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Case Study: Microgrid Saves High School $2M: Part 1 (Main Building)

by Steve O'Rourke



In an effort to give back to the community, Doe Run, a large lead producer and leading employer in Herculaneum, Missouri, chose to cover the cost of many EEMs (energy efficiency measures) for Herculaneum High School.

They enlisted the help of Microgrid Energy, who performed an energy audit on the campus that included lighting, HVAC, water heating, plug loads and building envelopes.

The findings of the study showed a number of areas where energy savings could be obtained either through more efficient equipment or operational changes. After careful review, Doe Run, Microgrid, and the Dunklin R5 School District chose to move forward with the measures that met a variety of criteria including visibility, comfort, serviceability, and environmental benefit.

This case study will focus on the solutions installed to one area of the school: the main building. Additional case studies will focus on upgrades made to the fine arts building and the gym.


Herculaneum High School has about 400 students and 50+ staff members. The main school building was recently demolished and rebuilt to house administrative staff, classrooms, a new library and cafeteria.  Connected to this building is a legacy “D-Wing”, an older Science wing of the school, and the Industrial Arts facility.


Based on the weighted rankings, a select group of projects were chosen for the main building complex. These included the installation of both lighting and HVAC upgrades, as well as a series of solar arrays totaling 25 kW.

When the new facility was constructed in 2011, standard T8 lighting was installed throughout the building.  However, the old D-Wing and science building still had older, less efficient T12 fixtures, which were all replaced with new T8 fixtures.  In addition, the 400W metal halide lights in the Industrial Arts shop were replaced with T5 high-output fixtures.  Finally, the metal halide exterior lighting, including 250W parking lot lights and 175W wall packs, were replaced with more efficient LED fixtures.

A 13 kW rooftop solar array with specialized SMA bi-directional inverters was designed to feed a lead-acid battery backup system to provide emergency power during outages. 

In addition, two 6 kW canopies were erected to demonstrate the dual benefits of solar, providing both shade and shelter.  A cantilevered canopy was installed at the top of the football stadium grandstand near the concession stand, where spectators can gather either on a rainy night or on a hot, sunny afternoon.  A second 4-post canopy was installed outside the cafeteria to offer students a place to sit or set up a booth before stadium events.

Both canopies use Fronius central inverters and translucent, frameless Lumos LSX solar modules to enable some light to pass through, but provide shade and shelter from the elements.  Gutters were installed and the gaps between the modules are sealed with a roofing tape to minimize any leaks during rain.

A Deck monitoring system was installed to pull energy production data from all of the solar arrays into a single user interface to compare output from the microinverters on the gym to the central inverters on the other arrays, and report aggregate energy production.

Finally, HVAC upgrades included a new Variable Air Volume air handler in the D-Wing of the main building, and a new high-efficiency boiler to heat the building.

All the lighting and HVAC work was completed during the summer to avoid disrupting class while school was in session, and the solar arrays were installed in the fall of 2013.


The combined solar arrays installed across the school are projected to produce almost 100 megawatt hours of energy this year, and almost 2,300 MWh of energy over the 25 year warrantied lifetime of the system for a projected savings of over $440K.  The three solar arrays connected to the main building are expected to produce a total of 31.8 MWh, saving the school over $2,800 in the first year alone.

Energy savings from the efficiency projects are estimated at over $7,800 a year for lighting, and over $21,000 annually for the HVAC upgrades.  In addition, these savings continue to increase as utility rates rise.   The total cost of the lighting and HVAC projects was approximately $230,000, and the lifetime value of the energy savings is projected to exceed $1.5M.

A final piece of the overall program was to produce an educational component that could be used at the high school.  Microgrid worked with the Missouri University of Science & Technology to complete a research project to analyze the technical and financial viability of a variety of energy storage systems used in conjunction with renewable energy.  This included a published paper and content for an outreach course covering the material studied.

Doe Run funded the entire project at a cost of over $591,000 ($391,780 for the main building), so the school district had no costs associated with the project.  While the lighting and HVAC equipment were donated, the solar arrays will be maintained by Microgrid over a 20 year period using a pre-paid lease funded by Doe Run.

There are a number of other companies that Microgrid partnered with to pull this complex program together.  The HVAC engineering was done by Dynamic Engineered Systems and installed by Sheet Metal Contractors, Inc. The lighting engineering was done by Lighting Associates, and the equipment was supplied by Metro Lighting and installed by Akron Electric.  The solar design work was done by Microgrid, with Schaller Design Group creating the custom-designed and built canopy structure on the football stadium grandstands.  Schaller also installed the Lumos LSX canopy kit, and Kaemmerlen Electric installed all of the solar arrays under the guidance of Microgrid.

Microgrid managed the entire project, coordinating lighting and HVAC engineers and contractors to design and install the EEMs.  The solar project was also a turnkey project, including the design, structural engineering, and procurement of equipment and construction of the arrays.  Microgrid will also provide maintenance and monitoring of the equipment over the 20-year lease.

The program has been a win for all involved, and an excellent demonstration of how to combine renewable energy and energy efficiency, and save the school over $2M over the projected lifetime.  It’s also a great educational opportunity to show how lead-acid batteries, which come from lead refined by Doe Run, can complement renewable energy systems.


About this Project

  • Location: Herculaneum. MO
  • Building Type: High School (Main Building)


Estimated Savings
Project Costs
Calculated ROI
Calculated Payback Period
Implementation Time





34 Weeks

About verification

The project details of this case study have been verified by Noesis on May 5, 2014. Learn more about our verification process.

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