Baraga Solar

Alternative Energy Enterprise - Fall 2020 Final Report

December 18th, 2020

Advisors: Jay Meldrum, Dr. David Shonnard

Team Members:

      Anna Browne                Sophie Owen

Jessie McInnis                Jenna McClintock                

Table of Contents

Introduction         2

Background        2

Scope          3

Working with the Keweenaw Bay Indian Community (KBIC)        3

Site Evaluation         4

Module Selection        10

Inverter Selection        12

Tracker and Racking System           13

System Size and Production Modeling        15

Economic Analysis        20

Conclusion and Future Work        21

References         23

Appendices         26

Appendix A        26

Appendix B        27

Appendix C        28

Appendix D        29

Appendix E        30

1. Introduction

The goal of the Baraga Solar project is to design multiple solar panel arrays in Baraga, MI, providing the Keweenaw Bay Indian Community (KBIC) a yearly energy royalty to reduce their overall energy costs. Motivation for this project stems from the KBIC’s desire to decrease their reliance on fossil fuels, reduce energy costs, and be a positive force in the community. Upon completion of the project, the array designs will be chosen with input from a solar installation company, a detailed financial analysis will be completed, and a guide for future installations in other Upper Peninsula and rural communities will be created. The majority of the project work completed this semester focused on establishing a relationship with the KBIC, selecting potential sites for the solar arrays, and completing production modeling.

2. Background

In communities across the United States, residential homeowners and business owners are seeking alternatives to conventional energy sources. The Keweenaw Bay Indian Community (KBIC) has recognized the potential benefits solar energy has to offer, including: reduction on operating costs, the return on the initial investment, opportunity for local jobs, and more [1]. Whether they aim to increase energy independence, invest against rising fuel costs, cut carbon emissions, or provide local jobs, they are looking to community-scale renewable energy projects for solutions. Advances in solar technology, an increase in federal and state tax incentives, and creative new financing models have made solar projects more financially feasible.

This project aims to provide an opportunity for the Keweenaw Bay Indian Community (KBIC) to invest in clean and efficient energy production. The project team plans to analyze potential cost savings and carbon emissions reductions that would be associated with building a solar project within the KBIC. The solar project is a way for the community to control their electric utility costs while helping to reduce their dependence on fossil fuels and energy companies.

With an increasing demand for cleaner energy production methods comes a need to provide “green” energy options where they may not be possible. Solar energy has long been dismissed in the Upper Peninsula of Michigan due to the cold, snowy winters with very short days. However, recent success of solar at higher latitudes has proven that solar is possible with shorter days, and various studies completed by the Keweenaw Research Center have shown that snow is not as large of a deterrent to solar as originally thought [2]. Additionally, the Keweenaw Bay communities have had a desire for increased energy dependence on solar. This can be seen in L’Anse, the city partially within the KBIC, with the L’Anse Community Solar Project completed in the Summer of 2019 [3]. Social studies completed by Chelsea Shelly and Richelle Winkler have determined that solar is a goal of the communities in the Keweenaw Bay [4].

3. Scope

The main objective of this project is to research and design several solar arrays based on multiple realistic constraints with the unique investment opportunity for the Keweenaw Bay Indian Community. Upon completion of the project, several aspects of the proposed solar arrays will be determined. These aspects are shown below

1. Detailed site analysis

1. Power bill analysis
2. Weather
3. Shading assessments

2. Production modeling of the site to determine solar production potential
3. Detailed engineering design of several systems for each site, 

1. Modules
2. Inverters
3. Racking system

4. Computer aided design of the system
5. Detailed economic analysis

1. Payback periods
2. Localized cost of energy (LCOE)
3. Return on investment (ROI) of each system

This project will be used to further cement the feasibility of solar within the Upper Peninsula of Michigan and other rural communities.

Based on the size and location of the installation site as well as the size of the Baraga customer community, four main sites will be considered within the Keweenaw Bay Indian Community: the Keweenaw Bay Tribal Hatchery in Pequaming, the Community Gardens on Brewery Road in L’Anse, two Tiny Homes in Zeba Trailer Park C, and the Ojibwa Casino in Baraga. Once a location is deemed feasible, system sizes will be developed for a potential solar system at each site. Some realistic constraints to determine which system will be implemented include the cost per panel, initial investment cost, payback period, and the cost of energy over the period. By increasing the size of the system, the cost per panel and the total cost of energy will decrease.

4. Working with the Keweenaw Bay Indian Community (KBIC)

This project expands on solar in the Keweenaw Bay Indian Community (KBIC). The KBIC is a federally recognized indigenous group located in the Keweenaw Bay area of Baraga County, Michigan [5]. The KBIC is part of the Michigan Community & Anishinaabe Renewable Energy Sovereignty (MICARES) project, a project that helps solve important societal problems related to access to low-carbon and affordable energy. In order to ensure success in the transition to renewable energy, the MICARES project explores the best practices for improving decision making. The MICARES project engages with Anishinaabe Tribal Nations and non-tribal rural communities. An outline of the project can be found in Appendix A.

        The team worked with KBIC and MICARES this semester and also attended meetings with the two groups. Valoree Gagnon gave the team a presentation on tribal nation sovereignty. The team found this presentation very informational and used it to learn more about working with the KBIC. The meetings helped the team learn about the potential sites and their energy needs and provide updates about the project to the KBIC. The findings of the energy bill analysis and site evaluations were presented to MICARES. MICARES was also updated on the next steps and future work of this project.

        A list of individuals involved in the project can be seen below.

1. Valoree Gagnon - MTU Director, University-Indigenous Community Partnerships, Great Lakes Research Center
2. Kathy Halvorsen - MTU Associate Vice President for Research Development
3. Jay Meldrum - MTU Alternative Energy Enterprise Advisor
4. Dione Price - Environmental Specialist for Environmental Services
5. David Seppanen - Hatchery Foreman
6. Evelyn Ravindran - Natural Resources Director (Department of Natural Resources)
7. Sarah Smith - Former CEO of the KBIC
8. Larry Denomie - Manager of the Ojibwa Casino
9. Doreen Blaker - Treasurer of the Tribal Council
10. Chris Swartz - President of the Tribal Council

5. Site Evaluation

Site evaluations were one of the main focuses of project work this semester. Before shading data and power cost analyses could be completed for each site, the team communicated with the Keweenaw Bay Indian Community (KBIC) to determine which sites would be considered for solar systems. Initially, the project involved working with both the KBIC and the Village of Baraga. However, after speaking with representatives from both entities and consulting with the Alternative Energy Enterprise’s advisors, it was decided that this project will focus solely on designing solar systems for the KBIC.

        Four sites were chosen by the KBIC as potential locations for solar arrays. They include the Keweenaw Bay Tribal Hatchery in Pequaming (Figure 1), the Community Gardens in L'Anse (Figure 2), the Ojibwa Casino in Baraga (Figure 3), and two tiny homes located in Zeba Trailer Park C in L'Anse (Figure 4). Once the site locations were established, the team visited each site in October with help from David Seppanen, a KBIC hatchery foreman.

Figure 1. Google Earth Image Showing Potential Sites at the Keweenaw Bay Tribal Hatchery in Pequaming

Figure 2.  Google Earth Image Showing Potential Sites at the Community Gardens in L'Anse

Figure 3. Google Earth Image Showing Potential Sites at the Ojibwa Casino in Baraga

Figure 4: Google Earth Image Showing Potential Sites at the Zeba Trailer Park C in L'Anse

At each site, the Solar Pathfinder was used to get an estimate of the shading. This device, which can be seen in Figure 5 , gives a panoramic view of the entire site on its transparent, plastic dome [6]. Trees, buildings, or other structures that would potentially block the sun can be seen on the sunpath diagram. To use the Solar Pathfinder, one would trace the outline of all trees and buildings. Once this has been completed, the numbers that are not blocked by the outline are added together. This gives the percentage of total radiation for south facing surfaces that is NOT impacted by shading. An example of how the Solar PathFinder works can be seen in Figure 6. This image shows the sunpath diagram with tracing for the Pequaming Fish Hatchery site. At the Fish Hatchery there are two potential locations for solar arrays. Figure 6 shows location one, which is in front of the main office. The percentages for location one are shown in Table 1. These percentages indicate how much total radiation the site would receive after accounting for shading blockages. Shading at the Fish Hatchery was overestimated in order to account for the seasonal change of leaves on deciduous trees. In the winter months, which is when the shading assessment was completed, there will be less shading at the site.

Figure 5. A diagram of the Solar PathFinder

Figure 6. Sunpath Diagram Used to Evaluate Shading at Site One for the Pequaming Fish Hatchery

Table 1. Total Radiation Percentages at Location One of the Pequaming Fish Hatchery

 As of right now, the Fish Hatchery is the only site for which a detailed shading analysis has been completed. Next semester the team will complete a shading analysis for each of the three remaining sites.

Another important aspect to consider at each site is the amount of snowfall. As each site is located close to L'Anse county, the data for L'Anse will be used. Figure 7 shows the average annual snowfall in L'Anse per month. As seen in the graph, L'Anse has a much higher average snowfall than the rest of Michigan or the United States. This data will be taken into account for the SAM production modeling in order to get an accurate reading of the AC power produced by the solar arrays. Additionally, this data will be used to determine the best racking and tracking systems for each site. Snow accounts for approximately 5-12% of power losses for solar arrays [2]. This information will be used in the SAM production modeling in order to obtain the proper data for power production by the solar system.

               Figure 7. Average Annual Snowfall in L'Anse by Month [7]

In addition to the shading evaluation, a power cost analysis was started for each of the four sites. This analysis was completed using information from power bills provided to the team by KBIC members. As of right now, only the power bills for the Fish Hatchery and the Community Gardens have been received. Once the other bills have been provided, the team will complete a power cost analysis for the remaining sites.

For the Pequaming Fish Hatchery, three different power bills for 2019-2020 were given. Each power bill was summarized in a table, an example of which can be seen in Table 2. These tables show the electricity cost in price per month, minus the monthly demand charge, the usage in kWh, and the price per kWh. It is important to note the difference between kW and kWh. Kilowatts (kW) are a measure of power, which is a rate of electricity usage. Kilowatt-hours (kWh) are a measure of energy, or the total amount of electricity used. The values for each power bill were added together to get a total price per kWh. This was found to be $0.1513. This value was used in the PVWatts and SAM production modeling to help calculate the overall costs. More information about the production modeling can be found in section IX. The table with the total values is Table 3 below.

Table 2. Power Bill Information for the Pequaming Fish Hatchery

Table 3. Total Power Bill Information for the Pequaming Fish Hatchery

        As seen in the tables above, the power usage at the Fish Hatchery was greater in the winter. This is partially due to the heating requirements for the building in the winter. Additionally, the hatchery is more active in the winter months (October - May) due to the breeding season [8]. The most water is moved during these months, resulting in higher power use. In the summer, there is no heating or cooling system being used so the power usage is much less. The Fish Hatchery is a major power user year-round which makes it a great candidate for a solar system.

        For the L'Anse Community Gardens, power bills were also provided for 2019-2020. However, there are new buildings and power users being installed at the site which makes it difficult to analyze the power usage and cost from the power bills. Because of this, further communication with the KBIC is required in order to fully understand the power usage at the Community Gardens.

6. Module Selection

        The following sections describe the components of a solar system. This is the first semester of this project, so the team focused on preliminary research this semester. The research will be useful in selecting the system components as there are many different factors that are important to consider when designing a solar array. This section will focus on module design.

        One of the important factors that need to be considered is efficiency of the modules. Most solar panels have an efficiency of 15% to 20% which means that these solar panels are able to convert 15% to 20% of solar energy into usable energy. Some of the higher quality panels can have an efficiency of over 22%, but most available solar panels do not have an efficiency above 20% [9]. In order to meet a particular energy requirement, a solar system made up of panels with a lower efficiency would require more panels than a system with panels of a higher efficiency. This makes the efficiency of the panel an important factor when working with limited space. There are many factors that determine the efficiency of the solar panels. These factors include the material, the reflection, and how the panel is wired. [9]. Solar panels are becoming more efficient due to advances in technology. They are also becoming cheaper. The cost per watt of a solar module in 1976 was $106 which is much higher than the cost in 2019 at $0.38 per watt. The efficiency and longevity of the solar panels increased in this time [10].

        The efficiency of a solar panel is used to determine the power output. Most solar panels usually produce between 250 and 400 watts. Solar panels are rated by how much power they produce under test conditions. The actual power output of a solar panel when it is installed depends on the orientation, shading, and hours of sunlight. The physical size of the solar panel also affects the power output. Therefore, if two solar panels with the same efficiency have different sizes, the larger one will have a higher power output [11].

Solar modules are made up of cells that absorb the sunlight to generate electricity. The most common cell counts for solar modules are 60 and 72 cells. Because the 72-cell solar panels contain more cells, they are larger than the 60-cell panels. The 60-cell panels are usually six cells wide and ten cells tall. The 72-cell panels are also six cells wide, but they are twelve cells tall. This makes them harder to fit in smaller spaces. Because the 72-cell panels fit more cells per panel, fewer panels may be needed to meet certain energy requirements for larger scale applications. Therefore, solar systems with 72-cell panels cost less for large applications because less racking is needed for these panels [12].

        Another important factor is the temperature sensitivity of solar panels as this can affect the efficiency. Solar panels are tested at 25°C, and temperatures beyond this can affect the energy output. The amount of maximum energy that is decreased per each increase in temperature of 1°C is known as the temperature coefficient. This value is found on the data sheet for the solar panel [13]. Snow also has an effect on the output of the solar panel. This is because heavy snow that accumulates on the solar panel will block sunlight, preventing usable energy from being produced. Solar panels with a landscape orientation perform better in snow than solar panels in a portrait orientation. This is because the snow that gets accumulated on the portrait solar panels leads to production losses due to the panel-cell interconnection [14].  

        This preliminary research will be useful in the module selection process. A decision matrix will be used to help determine the module that will be used. The decision matrix will include information about the cell count, wattage, size, open circuit voltage, short circuit current, price, and price per watt. The modules will be entered into a production model using System Advisor Model (SAM) before a module selection is made.

VII.        Inverter Selection

        A solar inverter is one of the most important components of a solar system. In order to use the energy generated at a solar panel, a conversion from direct current (DC) energy to alternating current (AC) is needed. AC is the present standard used by all commercial appliances, so once converted, the AC electricity can be fed directly into the home or business to operate the desired appliances, lighting, and other electric loads. Most inverters have communication abilities that allow solar owners to keep track of the real time output of their solar system. Monitoring the power output of a solar system is crucial in ensuring maximum efficiency of the overall system. Converting the DC energy to AC energy that is usable in homes and businesses and allowing for observation of the solar system’s production makes solar inverters the hardest-working component of a solar system [15].

The Baraga Solar team has decided to analyze three different types of inverters. The type of chosen inverter will depend on factors such as available budget, shading at the location, ease of accessibility of the location, and more. The three different types of inverters being analyzed for this project are string inverters, power optimizers, and microinverters.

String, or also known as centralized, inverters comprise the vast majority of the global inverter market, specifically for large scale systems. String inverters are the most cost-effective option, which is one of the key takeaways when deciding which inverter is going to be used. Depending on the available funds for this project, this could be a deciding factor. Hence the name, string inverters are arranged into groups connected by strings. Multiple strings of panels can be connected to a single inverter where the DC to AC conversion takes place. Because string inverters are connected by strings, they can only optimize power output at the string level, rather than the individual panel level which is a reason why microinverters and power optimizers are growing in popularity. Because of this limitation in string inverters, this option may not be optimal for homes or businesses that are prone to shading throughout the day because shading on one panel will affect the performance of the whole system. Despite these limitations, there are options of removing shading, like cutting down trees, that can make them an overall efficient and cost-effective option [16]

The second type of inverter being considered for this project is a microinverter. Microinverters are categorized as module level power electronics (MLPE). Contrary to string inverters, microinverters are typically installed on each individual panel in a solar system. This arrangement allows the system to take full advantage of the production capability of each panel. This makes shading less of an issue, because minimal shading will not reduce the overall system output to the lowest performing panel’s output. This option is attractive to our projects, considering our projects are located throughout the rural Upper Peninsula of Michigan, where snowfall and/or shading is inevitable. However, microinverters are significantly higher in cost than string inverters and can be more difficult to maintain or repair [16].

        Lastly, another MLPE, known as power optimizers, is being considered. Microinverters and power optimizers are very similar since they can be optimal for locations with marginal shading and they are able to monitor panels’ individual performance, but they do have a few differences. Contrary to microinverters, power optimizers convert their energy at a centralized inverter rather than finishing the conversion at each individual panel. In terms of cost, power optimizers are known to be cheaper when considering large scale systems [16].

        Power optimizers and microinverters can also be optimal for buildings with complicated roofs, due to their flexibility with marginal shading. However, because of where the team stands on the timeline of this project, roof/ground mounting has not been confirmed for each location therefore meaning inverters have not been finalized, although ground mounting is more likely. Ground mounting will allow for easier accessibility/maintenance. Because there is confidence in the availability of grants, the team may look into presenting microinverters and their performance benefits once the funds are confirmed. On the other hand, removing the necessary shading and choosing string inverters will also be presented as an option and an economic analysis will be done on both of these options to decide which will be of best interest. The team will continue to compare and contrast the type of inverters as the System Advisor Model (SAM) evaluations continue into next semester.

VIII.         Tracking and Racking System

                Other important aspects of a solar array are the racking and tracking systems. This semester preliminary research was conducted in order to help the team make informed decisions for which specific racking and tracking systems to use in the future. The final decisions for the racking and tracking systems will be made next semester and will be included in the Spring 2021 final report.

                A tracking system is used to decrease the angle of incidence between incoming light from the sun and the panel in order to increase the energy production of the solar array [17]. Tracking systems essentially follow the sun’s path in an active or a passive manner. Active trackers use a controller to monitor the sun’s position in the sky in order to direct motors that move the trackers. Passive trackers depend on the heat from the sun to move the panels. A fluid is driven to one side of the panels or the other as it is heated up by the sun. There are also different ways to rotate tracking systems [18]. This can be done by a single axis tracker (which rotates about either the x or y axis), a dual axis tracker (which rotates about two axes), a fixed tracker (which does not rotate), or an azimuth tracker (which rotates 180 degrees about a vertical axis). With each different method of tracking, there are benefits and drawbacks. A fixed tracker, while it is the cheapest, produces the least amount of energy. Single axis trackers are more expensive, but can produce more energy. However, they do not produce as much energy as dual axis trackers.

                Each tracking rotation can vary in the frequency of its movements, operating daily or seasonally. Day-to-day tracking follows the sun’s path across the sky each day. This makes for an extremely efficient system that produces a large amount of energy. However, day-to-day tracking can be very expensive. Seasonal tracking is less expensive, but less efficient. This method of tracking involves following the sun’s movement for each season. These trackers change about four times a year and can be adjusted manually or automatically by controllers. It is important to remember that tracking systems allow one to increase the energy produced by the solar array, even though they do increase the cost of the entire system.

                The last thing to consider for a tracking system is the tilt of the panels. In northern hemispheres, it is important to tilt the system’s panels at different angles throughout the year. This is due to snowfall in the winter, which must be able to slide off the panels, and also due to the fact that the sun changes its angle in the sky as the seasons change. For northern latitudes, those above 45 degrees, it is recommended that the panels face geographic south [19]. Additionally, the recommended tilt angles are as follows: in the spring and fall, tilt the panels to your latitude, in the winter tilt the panels to your latitude plus 15 degrees, and in the summer tilt the panels to your latitude minus 15 degrees. The benefits of tilting panels and using a tracking system can be seen in Figure 8. This graph shows the power produced by a solar array and how different adjustments to the array will change the amount of power produced. For example, the green line represents a solar system with a tracker which clearly produces the most power year-round in comparison to the other system options. The red line represents a system with seasonally tilted solar panels, which increases the power production in comparison to a non-tilted fixed system (shown in light blue).

           Figure 8. Graph of Power Production vs Different System Adjustments

After talking to Jay Meldrum, the Alternative Energy Enterprise advisor, the team has tentatively decided on using a seasonal, single-axis tracking system with a seasonal tilt of the panels. Seasonal single-axis tracking systems are oriented in a north-south direction in order to follow the sun’s seasonal change in position. This is the most beneficial option for northern latitudes since being farther from the Earth’s equator causes the sun’s position in the sky to change drastically throughout the year. A seasonal tilt of the system’s panels is necessary to reduce the amount of snow that sticks to each module. This decision on a tracking system might change for each site due to shading considerations. However, after conducting PVWatts production modeling for the Pequaming Fish Hatchery and the L'Anse Community Gardens, the team was able to narrow down the tracking option to either a fixed or single axis system. A fixed system is the least costly option, but does reduce the amount of energy the solar array produces. A single axis system increases the power production, but also increases the cost of the overall system. More research and production modeling will be completed next semester in order to narrow down the exact tracking system that will be used at each site. Additionally, the team will consult with representatives from the KBIC in order to determine the exact financial parameters for the project.

Racking systems, while not as complex as tracking systems, are another important aspect of a solar system. Solar arrays can be either ground mounted or roof top mounted. Ground mounting is less costly and easier to maintain, but does require more space. Rooftop solar systems are more costly (since a full structural analysis of the building must be completed) and more difficult to maintain, but they do make use of available space. Most likely, the Pequaming Fish Hatchery, Community Gardens, and the Ojibwa Casino will all have ground mounted solar arrays. This decision was made due to the lack of rooftop space available at each site. The solar systems for the two tiny homes will be roof mounted, as the KBIC has requested.

IX.         System Size and Production Modeling

        When considering the four potential sites for solar, as well as the energy use of those sites, realistic system sizes become apparent. These system sizes were determined by the energy usage of the site, the available area to build solar, and the production values associated with latitude, design considerations, and weather. To begin a base analysis on the sites, the PVWatts software from the National Renewable Energy Laboratory was used [20]. This system provides a preliminary production model from the locational data and basic system information. The locational data provides the length of day throughout the year to calculate the amount of solar radiation available at the site in watts per square meter. Solar radiation can also be represented as kilowatt hours per square meter per day. For Pequaming, Michigan, the site of the Fish Hatchery, the average yearly solar radiation is 4.44 kilowatt hours per square meter per day, as seen in Table 4.

Table 4. Solar Radiation Per Month for the KBIC Fish Hatchery

        As can be seen by Table 4, solar radiation is larger during the summer months than in the winter months. The latitude of the Fish Hatchery site is 46.85 degrees north. When looking at the length of days for this site, the winter solstice on December 21st, the day with the least amount of daylight each year, only has 8 hours and 31 minutes of daylight. This is 7 hours and 21 minutes less than the amount of daylight on the summer solstice on June 21st, the day with the most amount of daylight each year [21]. This results in available solar radiation being vastly different throughout the year. However, the month with the largest solar radiation is August, as seen in the figure. This is because with a fixed system at an angle of 45 degrees, August would produce a more optimal production curve. It is important to note that the solar radiation value will change depending on the type or racking and tracking system used.

        Looking beyond solar radiation, PVWatts also takes system size, type of module, system losses, type of tracking, tilt of panels, azimuth, and cost of energy into account. These systems enable the user to get a simple snapshot of the expected energy production of the solar site per month, in kilowatt hours, and the expected amount of savings from this produced energy [20]. PVWatts simulations were run on two sites within the Fish Hatchery, with each having a safe and risky option for the clearances needed between existing equipment. The safe option uses maximum allotted clearances and worst case scenario shading, resulting in a smaller system size. The risky option uses minimum allotted clearance and best case scenario shading, resulting in a larger system size. The front location, with a shading diagram seen in Figure 6, had minimal shading but had to be located around an existing septic system underground. The data and proposed locations can be seen below.

Table 5. Pertinent PVWatts Data from the Front Site at the Fish Hatchery

Figure 9. Geographic Representation of the Safe Solar Option for the Fish Hatchery

Figure 10. Geographic Representation of the Risky Solar Option for the Fish Hatchery

        As seen in Table 5, system sizes, DC:AC ratio, tilt, and tracking type are taken into account to provide an annual production and cost savings. The system size, or nameplate capacity, refers to the power production of that site in watts. This can be given in DC capacity, meaning the overall wattage of each module multiplied by the number of modules, or given in AC capacity, meaning the overall output wattage of the inverter multiplied by the number of inverters. The ratio between DC capacity and AC capacity is known as DC:AC ratio, and is typically desired to be between 1.15 and 1.35 [22]. As can be seen, the size of the array and the tracking style of the array can greatly affect the production. Production refers to the energy produced by the array, and is typically represented in kilo-watt hours, or kWh [23] The safe system is shown in Figure 9 and the risky system is shown in Figure 10. Data for the other locations, including the second location from the Fish Hatchery and the three locations at the Community Gardens, can be seen in Appendices B through E.

        In order to determine a realistic system size, the usage and space limitations were considered for the Fish Hatchery. With a total usage of around 234,000 kWh annually, but only the potential to produce around 100,000 kWh annually, the team realized that all power needs were not going to be met. In order to get more accurate monthly data to determine a realistic system size, production modeling using the System Advisor Model (SAM) was completed. Using SAM, the team was able to input shading data, snowfall, temperature, specific module and inverter specifications, detailed tilts, cost of energy, and usage to receive a more accurate representation of power production [24]. A SAM production modeling assessment was performed twice at the Fish Hatchery to get baseline data, and enable the team to better understand the system.

        The first assessment was completed as a residential photovoltaic system that would fit the space limitations well. This system, designed as a 140 module, 47 kWdc nameplate capacity, 38.5 kWac inverter capacity solar array, produced around 64,000 kWh of energy annually. The system can be seen in Table 6. With a seasonal tilt of 30 degrees from May through August, 45 degrees from September through November and from March through April, and 60 degrees from December to February, this system is optimally positioned for the site’s northern latitude and snowfall received during the winter months [19]. Then, using the snow losses estimated from the site evaluation data, the electricity load of our site, and the power values taking in standard losses, the following system was created [2].

Table 6. Detailed Results from the 47kWdc Residential System at the Fish Hatchery

        With over 55,000 kWh produced annually, this system satisfies around 23.7% of the overall needs of the site. However, given the Fish Hatchery uses substantially more energy during the winter months, this system would not do as well during the winter months when shading, snowfall, and shorter days are taken into account.

        With this in mind, the team decided to complete an almost identical simulation to the previous, but as a commercial photovoltaic system that will be able to completely meet the energy needs during the summer months. This system, designed as a 240 module, 74.5 kWdc nameplate capacity, 59.8 kWac nameplate capacity solar array, produced around 102,000 kWh annually. The system can be seen in Table 7. With a seasonal tilt matching the previous system, this system is optimally positioned for the northern latitude of the site and the snow the site receives during the winter months [19]. Using the snow losses estimated from the site evaluation data, the electricity load of our site, and the power values taking in standard losses, the following system was created [2].

Table 8. Detailed Results from the 74.5kWdc Commercial System at the Fish Hatchery

        With over 87,000 kWh produced annually, this system satisfies around 37.5% of the overall needs of the site. This system also essentially powers the site during the summer months, where the largest production and least usage is. Because of this and the lack of net-metering at the site, the team will not look at solar sites any larger than this for nameplate capacity. However, to potentially assist in production through the fall and spring months, a battery system will be considered. This battery system may enable the extra power during the summer to last into the fall, allowing the site to completely power itself for a larger portion of the year.

        At this point, production modeling and system sizing information has not been completed on the Ojibwa Casino, Tiny Homes, or the Community Gardens. The team is waiting on detailed usage, energy costs, and more information from the KBIC before proceeding with the production modeling for the remaining sites.

X.        Economic Analysis

Once the team determines the optimal design characteristics of the system, a detailed economic analysis will be completed. This economic analysis will build off of the production modeling information from the SAM model to determine various financial parameters of a system. This includes the return on investment (ROI), levelized cost of energy (LCOE), and the payback period for the system. To calculate these values, the team will need to perform additional analysis on the power bills of each site to understand demand charges and when they are added to the total cost. Assessment will be done to determine which demand charges would be eliminated by the solar system throughout the year. Taking the decrease in demand charges and the cost savings on standard power use, the team will determine the overall cost savings of the site.

Comparing the cost of the system from SAM and from an authorized retailer of the components, the team will calculate the price of each site. This will include an estimation on the solar installation cost. This cost will be weighed against the savings of the system to determine the return on investment and the payback period. Once this is determined, a LCOE will be completed.

A simple economic analysis was completed using the Fish Hatchery site. This analysis exclusively used data from SAM and the energy cost of the site. Using data from the commercial system seen in Table 8, an initial investment of $124,546.00 will produce energy savings of $496,163.00 over a 25 year period. This is a return on investment value of 298% over the course of the 25 year lifetime. Using these values, the breakeven date is just before the start of year 9. These numbers are based on estimated values of equipment, engineering, and installation to make the assessment. The team will need to verify these values for local costs to determine the true cost and savings of the system.

XI.        Conclusion and Future Work

        The Baraga Solar Project is in its first semester. Because of this, there are many items that will need to be completed next semester. The goal of this project is to have a completed design, economic analysis, life cycle assessment, and production model for each site by Spring 2021. With that being said, this section will go into more detail about the future project work.

        As mentioned in section V, power bills were provided for the Pequaming Fish Hatchery and the Community Gardens. A complete analysis of power usage and cost was made for the Fish Hatchery. The same analysis will be done on the Community Gardens, Ojibwa Casino, and tiny home sites after the power bills are received. This means the team will need to continue communicating with representatives from the KBIC and receive the information necessary to complete the power analysis.

        Much of the project work this semester was focused on preliminary research so each team member could begin to understand the components of a solar system and how it works. A final solar design for each site will need to be completed in the future. Additionally, specific models of inverters, modules, tracking systems and racking systems will need to be chosen in order to complete an in-depth economic analysis.
        A simple economic analysis was completed this semester for the Pequaming Fish Hatchery. However, since there are still many unknown variables in this project (specific site location, tracking system, inverter model, etc.), a complete economic analysis will need to be completed next semester. This analysis will provide the KBIC with information about system cost, buyback period, and return on investment. A levelized cost of energy will also be included using the National Renewable Energy Laboratory’s calculator [25].

        When the project findings are presented to the KBIC, a 3D model will be completed to show the representatives what the solar system will look like. Additionally, a full production model will be presented. Preliminary production modeling has been completed for the Pequaming Fish Hatchery, but each of the three remaining sites will also need to have production modeling completed. As previously mentioned, SAM and PVWatts are the software systems used to compute this information. This production modelling will provide data on the power production at each site as well as financial information that will be used in the economic analysis.

        Finally, a complete life cycle assessment of the final solar system will be conducted. This life cycle assessment will allow members of the KBIC to be informed about the environmental impacts this system will have throughout its lifetime.

        It is evident that there is still work to be done in order to finish this project. This semester has been a period of finalizing project parameters and understanding how this project will be completed. In the coming semester, the team will begin more technical design and analysis.

XII.        References

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[2] Negin Heidari, Jephias Gwamuri, Tim Townsend, Joshua Pearce. Impact of Snow and Ground Interference on Photovoltaic Electric System Performance. IEEE Journal of Photovoltaics, IEEE, 2015, 5 (6), pp.1680-1685. ff10.1109/JPHOTOV.2015.2466448ff. Ffhal-02113582f. Available: https://hal.archives-ouvertes.fr/hal-02113582/document

[3] K. Christensen, “Solar for the People,” Michigan Technological University, 02-Mar-2020. [Online]. Available: https://www.mtu.edu/news/stories/2020/march/solar-for-the-people.html. [Accessed: 11-Dec-2020].

[4] Michigan Technological University, “Growing Solar From the Ground Up,” YouTube, 08-Nov-2020. [Video file]. Available https://youtu.be/QsSMiob4tBs. [Accessed: 10-Dec-2020].

[5] “Member Tribes,” Keweenaw Bay Indian Community. [Online]. Available: http://www.itcmi.org/keweenaw-bay-indian-community/. [Accessed: 11-Dec-2020]

[6] “How the Pathfinder Works,” Solar Pathfinder. [Online]. Available: https://www.solarpathfinder.com/pdf/pathfinder-how-it-works.pdf. [Accessed: 10-Dec-2020].

[7] “L Anse, MI Weather,” USA.com. [Online]. Available:

http://www.usa.com/l-anse-mi-weather.htm. [Accessed: 9-Dec-2020]

[8] A. Browne and D. Seppanen, “ Annual Power Usage at the Keweenaw Bay Tribal Hatchery,” 23-Oct-2020.  

[9] V. Aggarwal, “What are the most efficient solar panels on the market? Solar panel cell efficiency explained,” EnergySage, 12-Jul-2020. [Online]. Available: https://news.energysage.com/what-are-the-most-efficient-solar-panels-on-the-market/. [Accessed: 11-Dec-2020].

[10] K. Toussaint, “The price of solar electricity has dropped 89% in 10 years,” Fast Company, 09-Dec-2020. [Online]. Available: https://www.fastcompany.com/90583426/the-price-of-solar-electricity-has-dropped-89-in-10-years. [Accessed: 11-Dec-2020].

[11] V. Aggarwal, “Solar Panel Output: How Much Do Solar Panels Produce?” EnergySage, 21-Sep-2020. [Online]. Available: https://news.energysage.com/what-is-the-power-output-of-a-solar-panel/. [Accessed: 11-Dec-2020]

[12] K. Thoubboron, “60 Cell vs. 72 Cell Solar Panels: Which is Right For You?,” EnergySage, 30-Aug-2018. [Online]. Available: https://news.energysage.com/60-vs-72-cell-solar-panels-which-is-right/. [Accessed: 11-Dec-2020].

[13] T. Grinenko, “How Temperature Affects Solar Panel Efficiency,” Renvu, 23-Aug-2018. [Online]. Available: https://www.renvu.com/Learn/How-Temperature-Affects-Solar-Panel-Efficiency. [Accessed: 11-Dec-2020].

[14] S. Bushong and S. Bushong, “Mounting solar panels to vertical rails can encourage snow shedding, says whitepaper,” Solar Power World, 19-Jan-2016. [Online]. Available: https://www.solarpowerworldonline.com/2016/01/mounting-solar-panels-to-vertical-rails-can-encourage-snow-shedding-says-whitepaper/. [Accessed: 11-Dec-2020]

[15] K. Misbrener, “What does a solar inverter do,” Solar Power World, 10-Jun-2019. [Online]. Available: https://www.solarpowerworldonline.com/2019/06/what-does-a-solar-inverter-do/. [Accessed: 11-Dec-2020].

[16] S. Matasci, “How do solar inverters work? Comparing inverter types and technologies,” EnergySage, 19-Jun-2020. [Online]. Available: https://news.energysage.com/solar-inverters-comparing-inverter-technologies/. [Accessed: 11-Dec-2020].

[17] “How Do Solar Trackers Work?,” Ask Solar Mango, 19-Oct-2015. [Online]. Available: http://www.solarmango.com/ask/2015/10/14/how-do-solar-trackers-work/. [Accessed: 10-Dec-2020].

[18] K. Cilli, “Solar PV Tracker vs fixed comparison,” Solar Blog by Kerem ÇİLLİ, 14-Sep-2019. [Online]. Available: http://www.keremcilli.com/solar-pv-tracker-vs-fixed-comparison/. [Accessed: 10-Dec-2020].

[19] “Tilt & Azimuth Angle: Find the Optimal Angle to Mount Your Solar Panels,” Unbound Solar, 22-Jan-2020. [Online]. Available: https://unboundsolar.com/blog/solar-panel-azimuth-angle. [Accessed: 10-Dec-2020].

[20] “PVWatts Calculator.” National Renewable Energy Laboratory [Online]. Available: https://pvwatts.nrel.gov/. [Accessed: 11-Dec-2020].

[21] “Pequaming, Michigan, USA - Sunrise, Sunset, and Daylength, December 2020,” timeanddate.com. [Online]. Available: https://www.timeanddate.com/sun/@5005325. [Accessed: 11-Dec-2020].

[22] “An optimal DC to AC ratio for solar inverters,” Renvu Solar, 03-Mar-2019. [Online]. Available: https://www.renvu.com/Learn/An-optimal-DC-to-AC-ratio-for-solar-inverters. [Accessed: 11-Dec-2020].

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[25] “Levelized Cost of Energy Calculator,” NREL.gov. [Online]. Available: https://www.nrel.gov/analysis/tech-lcoe.html. [Accessed: 10-Dec-2020].

XIII.         Appendices

Appendix A - MICARES Project Summary and Overview

Appendix B - Fish Hatchery Site 2

Table Appendix B.1. Pertinent PVWatts Data from Site 2 at the Fish Hatchery

Figure Appendix B.1. Geographic Representation of the Safe Solar Option for Site 2 at the Fish Hatchery

Figure Appendix B.2 Geographic Representation of the Risky Solar Option for Site 2 at the Fish Hatchery

Appendix C - Community Gardens Site 1

Table Appendix C.1. Pertinent PVWatts Data from Site 1 at the Community Gardens

Figure Appendix C.1. Geographic Representation of the Safe Solar Option for Site 1 at the Community Gardens

Figure Appendix C.2 Geographic Representation of the Risky Solar Option for Site 1 at the Community Gardens

Appendix D - Community Gardens Site 2

Table Appendix D.1. Pertinent PVWatts Data from Site 2 at the Community Gardens

Figure Appendix D.1. Geographic Representation of the Safe Solar Option for Site 2 at the Community Gardens

Figure Appendix D.2 Geographic Representation of the Risky Solar Option for Site 2 at the Community Gardens

Appendix E - Community Gardens Site 3

Table Appendix E.1. Pertinent PVWatts Data from Site 3 at the Community Gardens

Figure Appendix E.1. Geographic Representation of the Safe Solar Option for Site 3 at the Community Gardens

Figure Appendix E.2 Geographic Representation of the Risky Solar Option for Site 3 at the Community Gardens