Fixed-tilt mechanical racking, consisting of proprietary aluminum extrusions, can dominate the capital costs of small-scale solar photovoltaic (PV) systems. Recent design research has shown that wood-racking can decrease the capital costs of small systems by more than 75% in North America. To determine if wood racking provides enough savings to enable labor to be exchanged profitably for higher solar electric output, this article develops a novel variable tilt angle open-source wood-based do-it-yourself (DIY) PV rack that can be built and adjusted at exceptionally low costs. A detailed levelized cost of electricity (LCOE) production analysis is performed after the optimal monthly tilt angles are determined for a range of latitudes. The results show the racking systems with an optimal variable seasonal tilt angle have the best lifetime energy production, with 5.2% more energy generated compared to the fixed-tilt system. Both fixed and variable wooden racking systems show similar LCOE, which is only 29% of the LCOE of commercial metal racking.



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 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

Wavelength-Selective Photovoltaic Systems (WSPVs) combine luminescent solar cell technology with conventional silicon-based PV, thereby increasing efficiency and lowering the cost of electricity generation. WSPVs absorb some of the blue and green wavelengths of the solar spectrum but transmit the remaining wavelengths that can be utilized by photosynthesis for plants growing below. WSPVs are ideal for integrating electricity generation with glasshouse production, but it is not clear how they may affect plant development and physiological processes. The effects of tomato photosynthesis under WSPVs showed a small decrease in water use, whereas there were minimal effects on the number and fresh weight of fruit for a number of commercial species. Although more research is required on the impacts of WSPVs, they are a promising technology for greater integration of distributed electricity generation with food production operations, for reducing water loss in crops grown in controlled environments, as building-integrated solar facilities, or as alternatives to high-impact PV for energy generation over agricultural or natural ecosystems.

Collocating solar photovoltaic (PV) technology with agriculture is a promising approach towards dual land productivity that could locally fulfil growing food and energy demands particularly in rural areas. This ’agrivoltaic’ (AV) solution can be highly suitable for hot and arid climates where an optimized solar panel coverage could prevent excessive thermal stress during harsh weather thereby increasing the crop yield and lowering the water budget. One of the concerns with using standard fixed tilt solar array structure that faces north/south (N/S) direction for AV farming is the spatial heterogeneity in the daily sunlight distribution for crops and soil water contents, both of which could affect crop yield. Dynamic tilt control through a tracking system can eliminate this problem but could increase the system cost and complexity. Here, we investigate east/west (E/W) faced vertical bifacial panel structure for AV farming and show that this could provide a much better spatial homogeneity for daily sunlight distribution relative to the fixed tilt N/S faced PV structure implying a better suitability for monoculture cropping.

Montana Renewable Energy Association (MREA) gives steps, tips, and tricks to install solar at your home, businesses, farm or ranch, or school to save money on energy and increase your energy independence. Installing solar at your home, businesses, farm or ranch, or school will save you money on your energy bills and increase your energy independence. (1) Gather information: Do some research online and talk to the Montana Energy Office at the Dept. of Environmental Quality and a renewable energy advocate like the Montana Renewable Energy Association (MREA). A few questions to consider: Do you have a location on your property in mind already? Roof? Ground? Does the location get sun? Do you want to stay connected to the grid, or go off-grid? What is your budget for the project? (2) Contact local solar installers: Request bids from several installers to find the right fit and price for you. Ask for an in-person site visit to assess structural issues, electrical connections, and shading. Review historical energy usage to size the system properly. Discuss your energy goals. Do you want to cover all of your energy use or just some? (3) Review costs and financing: Does the cost meet your budget? Will you save as much as you were hoping on your energy bills? What tax credits are available to you? What loan or financing options are available? (4) Sign a contract: Once you’ve made your decision to move forward, contact your installer and sign a contract. Then, work can begin! (5) Installation: The timeline will depend on things like weather and the installer’s schedule, and inspection appointments. For net metering customers, expect additional time for the utility to install your net meter. (6) Start producing energy: Congratulations! Every kWh you produce is saving you money and increasing your energy independence.

This report compares the economics of a solar rooftop mandate for new detached residential homes with a conventional home with gas heating and central air-conditioning. The home with rooftop solar is assumed to be an all-electric, net-zero-energy home that would generate as much solar electricity on its rooftop each year as it uses. The gas-heated home would be built to the same standard in all respects other than the gas space and water heating and gas cooking are replaced by efficient electric devices in the net-zero-energy home. The context is Montgomery County’s 2017 ambitious climate emergency resolution and a more recent statement by County Executive Marc Elrich about the possibility of a rooftop solar mandate. The County’s goal is to reduce greenhouse gas emissions by 80% by 2027 and achieve 100% elimination of emissions by 2035

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. We 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.

The potential resource base for PV in the United States is enormous; however, there are a number of challenges related to realizing this potential including relatively high cost, intermittent output, and potentially significant land use. The costs of PV have been declining significantly during the past couple of decades, and there are strong prospects for further declines in cost during the next decade. The issue of intermittency can be addressed through a number of potential means, and will likely become increasingly important as market penetration increases beyond a few percent of electricity consumption. The issue of land use is often cited as an important issue for renewable energy technologies. Determining the land requirements of solar PV at high penetration helps evaluate its potential to reduce both the carbon emissions and the “Ecological Footprint” associated with electricity generation and use.