NREL: It’s Go Time for Low-Cost, Net-Zero Affordable Housing

The U.S. construction industry is facing a housing supply deficit on the order of millions—and growing—at a time when climate targets mean that every unit should be built as efficiently, sustainably, and affordably as possible. To help meet this need, the construction industry must modernize to increase the speed and scale of high-performance building delivery.

National Renewable Energy Laboratory (NREL) researchers are eager to give partners a blueprint for optimizing performance by leveraging industrial construction methods. Techniques such as high-volume off-site construction, prefabrication, and on-site construction automation provide a pathway to decarbonization that also addresses the affordable housing crisis.

On Sept. 21, the NREL Industrialized Construction Innovation team hosted an Industry Demonstration Day in conjunction with the Modular Building Institute’s Off-Site Construction Expo in Denver, Colorado. Industry leaders received an overview of NREL’s seminal research in the field, as well as their very own blueprint—a copy of the Energy in Modular (EMOD) Buildings Method report.

“The EMOD guide represents the culmination of our industrialized construction research over the past five years,” said Shanti Pless, a senior energy-efficiency research engineer at NREL and lead author of the guide. “We now know the ideal approach for integrating energy efficiency strategies at the whole-building level, including subassemblies of components, pods, panels, and volumetric modules.”

The question is no longer how but how fast EMOD principles can be put into practice. Demo Day allowed NREL to get applicable research and experimental results directly into the hands of industry influencers who can rapidly scale these next-generation modular building technologies. NREL also hosted a listening session to better understand the industry needs and challenges that researchers could partner to address.

Reimagining Buildings as Manufactured Products
Process improvements are behind some of the biggest cost reductions fueling the adoption of low-carbon technologies. In recent years, falling prices associated with more efficient solar panel production, wind plant development, and light-emitting diode (LED) manufacturing have led to rapid growth in those industries. But green building upgrades seem to be on a steeper learning curve.

“Anyone who manufactures anything models their industrial process,” Pless said. “But because we haven’t traditionally thought of buildings as manufactured products, the industry was repeatedly experimenting with one-off approaches that remained costly. For the first time, we’ve adopted productivity optimization tools and applied them to energy-efficient building.”

With a boost from DOE’s Advanced Building Construction (ABC) Initiative, NREL’s Industrialized Construction team leveraged design for manufacturing and assembly (DfMA) approaches to develop, model, and streamline low-carbon strategies into a cohesive building solution. Multiple projects across varying scales led to the five strategic recommendations outlined in the EMOD guide.

One of those concepts, the Energy Exchange Pod, is a turnkey product that combines a building’s mechanical, electrical, and plumbing systems into one factory-installed package. This “utility closet” of sorts integrates space conditioning, domestic hot water, high-efficiency appliances, power distribution, and more directly into individual apartment units. For an ideal configuration, the EMOD approach creates a volumetric module by combining an Energy Exchange Pod with a highly insulated airtight envelope, smart controls, and a solar plus energy storage system.

All the Cool Buildings Are Digital-Twinning These Days
Full-scale applications of the EMOD principles, as well as NREL’s underlying research strategies, were on display at Demo Day for guests, including the Modular Building Institute’s board of directors, national industry representatives, and local factory developers.

The group learned about NREL’s Immersive Industrialized Construction Environments (IICE), which are virtual-reality modules representing the realities of construction uncertainties without the need for full-scale physical prototypes. NREL is using IICE to enable widespread adoption of energy-efficient products and Industry 4.0 construction automation techniques through worker-machine interaction pilots.

“One challenge of Industry 4.0 adoption is the workforce training required to use emerging energy-efficient products, like pre-insulated wood studs and bio-based materials,” said Ankur Podder, a buildings advanced manufacturing and integration science research engineer at NREL. “Our IICE research suggests that digital twins and virtual reality could make continuing construction education more affordable, accessible, scalable, immersive, and safer.”

Demo Day also included a tour of NREL’s Research Block, an outdoor modular research pad for modular performance demonstrations and development at scale. The Industrialized Construction Innovation team is currently performing a series of experiments on two modular apartment units—iUnit and Blok—as well as an ABC project exploring wall panel overclad retrofits.

The individual Blok unit demonstrates how one active leader in the industrialized commercialization space, Blokable, partnered with NREL as a startup through the Wells Fargo Innovation Incubator (IN2) program. The company recently received a 2022 Gold Edison Award at Phoenix Rising for Blokable, which provides an all-electric permanent housing solution for low-income residents of Valley Cities Behavioral Health Care in Auburn, Washington.

While such early demonstrations are promising, significant challenges still exist when it comes to financing large-scale projects. One Demo Day attendee, CEO of Vederra Building Systems Nathan Peterson, is currently finalizing financing for an affordable housing modular factory in Colorado.

“Through our partnership with NREL, we have developed a low-cost housing option with a superior building envelope, battery storage, and heating system that can be supported by a factory-installed solar array,” Peterson said. “But while there is more than enough demand in Colorado to support multiple modular factories like the one we are proposing, we have found it takes a lot of time and know-how to assemble the right combination of financing and like-minded investors who believe in supporting energy-efficient, affordable housing.”

There is no time like the present. NREL is actively working with partners like VEIC and KBS Builders to deploy more than 50 Energy Exchange Pods across multiple sites in Vermont this year, and this initial market introduction represents only a small sign of things to come. One Demo Day attendee said he already has a need for upward of 10,000 modular housing units in the next year alone.