Rochester

Nature center's solar + battery project offers model for energy self-reliance

January 2021

By Chris Meyer

“We are energy chasers here at Prairie House,” said Pam Meyer Executive Director of Friends of Quarry Hill Nature Center. Meyer was talking about efforts to make solar energy stored in their battery system stretch further by reducing energy use at the educational building, which is part of the City of Rochester Parks and Recreation.

A battery storage system was installed at Prairie House in the summer of 2020 to maximize self-consumption of electricity generated by the facility’s solar array. Meyer continued, “There are lots of ways to define net-zero carbon buildings. We know our solar system over the course of a year produces more energy than the building will consume."

Clean energy technologies are the future and it is exciting to demonstrate what is achievable. It is a great step forward in our mission.

Pam Meyer, Executive Director, Friends of Quarry Hill Nature Center

In 2018, its first year of operation, Prairie House generated 8.8 MW hours of electricity, almost twice the building’s consumption, but was unable to store any of that energy. Built to be a model for sustainable building design and operations, staff considered a next step could be to achieve a zero-carbon status. They wanted to fully offset and minimize the amount of energy purchased from the utility. A 10-kW battery system was installed to store electricity generated in excess of building consumption during the day. At night the building draws from the batteries first, and when they are depleted, from the grid. Meyer said the system has performed as expected, “meeting as much as 90% of the building’s energy needs in the summer and 50 to 60 % in the winter.” Meyer would like to increase the share of power provided from the solar panels and battery installation and is using the SolarEdge monitoring system to help.

Curt Shellum, owner of Solar Connection in Rochester who installed both the original solar array as well as the battery storage system, shared monitoring information. On a sunny July day in 2020, for example, the solar panels generated over 6 kW hours of electricity, meeting 100% of demand during the day and charging the batteries fully. The batteries then powered the building overnight so that only 6% of the total energy consumed for the day came from the grid. Shorter days in the winter mean less electricity is generated by the solar panels, while energy consumption is higher. On a sample October day, 67% of the energy used had to be purchased from the utility. Shellum and Meyer have been using the building energy consumption data in comparison with expected loads to determine if adjusting the ventilation systems could reduce nighttime energy use. “Now that we have an understanding of our usage, we are looking at ways to cut our overall energy consumption,” Meyer said.

According to Meyer the project is not about monetary savings, but testing and demonstrating of what is possible to “lighten the load on the land.” Shellum shared that there are 6 or 7 operating modes for a solar + battery installation, such as discharging at peak electricity prices, off -grid, or battery backup. This is the first installation he has worked on for maximizing self-consumption. Shellum said that backup power is currently the most common battery installation for his company. Using batteries to offset higher peak rates, if applicable, does not have a very good payback at this time. He noted, however, that “battery prices keep falling. Even in the six months since the Prairie House project was completed.” Meyer was also optimistic, sharing: “Clean energy technologies are the future and it is exciting to demonstrate what is achievable. It is a great step forward in our mission.”

In the spring we will develop a class that will use Prairie House components to teach all 6th graders in Rochester Public Schools. It will feature the battery and solar system, real-time monitoring, as well as the thermal mass floors and sustainable pellet furnace… When kids come in and the lights come on, we show them that energy comes from the sun and that heat is generated from a wood byproduct that would otherwise go to a landfill.

Pam Meyer, Executive Director, Friends of Quarry Hill Nature Center

Prairie House staff have been sharing their energy story through the local news and social media so far, but are also working on curriculum for 2021. “In the spring we will develop a class that will use Prairie House components to teach all 6th graders in Rochester Public Schools,” Meyer shared. “It will feature the battery and solar system, real-time monitoring, as well as the thermal mass floors and sustainable pellet furnace. Prairie House is mission driven. When kids come in and the lights come on, we show them that energy comes from the sun and that heat is generated from a wood byproduct that would otherwise go to a landfill.”

Meyer said that the facility has had limitations due to the pandemic, but as soon as is safely possible will bring students back. “While screen time is not preferred for ‘green time’, in some instances virtual programming has broadened our reach and made us accessible to a wider audience,” she continued. The expectation is that their programs and visitation to the Nature Center will reach almost 100,000 people a year.

The project was funded by the City of Rochester Parks and Recreation, The Friends of Quarry Hill Nature Center, and a Southeast CERT Seed Grant. CERTs will again be accepting Seed Grant applications in the fall of 2021. If you have a clean energy project you would like us to consider you can learn more on our website, contact your regional CERT coordinator with questions, and get on our mailing list for the grant announcement.

Learn about renewable energy at other Minnesota nature centers:

More Photos from Quarry Hill

Technology: Battery Storage
SE CERT Seed Grant: $910
Total Project Cost: $8,080
Other Funds: city budget for parks and recreation; community donations through the Friends of Quarry Hill Nature Center non-profit
Project Team: Pamela Meyer, Quarry Hill Nature Center; Michael Nigbur, City of Rochester - Parks & Recreation; Curt Shellum, Solar Connections; Kevin Bright, City of Rochester - Sustainability & Energy
People Involved and Reached: 2,294 (or 3,640 if no one opposes including the 6th graders.)
Energy Storage Capacity: 10kW

(CERTs is learning! On-site renewable energy use as a result of use of the battery storage system will be better understood after a year of operation and will be shared in kWh.)