As summer is winding down and our research is coming to an end, we would like to share what we have been doing since our last post. We have spent most of our time gathering data on the huts’ electricity production and usage to see how well their solar power systems are working. We have been entering our data into a modeling system called SAM, which was developed by the National Renewable Energy Lab in Colorado. SAM uses detailed weather data and solar panel performance statistics to model energy losses and predict annual energy production. It also creates financial models, which we have been using to optimize Maine Huts & Trails’ energy savings and calculate returns on potential investments.
Storage is key to the success of any off-grid solar power system, and investing in storage can have a considerable impact on efficiency. Off-grid systems rely on batteries and backup generators to make it through cloudy weeks and do not allow for the sale of excess solar energy. This means that whenever the battery bank fills up, the solar panels give off excess energy in the form of heat, and all the energy that is not required to meet the electrical load is wasted. Our models show that Maine Huts & Trails could store more solar energy and spend less on propane if it invested in much larger battery banks for each of its off-grid huts. By increasing the storage capacity of the huts, the organization would decrease its generator usage and rely less heavily on propane for power. When we doubled Flagstaff’s battery bank in SAM, its estimated propane spending decreased dramatically because there would be more battery capacity to harvest solar energy. Adding more solar panels in addition to doubling the battery bank showed an even greater impact with higher energy production and less dependence on the generator.
Earlier in July, we had a meeting with Calen Colby, a board member of Maine Huts & Trails and co-owner of Colby Engineering, to present our preliminary findings while we were still working our way toward these conclusions. In preparation for our meeting, we compiled our research into a document for Mr. Colby to read over. We also created a schematic of the energy flow for Flagstaff Hut to confirm our understanding of how the systems work together. It was a pleasure to talk to Mr. Colby about our research and to listen to his ideas about future projects for the huts as well as the feedback he had on our conclusions. It was clear that he is passionate about Maine Huts & Trails and sustainable energy through his company’s efforts to repair the hydropower system at Poplar Hut and his ideas about adding wind power to Flagstaff Hut. It was helpful to hear his thoughts on the sizing of the generators at the huts, which is a source of some inefficiency and translates to increased spending on propane and solar energy waste. He explained that the organization decided to invest in generators that can work at high wattages because these generators last longer.
This past weekend, we had the opportunity to talk about our research for a second time at the Colby Undergraduate Summer Research Retreat (CUSRR) in The Forks. We also listened to our fellow summer researchers speak about their projects and went white-water rafting down the Kennebec River. Overall, CUSSR was a great experience for us as we were able to share our work with others and prepare for our upcoming presentation to the Maine Huts & Trails board members this week.
For our meeting with the board members, we have compiled a list of potential investments Maine Huts & Trails could look into to improve the current energy systems. These include purchasing more batteries to increase the battery capacity and having additional staff training on how the systems work. This summer has been very informational and educational to us and Maine Huts & Trails. If we had some more time to continue our research, we would install current clamps to obtain more accurate electrical load data, look into Mr. Colby’s idea of investing in wind power at Flagstaff Hut, and investigate the possibility of using programmable logic controllers to efficiently control the photovoltaic and generator systems.
At the beginning of the summer, our knowledge of sustainable energy and waste systems was limited to the basics of solar power. After ten weeks of working with
Maine Huts & Trails, we have gained valuable knowledge about sustainable energy systems and its applicability to residential homes. We have realized while that it is important to have sustainable energy systems, it makes an even greater impact to have compatible and effective configurations that actually make use of the sustainable technology. Learning about these systems is important because it helps us to think of ways we can reduce our carbon footprint and promote sustainability in the future. We have enjoyed our time working with Maine Huts & Trails and cannot wait to visit the huts again in the future!
-Sarah and William