porters-zch

If you look back through the posts to 2011 and 2012 the solar PV system on the house was installed as the house was built. It is an “in-roof” system, rather than “on-roof”. Apart from anything else, it save tiles – or in this house’s case, slates. (I started to write this in August, btw.)

It has been a frustration for some time that, if there was a day time power cut, the solar PV turned off. The inverter could see the mains or lack of it, and shut down. Clearly, without some safety devices it has to, so that the linesmen repairing the fault don’t get electrocuted by the power that the system would continue to export to the grid. But I have considered that it should not be beyond the wit of an electrical engineer to create system that, in the event of mains failure, isolates the house from the mains and makes it impossible to re-connect until the power outage has been rectified. And, indeed you now can. Interesting video on the Fully Charged website showing the big “backup” box, which does just that – it switches over to the local battery instantaneously. And the solar PV continues to charge the battery/supply power to the house, provided that the sun is shining etc. But the key word here is battery.

To go back a bit. When the system was installed on this house, the Feed in Tariff (FiT) had just reduced from (very roughly) 40p/kWh generated to about 20p. Still worthwhile. Since then the FiT has been withdrawn – but the price of solar PV has much reduced. Whatever I write here will go out of date but, again very roughly, it’s now about £1 per watt peak installed. So a 4kWp system should cost roughly £4,000.

So where are we with batteries? When I last wrote about this, it was still far from being a sensible return on investment – I would not save enough (of the cost of) electricity to get my money back on the costs of a battery system – by a large margin. I don’t have that amount of spare cash to be able to indulge that level of “green altruism”! And, in my opinion, it still isn’t.

Step another bit forward – many of you will have seen articles about “V2G” which stands for Vehicle to Grid. If I had an electric vehicle (EV), then perhaps I could use its battery instead of buying one for the house separately – I’ve spent A Lot Of Money on an EV, why buy another far from inexpensive battery? Well, it’s coming, though not quite yet, I’m told.

I am in the throes of joining a trial called Powerloop, an experiment set up by Nissan, Octopus Energy, Octopus Electric Vehicles, UK Power Networks and two academic partners (can’t find their names at the moment). Essentially, provided I am in UKPN’s area, am prepared to lease a Nissan Leaf from Octopus EV, move to Octopus Energy (single tariff), am willing to connect the car 12 times a month to the special charger/discharger (Wallbox) between 6pm and 5am I will get paid £30/month. The Wallbox charger is supplied and fitted free and becomes mine at the end of the trial. See the Powerloop website, rather than my writing all the details here and possibly getting them wrong. You could join too. At the time of writing (October 2020) Octopus/Powerloop told me that there were still vacancies to join the trial. Oh yes, you have to own your own home and have off-road parking.

Checked out the car at a local dealer. Thought it might be a bit noddy. No! It’s rather larger than the Peugeot 2008 we have at the moment, really very well equipped and finished and with serious poke under the pedal. We both liked it so we’re prepared to go ahead. Currently going through the G99 process – which checks to see if UKPN happy to have this house connected to their local grid. Well, I would hope so, as we already have Solar PV which I am – obviously – hoping will charge the car’s battery at least some of the time.

Watch this space.

I’ve also looked in to Solar PV optimisers – but that’s a separate post.

It’s time to bring this up to date. I see that it has been a full two years since I wrote something about this house and our living in it. The frequency fell away because, well, the house went on doing its thing and we went on doing ours.

We went through last winter and, unlike the previous one when I had to start raiding the shed containing the next winter’s wood, we got through well. A less harsh/cloudy winter – and better wood. I say “got through”. That gives the impression that it was a struggle and a worry. It wasn’t. There was plenty.

That old shed – which was built of the old pallets and lumber left over from building this house itself – itself became firewood. Burning this was fine – except that I was riddling the ash to extract the nails. The ash – not much ash on a daily basis – gets put in a metal bucket. Metal, in case of accidents. See later! But I don’t want a lot of nails in the compost heap, which is where the ash goes. Relatively recently I read that it was better to put ash in the compost heap than directly on the soil in the garden, especially in winter, as the rain has washed away the goodness by the time the plants start growing, so there’s no benefit. Put it in the compost and it will still be there when the compost is spread on the soil later.

Moving on as this is not a gardening column – there’s not much ash because dry wood, burnt properly, doesn’t leave much ash. The chimney gets swept every year (of course) in the summer and the sweep is always very complimentary about how clean the chimney is. #smug

So the built-out-of-old-bits-of-wood-with-a-tarpaulin-over-it shed became firewood. Most of the wood which had been in this shed/store, moved – well, I moved it – to the ready-use store for the next winter. But of course the rest of it, and the deconstructed shed itself had to have somewhere to go. I had to be able to keep it dry and where was any other wood to go? And for the following years(s)? So we build a purpose made wood shed. Yes, with opposed slats outside and inside the studs, alternating with gaps! This is the sort of thing I am told you find in Scandinavia. It keeps the rain out but lets the wind blow through. I’m really quite proud of it, even if it doesn’t look terribly log-cabin-ey.

And it works! The wood dries. And as the photo shows, there’s a lot of wood there for winter 2021-22 already. With most of my other occupations cancelled by coronavirus, there’s been plenty – too much – time to cut/split/stack wood.

Oh yes, the accident. One day, some few years ago now, there must have been unseen (obv) charcoal embers in the ash. And it was shovelled into a (plastic) bucket and put back again in the back lobby (what our architect was pleased to call the boot room – it’s the “airlock” for the back door). Not that long later, the lobby was full of smoke, the plastic bucket was melting and flames were beginning to appear. There are smoke sensors throughout the house – but not in the lobby. It was all put out very quickly and easily with a quick jug of water, fortunately. The smoke alarm went off very shortly after the door to the lobby was opened of course, the noise of which makes it difficult to remain calm (get the jug of water before you open the door) and is quite bad for the blood pressure! But a salutary lesson. It could have turned into a bigger fire before the smoke got to the sensors. We now have a metal bucket – so if the worst happens and the embers have a new lease of life there will be smoke but no fire.

Next post will be revisiting the Solar PV. Things have moved on in the electric world and it’s time to revisit this.

. . the end of August?

It’s been pretty grey these last few days and today, 31st August, the forecast is for rain all day.  We had a fair bit of sunshine the day before yesterday and the thermal store temperatures got up to 70 at the top and not too bad below, so we have had hot water for yesterday and today – but will there be enough for a decent shower tomorrow morning?  We’ve got our younger son staying and so there’s more hot water needed!

Which prompted me to extract the data from the diaries for the last six months of last year and the first six months of this. So here’s the graph showing the number of times we lit the log burner and the number of barrows of wood we brought into the house.

If you look back to “Another article – and wood usage update” (published in June 2014) which gives a rather different graph – the weather was clearly not the same, though, interestingly, both have a sort of gap in March – a spell of sunny weather which means that you don’t have to light the burner.  Then April needs more heat.  Ah yes – Flanders and Swann (for those of a certain age) April brings the sweet Spring showers/on and on for hours and hours.  Which explains it all, of course!

In 2013-14 we used 35 barrow-loads of wood and lit the fire 96 times – vs. the figures above of 33 and 89.  Of course if we go away for  a few days . . .

But the point I’m hoping to make is that we only lit the fire 96 or 89 times.  Out of the 365 days of the year.  All the other days – three quarters of the year – we didn’t need to. All the heat came from the sun.  Even if we were using gas – even oil(!) we would not be using much and not often.  And that’s the point of building to Passivhaus standards.