Tuesday, 19 July 2016

Japan sees the future and it is zero-energy homes - Nikkei Asian Review

At least that's what this article in nikkei says!

This is great news, but the silver has a little bit of a cloudy lining.

According to the article:
"Japan's Ministry of Economy, Trade and Industry has set criteria that a house must meet before it can be dubbed zero-energy. It has to:
  • Be at least 20% more energy efficient than an ordinary home.
  • Be airtight and adiabatic enough to increase the efficiency of air conditioners and water heaters.
  • Allow for efficient ventilation.
  • Have a solar power or other renewable energy system that can keep the house from sipping electricity from the grid, or even spit some electricity back onto the grid."
Interesting definitions, but wouldn't it make more sense to determine a zero-energy house as one that uses less energy than it produces?

The article does mention insulation, but only after talking about solar panels, energy management monitors and fuel cells. That's a bit like only mentioning malaria mortality after talking about terrorist attacks and aircraft accidents. (Oh, yeah, that happens in the media all the time!)

In the definitions quoted above, I guess "adiabatic" is only possible with insulation, but that's not exactly a widely used term outside school physics lessons, and even there it is not universally understood. I don't think I've ever heard anyone say: "Japanese houses are cold in the winter and hot in the summer because they are not very adiabatic." People frequently lament the lack of insulation though.

The other really big question with "zero energy" homes is how much energy they are allowed to generate. You could balance any level of energy use if you add enough solar panels, as long as you ignore how much energy was used to make the solar panels. So it's nice that zero energy homes have to be 20% more efficient than ordinary homes. But what if ordinary homes become 20% more efficient?

I could also complain about them using the term "energy efficiency". You could fill one house with energy efficient appliances, and have another house with just one appliance that is not so efficient. The house with more appliances will use more energy. Selling energy efficient air conditioners is much more appealing to the market economy than not using air conditioners at all!

It's easy to be cynical. I'd really like to see Japan's future in zero-energy homes too! I know that's where my future is.