipated and the dimensions of social acceptance, including the opportunities and barriers associated with each dimension, can help inform decision making to enhance the growth of agrivoltaic development.

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Community Solar: An Opportunity to Enhance Sustainable Development on Landfills and Other Contaminated Sites

Community solar programs (also called “shared solar”) offer the economic and environmental benefits of solar to the 49% of Americans without traditional solar access. Such programs are experiencing rapid growth, with active projects across 26 states, up from 6 states in 2010. This market has the potential to grow more than 50-fold from the 110 megawatt (MW) capacity in early 2016 to between 5,500 MW and 11,000 MW by 2020. Previously, it was often uneconomic to develop individual solar projects of less than 2 MW in capacity (2,000 kilowatts [kW]) if they were not tied directly to or net metered with a customer site. With community solar, projects between 50kW and 2,000 kW are often viable because numerous off-site subscribers can purchase shares of a solar installation rather than hosting the installation themselves. By bringing an enormous source of new demand into the market and offering new contracting arrangements to the 51% of Americans who already have potential solar access, community solar is expected to greatly expand the market for mid-sized solar projects. One strong but sometimes overlooked source of suitable sites for community solar are those covered by the U.S. Environmental Protection Agency (EPA) RE-Powering America’s Land Initiative. The RE-Powering Initiative provides data, tools, analysis, case studies, issue briefings, and outreach resources to encourage renewable energy development on contaminated lands, landfills, and mining sites (collectively “RE-Powering sites”). Community solar can overcome financing, contract flexibility, project size, and siting challenges that largely shut out LMI homes, apartments, and small businesses from the solar market, while offering added local economic development benefits if the community solar project itself is located in LMI areas. Because RE-Powering sites are frequently located in or near LMI areas, this paper will explore not only the general potential for developing RE-Powering sites for community solar, but also where siting adjacent to LMI areas extends their benefits. This market intersection is conceptually depicted in Figure 1. Within and outside LMI areas, this paper is intended to support sustainable re-use by characterizing the potential and pointing out the challenges and opportunities of community solar development on RE-Powering sites.

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Community Solar: Best Practices for Utilities in the South

As solar energy continues to become more affordable, many families are expressing interest in this local, clean power source, but are unable to install a solar system at their homes for various reasons. In fact, due to structural constraints, shading from trees, and other issues, about 75% of residential rooftop area in America is not suitable for hosting a solar system. This prevents a large segment of the population from taking advantage of solar energy. The solution to this problem is Community Solar. Community Solar (aka Shared Solar) takes place through the development of solar energy projects that provide power to multiple community members. Community Solar systems are typically sited close to the community they will serve. These programs leverage economies of scale to reduce the price of solar for individual customers. This model allows Southerners to access the benefits of solar energy even if they would be unable to install solar panels on their own homes or businesses. Community Solar can be utility-sponsored (either a utility developing its own program or working with a solar company to offer a program), or it can be third party-sponsored in states that allow for competition. By offering well-designed Community Solar projects, utilities can give their customers meaningful access to affordable, local solar power and tangible control of their energy choices. By providing families more options to lower their energy costs and take advantage of the South’s vast solar resource, Community Solar can create healthier, cleaner, and stronger communities across the region. Community Solar programs also provide benefits for utilities by increasing customer satisfaction, bolstering clean energy investment, and contributing to local economic development. Utilities can take advantage of economies of scale by choosing the optimal system size and number of participants. They can also decide which location will offer the most value to the grid. Community Solar can be a win-win by providing tangible benefits to participating customers, strengthening local communities, and delivering valuable clean energy to the grid. We encourage utilities to adopt the following best practices when developing Community Solar programs to ensure that all customers receive meaningful access to solar power through this innovative program.

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Energy Policy for Energy Sovereignty: Can Policy Tools Enhance Energy Sovereignty?

The concept of energy sovereignty redefines the priorities for decision making regarding energy systems while encouraging increased reliance on renewable energy technologies like solar. Energy sovereignty involves centering the inherent right of humans and communities to make decisions about the energy systems they use, including decisions about the sources, scales, and forms of ownership that structure energy access. Current U.S energy policy does not center concerns of energy sovereignty, and in many cases may work against it. Policies to enhance energy sovereignty can accelerate electricity decarbonization while also empowering community scale decision making and offering communities control to reduce the myriad externalities associated with the fossil-fuel energy system. Energy policy designed based on the concept of energy sovereignty would prioritize community voices in energy system decision making, ensuring that communities are given an opportunity to express their right to self-determined sovereignty in energy systems transitions and energy system use. Energy sovereignty is an inherently place-based practice, and policy tools that center energy sovereignty would enhance community capacity to plan for transitions while embracing considerations of the health and wellbeing of communities, both human and non-human, now and in the future. The policy tools most effective for enhancing energy sovereignty may not yet exist, but they are essential for promoting a just energy transition that benefits all communities based on their own understanding of energy transition priorities and values.