Originally published in USGBC+
October 1, 2014
The architects and builders of the Department of Energy’s new Research Support Facility (RSF) in Golden, Colorado, were confident they could design and build the world’s largest net-zero energy building. The new structure, within the campus of the National Renewable Energy Laboratory (NREL), was expected to be a trailblazer for the green building industry and a model for others to follow when the project got underway in 2008.
“Part of our mission is to be national leaders in energy efficiency,” says Shanti Pless, top efficiency champion at NREL and one of the facility’s project leaders. “Costs and efficiencies of many energy technologies have improved significantly in recent years, and we had the opportunity to walk the talk and show the industry how to do it.”
Still, they held their collective breath. They had to wait until the first full year energy consumption data was tallied with all systems up and running to see if they could really achieve net-zero energy. That way, they could verify whether the total energy the building produced through its own renewable energy sources was greater than the energy the structure consumed over a 12-month period.
The verdict? Mission accomplished. In April 2014, the Department of Energy announced it had collected real-time verifiable data demonstrating the Research Support Facility produced more energy than it consumed between April 2013 and April 2014.
Even though the first 800 occupants of the building moved into the 220,000-square-foot building after construction of Phase One in 2010, the ambitious project wasn’t fully completed until 2012. That’s when an additional wing was added for a combined total of 360,000 square feet and 500 more NREL and Department of Energy staffers moved their operations to the new building.
The primary source of renewable energy was drawn from the building’s 2.6-megawatt solar photovoltaic (PV) system that blankets the roof and stretches onto a canopy over the adjacent parking areas. What’s more, the building was designed with a multitude of energy efficiency features—some high-tech and others pretty basic—so the structure could operate using at least 50 percent less energy than most other Class A buildings of the same size.
Of course, operational efficiencies have to occur year after year for a true net-zero energy success, compared to sustainability design goals that are measured as a one-time accomplishment, Pless notes. The RSF also was awarded the U.S. Green Building Council’s (USGBC) top Platinum rating for Leadership in Energy and Environmental Design (LEED) for each completed phase of the complex.
“Net-zero energy is the holy grail of all targets on the sustainability side of creating large-scale buildings,” asserts Pless, who spent the first decade of his 25-year career in the commercial sector as a mechanical engineer meeting energy goals for high-performance buildings, including the Lewis Center at Oberlin (Ohio) College. “It’s only in the last five years that large-scale buildings can be thought of as a realistic goal.”
Climate Change—a Catalyst
Concerns about climate change have been mounting in both the public and private sectors and many experts point to buildings as a major contributor to greenhouse gas (GHG) emissions. In the U.S., buildings account for 30 percent of all GHG emissions, according to the U.S. Environmental Protection Agency. That should come as little surprise, considering buildings are responsible for about 36 percent of total energy use and 65 percent of all electricity consumption domestically, the EPA says. Since NREL aims to be at the forefront of energy efficiency ideas, administrators there figured attaching aggressive criteria for energy reductions to its planned Research Support Facility was a way to combat the growing threat of climate change as well, says Pless.
“Decisions made today in building design will impact emissions of our buildings for the next 30 to 40 years,” he observes. “You’ve got one chance to get it right because once you have an existing building it becomes difficult to change.”
The team that designed and built the new facility factored in operational carbon emissions as part of its definition for the net-zero energy goal because minimizing GHG emissions was just as important as the energy efficiency component from an environmental standpoint, asserts Tom Hootman, director of sustainability at RNL Design, a global design firm specializing in sustainable, integrated design, and one of the partners on the team that won the competitive bid for designing and building the new facility. “It forces you to think through the design problems in terms of operational carbon emissions, which can influence design strategies and energy sources,” he explains.
To that end, the designers opted for onsite generation of clean, renewable energy and passive design strategies as the primary sources for powering the building’s operations and keeping energy needs at a minimum, says Hootman. “These strategies add resilience to our built environment, which can help mitigate future impacts to our changing climate,” he adds.
What’s more, one requirement for the design/build team was to guarantee all materials used met the criteria of a 50-year life span to stretch the time that a major renovation or demolition would be required, says Brian Livingston, a senior project manager at Haselden, the Centennial, Colorado, general contractor that was awarded the design/build contract for the project with RNL Design. Life span requirements for buildings are typically 30 to 40 years.
“A building with a 50-year requirement rather than a 30-year would have stricter structural requirements because concrete deteriorates over time,” explains Livingston. “We had to prove either through examples of in-place construction or through a testing data mechanism that materials would meet that durability standard.”
Livingston adds: “When you demolish a building, you emit carbon dioxide with equipment that’s used and some of those materials end up in a landfill,” which produces methane, a potent GHG. “This requirement was about being mindful to the future and not contributing to climate change.”
The project leaders at NREL knew they were raising the stakes in their quest for a net-zero energy structure on a scale that hadn’t yet been achieved, so they took a dramatically different approach in the criteria for the request for proposal (RFP) they put out to the green building industry. They sent out a performance-based design/build RFP that placed energy criteria for the building’s operations as a required top priority requirement alongside cost and schedule, explains Pless. For example, the RFP said they required design and construction that results in a building that uses 25,000 BTUs per square foot for the first two years.
“What we learned is that when energy efficiency is a requirement from the beginning, energy efficacy decisions can be made early on and integrated cost-effectively,” asserts Pless. “That wasn’t really done before. Early energy efficiency goals can inform the design delivery process, rather than extra efficiency measures that are bolted on after the design has been developed.”
In addition, NREL for the first time wanted a design/build team to create the building instead of the typical two-step process. In this instance, a partnership of architects and a contractor design the facility and begin building it in an integrated manner instead of first having one team design the entire structure and then soliciting RFPs for the building phase, explains Pless. The integrated team saved money and slashed about 18 months off the total project’s start-to-finish time, he estimates.
“Performance-based design/build with energy efficiency integrated into the design is the one key replicable strategy that we’ve used in nine of our own projects since then,” he says.
Hootman, who was one of the main designers of the RSF and authored a book about the process, notes there was a requirement for LEED Platinum in the project, which was not new for his firm. However, it was the first time the energy goal was expected to be a deliverable as well, instead of having it on the wish list of hoped-for outcomes, he recalls.
“It changed the dynamic and seriousness of the project,” he says. “It aligned the entire theme of energy efficiency in a more profound way because now it was a contract requirement instead of a goal. Goals sometimes get lost when suddenly the budget gets tight or you’re running out of time. Here it wasn’t allowed to happen.”
Mix of New and Old
Improvements in some newer technologies and dramatic reductions in cost inspired Pless and others at NREL to view a net-zero energy building as a realistic possibility. Cheaper LED (light-emitting diodes) lighting, which requires far less energy than standard lighting, suddenly made that an option building-wide. Less expensive PV panels also enabled the design team to add solar as the primary renewable energy source. Colorado is known for its days of sunshine year-round, so that energy source was a good choice for a building there, he says.
In addition, some of the energy efficiency solutions were passive strategies based on simpler technologies that have been employed for hundreds of years. Those elements also are expected to contribute to the improved health and productivity of employees working there.
Two of the best examples are an emphasis on natural daylight and natural ventilation. A hundred years ago when buildings were designed, most were naturally ventilated and naturally lit, says Pless. “There was good shading, good insulation, thermal mass, lots of precast concrete and ventilation and daylighting,” he explains. “Now we’re learning how to integrate these simpler technologies into modern, high-performance buildings.”
At the RSF, the building’s operations will never turn on a light for an employee, except in the restroom, says Hootman. When employees enter their workspace, they decide whether they need more lighting beyond available natural daylight and they have the option of flipping their own dedicated light switch.
“Once the occupant turns a light on, the building finds a way to turn it off,” explains Hootman. “Sensors detect when you leave your space and your lights will be turned off automatically. The same will happen when the sun comes out, and at 6 p.m. there’s a hard lights-off again. This building only uses 15 percent of what a regular building would use in lighting energy.”
An open floor plan also enables workers to benefit from the natural daylight streaming in through the windows. There are no carved-out private offices blocking access to outdoor lighting. In addition, open work areas allow natural ventilation because there aren’t walled-off spaces that interfere with air flow.
Initially, employees had to get used to working in an open-space environment since many previously had secluded offices. The new layout includes private call rooms and conference rooms for meetings, plus a lot of attention was paid to good acoustics to minimize noise travel. Pless notes the way for these passive features to work best is to change office culture and get buy-in from workers.
For example, the building was equipped with operable windows for natural air ventilation that can easily be opened by people working there, says Livingston. “From a construction perspective, we considered the building ‘delicately simple’ because much of the work didn’t need specialty engineers or workers,” he says. “Anyone can install a window that opens.”
In more complex “smart” buildings, numerous problems crop up when sophisticated systems break down, observes Hootman. “Fancy controls eventually stop working and it takes a specialist to come back and recalibrate,” he says. “Or employees don’t like what’s installed so they circumvent it by covering occupancy sensors. Our building was brilliant in its simplicity.”
The passive architecture served another important purpose: Those design features also were intended to maximize employees’ health and improve their sense of well-being while at work. Fresh air from open windows (especially in Colorado) is generally better than sealed-off air that’s continuously recirculated in a building, for example. Happier workers also typically are more productive and take fewer sick days, notes Pless. “We believe everyone has a right to daylight and the right to a good view.”
Air quality was enhanced in the new building by rounding up all the printers and toners, which emit VOCs (volatile organic compounds), and housing them in a separate self-contained ventilated room. At their old workstations, every other NREL employee had his own desktop printer, says Pless. “That was a lot of VOCs to breathe, so we changed our standards (with the new facility) and bought high-speed multifunction devices and put much fewer of them in the closed-off rooms,” he explains. “Now when I go into buildings that aren’t naturally ventilated and day-lit, I feel like I’m in a cave.”
When the RSF design was on the drawing board, there were no large-scale net-zero buildings standing, recalls Pless. The largest were 10,000-square-foot structures and most were experimental, he says. The objective of the RSF project was to demonstrate the scalability and replicability of the concept so others could follow, he notes.
“The industry has now recognized that it can be done on a large scale and they’re learning how to do this,” says Pless, who spends time on the lecture circuit sharing his experience with industry professionals. Project leaders also developed a manual with design details that is shared publicly. Hootman describes the experience of this project as “transformational.”
“It changed the way I work and the way I think about design,” he admits. “Given that I’ve always been a LEED AP sustainable designer, this was a far more radical approach to designing around energy. It vaults you to the next level.”
Historically, architects weren’t trained in the details of BTUs of energy and other energy minutiae, notes Hootman. But that’s changing, he says—noting that some architectural programs are even incorporating net-zero energy into design class curricula. For his part, Hootman is pushing other architects to adopt these new approaches and insists the industry is on the cusp of a growing trend.
There currently are a couple hundred net-zero commercial buildings in various stages of design and construction. Many large-scale retrofits with net-zero energy goals are underway as well, says Pless. The majority of new construction is found in the government and education sectors, while retrofits are occurring across the board.
“Net-zero building today is where LEED Platinum was 15 years ago—a few leaders were trying to go all the way and soon after others followed,” he says. “I’m pretty excited to see this happening.”
Green building visionaries like Pless, Hootman, and Livingston applaud net-zero building as a vital component to mitigating the impact of climate change, but they are realistic about what will motivate others to jump on the bandwagon. “When commercial developers figure out how to build it, sell it, and create a marketplace for it like they’ve done for LEED, that’s when you’ll know net zero has become mainstream,” Pless predicts.