MikeSharp01

Bonkers or Brilliant - 'POWERHOUSE' the Jury is out

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Just been reading the latest Passive House magazine (sad I know) but came across the new 'Powerhouse' standard that has been suggested in Norway. In this standard you first have to build a passive standard building and then ensure that it, or systems associated with it, can generate enough renewable energy over the building's lifetime to: (Wait for it) 

 

  • pay back the energy used in manufacturing all the materials.
  • pay back all the energy used in its construction.
  • cover all the energy use of operating the building.
  • cover all the energy used for maintaining and renovating the building - including materials used.
  • pay back the energy used in demolishing the building.

 

So you need a SAP value of more than 100 (if you believe in the SAP values anyway) and then you need to work out / find all those energy consumption values. Wonder how much energy it takes to make 1 meter of 15mm plastic water pipe!  So if you have a SAP of 110 I wonder how long the average buildings life has to be?

 

Somebody somewhere seems to get it - the Norwegians, but I cannot see any of our major builders doing it or self builders for that matter. There won't be a collective opinion on this but it would be interesting to hear the thoughts from the forum.

 

Anybody worked it out for their build?

 

Edited by MikeSharp01

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Based on a 60 year life span isn't it?

Edited by Onoff

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5 minutes ago, Onoff said:

Based on a 60 year life span isn't it?

Yes - I hope mine lasts more than that though, but I suspect that is just another of the variables - you factor in 60 years at the outset to figure out how much energy you are, or think you are, going to need. I was wondering about those that have already been built. EG does @JSHarris's pad do it as is (his SAP is 107 I think although SAP does not really tell you much about energy production as you get points for all kinds of things which, on the face of it, don't count in the energy equation) or would you need need much more generation. I guess you can factor in COP benefits from ASHP's etc as well which might help. Either way you have the, on the face of it, nightmare of working out how much energy was used to create the materials, build the building, run it in energy terms (100 of the 107, simplistically I guess). Throws down a challenge though don't it?

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18 minutes ago, MikeSharp01 said:

pay back the energy used in manufacturing all the materials.

that's a killer in its own right, what's the cost of the renewables on their own. at least they don't make you recycle and add those costs in once demolished.

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I can see that my weekend is going to be taken up trying to work this out.  On the plus side our house has a SAP EPC of A107, and an EER of A107 (minus 0.9 tonnes CO2/year), and is clad with larch grown 6 miles away and milled 3 miles away.  On the minus side the frame timber came from Scandinavia, was built into frames in Cahir, Tipperary, Ireland, then transported here, the 300mm EPS under the slab came from Kore in Ireland, the recycled plastic "slates" came from Canada and we do have quite a lot of concrete in our retaining wall, and a bit in our passive slab.  Other positives though, are that we are water-cycle neutral, in that we have our own borehole and dispose of our effluent via a treatment plant to the stream alongside.

 

We do generate around 50% more energy per year than we use, though, and I worked out that our negative CO2 emissions equated to the CO2 sequestered by around 40 mature trees (more than would fit on the plot), plus around 50% or so of the energy my car uses comes from our own PV system.

 

Be interesting to try and see how many years it will take to recover all the energy and CO2 that went into building the house.

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1 minute ago, JSHarris said:

I can see that my weekend is going to be taken up trying to work this out. 

Sorry Jeremy didn't mean to give you work to do - will be interesting none the lessO.o

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15 minutes ago, JSHarris said:

I can see that my weekend is going to be taken up trying to work this out.  On the plus side our house has a SAP EPC of A107, and an EER of A107 (minus 0.9 tonnes CO2/year), and is clad with larch grown 6 miles away and milled 3 miles away.  On the minus side the frame timber came from Scandinavia, was built into frames in Cahir, Tipperary, Ireland, then transported here, the 300mm EPS under the slab came from Kore in Ireland, the recycled plastic "slates" came from Canada and we do have quite a lot of concrete in our retaining wall, and a bit in our passive slab.  Other positives though, are that we are water-cycle neutral, in that we have our own borehole and dispose of our effluent via a treatment plant to the stream alongside.

 

We do generate around 50% more energy per year than we use, though, and I worked out that our negative CO2 emissions equated to the CO2 sequestered by around 40 mature trees (more than would fit on the plot), plus around 50% or so of the energy my car uses comes from our own PV system.

 

Be interesting to try and see how many years it will take to recover all the energy and CO2 that went into building the house.

I was just going to agree with you Jerremy But noticed I’ve gained an extra pip 😀

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1 hour ago, Onoff said:

Based on a 60 year life span isn't it?

:o So you have to die in it to get your blue peter badge ? 

Id rather concentrate on beer an happiness. 

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10 minutes ago, Nickfromwales said:

:o So you have to die in it to get your blue peter badge ? 

Id rather concentrate on beer an happiness. 

 

Moot point. The assumption is it get finished in that time...

 

:ph34r:

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34 minutes ago, Onoff said:

 

Moot point. The assumption is it get finished in that time...

 

:ph34r:

You set them up......

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It does seem a rather high bar that they have set, but I do think it is worth considering all the other impacts of what we build.  I can't wrap my head around using lots of polystyrene and concrete in order to build passive for example - that doesn't seem green at all and I guess this standard would highlight that.  Or at least get people thinking about it.  Or something.

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About 90% of our insulation is cellulose, really just chopped up old newspapers turned into fluffy fibres, so 100% recycled.  It's hard not to use things like EPS and concrete, but in the house itself we only have EPS where we really had no choice, as the load-bearing insulation under the passive slab.  Likewise, our 100mm thick passive concrete slab almost certainly has very little more, maybe less, concrete than a conventional strip foundation.

 

The only really low concrete system I know of is the Segal system, but that comes with the penalty of needing more underfloor insulation in order to achieve the same sort of low heat loss in cold winter weather, where the undercroft temperature could be a fair bit lower than the ground temperature.  Not hard to overcome, but needs a bit more floor build up.

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I vote Bonkers. Norway is 98% hydro anyway with fairly limited interconnection potential, so trying to design a house that generates a lot of power (probably from PV - in Norway) really doesn't get you much. Minimising heat demand makes a lot of sense, as does trying to use timber framing rather than concrete as much as possible to ensure that embedded energy is held down. I get the feeling that a lot of this is about drumming up work for architects and associated certification professionals, rather than trying to reduce net emissions - for the same investment you'd get a lot more net generation from large scale hydro.

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They forgot the energy needed to drive to work from your rural retreat. 

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21 hours ago, Onoff said:

 

Moot point. The assumption is it get finished in that time...

 

:ph34r:

is that the beer or the bathroom?

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2 minutes ago, Simplysimon said:

is that the beer or the bathroom?

 

I always finish...my beer.

 

Only another 20 to go and I can make the cider kit!

 

20180818_175321.thumb.jpg.12f033749e8a30b547c39b117d0b091e.jpg

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