I could do without the old style HoJo roof.

You could probably turn your own house into a carbon negative house with enough houseplants.

Based on the photos, most of it looks manufactured and not just mud and leaves. So from the copper in the wiring to the rolled aluminum safety rails, big business with a big carbon footprint built this house. It may not take much energy to run the house but it took a lot of energy to build it.

JammerJim: The Laws of Thermodynamics would like a word.

With you, maybe.

With the house, no. The photovoltaics on the roof generate more energy than the house requires, thanks to an external energy input. This violates no laws of physics.

Galloping Galoshes: So, where do all the materials come from? And I'm sure their manufacturing is also carbon-neutral, as is the manufacturing infrastructure.

Generally depends on the time scale. For example, current PV systems pay back the energy required to produce them (including the panels, the balance-of-system stuff like mounting, etc.) over the first 3 years, and generally come with a 30-year warranty.

They mention an emphasis on locally-sourced materials, but don't give enough detail to say much about the overall energy payback, or the lifetime of these components. One of the problems with the construction techniques (in the US) during the 1970s-1990s was an emphasis on plastic parts that can't be repaired, and wear out too quickly. Sure, stone, hardwood, and steel are energy-intensive to craft, but if it lasts 100 years with minor upkeep, it's a better investment than 5-10 generations of cheaper material. It's the "IKEA" problem-- that desk looks inexpensive until you realize that it will be wobbly and the screws will tear out of the particle board in a few years. In the meantime, we've inherited hardwood furniture so old that no one can remember when it came into the family, and it's rock solid.

Still, this house is a big step forward from "Needs energy to make and more to live in" to "Needs energy to make".

aneki: The tone of the article is trying to push it as a mainstream solution. It can't do that without something resembling a price tag.

Any pricetag for a custom job like this will be off the mark. You're eating tons of architect hours. Construction will be slow because of all the custom training and processes you need to develop. You're probably not getting it all right the first time. You're ordering custom parts in small quantities.

What you really want in a manufacturing plan that asks what 10,000 of these houses would cost. The house is designed to use pre-fab modular parts, so it should be especially amenable to production-line manufacturing. You build the guts the same way every time, assemble them differently to make several common variants, and change the surface stuff to make each one look a little different.

If you balk at the fact that these houses will start to look alike after a while, ask yourself how distinctive your home really is. Real estate listings are full of terms like "Cape Cod", "Rambler", etc. because most houses fall into one of a few categories that they teach architects and construction crews how to make in bulk.

chimp_ninja: JammerJim: The Laws of Thermodynamics would like a word.

With you, maybe.

With the house, no. The photovoltaics on the roof generate more energy than the house requires, thanks to an external energy input. This violates no laws of physics.

I wonder how long it will take for us to realize that there is a price to pay for converting a percentage of the solar load into a form other than reflected heat.....I guess im suggesting that the laws of physics would be happy to allow several layers of complexity to be inserted between the term "free energy" and the term "collateral environmental impact". Same thing with wind.....how much energy can you take from the jet stream before it effects the weather?

Still, this house is a big step forward from "Needs energy to make and more to live in" to "Needs energy to make".

Hopefully they can come up with a rock solid answer. In my area we dont have enough sunny days for a PV system to pay for itself in any reasonable time frame. I live in a turn of the century mansion that costs about $500 a month on even billing to heat with gas. Switching to electric heat would be an expense of more than $40,000 for installation of individual electric HVAC for each unit, plus to cost of a PV system which might work for 50% of the year. Money wise it makes more sense for me to invest that money and use the interest to pay the bills and save for system replacement costs every 25 years or so.

archichris: I wonder how long it will take for us to realize that there is a price to pay for converting a percentage of the solar load into a form other than reflected heat.....I guess im suggesting that the laws of physics would be happy to allow several layers of complexity to be inserted between the term "free energy" and the term "collateral environmental impact". Same thing with wind.....how much energy can you take from the jet stream before it effects the weather?

1) The entire world in 2004 used 15 TW (1.5x10¹³ W) on average. Let's pretend we somehow replaced all of that tomorrow with 100% efficient (not possible) PV or wind. The sun dumps 162,000 TW of light on the earth. Using 15 of them to do something else will be negligible (*).

2) Even the fraction of the solar energy gets absorbed and used for power ends up as waste heat somewhere down the line. Conservation of energy plus entropy is a cruel pair of masters.

3) In reality, we're talking about 19-21% efficiency from top-tier PV, but the bulk of the remaining ~80% gets absorbed and converted to heat right on the surface of the panel. (Don't touch a PV panel that has been on your roof in the summer. They get extremely hot.) This is a net warming effect-- the PV panel reflects less light (by design) than your roof probably did. It's of negligible magnitude, but it's backward to think that the PV system is somehow consuming energy and throwing it into a void.

(*): The reason greenhouse warming is so powerful is that it changes the amount of those 162,000 TW that we retain by a small fraction, but even a small fraction of 162,000 TW is a tremendous volume of energy, capable of changing the climate.

Teenwolf: [Lego image]

Yup. Just don't pretend that ~300M Americans all live in unique snowflake homes. :)

Seems like they made a LOT of assumptions with this place.

Recycled water and low flow faucets/showers = you can't wash the shampoo out of your hair, but it doesn't matter much, since the water itself is pretty funky.

Open floor plan and fully openable windows = assuming a perfect climate for just about zero use of HVAC systems... there's just not that many places where you're doing that all that much.

Photovoltaics for electrical energy = you're paying more than if you'd just have bought from the electric company, even at the "renewable" option rates.

Sure, as an idea generator it is worthwhile. In all practical terms it just isn't going to happen. But pieces of it can be used here and there.

Hollie Maea: Reverend Monkeypants: Gallium arsenide is a nasty freaking chemical, nevermind the process of making it.

The overwhelming majority of solar panels are made of Silicon, not GaAs.



What about nanotechnology?

Galloping Galoshes: Still sounds more like marketing. And the 3-year return is only on the incremental carbon cost of producing a single unit, not the overall average cost. And to what extent are you sure that their calculations are anything more than more marketing?

I cited a publication from NREL. They're part of the Department of Energy, and they are one of three places in the world that you can have photovoltaics internationally certified for their efficiency. They publish a huge number of primary research studies, including most of the methodology which is used to test and evaluate photovoltaics. NREL represents one the most concentrated source of expertise on this matter in the United States.

As for the calculations, I gave a summary document because not everyone wants to read longer technical articles.

As an example of that, had you read all the way to page 2, you would have seen the "References" section, which cites the following:

"References
E. Alsema, "Energy Requirements and CO2 Mitigation Potential of PV Systems," Photovoltaics and the Environment, Keystone, CO. Workshop Proceedings, July 1998.
R. Dones; R. Frischknecht, "Life Cycle Assessment of Photovoltaic Systems: Results of Swiss Studies on Energy Chains." Appendix B-9. Environmental Aspects of PV Power Systems. Utrecht, The Netherlands: Utrecht University, Report Number 97072, 1997.
K. Kato; A. Murata; K. Sakuta, "Energy Payback Time and Life-Cycle CO2 Emission of Residential PV Power System with Silicon PV Module." Appendix B-8. Environmental Aspects of PV Power Systems. Utrecht, The Netherlands: Utrecht University, Report Number 97072, 1997.
K. Knapp; T.L. Jester, "An Empirical Perspective on the Energy Payback Time for PV Modules." Solar 2000 Conference, Madison, WI, June 16-21, 2000.
W. Palz.; H. Zibetta, "Energy Payback Time of Photovoltaic Modules." International Journal of Solar Energy. Volume 10, Number 3-4, pp. 211-216, 1991."

These are available online, although you may need to buy journal subscriptions if your workplace doesn't maintain one. A nearby university library will likely have Palz and Zibetta. You may not want to make a trip for it, but anyone who has a serious interest in the topic can pull the paper and review the work.

It's also worth noting that the document was published in 2004, and efficiencies have come up a bit since then. The payback times are likely lass than 3 years now.

Of course, that's just the published conclusion from NREL. It's hard to weigh it against your knee-jerk response based on a bare assertion of personal opinion.

Thrag: As soon as I perfect my generator that runs on knee-jerk naysaying, threads about alternative energy will become a form of alternative energy.

If you add a second input for the energy generated from idiots pounding their desks in anger whenever the word "science" is mentioned, it might boost your system efficiency.