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Buildings Osaka Gas and Sekisui House Complete Experimental Smart House

Published on August 7th, 2012 | by Charis Michelsen


Smart Home Test Shows 88% Reduction in Household Power Consumption

August 7th, 2012 by  

Osaka Gas and Sekisui House have been cooperating in an experimental project for the past year and a half to answer the burning question “Yes, but how well does it actually work?” I speak, of course, of the rising trend of smart homes and communities.

Osaka Gas and Sekisui House Complete Experimental Smart House

The partnership between Osaka Gas and Sekisui House (two well-known names in Japan) started back in February 2011, with the Smart Energy House project. The idea was to test out ways to reduce both reliance on outside sources of energy and also carbon dioxide emissions — in other words, meet energy efficiency goals — and the test parameters involved a lot of batteries.


On Practical Evaluations and Multi-Type Battery Systems

The first step was building and equipping the house – with a 700W natural gas fuel cell, a 5.08kW solar cell, and 3.5kWh lithium ion batteries. A HEMS (home energy management system) was installed to balance out the three power sources, and various bits of the house were constructed with energy efficiency in mind (think stuff like LEDs everywhere).

The second step was to stick a three-person family in the house and watch them for a year (it’s less creepy than it sounds). The experiment ran from July 1st, 2011 to June 30th, 2012. After it was completed, all the information gathered was carefully analyzed.

Just the Facts, Ma’am – Analyzing Results

According to the partnership’s numbers, power consumption was reduced by 88%. The amount of power purchased from outside the home was 584kWh – average in Japan for a three-person household for a one-year period is 4830kWh. Reducing carbon dioxide output was even more successful. Specifics on how, exactly, this was accomplished has not been published (at least, not where I can find them), but the partnership claims that the house generated a negative 137kg over the course of a year. As a comparable household generates something like 4770t of CO2 per year, they’re calling it a 103% reduction. Also not published were initial costs of the batteries installed, or the cost of potential replacements.

Although the one-year experiment is now complete, Osaka Gas and Sekisui House aren’t finished. Research is slated to continue through the end of 2014, focusing on better balancing and control of the battery systems. Further experiments with incorporating electric cars into the house grid are on the table, as well as a return to using proper ventilation and pure solar heat instead of total climate control of closed-off rooms to manage comfortable living spaces.

The current project schedule calls for these houses to go on the market in 2015. I wouldn’t go back to Japan for one, but I’d be curious about similar projects in the U.S. – what about you? Let us know in the comments, below.

Source: Eco Japan
Image Credit: Wikimedia Commons

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About the Author

spent 7 years living in Germany and Japan, studying both languages extensively, doing translation and education with companies like Bosch, Nissan, Fuji Heavy, and others. Charis has a Bachelor of Science degree in biology and currently lives in Chicago, Illinois. She also believes that Janeway was the best Star Trek Captain.

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  • I have managed to reduce the electricity consumption in our house by over 40% through automation, see http://blog.abodit.com/2010/12/smart-home-energy-savings-update-for-2010/ and that’s without solar cells, batteries or fuel cells.

  • Matthew

    I would absolutely prefer a home like this over old school homes.  Living in Florida, loosing power is a reality and if I could generate my own power during or after hurricanes wipe it out, that would be a huge deal maker for me.  Also, cutting costs is the single best way to get rich.  The more you spend, the poorer you are.  Not wasting money on energy, something that doesn’t have a profitable return, is something I would prefer.

  • Anonymous

    Sorry. Is that an 88% reduction in power CONSUMPTION or power PURCHASE. You state the reduction in power purchased from outside the home, but also that they have a solar PV array on the house. So the combination of own-generation and efficiency leads to an 88% reduction in power purchases, but without stating how much energy they produce.

    A 5.08kWp ‘cell’ as you called it, at a 10% capacity factor over 8,760 hours per year would produce 4450kWh of electricity. So essentially, all of your figures above are useless without any analysis.

    • Bob_Wallace

      Consumption works here because the house is consuming 88% less grid power.

      That could be made a bit clearer/earlier in the text.  What’s very interesting to me is that we could be building new houses (and commercial buildings) that rely on the grid for only a small portion of their power needs.  

      Although I don’t think we should be looking to natural gas fuel cells as part of the picture.  

      • Matt

        I would agree NG feul cell is a question make. Unless maybe it only used in winter when you need heat.

        Maybe it is to ease fears of backouts in Japan. Of course if there is no power at all then likely the company suppling gas isn’t pumping. Or maybe the compressors run on NG.

        • Bob_Wallace

          In the winter there’s often a lot of wind. Since the house is already connected to the grid why not rely on the cheapest way to produce energy and avoid adding more carbon to the atmosphere and ocean?

          This house spends more and pollutes more when it turns on the fuel cell.

      • Freealex1

        Bob, agreed that there’s no question that its purchase from the grid is down by 88%. But what the story leaves absolutely unclear is how much of that is due to increases in efficiency (and therefore reduced consumption of electricity through use of LEDs, etc), vs how much is ‘simply’ putting a PV array on the roof. Installing self-generation can achieve 100% reductions if the system is big enough.  What’s ‘interesting’ about the story – or should be – is how much they reduced via efficiency, and therefore how much less own generation (as well as grid purchases) they need.

        This website has a habit of ‘so what?’ points often missing key figures or analysis.

        • Bob_Wallace

          The quality of writing varies from author to author. Some, in particular Zach, dig deep and think hard while others seem to do little more than a quick rewrite of what some company’s PR department produces.

          I suspect most who publish here are interested in doing a good job.  Ask them the questions that they didn’t ask themselves.  Maybe we can shape them up a bit.  ;o)

          None of the above was aimed at you in particular, Charis.  I don’t have a formed opinion on your work in general.  This piece could have used some breakdown of how much of the “88%” was due to efficiency, how much to PV, and how much to localized gas use.

          And I do realize that your source may not have given you those details. 

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