Building Tomorrow's Eco-Home

It’s just about here. For years, renewable energy advocates promised that solar would one day be affordable to all American consumers -- who have, by and large, relied on federal tax rebates to lower the out-of-pocket costs for new installations. The U.S. rooftop solar industry lived up to that prediction in the past year, thanks to breakthrough innovations that helped to change the landscape of North America’s most popular renewable energy.

Still, if there is any takeaway to be gained from the last half of 2016, it’s that solar is truly a global industry, fueled by global change. Plummeting production costs and two unexpectedly low construction bids in Abu Dhabi and China helped underscore solar’s potential for inexpensive, sustainable energy worldwide.  The increasing use of solar to power remote, off-the-grid impoverished communities in Africa, India and Latin America helped to drive home the diverse appeal and benefits of a global renewable energy market.

Here in the United States, access to solar power is still largely limited to mid- and upper-income families. The George Washington Solar Institute found that a whopping 40 percent of households that qualify for solar under U.S. federal tax incentives have annual incomes below $40,000. Yet only 5 percent of those households actually have installed solar. The reasons aren’t surprising: Credit “worthiness,” adequate disposable income, tax credit ineligibility (which is impacted by income) and lack of property ownership if they are renting often govern whether the country’s lowest-income earners can actually benefit from the country’s most popular renewable energy incentives.

Of course, solar isn’t the only ingredient that defines a sustainable home. Smart appliances, well-designed infrastructure like a gray water catchment system, composting, and architecture that addresses potential climate change risks are just as much a part of what defines a sustainable home these days as the way power is sourced.

Solar decathlon

One arena that helps showcase the potential for sustainable housing is the U.S. Department of Energy’s Solar Decathlon. Launched in 2002 on the National Mall in Washington, D.C., the competition was designed to inspire American universities and colleges to explore the many ways that solar and other sustainable concepts could address conventional housing needs.

And the Decathlon's success says a lot about what we really feel sustainable housing should be. Rather than providing a sort of “cookie-cutter” example of how smart architecture and innovative development can lower our carbon footprint, the entries reinforced the fact that our concept of sustainability is often driven by social factors: the local demands of our environment and society.

On the shores of New Jersey, that emblematic solar house might include an open, inviting design that can be buttressed quickly against an unpredictable storm surge and takes advantage of state-of-the-art smart technology. In the semi-rural farmlands near the University of California, Davis, smart living might mean smaller and more affordable living spaces that can accommodate the needs of migrant workers and lower-income families during triple-digit summers.

Then again, it might mean incorporating sustainable food production into the way residents live and interact within their “smart” home, as the State University of New York at Buffalo recently suggested in its 2015 entry.  It might mean less focus on pre-programmed amenities and more design features to let residents interact with their environment in the way that best suits their needs and their interests.

Martha Bohm, who oversaw the planning and construction of the University at Buffalo's GRoW Home, said when determining what would make a sustainable structure, the team looked beyond the appliances and low-footprint power sources they wanted to use.

Bohm is an assistant professor in the Department of Architecture for the State University of New York. Incorporating sustainability into the architecture, she said, meant considering not just what "smart" functions the house might be able to do, but the ways the house could help shape interaction between the users and the world outside.

The household's low-energy usage, which was generated both by photovoltaic and thermal sources, helped define its sustainability, but so did its potential for lowering another, more nebulous but equally critical footprint: the cost of sustenance.

The team, which won second place in the 2015 Decathlon, took a page from Buffalo's historic neighborhoods, where gardening is often considered much more than an urban past time. For some residents, that small plot of veggies, fruits and herbs by the door serves to reduce the daily cost of purchasing and transporting food from stores. Bohm said the team came to realize that any enduring architecture would have to be one that could help enhance the residents' ability to reduce that 'energy overhead' as well.

"This is one that doesn't show up on the energy meter and your energy bill each month. But we consider the food that is brought into the house each month to sustain the residents is part of the energy footprint of the house," Bohm said. "So we tried to incorporate food production at a very local and sustainable level within the house in the greenhouse that is attached to it."

That self-sufficiency element helped tie in another quality that the team felt was essential to a sustainable lifestyle: a house that could support and encourage an active, engaged life.

"Rather than following a very exciting and interesting trend in architecture, which is going toward more computer controlling and smarter technology, we were endeavoring to create a smarter user of the house by having them do more activities," Bohm explained.

Interactive features gave users more control when it came to ventilation, natural lighting and food production. Walls could be adapted to increase functionality of a room. Furniture was built with multipurpose uses in mind. The enclosed solarium served both as a recreational and gardening area during daylight hours and as a protective envelope of warmth during the night.

Solar affordability

The GRoW Home was meant to serve as a prototype for a competition with rather unusual transportation requirements (the house was built in Buffalo, but would be showcased at the Decathlon in California in 2015). It wasn't, for example, designed to prove the cost effectiveness of renewable energy on a mass scale or how the house could be most effectively reproduced in alternative settings. Still, affordability was a key issue, much as it often is in any renewable energy home these days.

But when it came down to overhead, Bohm said, it wasn't the solar system that was driving decisions about cost. It was things that are often faced in any conventional housing construction, particularly with climate change issues in the mix: the most affordable and effective heat pump to use, what kinds of windows to use in a cold-climate home, and what auxiliary venting systems might be needed to help reduce heat build up during the summer.

The project, which was able to cut costs through donated labor and fundraising, confirmed a critical issue when it came to solar homes: It isn't the cost of hardware that is driving the cost of solar these days, but labor.

"The costs are definitely coming down in terms of the equipment," Bohm said. But when it comes to getting those panels up on the roof, well, that presents another challenge. "The cost of labor has not come down as quickly.  So even though the stuff is [less expensive now], getting it on to houses is not as cheap as you would want it to be."

Bohm said this dilemma forced some solar companies to start looking at alternative manufacturing techniques that would streamline the installation requirements  in most PV installations. Standardization of racking systems, uniform installation plans and equipment are now making it easier to ensure labor costs can be reduced to a minimum.

"[Having] a set of details that work with different roofing types and roof pitches, and having all of that pre-figured out" has become one way of expediting solar orders, she said. So have new contract options that take the cost of solar installation off the table for the consumer.

Power purchase agreements, in which the solar provider strikes a deal to use the consumer's rooftop to generate solar power, are gaining popularity in places like Southern California. Bohm said she expects the country will see more of these types of dynamic partnerships in the coming years.

New innovations and old, but usable stock

From an energy perspective, Bohm cited other things that can be done to improve our environmental footprint which have just as much of an impact on cost and effectiveness as the type of energy we generate.

"We have a lot of old building stock that was built at a time when our energy codes were not as stringent as they are now. What we need in a lot of our houses is really unsexy stuff like new windows, better insulation, reducing the amount of leaks that are in the building that create drafts and lose energy that way."

Fixing water supply systems, such as in Flint, Michigan, and upgrading low-cost rental housing stock in tourist-destination New Orleans, she said, goes hand-in-hand with building a resilient renewable energy infrastructure.

The coming years will be exciting for the renewable energy market, said Bohm, who predicts small but significant leaps in a broad spectrum of industries: improved windows that allow for better heat retention through specially coated formulas, new heating systems and a continually improving array of building materials will continue to nuance the conversation when it comes to the definition of the affordable solar home.

Finding ways to tailor the home to address those "hidden" environmental impacts, like food production and the everyday demands of building a resilient urban lifestyle may become the next challenges to defining the perfect eco-home.

Images: University at Buffalo 2015 Solar Decathlon entry exterior and interior views - Thomas Kelsey, U.S. Department of Energy Solar Decathlon