Net-zero energy buildings are today’s ultimate green building statement. From the proposed Bride of the Gulf in Basra, Iraq — which will be the tallest building in the world if completed — to Tesla's gigafactory in Reno, NV, the biggest players in building design and innovation are choosing the net-zero path.
But if you set aside the often short-lived burst of excitement generated with each net-zero announcement, the concept is very simple. Net-zero status simply requires that a building, or group of buildings, produces as much energy as it consumes. Certification requires that the building maintain that net-zero status for one year.
As with most major developments, net-zero might appear easy once its elements are incorporated, but getting there can be a challenge.
Benefits of net-zero buildings
But why make the effort? Isn’t setting the temperature a little higher on the air conditioner or making sure the lights are off before leaving for the day enough?
San Francisco Regional Manager Mike Humphrey of DPR Construction said the answer to that question is no.
"As long as (DPR) has been around, we’ve really thought sustainably," he told Construction Dive. "The construction world — the built world — produces about 40% of the waste that goes into landfills, so if we in the construction industry can’t change it, then who will?"
DPR was the subject of some serious net-zero-envy this year when its office became the first certified commercial office net-zero energy building in San Francisco by the International Living Future Institute.
Impact on employees
Humphrey said that before the company embarked on the journey to net-zero, it was important to "ask permission" from their employees because office behavior is a major factor in whether or not this kind of endeavor is successful.
"Some days it’s a couple degrees colder than an average office or on hot days maybe a couple degrees warmer, but we talked about that with everyone before we moved over and set the expectation," he said. "We gave out fuzzy blankets on day one just in case they got cold."
In general, though, Humphrey said he believes DPR’s employees appreciate the extra commitment the company has made to net-zero, as well as to their well-being.
"There's something about net-zero equating to health," he said. "You come into a building like this, and something feels a little different. You feel a little more creative, maybe a little more inspired."
Humphrey said employees are paying more attention to their health, wellness and work-life balance as well.
"They’re just talking about wellness in a different way. The environment itself supports that feeling. It supports relationships, and there’s a lot of things that spin upward just by creating a space that makes people feel comfortable," he said.
Impact on the bottom line
And, of course, there's the thrill of how net-zero has impacted DPR’s bottom line.
"Our electric bill in the old building was $3500 a month, and our first PG&E bill was $19 the first month and $22 the second month. People were saying, 'Who spent the extra three dollars?' It was a big deal. We celebrate it," Humphrey said.
'Pushing the envelope'
Like DPR, construction giant Skanska is also committed to green building and sustainability, according to Stacy Smedley, director of sustainability at Skanska USA.
"It’s definitely a place where pushing the envelope and making our buildings more sustainable, and almost restorative in some ways, is a core value," Smedley told Construction Dive. "I think people see that and seek that out."
Smedley, who is also founder and CEO of SEED Collaborative, which produces net-zero modular classrooms, said she got to know the Skanska team while working on the net-zero Bertschi School project in Seattle. Bertschi's science wing was one of the first buildings in the world to pursue the even more stringent net-positive-energy Living Building certification, which "integrates urban agriculture, social justice and universal access issues, and the use of healthy building materials," according to Skanska.
How to approach a net-zero project
The starting point of a sound net-zero strategy is site selection and orientation, according to Michael Kearns, project executive/regional director for Western Massachusetts at Shawmut Design and Construction,
"You want the building to reject solar gain in the summer and pick up the benefit of solar gain in the winter," he told Construction Dive. "Then you start to look at how you’re going to orient your building on the site, what types of exposure it’s going to have during certain times of the year and how you really optimize the sun."
Site orientation, he said, also includes positioning the building for optimal lighting, which can reduce electric and heating bills.
The next step, according to Kearns, is for builders to ensure they have a high-performance, well-insulated building envelope that can retain all of the cold-treated or heat-treated air, depending on the time of year.
After that, builders should consider various mechanical, electrical and plumbing (MEP) systems for energy efficient ways of heating and cooling the building, including options like geothermal heat pumps, which use the relatively stable temperature underground, via a piping system, to cool, heat and provide hot water.
He added that it's important to keep the people who will be working on the systems in the loop during the MEP selection process.
"Often these systems might be things that they don’t currently have," he said. "They’re going to require training and buy-in to make sure that they’re on board with this so that it’s successful."
Using water and piping for temperature control is similar to what Under Armour previewed at the announcement for its future 50-acre South Baltimore headquarters campus. The plan is to filter runoff and water pumped from the Patapsco River to cool the complex’s buildings before circulating it back into the river.
Kearns said this practice is fairly widespread, particularly among industrial buildings. "A lot of process facilities will pull water from the ocean or river and run it through their manufacturing facilities for free cooling," he said.
When builders have the basic systems set up for a building — minimizing energy consumption as much as possible — then it’s time to select how to produce enough energy to offset that consumption. Solar, Kearns said, is the most common, but biomass — plant matter and animal waste — and wind turbines are options as well.
Intimidating for smaller companies?
As popular as net-zero is in some circles, however, it can still sound intimidating to building owners or companies who are exploring it for the first time, especially those without the resources of a DPR or Tesla.
Humphrey said one goal in building DPR's office was to keep costs down to $200 per square foot, which, given the specialty items being installed, was no easy feat. But the company achieved that in a pricey market like San Francisco — which should serve as inspiration to smaller companies who want to give net-zero elements a try, he said.
Humphrey said DPR considers its office to be a "living lab" where the builders can try out certain green elements and then show customers the kinds of things they can successfully incorporate into their own projects, like living walls, fans or special lighting.
"We give away information. It’s not like it’s a trade secret," Humphrey said. "We walk (customers) through things that worked and things that didn't."
Smedley said the industry needs the high-profile net-zero projects like Tesla’s gigafactory to generate buzz and to show the world what’s possible. Oftentimes, she said, the key to wider net-zero adoption is to approach it in a series of steps rather than going all in right away.
"I think that you've got to have those projects that are more accessible that show real, applied examples on a smaller scale too," she said.
What's next for net-zero building
So what does the future hold for net-zero?
"It’s an exciting time right now," Smedley said, "because of what I would call a groundswell to actually build these types of projects. Whether it’s on the innovation side or the testing side or actual payback side, (net-zero buildings) are starting to make sense, so I think it’s exciting that we’re finally getting there."
She added, "I think we’re at the tipping point, and it’s going to be exciting to see what the next handful of years brings."