Published in Energy
Habitat for Humanity of the Grand Traverse Region built zero net energy homes in the Depot Neighborhood development in Traverse City. The homes feature rooftop solar energy systems that produce energy and generate savings on residents’ utility bills. Habitat for Humanity of the Grand Traverse Region built zero net energy homes in the Depot Neighborhood development in Traverse City. The homes feature rooftop solar energy systems that produce energy and generate savings on residents’ utility bills. COURTESY PHOTO

Builders, contractors call ‘zero net energy’ the future of construction

BY Sunday, May 26, 2019 11:02pm

Some people might assume homes built by Habitat for Humanity are typical, nuts-and-bolts affordable housing adhering to basic building codes.

However, that assumption would be wrong.

Multiple Habitat for Humanity of Michigan affiliates have begun adhering to a construction principle known as zero net energy, which loosely means a building produces as much energy as it consumes. Although definitions vary over how energy use is offset, the concept hinges on high-performance energy features that maximize efficiency.

“It’s kind of funny: Habitat for Humanity has a reputation for cheap houses,” said Tom Phillips, sustainable housing director for Habitat for Humanity of Michigan. “We found we could build a much better home and justify the extra costs because savings on the utility bill exceed the amount on the mortgage to build a better house.”

Habitat for Humanity affiliates in Traverse City, Grand Rapids and Kalamazoo are at different stages of completing zero net energy projects, taking high-efficiency standards required by the group’s homes statewide to the “next level,” Phillips said. The Depot Neighborhood in Traverse City — completed in 2014 — includes 10 homes equipped with rooftop solar, capable of producing more power than the homes consume. Phillips said affiliates in Kalamazoo have built “zero net energy ready” homes that could easily be equipped with solar.

Habitat for Humanity projects have another benefit by delivering energy savings to low-income residents who otherwise pay a higher share of their income in utility bills. However, it’s difficult to calculate individual payback periods for new construction and retrofits in general as household energy use varies among residents.

Still, Phillips says builders — and customers — who are hesitant to embrace the concept miss out on long-term savings and the broader benefits of less energy usage.

“If you’re a builder who builds a home to Michigan’s residential building code, we call that the worst home you can legally build,” Phillips said. “The big step to net zero energy ready is a lot of detail but not a ton of money. If we can totally justify it in affordable housing, how can you not in market-rate housing? In our opinion, it’s kind of a no-brainer.”

Grid resource

Zero net energy is an emerging concept among builders and contractors like those who install heating and cooling systems. Pairing high energy efficiency with renewable energy like solar and geothermal systems is increasingly economical, with higher upfront costs paying off with little to no utility bills.

It’s typically easier to equip new construction with zero net energy features than it is in a retrofit project, although the latter is a major opportunity in Michigan, said David Gard, executive director of the Michigan Energy Efficiency Contractors Association (MEECA).

One noteworthy zero net energy building in Michigan is the retrofit of an International Brotherhood of Electrical Workers (IBEW) facility in Detroit. Completed in 1965, the original cinder block facility was transformed to include new insulation, LED lighting, geothermal for heating and cooling and rooftop solar. Gard said the facility now pays “dollars per month” in utility bills.

“You can situate the concept of zero net energy into the wider energy system as really an untapped resource we can be investing in over time,” Gard said. “We have a huge resource and building stock that could be renovated.”

Gard said zero net energy buildings also include self-contained sites that don’t require inputs from the grid or gas lines, often via the use of passive design or batteries. For residential buildings, most will continue to be hooked up to the grid, however.

Energy offsets typically are calculated over the course of a year. For instance, if solar panels are producing more than a home needs during the summer months, that generation is banked during lower-producing winter months.

Gard also says getting to net zero energy is a process and doesn’t have to all be done at once. That’s particularly true when retrofitting older inefficient buildings: You wouldn’t install solar panels on a building before maximizing its efficiency.

“The logic is you want to minimize the load then size your renewables to match,” Gard said.

Ultimately, zero net energy facilities can act as a resource that benefits utilities both on the supply and demand sides. Zero net energy facilities can reduce demand — and the need for new generation — while also sending power back to the grid when it’s valuable.

Consumers Energy is in the second year of a three-year pilot program that gives incentives to customers building zero net energy projects. The program has paid out $350,000 in incentives to eight customers at various phases of their projects. The utility says the pilot program aligns with its broader energy efficiency goals.

“Thinking about this as a utility resource will be a useful policy approach,” Gard said.

Raising the bar

In early May, MEECA led a day-long conference in Grand Rapids to convene builders, contractors, architects and renewable energy installers.

“There’s growing excitement about it,” Gard said. “More contractors and builders are starting to hear from the marketplace. We really need to educate at this time and get people to understand how big of a scale the opportunity is.”

Gard also believes the state’s building code should be strengthened with stronger energy requirements.

“I don’t think we should be building any new building in Michigan unless it sets a really high bar,” he said. “The building code isn’t that high.”

One opportunity for new construction is in 2030 districts, which have been adopted in Grand Rapids, Ann Arbor and Detroit.

Cheri Holman, executive director of the U.S. Green Building Council West Michigan, said while attention is increasing among utilities, builders and local governments, “getting down to the user level takes time. We’re trying to change the mindset of everyone and put things in place to enable it.”

She added that it’s important these energy savings are accessible to all utility customers.

“Social equity is a huge layer on top of all of this,” Holman said. “If it’s not available to all of us, it won’t be successful.”

The challenges ahead for zero net energy focus largely on education — changing the culture of traditional building practices and ensuring higher upfront costs provide long-term energy savings.

“A zero net energy building doesn’t happen by throwing high-efficient equipment together,” Holman said. “We have to educate our service providers to help them work together.”

However, Phillips says zero net energy is “absolutely” the direction the industry is heading.

“We’re going there, and we’ve changed the entire culture in the way we’ve built in the state,” he said. “Now we’re looking at how we can impact the rest of the market and is there a way we can help other people learn.”

Read 3121 times Last modified on Saturday, 25 May 2019 18:03
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