University of Alaska Anchorage Solar PV Pre-Feasibility Assessment
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Alaska Center for Energy and Power Technical Report University of Alaska Anchorage Solar PV Pre-Feasibility Assessment Henry Toal Erin Whitney Michelle Wilber Chris Pike May 28th, 2020 1 Table of Contents Executive Summary ....................................................................................................................................... 3 Introduction .................................................................................................................................................. 5 Existing Solar PV Systems in Alaska .......................................................................................................... 5 Overview of a Typical Solar PV System ..................................................................................................... 5 Photovoltaic (PV) Panels ....................................................................................................................... 5 Mounting and Racking .......................................................................................................................... 5 Inverters ................................................................................................................................................ 5 What to Expect from this Pre-Feasibility Assessment .............................................................................. 6 Why There are Two Simulations for Each Rooftop Model ................................................................... 6 Wall-Mounted System Models ............................................................................................................. 6 Parameters Used to Compare Buildings ............................................................................................... 7 Policies for Installing Solar PV on Alaska’s Railbelt ....................................................................................... 7 Net Metering ............................................................................................................................................. 7 Qualified Facility........................................................................................................................................ 7 Power Purchase Agreement (PPA) ............................................................................................................ 7 Assumptions and Technical Details ............................................................................................................... 8 Panels ........................................................................................................................................................ 8 Rooftop Systems ....................................................................................................................................... 8 Tilt ......................................................................................................................................................... 8 Row Spacing .......................................................................................................................................... 8 Shading .................................................................................................................................................. 8 Rooftops ................................................................................................................................................ 9 Weather Data ........................................................................................................................................ 9 Wall-Mounted Systems ............................................................................................................................. 9 Walls ...................................................................................................................................................... 9 Buildings Ranked by Productivity at 10% Maximum Shading ..................................................................... 10 Appendix – Aurora Solar Reports ................................................................................................................ 12 2 Executive Summary As solar photovoltaic (PV) technology matures, the amount of energy harvested per square foot of roof space is increasing while, at the same time, installation costs are decreasing. As this trend continues, the economics of installing a solar PV array in a high-latitude location, such as Alaska, continue to improve. Before committing resources to a solar energy project, it is important understand which locations on a property would be most ideal for siting a solar array, both in terms of (1) the size of array and (2) how much energy per 1 square foot can be generated. This report provides an Rank Building Name Productivity in-depth analysis of 27 buildings on the University of [kWh/kWp] Alaska Anchorage (UAA) campus based primarily on Eugene F. Short Hall 1 these two criteria and also contains a ranked list of (ESH) 900 the buildings based on their respective productivity Gordon W Hartlieb 2 (how much energy can they produce relative to their Hall (GHH) 896 theoretical maxima). 3 Central Parking Garage (CPG)* 894 This analysis was completed using Aurora Solar, a 4 Auto/Diesel program which integrates three-dimensional Technology Building 892 modeling, satellite imagery, solar irradiance data, and (ADT) elevation data to accurately simulate solar 5 Seawolf Sports productivity and shading of a given roof surface and Complex (SSC) 885 automatically generate solar array configurations for 6 Social Science Building maximum efficiency. Each building was rendered in (SSB) 883 Aurora and tested under 365 days of simulated 7 Health Sciences sunlight with one varying parameter: maximum Building (HSB) 883 allowed shading of the solar array. For each building’s Engineering & roof surface, this shading parameter variation 8 Industry Building (EIB) 878 allowed for a comparison between an array design 9 Administrative/ where panels where placed strategically to minimize Humanities Building 878 shading and an array design on the same roof where (ADM) panels covered the entire usable roof surface. Where 10 Wendy Williamson possible, wall-mounted systems were also modeled Auditorium (WWA) 878 and simulated under similar conditions. Table 1 – Top 10 UAA Campus Buildings for Productivity To ensure an accurate comparison between *Assuming a solar canopy were to be installed over the top level of CPG buildings, each Aurora simulation was done using identical technical parameters such as the spacing between rows of solar panels, the offset from the edges of roofs, solar irradiance data, and the way in which objects, such as trees, impacted productivity. These technical details as well as the assumptions made during this analysis are explored in further depth below. This assessment is the first step in making an informed decision about expanding UAA’s solar PV capacity. It provides an analysis of the solar resource potential of each roof but does not take into account engineering factors such as the condition of the roof, wind shear, weight requirements, etc. It also does not consider the economics behind any of the rooftop systems. For an actual project, the next steps would include the solicitation of a detailed bid from qualified solar installers. 1 Measured as kilowatt-hours per peak kilowatt (kWh/kWp). This is a widely accepted standard metric for the relative productivity of a solar PV array. 3 Figure 1 – UAA Campus Map with Buildings Color Coded by Productivity 4 Introduction Before exploring the technical details of how the UAA campus roofs were analyzed, it is important to understand the current state of solar PV power production in Alaska. Existing Solar PV Systems in Alaska In recent years, the number and size of installations on Alaska’s Railbelt have been growing rapidly. The region had almost no grid tied solar PV systems in 2010 when Alaska’s net metering law went into effect, and now there are almost 63 MW of installed capacity. Many of these systems are small residential and commercial systems under 25 kW, but more recently larger systems have been constructed, including a 563 kW array installed in October of 2018 that is owned and operated by Golden Valley Electric Utility, and a 1,300 kW system completed in Willow, Alaska in 2019. The latter system is owned and operated by Renewable IPP, a private developer with a mission to “increase the renewable energy contribution to Alaska's power supply by developing economically viable, commercial scale solar PV energy projects.” Overview of a Typical Solar PV System To better understand this assessment’s findings, it is helpful to summarize the basic components that make up a solar PV system and how they function together to produce usable electricity. While the exact system equipment will vary depending on user needs and system size, commercial grid-tied systems such as any of the potential systems found in this report will always have a few necessary standard components. Photovoltaic (PV) Panels Typically constructed from a grid of silicon wafers, PV panels use sunlight to excite electrons and create an electric current. They produce direct current (DC) electricity, as opposed to the alternating current (AC) that is distributed via the electric grid and provided from wall outlets. In order to utilize power produced from solar panels, DC power must be converted to AC power using an inverter. Mounting and Racking Mounting racks