I posted on a new development of zero energy/net positive houses in Houston, which depended on a fuel cell concept for some of its energy production. Obviously fuel cells are not the final answer, but not a bad option for many homeowners.
Above, net zero homes in Canada – which seems like a good test bed for the concept. It also illustrates the reality that homes like this may still be tied to the grid, at least with current tech. Plenty of room for innovation here.
As is so often the case, California is on the cutting edge, with Governor Jerry Brown continuing to push the envelope. Things like this tend to spread to the rest of the country. Think hot tubs.
Starting in 2014, California is implementing a tsunami of building code revisions called Title 24. These revised building codes will move California’s residential and commercial buildings toward Zero Net Energy (ZNE). In a ZNE building, the annual energy consumption is equal to its annual production of renewable energy. Under Title 24, all new residential construction is to be ZNE by 2020 with all new commercial buildings achieving this ZNE goal by 2030.
Title 24 moves building design toward “comprehensive building solutions.” This building design approach first focuses upon reducing energy consumption through the integration of smart and energy efficient technologies. The final design step after reducing the building’s energy consumption is to install onsite renewable energy generation like solar panels.
As these new codes are being analyzed by the construction and real estate industries, there is a growing realization that Title 24 will apply to existing buildings that implement threshold-sized remodeling or repurposing construction projects. In addition, California’s Governor Jerry Brown has authorized through an executive order that state agencies shall take measures towards achieving ZNE for 50 percent of the square footage of existing state-owned buildings by 2025.
In coordination with these code revisions, the California Public Utility Commission (CPUC) is revising the financial incentives offered through utilities to encourage energy efficiency investments by building owners. The CPUC is reducing or eliminating past financial incentives for energy efficiency investments that are now mandated by Title 24. In 2014, a new set of financial incentives are being launched that support comprehensive building solutions.
Other locations and concepts below.
The stereotypical question of a mother to a small child about why they’re not supposed to do something: “What if everybody did it?”
The zero-net-energy house sounds like a good idea, but the devil is in the details. Such a house is going to generate its surpluses during the day, and seasonally during the summer. Who or what is going to consume these surpluses if everyone’s doing it? There’s no requirement for storage—for the owners to “eat their own dog food”. Then at night, the house will swing from net surplus to net deficit. Other than batteries or pumped hydro, what can swing into action fast enough to keep pace with that reversal? And what can store summer’s sun against winter’s winds?
Maybe there’s some cheap-enough storage scheme out there that can be put in play before this becomes a major problem. But if not…
It’s not like it’s a disaster if some of the energy generated is wasted during the day/summer. It just means that the reduction in total fossil fuel usage isn’t quite as great as it would be with better storage.
Larger grids are part of the solution – “What if everybody did it?” right now means that if everybody in California did it, California would be an energy exporter in summer. The bigger the grid, the less (relative) storage is needed as the variability in sun & wind averages out. It ain’t perfect – solar and wind need more excess capacity than other systems to guarantee output. Ordinary Hydro can go a long way towards balancing out solar & wind though. And we’ll have a large new class of electricity usage – charging cars – which can be managed so that most of the usage is during peak production. That probably means more charging at work than at home.
Interesting development from Toyota and Hyundai on fuel cell cars:
http://www.bbc.co.uk/news/business-25023673
ZNE is designed for energy use to be two thirds of existing designs. Logistically, a reduction being met by conservation or by local generation is the same, except for the metering issues. The standard also calls for financing, codes, technical tools, and grid infrastructure.
http://www.californiaznehomes.com/#!framework/c5ro