Ferdinand

I'm trying to get to grips with this and other questions for my own house. As I read it, Tesla Tariff has a cap on usage at 9500 kWh from the grid per annum in day hours, at which point they make you switch. Does this affect you? If your daytime consumption (from 07:00-19:30) grows beyond 9,500 kWh per year, per-Powerwall-installed, you will be prompted to choose an alternate tariff that better suits your usage. Please note, if you own electric vehicle(s), scheduling your vehicle charging to occur outside of the daytime hours (I.e. charging any time between 19:31 and 06:59) will transfer a significant amount of your household consumption to off-peak hours. Whilst this reduces your daytime usage as a Tesla Energy Plan customer, this practice is also helpful for reducing the peak demand on the national grid, which further helps reduce national carbon emissions. https://octopus.energy/tesla/tariff/#/calculator Have you run it through the Tesla/Octopus calculator? A second issue is whether the 11p/11p tariff can be switched by Octopus and at what notice? (I'm on a FIT at about 14p per kWh for exports, so would not consider something dependent on a supplier's goodwill.) I think the current capacity of a Powerwall 2 is 13.5 kWh, and you install 2. https://www.jojusolar.co.uk/batteries-smart-grids/tesla-powerwall/#:~:text=A Tesla Powerwall 2 has,appliances are running at once. Having the option of charging the Powerwall to feed your ASHP in the day would give you a Plan B if you hit the daily limit on the tariff. To me a case for an ASHP dependent purely on a particular tariff sounds a shaky foundation - you need to know it will be worthwhile if that tariff eg doubles in price at some point soon.

There are options. Traditional hotlinking works iirc. It is under the "Other Media" option in the editor for either a forum post or a blog post. All you need is the unique address of the pic, and that the other end allow hotlinking. If you just copy and paste the image in via the clipboard, I think that creates a hotlink. IMO it is better to upload, however, as that can't be broken by a third party. Just make sure it is not many, many megabytes. ATB Ferdinand

Rainfuel? Does someone have a link? Thanks

You need to check what building regs you are subject to. If it is part of the dwelling, then you will need to insulate the wall to outside to the appropriate standard, as there are requirements to improve when you work on a thermal element of the building. Your local council are the people to ask. F

I think we will soon be seeing how quickly that can happen in Germany 🙂 . Though I am told there is capacity to use the European gas grid to mitigate in the meantime. F

If you are choosing to indulge in unnecessary personalised insults, I'm not interested. Don't bother replying to me; you are now on ignore.

If you have a sprinkler system I think you need a separate 32mm supply. Unless you have infrastructure such as a water storage tank.

ie Don't live in a dip in Bristol.

Nothing. It's a standard approach. You just need to make sure that it can take whatever you are going to have parked or driving on it. Eight wheelers? Removal vans? Hiabs from Wickes? Your rich uncle in his fatmobile? Two tonnes of bricks for the new garage just being delivered?

They all have power cuts and can#'t log on ?

That was one reason explained to me as a difficulty. The grid companies in a power outage will not want any risk of electric shocks for their repair staff, so will have insisted on failsafe technology.

I have a standby generator for my heating. It is a Super Ser.

Where would you keep them cold if not already in the freezer ?. Adding warm blocks after a power cut would thaw it out more quickly in my physics ! Mine live at the top and only get taken out for a picnic or if eg I'm going shopping elsewhere and need to keep eg coastally purchased fish cold for an extended period.

Can one not open the passive cat flap?

The "solar pv power in a power cut" is one that I have been reflecting on. Need to think about what the requirements are - do the rectifiers need a power supply themselves? The other mini thing I have in place is a couple of chunky phase change cooling blocks n the freezer which will keep it cooler for longer. These were supplied. No idea how they are specced, but total mass is 2.5kg.

Can you justify these numbers with a source before I rework, please? Happy to do so, however. Accept that. 24.4 GW current wind nameplate power capacity. This actually seems to be 17.6 GW, ie 25% higher than your number - though estimates such as we are doing need mean averages and totals, not peaks. On May 4 2021. https://www.theguardian.com/environment/2021/may/21/may-gales-help-britain-set-record-for-wind-power-generation I make that more like 8.6 GW, which is 50+% higher than your number. Based on wind energy generated of 75,369 GWh (2020 Govt Environmental Accounts), divide by (24*365), gives a mean average power output of 8.60 GW. Are you missing that Offshore wind has a far higher capacity factor than Onshore wind, and all the new fields are offshore? For offshore it is 46% - just under half, and for onshore it is 28%. For new offshore wind coming on stream it is higher, which is why I use 0.5 or 50% in my estimate. Seems so to me. 1 - In resilience terms, we get a new stable source of elec,which is overwhelmingly low carbon - 90%+ in No is hydro. Part of teh answer to "occasionally no wind, sometimes no sun"? 2 - In C02 terms that's clearly a benefit. National Grid have an animated presentation of live. Nat Grid say they save 3 million tonnes a year, even without full data from the new one. data: https://www.nationalgridcleanenergy.com/powerofnow/ 3 - In kWh, it is extra capacity if required - at a time when we are seeking to increase renewable supply availability. 4 - In £, it is a more open market, and aiui Norway Link gives us access to another pricing pool. Plus I see no reason why we can't end up being more of an exporter over say 8-15 years. 5 - Politically, diversity of supply has to be good, surely? I'll avoid politics, however, beyond noting Mr Macaron's efforts to use it as a political lever - electricity being France's 2nd or 3rd largest export to the UK. There's quite an interesting pipeline of interconnectors coming on stream (somewhat old list, and I'd expect some of these to fail): https://www.ofgem.gov.uk/energy-policy-and-regulation/policy-and-regulatory-programmes/interconnectors F

What low carbon progress do you expect to arrive over the next year to achieve such a startling change in energy generation? The reality is that we will likely see a rise in carbon-based UK electricity generation because our nuclear capacity is being retired early with 1.4GW due to be lost this year. New wind farm capacity will only nudge the dial a percent or two each year, for example the biggest recent news in wind farms was Triton Knoll which took years to build and came online last year with 0.8GW capacity. It isn't startling imo. Let me take you through it. My samples of elec generation (=elec use as near as dammit) are Gridwatch graphs. I am taking the last month as a proxy for "winter" and the whole year as a proxy for the whole year. Percentages of elec supply. Gas fired is orange. Offshore wind is turquoise. https://gridwatch.co.uk/demand/percent Actual amounts in GWh: Assumptions 1 - The % share for gas / wind / nuclear in energy production over the year are something like 40%:30%:20%, judging by that - but let's work with my generous 50% guestimate for now for % of electricity made by gas. 2 - Total demand is about 35 GW in the winter, falling to 28GW in the summer - a fall of 20%. 3 - Offshore wind farm availability is now around 60%. ie a 1GW nameplate capacity windfarm will produce an average of .6GW output (Production Based Availability, which is the one relevant to total generation). https://www.ourenergypolicy.org/wp-content/uploads/2017/08/Definitions-of-availability-terms-for-the-wind-industry-white-paper-09-08-2017.pdf Generation of Electricity 4 - So eg Triton Knoll with 857 MW nominal capacity should produce something around 514 MW, or call it 0.5 GW. The first turbine there went active in Sept last year, and will be fully operational by end of Q1. 5 - There are two big wind farms coming on stream this year in addition to Triton Knoll. That is Hornsea 2 (1,386 MW nameplate capacity = .83 GW actual), and Moray East (950 MW nameplate capacity = .57 GW actual). 6 - In addition we now have an up to extra 1.4 GW actual supply from the North Sea Link, which was half turned on in Oct 2021, and is now fully active at 1.4 GW. This is 2 way so is available when we need it, and ditto Norway. 7 - Plus the burnt down French interconnector is due back online by Dec 2022. That is worth another 1 GW, and usually exports from France to us the majority of the time. 8 - So to set against the 1.4GW going offline with the nuclear, between Sep 21 and Dec 22 we have 1.9 GW actual which is ours coming on stream, and another up to 2.4GW which is available as required. Up to 4.3 GW overall. Gas Calc 9 - Now consider if Gas currently supplies my over-estimate of 50% of electricity, and Winter Demand is 35 GW. And summer demand is 28 GW. Gas therefore supplies around 17GW of electricity in winter, and 14 GW in summer (though the 12 months of data above argues that it is more like 14-15 GW and 11-11.5 GW respectively due to my generous 50% assumption). 10 - Our new coming-online resources are worth a conservative 3.5 GW of generation, which can switch directly out from gas, and on gas generation of 14 GW or 17 GW represent 20% of gas generated electricity in winter and -25% of gas generated electricity in summer. Halve those to get a % of the overall electricity supply and you get 10% or 12.5% shift from gas generated electricity to other sources. 11 - Which numbers, once we use the data from the graphs at the top, give a reduction in the 10-15% range ie Gas generated electricity falling to 35-40% from the current 50%. Which is very roughly where my estimate came from. 12 - I think my assumptions are quite central and balanced, and I have not factored in reduced usage from higher prices, or the amount usage has been ticking down each year. 13 - To take account of the nuclear 1.4 GW closure that I was unaware of, my 50% base case for the amount of electricity generated from gas is generous as pointed out - and reducing that just to 45%, which I suggest is still generous, will account for that difference. A 10-12.5% shift of gas generated electricity to the other sources I have identified will put it in the range 32.5-35%. 14 - There are a few things we can quibble about around the edges, such as the impact on the winter 22 numbers of the first 200 GW of Triton and the first part of North Sea link being onstream, but I think the reduction in gas share of electricity generated in 2022 is going to be significant. 15 - Which is why I think the Govt have been right to take a short-term attitude to mitigating price rises, as I think they need to be nimble due to rapid change happening. But I wish they had done something far simpler such as "the cap will not rise at all, we will provide medium term borrowing to the industry for the difference, and this is the new expanded insulation etc programme that will take the £150 of green taxes off bills whilst doing the renovation job 3-4x more quickly". Which would have kept it all out of the inflation rate, and be totally flexible. 16 - I guess one potential change is if electricity jumps up after COVID, but as we will not all be at home all day it cuts both ways. The highest demand increase prediction for 2022 I have seen is 3-4%, whilst the 4 GW approx new supply capacity is much larger. (As you know, I do not think that electric cars will drive up demand appreciably for several years.) F

You talk to yourself too much.

I think sales of 500k units in 2005 growing to 1.6 million a year last year is significant, yes. Certainly in terms of a technology no longer being "early adopter".

Heat pumps are hardly leading edge. The market for them in Europe (including UK) has been significant for many years. https://www.rehva.eu/rehva-journal/chapter/european-heat-pump-market It's more to do with mass-unfamiliarity in the UK. And some rather vivid scaremongering from our wazzock-ridden media, and industry lobbies seeing the 21st C version of a Spanish Treasure Fleet, so running up the Jolly Roger.

That could be down to 30-35% over the summer, and only go back to 40% at this time next year.

That one looks like a return or similar. Not how I would get a boiler. “Image on the listing is from the item catalogue. The item is in an as new condition. It has been inspected and fully checked and is in full working order. The item is complete with all parts and accessories included. The item may show minor cosmetic marks and/or scratches. Packaging may have been replaced and/or may show signs of storage damage.” As for the fitting charge - no problem with that as I get an excellent, comprehensive, very cost-effective service. And I don't have to co-ordinate anything or deal with the students.

For a data point, I've just had 2 boiler replacements in student houses. 2 x Baxi 830. With new magnetic filters. 10yr guarantee. £3200 including fitting for the two. Organised by our LA who manage a couple of hundred properties and have in house labour, so probably a decent price. That's including VAT.

In Germany they have also cancelled two or three projects to provide 'Plan B' LNG terminals in the last decade, which is a material risk factor. And it works both ways - Europe is currently I think 80% of Russian gas imports. They have just opened a pipeline to China, but that is only about 10% of the capacity of current exports. I am not clear whether potential sanctions would also encompass the existing Nordstream I pipeline.

I'll be cleaning my panels early this year, having missed last year. They are very green. One issue is that even though our energy use is relatively low, many contracts are linked to global markets. Though elec demand falls by 15% or so in summer, and gas demand plummets of course. There is also a *lot* of new or repaired elec supply coming back during 2022. I am not enough of an energy market analyst, or know enough about how much difference the reduced elec demand from gas plants will impact gas demand and cost. Or how they could nobble the formula.