Zero Net Energy + Historic Preservation: Turning a Building From the Past Into a Model for the Future

by: Kelly Elmore, LEED AP BD+C
Historic Preservation
When the State of California issued a goal in 2008 for all newly constructed and renovated commercial buildings to consume zero net energy by 2030, we applauded our State for its leadership and progressive thinking.

ELS believes that all buildings should push to achieve this goal. Having graduated from the University of Oregon’s architecture program with a focus on sustainable design and planning strategies, this is one of the characteristics that attracted me to work at ELS. I am lucky to be surrounded by colleagues who share a passion for making a difference in the world. As architects and designers, we can leverage our creativity to impact communities, as well as ecosystems, and influence real change.

In 2013, ELS joined the AIA 2030 Commitment to reduce the operational energy use of our buildings and achieve carbon-neutral construction by 2030. We also have our own sustainability committee – currently a team of 8 people within ELS – to help us and our clients find innovative ways to achieve these bold goals. These aren’t just empty promises; we put the words into action. We’re certified as an Alameda County (now California-wide) Green Business, which means our office in downtown Berkeley operates efficiently and our suppliers and business partners are sustainable as well. For our clients, our committee develops tools such as energy models that measure energy outcomes (and thus project a building’s performance) before projects are built. And we have fun, too – getting outside to help restore local habitat with organizations like Save the Bay. We attempt the integration of sustainability into everything we do.

We embrace the challenge to make zero net energy (ZNE) real. By definition, a ZNE building generates as much renewable energy as it consumes each year. This can be achieved by installing photovoltaic solar panels onsite, and by increasing natural light and ventilation while using high-efficiency lights, appliances, and mechanical systems. When ZNE is achieved, our client benefits from thousands of dollars saved on electric bills, not to mention the reductions in carbon emissions and greenhouse gases that benefit all of us and the planet.

California is a leader in achieving energy reduction goals, evidenced by the state’s ambitious goals for 2030 and beyond, and many of our public projects with government-funded clients are particularly focused on sustainable design. The City of Berkeley’s Adult Mental Health Services (MHS) Center is one such client. But there’s a catch: MHS operates out of a building that opened nearly 100 years ago. Can such an old building operate like a modern one while meeting ZNE standards? Our team took it to the test and the project – which broke ground in March 2019 – includes seismic improvements, tenant improvements, and upgrades to the electrical, lighting, and mechanical systems.

Fortunately, MHS’ goals of creating a welcoming, clean, and secure facility for its community-based mental health services and to improve quality of care are well-aligned with the goals of sustainable design. Just as access to natural light and air reduces energy consumption, it improves mental health for clients and their care providers as well as office workers. Even some of the design principles associated with historic preservation lend themselves to energy conscious design. For example, we cut back on consumption when we restore and reuse existing materials rather than replace them. A building that withstands the test of time is truly a sustainable one.

But there are challenges, too. The MHS building is 8,000 square-feet, which means it’s smaller than most commercial buildings. The fact that it has historical significance dating back from 1925 means it’s less flexible. To achieve ZNE, we needed to add as much natural daylight to the building’s interior spaces as we could. In the inner-most rooms without exterior walls and windows, we had to design tubular daylighting devices that bring light down through the ceiling. But herein lies another challenge: to generate electricity onsite, we need solar panels on the roof, not to mention mechanical equipment and access aisles. The roof plan was a jigsaw puzzle of photovoltaics, daylighting tubes, and HVAC units, but we made it all fit. We also incorporated transom windows in another enclosed interior space, allowing it to borrow daylight from an adjacent daylit space. As a result, everyone at MHS will work in a room with natural light.

A rendering of the waiting room at the City of Berkeley's Mental Health Services Building.

Coming up with creative design solutions that support ZNE operations can feel like a guessing game, so this is where energy modeling by Integral Group came in handy. And thanks to a grant from the California Energy Commission through Lawrence Berkeley National Lab (also known as the Berkeley Lab or LBNL), we have taken MHS a step further. Leveraging Berkeley Lab’s FLEXLAB® facility, we have been able to evaluate how the MHS building will perform before it’s built, and we’ll be able to continue to track its performance after it opens.

There are several ways that the early tests have helped us improve our designs and save our client money as well as energy. For example, LBNL and FLEXLAB helped us test different energy-saving strategies for MHS’ renovation project – including variations to the HVAC systems, lighting, insulation, windows, and glazing, appliances, and other plug loads – and used different combinations of these strategies to create package options. LBNL ultimately validated a strategy that focused on internal loads and mechanical systems instead of one that would require the entire historic building envelope to be retrofitted. With access to real performance data early in the design process, we knew that adding insulation and improved glazing would not be effective from a cost or energy consumption perspective (of course Berkeley’s moderate climate helps with this as well). We would have a much greater impact by focusing on onsite energy generation and overall reduction of electric consumption through mechanical systems (like a high-efficiency zoned HVAC system), Energy Star appliances, and low-energy lighting.

LBNL also did studies on the tubular daylighting devices (TDDs) and their impact on visual comfort and energy consumption. Light sensors and high-dynamic-range imaging cameras were placed around our model room to mimic the perspective of people sitting at computers and to measure the glare they might encounter. Test results proved that the TDDs had a low daylight glare probability from these perspectives, while providing significant amounts of energy savings. In a real office environment most people would probably still prefer to sit next to a window, but in spaces where it’s not feasible to punch through existing walls, we now know that TDDs are a fantastic option to improve the employee’s experience of the space and to reduce the use of electric lighting.

Regardless of age, small existing commercial buildings like MHS’ are notoriously one of the hardest to adapt to California’s 2030 energy consumption goals. Their owners often don’t have awareness of or access to information about energy-saving strategies and fear they won’t see a profitable return on investment after a retrofit or renovation project. Again this is where Berkeley Lab and projects like MHS pave the way. According to FLEXLAB’s executive manager, Cindy Regnier, “Berkeley Lab is developing cost-effective packages of pre-commercial and underutilized energy efficiency measures to inform the online Commercial Building Energy Saver tool. This will enable small commercial building owners, contractors and other parties to evaluate cost-effective strategies for their building to achieve ZNE performance.”

The LBNL FLEXLAB where the building's energy saving strategies were tested.
Credit: Berkeley Lab ©The Regents of the University of California, Lawrence Berkeley National Laboratory

My own hope is that by promoting broader access to energy modeling and benchmarking, we’re highlighting the positive impact of sustainable design not only on energy consumption, but also on health and wellbeing. The MHS building that we’re renovating was closed in 2016, deemed unfit due to its deteriorated condition. As you can imagine, MHS employees were not excited about the prospects of returning to work in that old building, even after renovation. But when they saw renderings of their new space, their perspectives changed. They saw a renewed space filled with light, air, and access to nature – a design that makes the vital work they do just a little bit easier. Their building’s important position in Berkeley’s history will also be restored and its legacy becomes even more meaningful. It also proves that if ZNE is possible for a century-old building like MHS, it’s possible for just about anyone.

If more buildings were ZNE, consider the impact we could have. Berkeley Lab projects that with a 5% adoption rate of ZNE in California by 2030, we’ll see savings of $32 million per year in electricity and natural gas costs and will reduce greenhouse gas emissions by 83,000 metric tons. Consider how much bigger those numbers become as the adoption rate grows. I look forward to the challenge of achieving that goal, and even more to the future that is made better because we did it!