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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    •  
      CommentAuthorfostertom
    • CommentTimeMay 14th 2021 edited
     
    With 'deep' smart-metering (e.g. pricing by half-hour chunks), if it was practicable to harvest only the lowest-tariff periods and store as heat, sufficient to heat a hard-to-insulate house by non-fossil means, where a heat pump is unsuitable -
    What would be the effect, on the primary source of the electricity being harvested?

    In other words, with smart metering, is the supply during lo-tariff periods (when supply can't be shut down enough to match demand) inherently composed of some inconveniently-timed peak of renewable energy - or in fact the reverse, composed of non-shuttable fossil (or indeed nuclear)?
    •  
      CommentAuthordjh
    • CommentTimeMay 14th 2021
     
    Posted By: fostertomIn other words, with smart metering, is the supply during lo-tariff periods (when supply can't be shut down enough to match demand) inherently composed of some inconveniently-timed peak of renewable energy - or in fact the reverse, composed of non-shuttable fossil (or indeed nuclear)?

    Both. Electricity is priced in advance for domestic purposes, so it might be middle-of-the-night nuclear or it might be middle-of-the-storm wind. I don't think there are any non-shuttable fossil plants these days, or not many anyway?
    • CommentAuthorRobL
    • CommentTimeMay 14th 2021
     
    It's fascinating to see negative pricing, and I can understand wanting to make use of it. I guess to heat a house via electricity you might make some use of that, but also be forced to mostly make use of more conventional prices similar to E7 in your storage heaters.

    As electricity becomes more renewably sourced, there will be higher pricing variance, helping the above.

    As more people get electric cars I think this variance will be reduced - as the cheap rate is eaten up by car charging which is of higher value. We actually have a V2G system on our elec car - I'd like to think it will dominate, but I'm not sure it will in any of the forms I have seen at the moment. Charging a car at a particular time or on demand to match a TOU tariff is cheap and simple and possible right now though.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 14th 2021
     
    Thanks
    Posted By: RobLalso be forced to mostly make use of more conventional prices similar to E7
    Not sure why, necessarily - that wd depend on how much of the (new breed) storage heater capacity you install, as well as the shape of the curve of tariff against time, and how far into 'merely moderately good' tariffs you'd be prepared to go.

    And the idea depends on a long-future guess as to whether or not tariff price differentials will continue, increase or decrease.

    Of course, you'd be using more electricity than you would if benefiting from a heat pump CoP - but that wouldn't matter so much as long as assured you were using mainly- or all-renewable source.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 14th 2021
     
    Posted By: djhElectricity is priced in advance for domestic purposes
    Is that so even with deep' smart-metering (e.g. pricing by highly variable half-hour chunks)? The recent tales of Texans on variable-rate tariff being charged $1000 per kWh or something can't be 'priced in advance' - sounds very 'spot'.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 14th 2021 edited
     
    Posted By: djhElectricity is priced in advance for domestic purposes
    Is that so even with 'deep' smart-metering (e.g. highly variable pricing by half-hour chunks)? Recent tales of Texans being charged $1000/kWh sounds pretty 'spot'!

    Even if so, I don't follow why that particularly means
    Posted By: djhso it might be middle-of-the-night nuclear or it might be middle-of-the-storm wind
    • CommentAuthorEd Davies
    • CommentTimeMay 14th 2021
     
    CCGT (closed-cycle gas turbine) generation has not gone much below 5GW in the last month. The times where it's completely off (i.e., we're running purely on nuclear and renewables) are pretty rare so I think it's reasonable to assume that almost any increase in consumption from the grid as it stands now will come from gas except for maybe a few hours a month during summer nights which is when you care least about heating.

    https://gridwatch.templar.co.uk/

    For the future, it's a race between installing new renewables and expanded substitution of electricity for fossils for heating and vehicles. I don't think anybody really knows how that'll go but I think it would be quite optimistic to think that there would be sufficient hours in the winter where use of resistive heating will not cause more CO₂ emissions than burning gas or oil on site.
    •  
      CommentAuthordjh
    • CommentTimeMay 14th 2021
     
    Posted By: fostertom
    Posted By: djhElectricity is priced in advance for domestic purposes
    Is that so even with deep' smart-metering (e.g. pricing by highly variable half-hour chunks)? The recent tales of Texans on variable-rate tariff being charged $1000 per kWh or something can't be 'priced in advance' - sounds very 'spot'.

    Yes. Dunno about arrangements outside the UK though. Why does the Texas experience make it more difficult to understand? They knew 12/24 hours in advance what the available supply was.

    Posted By: fostertomEven if so, I don't follow why that particularly means
    Posted By: djhso it might be middle-of-the-night nuclear or it might be middle-of-the-storm wind

    Because the cheap electricity might be due to either of those causes? I don't understand what is difficult to understand?
    •  
      CommentAuthordjh
    • CommentTimeMay 14th 2021
     
    Posted By: fostertomthat wd depend on how much of the (new breed) storage heater capacity you instal

    No, it depends on how well you insulate your house. We don't have any storage heaters at all. That's what the structure of the house is for - to act as a heat storage reservoir. In fact I've been quite surprised that it seems the thermal storage of our first floor structure itself is able to store pretty much all our heat demand for the next 17 hours. And that structure is pretty light - just Rockwell acoustic insulation, some plastic ductwork, chipboard flooring and plasterboard ceiling, plus joists etc.

    TL;DR you don't need storage heaters in a reasonably built property.
  1.  
    Generally +1 what Ed said,

    In the very short term, any time you switch on an electric heater, the marginal generator which gets turned up a notch is going to be a gas turbine, or even a Continental coal power station

    In the fairly-short term, if you keep switching on electric heaters every day, the market will be encouraged by the opportunity and build an extra wind turbine or two.

    In the not-very-long term (2035 apparently, says the UK national 6th Carbon Budget) all the gas turbines will have CCS, or run on CCS-made hydrogen. So then using resistive electric heating will be carbon-free and guilt-free and you can rip out all of your insulation and burn it in your wood burner... :shocked:

    That will vastly widen the cost difference between gas-CCS (£70-100/MWh) and wind (£40/MWh and falling, but £0 marginal cost) so the daily peak/off-peak price swings should get much wilder... but who knows...?!

    The wind generators will run even if the grid is oversupplied and the price is negative, because as long as they are generating, they can claim FITs. Will be interesting what happens with CFD and with 3x as many wind turbines.
    • CommentAuthorphiledge
    • CommentTimeMay 14th 2021
     
    Posted By: fostertom

    In other words, with smart metering, is the supply during lo-tariff periods (when supply can't be shut down enough to match demand) inherently composed of some inconveniently-timed peak of renewable energy - or in fact the reverse, composed of non-shuttable fossil (or indeed nuclear)?


    Have a look at gridwatch.co.uk and see for yourself how much orange(CCGT gas generation) there is at anytime of the day/week/month/year. We're years away from being able to routinely have spare green electric available even in the dead of night.
    •  
      CommentAuthordjh
    • CommentTimeMay 14th 2021
     
    Posted By: WillInAberdeenSo then using resistive electric heating will be carbon-free and guilt-free and you can rip out all of your insulation and burn it in your wood burner...

    Of course the fallacy is that if you rip out your insulation (or fail to build it in the first place) then you will increase the demand for electricity faster than we can build new wind turbines (or other renewables) so the CCGT keep being turned up. The fantasy is that any insulation is suitable or allowed to be burned in a wood burner ...

    But as you wisely say ... who knows :bigsmile:
  2.  
    :bigsmile: who knows if wood burners will still be allowed in 2035?

    The CCC make the point that insulation and heatpumps are necessary to enable the renewable and CCS/H2 electricity supply to grow faster than demand does. However looking at their figures, while the energy for heating houses is a large amount in absolute terms, it is not an overwhelmingly large fraction of the electricity supply they anticipate. So plus/minus some insulation and heatpumps could delay the date of reaching zero carbon electricity, but not by a lot AFAICS.

    It's a whole new paradigm for me, not sure what it means anymore!
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    Posted By: djh
    Posted By: fostertom
    Posted By: djhElectricity is priced in advance for domestic purposes
    Is that so even with deep' smart-metering (e.g. pricing by highly variable half-hour chunks)? The recent tales of Texans on variable-rate tariff being charged $1000 per kWh or something can't be 'priced in advance' - sounds very 'spot'.

    Yes
    Do you mind saying more about this Dave, if it's something you've studied? https://electriccarhome.co.uk/smart-meter-tariffs/ talking about e.g. Octopus Agile, says "48 rates a day, tied to wholesale prices (this is radical stuff)" - does even that mean "priced in advance for domestic purposes"?

    "Plunge Pricing pays you to take excess energy off the grid
    Across the UK, whenever more electricity is generated than consumed, energy prices fall – sometimes to the point where prices drop below zero, and suppliers are paid to take energy off the grid.
    Agile Octopus introduces Plunge Pricing – a world first that lets you take advantage of these negative price events, and get paid for the electricity you use. Receive alerts whenever prices drop below zero"
    •  
      CommentAuthordjh
    • CommentTimeMay 18th 2021
     
    fostertom asked: "Do you mind saying more about this Dave"

    Sure, if you look about half-way down on https://octopus.energy/agile/ you'll see:

    "Between 4-8pm every day (usually nearer 4pm), your unit rates are updated for the next 24 hours, based on the wholesale market rates."

    i.e. they set the prices 24 hours ahead. Obviously that's based on the predicted wholesale price and their estimates of likely costs and sales. It's done that way so that you can look at the prices and make your decision about how much electricity to use tomorrow without any price risk. It's a domestic sale, after all, not a trader in a marketplace.

    The wholesale markets have both spot and futures markets. Obviously with a product like electricity there has to be a near instantaneous price for delivery of the electricity in the immediate future. But you can also agree a price for electricity to be delivered in a day's time, or even next month; just as you can for oil or pork bellies.

    There's some more info at https://www.ofgem.gov.uk/electricity/wholesale-market/gb-electricity-wholesale-market
  3.  
    Different companies offer different tariffs Tom, and hopefully more should be coming to market soon.

    The Octopus Agile product afaik announces their prices at 4pm for each half-hour of the next day, so you get told the prices >8hours ahead, which might/not be what you consider to be 'in advance'. Their prices are based loosely on the spot market* but with a price cap (30 or 40p?) so you don't get unexpected $1000 peaks.

    The hope is that other companies will introduce variable pricing products, with more or less degree of variability/certainty to suit different folks' tastes. EG Octopus also have other products, with guaranteed cheap electricity for a few hours overnight. Bulb have a variable price tariff too.

    * The spot market is a bit artificial in the UK, most power is still bought well in advance by utilities.

    Edit: crossed with DJH
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    Thanks Dave. I wonder if anyone will introduce a tarrif, for the brave and tech-savvy, which really follows spot price, the consumer relying on their own decision-making mechanism (algorithm?) as to whether to connect or disconnect. I guess that would be an 'industrrial' tarriff.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    To return to the original proposition/thought/query, it's looking around for a non-fossil alternative, for heating those houses etc which will remain 'hard to insulate' for good reason (i.e. not just because of failure to insulate properly) such as Listed Buildings, where the exterior (or principal elevations) can't be EWI'd and interiors also are too precious for IWI.

    I see plenty of those; I put much ingenuity into nevertheless doing as much as possible, not least to combat mould - roofs, elevations 'round the back', subfloors, windows, airtightness/ventilation - but still, major heating demand remains.

    Typically, in such cases, high-temp heat emitters are inevitable - UFH usually isn't possible for similar 'Listed' reasons re: walls, and even if it were, would have to output a lot of heat/m2 hence be nudging into 'high-temp emitter' territory. Despite suggestions otherwise for particular models, heat pumps rapidly lose CoP (except in lo-demand spring/autumn 'shoulder months') so their advantage over on-peak electic vanishes.

    Heat pumps are not the fossil-free solution for hard-to-insulate buildings.

    So what alternatives?
  4.  
    Better radiators Tom.

    Think we discussed elsewhere your current/recent client has fashionable 'column' style radiators, with much less heat transfer capacity (was it 40% less?) than a bogstandard double-finned radiator, so needs corresponding higher CH flow temperature. The radiators are not original/listed elements in 17thC buildings, so look at replacement or additional rads, which are wider, taller or have more fins. So enabling heat pumps, especially the ones with the newer refrigerants, that are efficient at 50degC.

    Or A-A heatpumps.
    • CommentAuthorowlman
    • CommentTimeMay 18th 2021
     
    Posted By: WillInAberdeenBetter radiators Tom.

    Or A-A heatpumps.




    Yes, I don't understand the A-W obsession, regardless of application or suitability. A-A is much better suited IMO for more properties as a whole.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    Will, it's time I looked at these 'heat pumps with newer refrigerants' which I meant above by sceptical 'suggestions otherwise for particular models' - I'd be grateful if you cd point me at relevant make/model(s).

    Sceptical, yes, as AFAIK maintaining CoP of 3 right thro winter is non-negotiable, both to make elect significantly cheaper than fossil thus justifying the cost, and
    Posted By: WillInAberdeento enable the renewable and CCS/H2 electricity supply to grow faster than demand does

    And I don't think column vs steel panel w/ or w/o fins makes anything like enough difference, surely, to bring within range of 'efficient at 50degC'?

    A-A means ducted warm air, in a typical non-open-plan Listed Building - not feasible.
    •  
      CommentAuthordjh
    • CommentTimeMay 18th 2021
     
    Posted By: fostertomThanks Dave. I wonder if anyone will introduce a tarrif, for the brave and tech-savvy, which really follows spot price, the consumer relying on their own decision-making mechanism (algorithm?) as to whether to connect or disconnect. I guess that would be an 'industrrial' tarriff.

    I doubt it. It would be a very specialist product so probably not worth designing, building and supporting a system to run it. If anybody wants to trade electricity, I expect they're free to do it in a similar way to oil or pork bellies.
    •  
      CommentAuthordjh
    • CommentTimeMay 18th 2021 edited
     
    Posted By: fostertomTo return to the original proposition/thought/query, it's looking around for a non-fossil alternative, for heating those houses etc which will remain 'hard to insulate' for good reason (i.e. not just because of failure to insulate properly) such as Listed Buildings, where the exterior (or principal elevations) can't be EWI'd and interiors also are too precious for IWI.

    I see plenty of those

    ...

    So what alternatives?

    When we have a carbon tax (or internalise environmental costs some other way), the cost of running such a building will become so high that there'll definitely be similar situations to some Grade 1 properties at the moment, where nobody can be found who wants to buy and maintain it properly. Then the government and the electorate will have to face up to the question of whether I'm willing to subsidise my neighbour's listed house, or whether I'd rather the aesthetics were ignored (or at least treated as less important than the planet).

    edit: to correct choice of word
    • CommentAuthorowlman
    • CommentTimeMay 18th 2021
     
    Posted By: fostertom

    A-A means ducted warm air, in a typical non-open-plan Listed Building - not feasible.


    No it doesn't
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    Interesting - how would you distribute heat as warm air from an air to air heat pump, without ducting (substantial), around a sprawling (horizontal) or multi storey (vertical) Listed Building? Note - you'd work hard to find just one visually acceptable position for a single centralised air inlet/exhaust or 'box of fans' - no question of multiple (distributed) smaller units.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021 edited
     
    Posted By: djhWhen we have a carbon tax (or externalise environmental costs some other way)
    I guess that'll be 'internalise'?

    Indeed, LB Officers tend to have doctrinaire, tickbox/red-line articles of faith, equivalent of 'deemed to satisfy' in Bldg Regs, which they use as a bulwark against all the clueless things that people want to do with Listed Buildings (and there are many other non-Listed buildings which deserve the same consideration). Unfortunately, they're often too rigid to recognise visual sensitivity and ingenuity in energy-saving modification, equivalent to the 'from fundamentals/by negotiation' alternative in Bldg Regs, when they're offered it.

    Given the latter, there's quite a lot that can be done with LBs if lucky enough to be allotted an 'enlightened' Listed Buildings Officer - but still a lot more that shouldn't. I cd give many examples of things that look fine, totally respecting the building, but are usually forbidden, as if energy etc negligibly important.
    • CommentAuthorowlman
    • CommentTimeMay 18th 2021
     
    Posted By: fostertomInteresting - how would you distribute heat as warm air from an air to air heat pump, without ducting (substantial), around a sprawling (horizontal) or multi storey (vertical) Listed Building? Note - you'd work hard to find just one visually acceptable position for a single centralised air inlet/exhaust or 'box of fans' - no question of multiple (distributed) smaller units.


    The "heat" from the A-A external unit is distributed to the indoor unit via refrigerant gas circulating in insulated microbore pipework. In the case of centralised warm air distribution it is converted by an "indoor" unit and thence via ducting as you describe.
    However it can also be converted to warm or cool air via multiple single room indoor units. These can take various forms; wall, ceiling, low floor mount, etc.. The microbore refrigerant pipework, a power cable, and condensate pipe are the connecting requirements. Controls can be either hard wired to wall controller or hand held, or both.
    • CommentAuthorjms452
    • CommentTimeMay 18th 2021
     
    Posted By: owlmanHowever it can also be converted to warm or cool air via multiple single room indoor units. These can take various forms; wall, ceiling, low floor mount, etc.. The microbore refrigerant pipework, a power cable, and condensate pipe are the connecting requirements. Controls can be either hard wired to wall controller or hand held, or both.


    and if your house has some mass and is well insulated I imagine you don't even need a single room unit in each room. I had a plan for a Split A2A with one internal unit upstairs and one down (although it is smallish house) but the planning committee wasn't keen...
    •  
      CommentAuthorfostertom
    • CommentTimeMay 18th 2021
     
    Thanks - that's an eye-opener, guess I shd have checked first.

    In a hard to insulate i.e. large heat demand house, this would mean a large external unit - can this be 'quiet' as current A-W domestic units, which can be OK?
    A-A gives CoP of 3 or more, like A-W? And so this gets around the loss of CoP with A-W caused when wet rads require supply water flow at hi temp like 60C? because A-A with several remote indoor units has no need to produce hi-temp output, just sufficient comfort-temp warm air.

    Sounds like this could be quite lo-cost installation, even with several remote indoor units? I can see this cd be done with minimal ducting. Tho radiant heat is preferable to blowing warm air around.
    •  
      CommentAuthordjh
    • CommentTimeMay 18th 2021
     
    Posted By: fostertomGiven the latter, there's quite a lot that can be done with LBs if lucky enough to be allotted an 'enlightened' Listed Buildings Officer - but still a lot more that shouldn't. I cd give many examples of things that look fine, totally respecting the building, but are usually forbidden, as if energy etc negligibly important.

    My point partly was that there are an awful lot of listed buildings, such as my neighbour's, where the obvious thing to do is scrap the listing. Ditto a lot of rules in conservation areas. These aesthetic, and even minor historical, issues are grossly over-rated IMHO.
   
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