In 2007, a fire at an Interlake High School concession stand caused $40,000 in damage, zero injuries and was controlled by firefighters within 25 minutes of their arrival. The midnight blaze barely made news, receiving little more than a 99-word mention in the Seattle Times. It did, however, spark a series of events that contributed to Bellevue School District building several of Washington’s most energy efficient elementary schools.

Following the fire, Director of Facilities & Operations Jack McLeod took rebuilding the concession stand as an opportunity to experiment with eco-friendly building materials and photovoltaic (PV) solar panels. Not only did they install solar panels on the new stand’s roof, they connected them to a TV monitor in the school that tracked the system’s output in real time.

“The students and teachers loved it,” McLeod said. “And visitors seemed to take a real interest, too.”

McLeod took a similar approach in rebuilding Eastgate Elementary in 2008 by incorporating for the first time geothermal heat pumps. This system uses the consistent temperatures below the Earth’s surface (normally 54 degrees) to draw heat in the winter and release it in the summer, making air conditioning much more energy efficient. McLeod said Eastgate’s geothermal system provided considerable energy cost savings for the district, and has included in every project since.

Interested in Earth-friendly activities in Bellevue? Check out our write-up of the Bellevue Botanical Garden.

Improving energy efficiency

The Eastgate project set McLeod and Bellevue School District on a path of increasing the energy efficiency with each subsequent project. Energy Use Intensity – or EUI – is an energy efficiency measurement used for buildings that considers its energy use, renewable energy generation, and square footage. Using this measurement, an EUI score of 0 represents an energy neutral building while a score of 100 represents the least efficient buildings. According to New Buildings Institute’s 2019 Zero Energy Schools Watchlist, the national average EUI for education buildings is 58.2 kBtu/sf/yr (British Thermal Units (kBtu) divided by square footage (sf) per year (yr)).

In 2010, Bellevue School District completed construction on Ardmore Elementary, featuring geothermal heat pumps, a super-insulated building envelope, automated lighting systems, and lots of windows to allow natural light and heat. Ardmore achieved an EUI of 19.4 kBtu/sf/yr in its first year and, after a few years of tinkering with the controls, has since scored as low as 16.2 kBtu/sf/yr.

Cherry Crest Elementary, completed in 2012, had the same features as Ardmore with the addition of a 99.9kw PV solar panel system on its roof that contributes around 10 percent of the buildings energy. As of latest measure, Cherry Crest achieved an EUI of 13.6 kBtu/sf/yr. Even the district’s 28,426 square foot transportation and maintenance facility recently recorded an EUI of 39 kBtu/sf/yr – well below average for a building of its size and type.

McLeod said his team feels it’s important that they learn from past projects and build each one better than before.

“Now we have this group of people with the experience of several projects, so we are comfortable pushing the envelope,” McLeod said. “We also recognize that cutting edge and bleeding edge are not that far apart.”

In 2019, the district opened the doors to Clyde Hill Elementary, it’s newest and most energy efficient elementary school yet. It will take a year or two of data to measure an accurate EUI, but projections put the building at 8.3 kBtu/sf/yr. The school features:

  • LED light bulbs and automated lighting controls that shut off and dim lights
  • Automated air conditioning that utilizes outside air, natural light, and ambient temperatures to reduce unnecessary heating and cooling
  • Geothermal electric heat pumps
  • Rain gardens to manage storm water
  • An air-tight building envelope with thermal bridging and spray-foam insulation
  • 50kw of photovoltaic (PV) solar panels in addition to the standard 99.9kw rooftop system, and a battery system to store excess energy, which can be used or sold to Puget Sound Energy.
Clyde Hill Elementary
A recently opened Clyde Hill Elementary featuring tall windows to draw in natural heat and light. Photo submitted by Bellevue School District.

Building with bonds

Although the price of renewable energy is dropping, the district’s energy efficient taste comes with a high upfront cost. McLeod said it costs around $500,000 to drill 70-90 300-foot wells for geothermal heat pumps and the construction contract for Clyde Hill Elementary alone cost $48,716,000.

The district absorbs these upfront costs by using voter approved capital funds, or bonds, instead of the district’s general fund or state assistance. Once the bonds are approved, they are used only for building expenses and cannot mingle with the general fund.

“By using capital funds dollars, we actually make money for the general fund by doing energy savings projects,” McLeod said. “That’s money for teachers, resources for the kids and day-to-day operations.”

A 2020 capitol bond seeks to raise Bellevue’s property tax rate from $2.43 per $1,000 of assessed value to $2.46 per $1,000 of assessed value. If approved by 60% of local voters, the bond would generate $675 million for projects including rebuilds for the Big Picture School, International School and Jing Mei Elementary.

“We’re fortunate to build with bond money,” McLeod said. “The amount of state assistance varies from district to district, we’re at the low-end of that. Some other districts in the state are just having a tough time putting a building together for the kids – we’re just fortunate to have the resources of our community.”

McLeod said the district saves around $100,000 per energy efficient building each year and the payback on the energy savings systems is often less than 10 years. With an expected building lifespan of 50 years or more, the return on investment is relatively quick.

The district has also been able to save on maintenance costs by standardizing equipment, furniture and finishes across the new schools.

“We want to get down to zero”

display at Wilburton Elementary
A monitor at Wilburton Elementary displays a real-time feed of the solar power generated from the school’s PV solar system on a rainy January day. Photo submitted by Bellevue School District.

In January 2020, the district is scheduled to break ground on a new building for its Spanish-immersion elementary school, Puesta del Sol. McLeod said the engineers contracted for Puesta del Sol esitmated they could get the building’s EUI down to 10 kBtu/sf/yr, to which his team responded, “Hey that’s great, but we want to get down to zero.”

The new school will have all the “bells and whistles” of Clyde Hill in addition to a 300kW solar system with more battery storage and point-of-demand water heating that reduces the need for large heating tanks and an inefficient maze of water pipes running throughout the school.

With the additional features, the projected EUI for Puesta del Sol is negative 1.1 kBtu/sf/yr – meaning it could generate slightly more energy than it uses.

While McLeod and his team have come a long way since rebuilding the burnt down hot dog stand, he still uses at least one play from his 2007 playbook.

“One of the things we feel very strongly about in these buildings is using signage, like the real-time monitor that shows the amount of PV energy created at any moment,” McLeod said. “It’s an educational process, and the teachers have jumped on board and helped the kids understand the learning environment they are in.

“We realize previous generations maybe haven’t been so great for conservation and hopefully the kids improve on that. We just want to give them a lab to learn about it and become passionate about it. It’s a full circle deal.”

Feature photo: Bellevue School District cuts the ribbon on Clyde Hill Elementary, their most energy efficient project to date. Photo submitted by Bellevue School District.

© Emeraldology 2020