Modifications to the surface albedo through the deployment of cool roofs and pavements (reflective materials) and photovoltaic arrays (low reflection) have the potential to change radiative forcing, surface temperatures, and regional weather patterns. In this work we investigate the regional climate and radiative effects of modifying surface albedo to mimic massive deployment of cool surfaces (roofs and pavements) and, separately, photovoltaic arrays across the United States. The researchers use a fully coupled regional climate model, the Weather Research and Forecasting (WRF) model, to investigate feedbacks between surface albedo changes, surface temperature, precipitation and average cloud cover. With the adoption of cool roofs and pavements, domain-wide annual average outgoing radiation increased by 0.16 ± 0.03 W m−2 (mean ± 95% C.I.) and afternoon summertime temperature in urban locations was reduced by 0.11–0.53 ◦C, although some urban areas showed no statistically significant temperature changes. In response to increased urban albedo, some rural locations showed summer afternoon temperature increases of up to +0.27 ◦C and these regions were correlated with less cloud cover and lower precipitation. The emissions offset obtained by this increase in outgoing radiation is calculated to be 3.3 ± 0.5 Gt CO2 (mean ± 95% C.I.). The hypothetical solar arrays were designed to be able to produce one terawatt of peak energy and were located in the Mojave Desert of California. To simulate the arrays, the desert surface albedo was darkened, causing local afternoon temperature increases of up to +0.4 ◦C. Due to the solar arrays, local and regional wind patterns within a 300 km radius were affected. Statistically significant but lower magnitude changes to temperature and radiation could be seen across the domain due to the introduction of the solar arrays. The addition of photovoltaic arrays caused no significant change to summertime outgoing radiation when averaged over the full domain, as interannual variation across the continent obscured more consistent local forcing.
While solar facilities are a viable source of clean energy with many economic opportunities available to developers, landowners, and local communities, their recent deployment has led to a growing recognition of potential land use conflicts. The declining technology costs, tax breaks, financial incentives, and affordability of rural lands have been the main drivers of the recent development of solar facilities across Virginia. However, as these facilities grow larger and more prevalent, they will become an increasingly important component of local land use patterns in many parts of rural Virginia. Accordingly, proper land use planning serves a critical role in ensuring that Virginia successfully meets future clean energy goals while also promoting sustainable and efficient land use practices. Analyzing the ongoing land use impacts of utility-scale solar development, establishing a process for tracking future land use patterns, and providing guidance to consider the best land use practices is the primary purpose of this plan. The goal of this plan is not to undermine the opportunity and potential of solar energy. Instead, this plan seeks to inform solar energy development policies through a land use planning perspective to promote the sustainable development of solar facilities. The recommendations of this plan are intended for the Virginia Department of Mines, Minerals, and Energy and are informed by the results of this research. However, the findings and recommendations for this plan are also informative and useful for a variety of stakeholders. The sustainable development of solar energy facilities in Virginia will ultimately be a collaborative process and the following recommendations are intended to complement the ongoing work of numerous stakeholders across the state.
Wisconsin utilities are partnering with companies that want to develop more clean energy at scale, and support win-win solar development with a voluntary pollinator-friendly standard that will enable bees, birds, and soil to thrive where solar development sprouts up. RENEW Wisconsin answers some common questions about Wisconsin’s evolving solar energy landscape such as existing and developing utility solar arrays, land use, zoning, and benefits to local landowners and governments.
Berkeley Lab’s annual Utility-Scale Solar report presents trends in deployment, technology, capital expenditures (CapEx), operating expenses (OpEx), capacity factors, the levelized cost of solar energy (LCOE), power purchase agreement (PPA) prices, and wholesale market value among the fleet of utility-scale photovoltaic (PV) systems in the United States (where “utility-scale” is defined as any ground-mounted project larger than 5 MWAC). This summary briefing highlights key trends from the latest edition of the report, covering data on projects built through year-end 2020. Median installed project costs have steadily fallen by nearly 75% (averaging 12% annually) since 2010, to $1.4/WAC ($1.1/WDC) among 68 utility-scale PV plants (totaling 5.1 GWAC) completed in 2020 (Figure 3). Costs were lowest in the Southeast ($1.2/WAC or $0.9/WDC) and highest in CAISO. Projects that use single-axis tracking have slightly higher up-front costs than fixed-tilt projects, but the difference has narrowed over time, particularly since 2015. Looking ahead, the amount of utility-scale solar—and solar+storage—capacity in the development pipeline suggests continued momentum and a significant expansion of the industry in future years. At the end of 2020, there were at least 460 GW of utility-scale solar power capacity within the interconnection queues across the nation, 170 GW of which first entered the queues in 2020. Nearly 160 GW of the 460 GW total (i.e., 34% of all solar in the queues) include batteries. Solar (both standalone and in hybrid form, including batteries) is by far the largest resource within these queues, roughly equal to the amount of wind, storage, and natural gas combined. The growth of solar within these queues is widely distributed across almost all regions of the country, with PJM and the non-ISO West leading the way with nearly 90 GWAC each, followed by ERCOT, MISO, and the non-ISO Southeast, each with ~60 GWAC. Nearly 90% of the solar capacity in CAISO’s queue at the end of 2020 was paired with a battery; in the non-ISO West, that number is also relatively high, at 67%. Though not all of these projects will ultimately be built as planned (i.e., entering the queues is a necessary but not a sufficient condition for development success), the ongoing influx and widening geographic distribution of both standalone solar and solar+storage projects within these queues is as clear of an indication as any of the accelerating energy transition and the major role that the utility-scale PV sector will continue to play in the years to come.
Empirical Trends in Deployment, Technology, Cost, Performance, PPA Pricing, and Value in the United States.
The Morris Ridge Solar Project is a proposed solar farm on approximately 1,060 acres in the Town of Mount Morris, southern Livingston County, New York. The project site is within an area farmed primarily in a cash cropping rotation. The Morris Ridge Solar project is being designed to integrate agricultural uses, including a managed grazing system that utilizes sheep grazing to control vegetation growth under and around the solar panels. Sheep grazing is a method of vegetation control used on solar facilities around the world and is increasingly being used in the Northeastern United States to provide a solution that can promote and incorporate an agricultural use within a solar photovoltaic facility. The Morris Ridge Solar project is also being planned to accommodate honeybees and honey production. Through the incorporation of pollinator-friendly vegetation into the project design, solar farms can create suitable habitat for honeybees. Co-locating honeybee apiaries and solar farms has been proven to be a successful method of integrating agricultural use at solar farms throughout North America. The Morris Ridge Solar project will seek to contract the grazing through local farmers who either currently own sheep or wish to expand sheep enterprises as part of their farm business. To engage with these farmers and determine which candidates are best fit for the contracted grazing, MRSEC and AVS have worked to conduct outreach locally and assess interest from the farm community. Initial interest has been solid, with several area farmers expressing interest in contract grazing either parts of the site or the entire site. The solar site will be seeded with a seed mix designed for the special circumstances of the site: grazing, honey production, low-growing, shade and sun tolerant. The seed mix will be selected based on soil testing results, which is scheduled for fall 2020. The seed mix will be something akin to Ernst Conservation Seed’s Fuzz & Buzz Mix. A mix of pasture grasses, legumes (all flowering plants), and forbs (more flowers), it is a diverse and robust blend designed to balance the needs of agrivoltaic production. The seed mix is integral to the vegetation management plan. The vegetation management is planned to support perennial pastures that nearly always have flowering plants. This perennial rotation of the sheep keeps vegetation in sequence of rest and grazing. This sequence is cyclical, and the structure allows the legumes and forbs time to flower from May to October. With the planned rotation of the sheep, the availability of nectar from flowering plants across a large area that are stimulated to bloom consistently throughout the season should allow the bees to thrive. EDF-Renewables has taken care to strategically plan for a high level of agricultural integration at the Morris Ridge Solar Facility. The solar facility is proposed to create a new opportunity for a livestock grazier and a commercial honey producer in the region. Over the rest of 2020, AVS and EDF-Renewables will work to find the right farm partners to facilitate the plans identified above. The construction plans will be fine-tuned with a grazing operation in mind. The future site graziers will have several years to bring their livestock operations up to speed in harmony with the construction schedule. Our team looks forward to project success that incorporates and strengthens the regional agricultural community in the Morris Ridge Solar Project.
Across the U.S., many cities, counties, and states are taking advantage of affordable renewable energy sources, such as solar and wind energy. Over the past nine years, the price of installing solar energy projects has decreased by 70 percent, while the average cost of constructing a wind energy project has fallen by more than 67 percent per kilowatt hour since 1983.1,2 This rapid decline in cost has empowered Americans to embrace affordable, clean, and renewable energy. While all investments in conservation promote environmental improvement, developers can follow a few best practices to ensure project success. For example, native seed mixes offer the greatest return on investment when aiming to provide ecosystem services, such as habitat for pollinators and wildlife, as well as improved water quality and soil health. If possible, project developers should prioritize native seed selections over naturalized, non-invasive species of vegetation. Pollinators play a critical role in the robust food, fuel, and fiber production economy of the Midwest. By pollinating agricultural crops, this group of insects is crucial to ensuring economic and food security. Research shows the populations of all pollinators, including honey bees, native bees, and monarch butterflies, were three-and-a-half times greater on sites with investments in the reestablishment of native vegetation in central Iowa when compared to control sites. Seeding a site with native and naturalized, non-invasive vegetation presents opportunities for the introduction of livestock grazing for management. For example, pollinator-friendly solar sites have seen success with rotational grazing of sheep as a management option. Sheep are recommended for pollinator-friendly solar projects because goats and cattle could cause damage to on-site equipment. Renewable energy sources, such as wind and solar, are growing rapidly. As the industry continues to create hundreds of thousands of jobs, stimulate local and state tax revenue, and reduce greenhouse gas emissions, new investments in electric transmission infrastructure will inevitably occur. By developing resources for site managers of renewable energy infrastructure, public officials at all levels are well positioned to add value to these projects. Investments in native and naturalized, non-invasive vegetation ensure habitat for at-risk pollinators, including the monarch butterfly, while creating habitat for vulnerable wildlife species. These species are crucial for economic and food security in the Midwest and underwriting renewable energy projects with perennial vegetation improves quality of life for all.
This publication reviews planning the use of land for large-scale utility solar energy.
Wind and solar farms offer a major pathway to clean, renewable energies. However, these farms would significantly change land surface properties, and, if sufficiently large, the farms may lead to unintended climate consequences. In this study, we used a climate model with dynamic vegetation to show that large-scale installations of wind and solar farms covering the Sahara lead to a local temperature increase and more than a twofold precipitation increase, especially in the Sahel, through increased surface friction and reduced albedo. The resulting increase in vegetation further enhances precipitation, creating a positive albedo–precipitation– vegetation feedback that contributes ~80% of the precipitation increase for wind farms. This local enhancement is scale dependent and is particular to the Sahara, with small impacts in other deserts. Efforts to build such large-scale wind and solar farms for electricity generation may still face many technological (e.g., transmission, efficiency), socioeconomic (e.g., cost, politics), and environmental challenges, but this goal has become increasingly achievable and cost-effective. These results indicate that renewable energy can have multiple benefits for climate and sustainable development and thus could be widely adopted as a primary solution to the challenges of global energy, climate change, and environmental and societal sustainability.
Utility-scale solar development has expanded rapidly across the U.S. in recent years, driven by declining costs and improving technology. The most recent Lazard levelized cost of energy (LCOE) analysis shows utility-scale solar now equivalent to or below the cost of conventional generation, with a price range of $36-44 per megawatt-hour (MWh). Thirty-two gigawatts (GW) of utility-scale solar have been installed in the United States to date, and another 50 GW are planned or in development. By 2030, the Department of Energy SunShot program estimates that solar development will encompass between 1 to 3 million acres of land. As the geographic footprint of solar increases beyond the arid southwestern United States, so too has interest in the land use under the panels. In these new geographies, including the Midwest and Northeast, solar is often sited on agricultural land. The ideal tract of land for solar development is flat, dry, unshaded, and close to transmission and load. All of these characteristics are associated with farmland, raising possible tensions between solar and farming as competing land uses. For the most part, solar developers plant shallow-rooted turfgrass or spread gravel under panels, rendering that land unproductive aside from the generation of electricity. However, the co-location of solar projects and innovative vegetation management plans offers the potential to ameliorate this potential land use conflict. Improving the “landscape compatibility” of utility-scale solar has become a topic of great interest in the energy, land use and agricultural research communities. Examples of co-location include growing crops underneath solar trackers; grazing cattle or sheep among elevated solar panels that also provide shade for the livestock; and installing solar in the non-irrigated corners of center-pivot irrigation plots. These approaches can be grouped under the recently coined umbrella term “agrivoltaics.” The researchers developed an Excel-based modelling tool to understand the tradeoffs, costs and benefits between maintaining land as conventional farmland or converting a portion of it to either a conventional solar facility or a pollinator-friendly solar facility. The model accounts for spatial, economic and environmental differences across three counties in South-central Minnesota: Fillmore, Hennepin and Rock. The model is designed as a cash-flow project finance model that incorporates monetized environmental and social costs and benefits. As project finance is the predominant method for financing solar projects in the United States, and a large proportion of a project’s financial return is delivered through preferred tax status and tax credits, they modeled both pre- and post-tax cash flows from the solar projects. Their model also includes a cash-flow operating model for a conventional soy or corn farm. For all land uses, the model incorporates the monetized value of environmental externalities, including carbon emissions, soil erosion and groundwater recharge. Not all externalities and ecosystem services were modeled, due to data limitations and difficulties in quantifying benefits such as habitat creation and biodiversity. We created multiple scenarios within the model to analyze differences in private and social value streams across counties, crop type, and a range of upside and downside inputs. The model outputs are a series of cost-benefit analyses comparing the three main land uses — pollinator-friendly solar, conventional solar, and farming. The financial return of each use varies by crop type, location and upside/downside scenarios. Solar development in Minnesota and across the Midwest is poised to continue on land traditionally devoted to conventional agriculture. Growing interest in low-impact solar development and co-location of solar projects with pollinator-friendly plants represents an opportunity to mitigate energy-versus-food tensions and provide additional benefits to agriculture, ecosystems, and private developers alike. The model presented in this paper takes an important step towards quantifying and monetizing the benefits of pollinator-friendly solar development as a land use option in Minnesota. Understanding the full monetary value of pollinator-friendly solar is necessary to design policies that efficiently and effectively support its development in locations that optimize project value. As the practice continues to gain popularity, there is a pressing need for additional research that clarifies the value of ecosystem services created by this innovative land use. Improved understanding of the diverse social and private benefits of pollinator-friendly solar will allow for strategic deployment of these projects — and will maximize returns for all stakeholders.
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