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.”