Performing Department
(N/A)
Non Technical Summary
RUTE SUNTRACKER (RST) is a new hardware solution that supports PV solar above cattle pasture. RST is a cable-stayed, pole-mounted, high-clearance solar tracker system. High-clearance solar saves rangeland, saves water, and increases farm income, especially important for small ranches where income has decreased below sustainable levels due to climate stress. RST addresses USDA Strategic Goal 1: Combat Climate change to support America's working lands, natural resources and communities.The problem RUTE is addressing is the pressure to convert rangeland to solar and its effect on the rural communities. Solar is estimated to pentuple its existing footprint over the next 10 years and ranchland (and farmland) represent 2 of the most profitable land classes for development, as they have already been self-selected for optimum weather. Many of these properties are well positioned near load, making them extremely advantageous for PV development. Solar rents are well in excess of profits achieved through ranching, yet ranchers are reluctant to change their way of life and negatively affect their communities by converting to solar. RUTE's solution will allow ranching activities to co-exist with solar. This is particular of import to rural communities as the loss of even a few jobs can send a teetering community into a negative spiral. A ranch not only supports the direct labor onsite, but also all the supporting activities for the livestock (feed, medical, slaughter) and all the spending of the hands themselves (groceries, banks, grange halls).This SBIR will provide the funding to create and test a9 pole-mounted 20'x20' racks (suitable for holding solar panels), 12 cable anchorages (pitch poles), diagonal cables to stay the poles, 3 sets of rotator cables running N/S, and related winches mounted in the pitch poles. The test array will be used to evaluate the key components of the structure for strength and reliability. These tests will includeLoad tests in windy conditions to test cable requirementsLoad tests to test anchorages and materials with respect to cattle interactions.Winch test to determine accuracy and strength in calm and windy conditionsControls (SCADA) testing to confirm reliable and repeatable methods to position the solar panels to track the sun. RUTE seeks to show that our solution will be a cost effective way to develop solar lands on existing ranchland in a way that will benefit the landowner and not degrade the livelihood of the surrounding community. We hope this will not only benefit rural communities financially, but also reduce the friction in solar development and facilitate economically smart solar development that is good locally, regionally, and globally.
Animal Health Component
40%
Research Effort Categories
Basic
(N/A)
Applied
40%
Developmental
60%
Goals / Objectives
RUTE SUNTRACKER (RST) is a new hardware solution that supports PV solar above cattle pasture. RST is a cable-stayed, pole-mounted, high-clearance solar tracker system. Our topic is "Development of technologies & services that protect or enhance the environment & address climate change while promoting economic development." To accelerate the development and utilization of this agrivoltaics technology allowing small ranchers to participate in the solar economy, RUTE proposes to complete construction of a 3x3 RST array and begin to optimize the most commercial design. The complete structure will serve as our experimental test bed to validate our assumptions or create more refined solutions. These tests will provide valuable experimental evidence to support the field work and computational estimates performed to date. A proving ground site at the Oregon Manufacturing Innovation Center has already been secured with approximately ? of our components fabricated and installed The site plan right notes the elements that are needed.After completing construction of the 3x3 array test site. RUTE will research and develop 5 key elements so the product becomes a scalable solution with the following key questions to be answered. The tests in the R&D method column are explained in the Work Plan.The final technical objective is to survey stakeholders on the impact of dual-use solar, answering the following questions: (1) Would high-clearance agrivoltaics make a measurable impact in the viability of small ranches and their community? (2) Does high-clearance agrivoltaics use reduce siting issues in rural locations?6.1 Objective 1: Construct 3x3 array. 6 WeeksThe aim of the first objective is to construct a 9 pole array to allow for Objective 2, R&D efforts. Most RST components come from stock hardware, similar to conventional solar racking, and the prices for these are displayed in the budget justification. Local steel fabricators will fabricate custom components, such as the Stem Collar. Flatline Fabricators fabricated prototypes for the OMIC RST in summer 2022. Off the shelf jeep winches are currently installed at the test site, and these will be replaced in iterations with customized and scalable winch solutions that optimize the voltage, motor design, drum torque and cable payout capacity. The fabrication of scalable winches are included in the budget with Allied.Procurement of materialsFabrication of rack componentsPlacement of Stem Anchors & Reinforcement of Pitch Pole AnchorsAssemble Frames & ArraySetup SCADA Controls & Monitoring System6.2 Objective 2: Research & Development on Key Elements. 14 weeksThe tests below will be performed at the proving ground. The proving ground will be operational for a period of 14 weeks to experience a range of weather conditions and wind speeds and to implement component and system tests and optimizations.Key Element: Load Validation: Cow & wind load tests will enable us to optimize our design. The data will improve our structural models and validate that building standards are met. This in turn informs the specifications particularly of large components, our Pitch Poles anchors, cable trellis system, Stem and Lower Joint.Wind load test. Measure the force in the cables with 4 load cell sensors, one on each of the two rotator cables and the two stabilizer cables that lead to a single RST. Collect in a data logger for a 1 month period. Resting tension should be 800 lbs. Correlate the continuous force data with the anemometer data. Record measurements every 10 seconds. Verify and QA calibrations and results under different weather conditions.Cow load test. A cow impulse load will be simulated on a Stem of the array with a hydraulic jack. Load cells will measure the forces applied to the stem and the resultant forces on the cables. Deflection of the Stem and Footing will be measured to the ?-in. This will inform the Lower Joint optimization, as well as data for 3rd party validation of structural integrity. RUTE has sponsored an OSU Environmental Engineering Capstone Team to model cow forces on the RST. As an exception to the other R&D objectives, this will be completed before procurement on the already erected Stem & Lower Joint at OMIC.Key Element: Winches: The objective is to prototype a scalable winch. RST winches are the physical muscle of the system and control the cables. Krause will lead this task along with Allied. This team will be augmented by Kobierski, who will act as a component technician at OMIC. The 1-line diagram and wiring diagram will be completed by Solar Design Studio (see letter of support). The team will iterate through component options and then test the parts experimentally at the proving ground, seeking the right motor-gearbox-drum combination. A key product of this work is specifications for higher voltage scalable winches; the ubiquitous 12V winches are not economical due to their high amps and excessive copper conductor wire. Three tests will be carried out to optimize the winch design:Winch pull test. The winches must have the required capacity to move cables that rotate, raise and stow the full 3x3 array, and at scale, a 24x24 pole array. This will be tested by its capability to lift a block (e.g. concrete) of known weight.Winch brake test. The brake capacity is used to resist the wind loads on the system, up to a maximum of 120mph. To test this, another winch with sufficient pulling capacity will pull on the prototype winch cable to confirm the braking limit.Winch accuracy test. In order to accurately position the Blumes to track the sun, the winches must move the cable to a required precision. This will be tested by its ability to respond to the SCADA commands and position the RST within the acceptable tolerance.Key Element: Cable Clamps: To attach the cables to the Cable Collar and to the ends of the Blume, custom cable clamps will be designed. Standard cable clamp hardware is tedious, and not adjustable. A specifically tailored clamp is needed that provides simple installation, adjustment, and easy maintenance at the Blume elevation. The models for this component may derive from the lineman's Klein tool, ski chair cable hardware, and rigging tools. Krause will develop the cable clamp with assistance from Studio Murmur, an industrial design and product development studio with relevant experience and access to manufacturing (see alpha design above). Like the other components, a first prototype will be built, installed, tested and iterated through optimization steps.The capacity of the clamp will be pull tested by fixing the clamp and applying a large force.The cable clamp will then be judged on ease of use (determined by Kobierski and Krause) and cost to fabricate at scale.Key Element: SCADA: The SCADA system has been developed to the extent that the winches at the proving ground can now be controlled automatically and run on code. However a complete SCADA system needs to be built that takes inputs from sensors for weather awareness, position awareness and safety feedback, such that it can provide reliable year round tracking. Kobierski will install iterations of hardware and controller code and run and test implementations.6.3 Objective 3: Survey Impact of Dual-Use Solar. 10 Weeks.RUTE will engage rural extension services and county economic development offices to gauge the potential impact of creating a "second crop" for ranchers. RUTE will work with Business Oregon, Farmland Trust, Cattlemen's Associations, and/or the Oregon State University Extension Service to survey ranchers in 2 representative U.S. regions to understand their response to high-clearance agrivoltaics. The survey will focus on the (1) value of preserving ranching and related jobs and (2) if high-clearance solar facilitates siting issues. Time permitting, the long term value of providing shade to reduce heat stress will be explored.
Project Methods
MethodsThe main method for this project is building a complete demonstration array structure. Some components can be tested individually (winches) in advance, but others (cables, panel array, SCADA) it is the interrelation of the elements that is unknown, so it will require the full array to be built before testing can be performed.The main experiments will be stress testing of the loads on each element and preliminary evaluation of lifecycle testing. In each case we will compare the results from our experiments with our hypothesis and seek to confirm our estimates. Furthermore, we will use the wind data to extrapolate the full force that extreme wind events may have on the array to determine if additional reinforcement will be necessary to conform to any structural code requirements.and For each element, it will be placed into use and loads will be measured.EffortsOur efforts during this phase 1 will be limited. As we use the information gathered under these experiments to finalize our design we will share our findings as part of our marketing. We do not anticipate scientific publication as a result of our work under this phase 1. We do however anticipate significant findings once our demonstration array (and commercial arrays are deployed) has been installed. We are making every effort to partner with OSU scientists to evaluate the effect our array will have on the soil, crops, and livestock underneath our structures. We anticipate that after our phase 2, there will be several interesting findings.Evaluation.The methods above describe the experiments that RUTE will undertake to evaluate both the components and the interrelated elements. Our success factors for the product are as follows.Measured wind force on the cables in conformance with anticipated calculations.Extrapolated wind force calculations from experimental data shows stability in 120mph lateral winds from all directions. This includes cables, clamps, and winches (as well as all other structural elements)Winch is able to provide turning accuracy within 3"Winch controllers are 99% accurate in responsiveness to SCADACable clamps maintain their ability to hold against 70mph winds with a 2x safety factor.