National Renewable Energy

Solar-friendly designs could aid renewable energy efforts

A new report contends that designing solar-friendly homes would help spur the installation of alternative-energy systems.

The study entitled, "Solar Ready: An Overview Of Implementation Practices," by the respected National Renewable Energy Laboratory, argues that solar-ready design features, if they are implemented early in the design process, are typically "low or no cost," thus making it easier and cheaper to install solar-energy systems later on.

Authors Andrea Watson, Linda Giudice, Lars Lisell, Liz Doris and Sarah Busche estimate that some 7.8 million privately owned houses were finished in 2010. "These homes, if not compatible with solar technology, represent a large barrier to widespread solar deployment," they write. "Once a structure is built, structural and other solar access issues can prevent a solar project from being cost effective, and, in some cases, can make it entirely unfeasible."

In particular, the authors note that rooftop integrity and obstructions (such as vents), along with improper placement of shade trees, can restrict opportunities for adding solar power later. The researchers say solar-ready design is crucial if photovoltaic (PV) or solar hot water (SHW) technologies are to be installed during the building’s lifespan.

"Solar ready also allows owners to take advantage of a changing energy market," they write. "The economics for installing solar on a new building are not always compelling, but, in the future, that picture could change with rising electricity prices and/or falling solar technology costs. . . Building a home or commercial building that is not solar ready exposes owners to the risk of not being able to take full advantage of future economic scenarios for solar electricity and hot water. "

Rooftops should be strong enough to accommodate solar panels, the authors suggest, and vents and other obstructions should be grouped in one spot. In addition, architects and builders should consider landscaping that won't reduce the effectiveness of solar.

Positioning is key in solar installations, so preparing beforehand is important. This is from the report: "A 10-kilowatt (kW) PV array in Golden, Colorado, facing south and tilted 25° can be expected to produce 14,304 kW hours (AC) per year with an annual energy value of $1,201.00. . . A west-facing system will produce 10,999 kW hours (AC) per year with an annual energy value of $923.92. This represents a 16% to 23% reduction in PV production and cost savings when oriented 90° away from south."

Likewise, designing for solar water heating saves money later. The study calculates that mounting pipes, vents and panels to accommodate solar water heating during construction is 66 percent cheaper than installing them afterward.

So, how do local governments encourage solar-ready development? The authors analyze three methods: legislation, certification programs and stakeholder education. Let's look at them individually:

1/ Legislation

Several local jurisdictions have policies in place, but their effectiveness is hard to gauge. Policies can include mandating builders offer solar to their customers, adding it to green building codes, offering roof warranties that allow for new solar systems, and providing incentives to developers.

2/ Certification

Certifications could be incorporated into green-building programs or offered individually. Certification guarantees a certain level of quality, helps the property stand out from the competition and is a measurable metric. However, it doesn't guarantee installation of the solar system, and could end up rewarding property owners anyway.

3/ Stakeholder education

Education programs must reach a diversity of people, and the authors say a combo of solar-ready legislation and an educational campaign could be effective. They cite a Boston program as evidence. The city offers developers an integrated design and solar training in conjunction with a solar-ready requirement.

Whichever approach is used, the authors write that they hope it promotes more solar development in the United States. “With millions of new buildings constructed each year in the United States, solar ready can remove installation barriers and increase the potential for widespread solar adoption."