Energy Baseline Data Analysis - CivicWell

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Energy Baseline Data Analysis

By Abi Lloyd, CivicSpark Fellow at South Tahoe Public Utility District

Climate Change & Energy


December 4, 2023


During my service year, one of my main projects was to assist with the creation of an Energy Baseline. My site, South Tahoe Public Utility District (STPUD), is the largest electricity customer from our provider Liberty Utilities. The district uses a large amount of electricity every year because national and state laws prevent wastewater discharge into tributaries of Lake Tahoe, meaning the district must send treated wastewater out of the Tahoe basin. Our sewer system is designed to feed sewage into our Wastewater Treatment Plant where it is treated. Then the effluent is sent to Luther Pass Pump Station which pumps it up over Luther Pass into Alpine County where it is then used to irrigate cattle grazing land and grow alfalfa. The district is interested in our electricity use because it is one of our largest operational costs and is responsible for around 86% of our annual greenhouse gas emissions.

My predecessor Jocelyn and I compiled monthly kilowatt hour readings for over 8 years for 86 individual facilities into excel files. That’s more than 8,256 data points! A baseline year was set to serve as a representation of the district’s typical energy use. 2019 was selected as it was the only year between 2015 and 2022 that was unaffected by precipitation extremes, pandemic, or wildfires. I then created graphs depicting our annual energy usage compared to our baseline year, difference in energy use from year to year, facilities that use the most energy, cost compared to energy usage, and more. Through data analysis, we found that our wastewater facilities consume 80% of our energy demand, and 70% is just from use at the treatment plant and Luther Pass Pump Station. We also found that energy use at our wastewater facilities are highly correlated with precipitation, due to rainwater and snowmelt entering into the sewer system through inflow and infiltration (I&I). As annual precipitation increases, so does our energy usage. Our largest energy consuming years 2017 and the baseline year 2019, were first and second for precipitation. I&I increases how much water needs to be pumped through the system and how much energy it takes to pump.

I presented this information to South Tahoe PUD’s board of directors last week and received good feedback and ideas for next steps for the project. Over the next year, I’ll be researching recommendations for asset management programs that can help reduce energy use. I’ve attached a pdf of my slides for my presentation to our board of directors.

There are data management best practices that we can implement as I continue working on this project in my second service year. South Tahoe PUD is a member of Isle Utilities climate network group, which allows agencies from across the country and across Australia to discuss their progress on climate action and reducing GHG emissions. I just attended a session that was focused on data and learned about a few programs that could help me manage and visualize our data better. With a better understanding of our data, the district will be able to make informed energy efficient policy decisions in future.