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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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  1.  
    Well, maybe it's different in France, but in the UK if you can't pay for electricity then you get put onto pre-payment or disconnected, smart meter or no smart meter. There was a lot of tin-foil-hat stuff to start with, but it's mostly died down now here.
  2.  
    https://www.express.co.uk/finance/personalfinance/1657970/smart-meter-remote-cut-offs-disconnect-energy-bills

    "Smart meters: 'Remote disconnect' myth BUSTED"

    If you actually read the article, it doesnt bust the myth that energy companies cant or wont remotly disconnect. It just quotes an energy company spokeswomen saying they will customers every chance to pay, before doing so.
  3.  
    <blockquote><cite>Posted By: WillInAberdeen</cite>Well, maybe it's different in France, but in the UK if you can't pay for electricity then you get put onto pre-payment or disconnected, smart meter or no smart meter. There was a lot of tin-foil-hat stuff to start with, but it's mostly died down now here.</blockquote>

    Yea, but with out a smart meter an agent needs to come and do it physically. Which means you can keep your door closed. With SM they just discconnect with a button, and good luck if they have made a mistake. Which is exactly what happened to me.Disconnected suddenly by remote in the middle of winter due to a clerical error, and I had to fight to get it put back on. Not funny.
  4.  
    That's maybe another reason why they don't do that in the UK.

    Unfortunately, not answering your door is no defence against getting your power turned off in the UK, if you haven't paid. Maybe different where you are.
  5.  
    <blockquote><cite>Posted By: WillInAberdeen</cite>That's maybe another reason why they don't do that in the UK.

    Unfortunately, not answering your door is no defence against getting your power turned off in the UK, if you haven't paid. Maybe different where you are.</blockquote>

    According to Ofcom and CAB, they do do it.

    Not answering your doors means you dont get cut off. Having a SM means you get cut off remotely at the push of a button.

    One day I think ppl are going to realise that SMs are about handing over total control to the power companies.And that they were told stories to persuade them to do it.

    This winter we are going to start to see the realities of SMs.
  6.  
    WillnAbbadean is providing a compelling case for GBF not having a future.

    While this thread topic is exactly about the kind of green building GBF ought to be good at, instead we've had a sales person for micro inverters providing the usual scare stories and no data. And now a Tory spokesperson going on and on and on about how great smart meters are, and with a tinge of nationalism. It might seem a bit conspiracy theory'ish what bot de paille is saying, but there's an obvious element of truth to it - SMs make it easy for suppliers to do what they want.

    Meanwhile, anyone interested in installing solar tech has probably moved on.
  7.  
    Err - if you've been around Labour environmental campaigns much, then you'll know that smart meters were brought in by Ed Milliband, when he was Energy and Climate minister for Gordon Brown. Hardly a Tory policy!

    But if you are worried by the conspiracy theories, then there's no compulsion to get a smart meter in the UK. You can buy your own energy monitor if you like, and the solar battery incentive tariffs are completely optional.
    • CommentAuthorcjard
    • CommentTimeDec 8th 2022 edited
     
    "So 34kwh on a single house sounds quite alot"

    I perhaps need to look at this more closely - it's an all electric house, but the walls and roof are about 300mm of PIR; it's classically been a really easy house to heat - 12kw ASHP does a few hours a day producing 26 degree water, starts coming on around start of Dec and knocks off towards end of Jan. One induction hob, 2 ovens, 2 fridges.. Washer and dishwasher do run more than average to be fair, but since covid most of the family has switched to showering every other day so we only put the hot water on every other day.. No EV

    I always thought we didn't really use a lot but I'm revising that in light of the "house plus 2 holiday lets uses 2/3rds" bit!
    • CommentAuthorcjard
    • CommentTimeDec 8th 2022
     
    So, when a smart meter enabkes 30 minute billing, and the power co decides to charge £50/kWh for that 30 min segment when the grid was overloaded, what's the recourse? No one mentions the level of control power co's get out of smart meters as one of their cons..
  8.  
    The (only?) half hourly domestic tariff available at the moment is Octopus Agile, which has a contractual maximum price cap of 82p / unit - they can't just randomly decide to charge you £50!

    Last month their actual prices averaged at 28p/unit, cheaper during the daytime and more expensive in the evening. But back in August it averaged 54p so probably quite a few customers switched tariffs then, which is the fallback if a tariff isn't working out right for you.

    Most smart meter tariffs are not variable, the price is agreed up front. For example the Tesla tariff that was asked about in the OP has a fixed 26p price using a smart meter. Other battery incentive tariffs are available, often with a few hours fixed at around 10-15p then fixed higher prices for the rest of the time. Obvs the key is to find a tariff that suits you individually, eg the times when you are likely to import power, and whether you want a fixed price or variable.

    There were more choices available which were good for PV/battery owners (eg some with zero standing charges) but most of those stopped when the small suppliers were swallowed into the Big Six, or because everyone has switched to the 34p price cap. Hopefully more choice of different tariffs will come available again next year, but if buying a battery to take advantage of a particular supplier or tariff, worth considering that it could disappear before the battery is paid for.
    • CommentAuthorcjard
    • CommentTimeDec 8th 2022
     
    "But a smart meter is necessary to access the kind of battery tariffs being discussed above, where you get paid more for exporting after the sun has gone down, or on days that aren't windy. Yesterday Octopus paid 36p for daytime solar, or 56p for the same electricity in the evening, so 20p uplift for using your battery. Don't know how long that would take to pay for the battery."

    So it isn't just Tesla powerwall+octopus that pays a reasonable rebate for export? Are octopus offering to pay for export on other battery makes too?
    • CommentAuthorcjard
    • CommentTimeDec 9th 2022
     
    If solar panels should be kept cool, how come they don't offer a cooling circuit that i can plumb into the hot water tank - a sort of combined thermal and PV (granted it won't work as well as dedicated thermal tubes but it's a byproduct rather than main intent)
  9.  
    Posted By: cjardIf solar panels should be kept cool, how come they don't offer a cooling circuit that i can plumb into the hot water tank - a sort of combined thermal and PV (granted it won't work as well as dedicated thermal tubes but it's a byproduct rather than main intent)

    You can get a combined solar pv and thermal panel which keeps the PV part cool and would provide e.g. pre-heat for DHW but when I looked at them the price and fit up didn't justify the extra expense, it was cheaper to put up more panels to get the extra PV output. Of course if you are stuck for space different equations come in and current pricing might have changed things since I looked. See
    https://www.convertenergy.co.uk/pv-t-hybrid-solar
    • CommentAuthorphiledge
    • CommentTimeDec 9th 2022
     
    In the UK the number of times panels get hot enough to have any noticeable/significant drop in performance is likely less than a few instances a year. The time when it does happen is in the summer when demand is likely at its lowest so possibly not too much of an issue. Maybe more of a problem for integrated in roof set ups??
  10.  
    Posted By: cjardSo it isn't just Tesla powerwall+octopus that pays a reasonable rebate for export? Are octopus offering to pay for export on other battery makes too?

    Yes, that's correct, https://octopus.energy/outgoing/
    • CommentAuthorbhommels
    • CommentTimeDec 9th 2022
     
    Posted By: cjardIf solar panels should be kept cool, how come they don't offer a cooling circuit that i can plumb into the hot water tank - a sort of combined thermal and PV (granted it won't work as well as dedicated thermal tubes but it's a byproduct rather than main intent)

    For PV, the cooler the better. For DHW cylinder, the hotter the better. I have a hard time seeing how a combined systems would work well for both. And then there's the problem of scale: to keep a reasonably sized PV array cool in summer, day after day, you would need a rather large water tank and/or high demand for hot water.
    I can see a case where water is used from a (GSHP) borehole to cool the panels and perhaps even store the heat for winter, or make lighter work for the GSHP heating the DHW cylinder?
  11.  
    Posted By: bhommelsFor PV, the cooler the better. For DHW cylinder, the hotter the better. I have a hard time seeing how a combined systems would work well for both.

    It doesn't work well for both. What is said on the link I posted above is that you get low grade heat to water
    Quote
    ................This is usually observed in Hybrid systems where the low-grade heat from the panels can be used all year round. One such system using the Solimpeks panels is the Solar house in Leicester. Here the Solimpeks panels are used to charge an Earth energy bank under the building. This earth energy bank acts as an inter-seasonal store for the heat,................
    end quote
    So unless you have a need for a good amount of low grade heat in the summer(e.g lots of pre heat DHW or perhaps a swimming pool) I can't see the cost justifying the result.
    • CommentAuthorcjard
    • CommentTimeDec 12th 2022
     
    Trying to work out if it's worth installing racking systems that allow the angle of the panels to be changed - they would sit on a 30 degree roof facing southwest. If there were hinges at the base rail and some propping system at the top rail, such that the angle of the panel could be varied between 30 degrees (the roof slope) and 90 degrees..

    I tried plugging the europa calculator John gave with some pretend roof that was either 30 or 65 degrees, and it seems that broadly speaking 65 degrees gave the best winter production, but it's only (at best) ~14% better in oct-mar to run 30/65 in summer/winter than it is to run 42 year round (optimal slope, the calc claims)

    Does that seem about right, if any of you adjust your panels?
    • CommentAuthorcjard
    • CommentTimeDec 12th 2022 edited
     
    (Over the whole of the year, tilting the panels looks to improve output by about 1.6% - 14295kWh vs 14067kWh from a 17kw array; sitting them up at optimal 42 rather than roof slope 30 seemingly improves output by 0.3%)
  12.  
    You have to be careful tilting PV panels because without additional space between the rows some shading may occur by the lower panel to the one above. Also tilting the panel can cause additional wind loads either from the front or from lifting force from any wind coming over the ridge which will have to be assessed.
  13.  
    Be careful about deemed planning permission, there may have conditions such as the panels may not project very far above the line of the roof slope. Check what rules say in your part of the UK?

    Also, each extra kWh in winter might be more valuable to you than a kWh in summer, if you have electrified heating.
  14.  
    Another Octopus tariff launched, aimed at heatpump owners but that might be of interest for use with batteries/PV:
    https://octopus.energy/smart/cosy-octopus

    This one has a very short "peak" period from 4-7pm, and two "cheap" periods in the morning and afternoon.

    Would enable people to have just a small battery, enough to cover just 3 hours usage, which would be charged in the afternoon from PV or "cheap" grid electricity, and then discharged during the 4-7pm peak. Likewise just a small hot water store, or small storage heaters. People might have electric loads they would find difficult to shift to the middle of the night, but for this tariff they only need to be shifted a little, just out of the 4-7pm peak - perhaps electric showers. Or indeed heatpumps!
    • CommentAuthorcjard
    • CommentTimeDec 16th 2022 edited
     
    Thanks P&W - I think for me the premise of tracking the sun at all doesn't really work out; I've enough roof space that I could just add another panel or two, probably for financially less than I could engineer a manual tilt system that I risk life and limb adjusting twice a year!

    Mounting the panels at 42 degrees would be a boost, and leave it at that..
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