Loads of snow and no generation

For the first time we had zero electricity from our panels for a whole
day. Until then the least we'd generated in a day was 3 kWh. There's
no particular mystery as to why we had no electricity. It was snowing
all day, starting at around midnight and not finishing until after 4
pm. jma.go.jp reckons it snowed 22cm. This was a very
snowy day.

Also, the timing was not very good. It had been clear before it
started snowing, so the roof had been chilled below ambient
temperature, radiating its heat beyond the stratosphere. The first wet
snow falling onto it would have frozen on impact, making a perfect
foundation for the later snow to stick onto. So as well as opaque snow
falling while the sun was coming up, there was a layer on the roof
making the panels impenetrable to the sun's radiation.

The following day the sun was out, and I was hoping it would clear
some of the snow off the roof. When I got home most of the snow was
still there, and we'd only clocked up 3kWh for the day. A bit of the
snow had fallen off the bottom, south edge, and the first two or three
columns of panels from the west side of the roof were all clear. One
reason I can imagine for this is that the west side of the roof sticks
out from the side, so it will have been warmed by the air underneath
it. The rest of the roof, on the other hand, is a victim of the
insulated roof, and its bottom layer will have been kept nice and
cool, stopping the layer of ice from melting and helping the snow
sticking firmly to the panels.

Two days later, the sun is beating down from a beautiful blue sky, and
under normal circumstances we'd be generating seven kW. But only
around two were coming out.

Now I'm as concerned about de-glaciation as the next person but I
don't particularly want one forming over my solar panels. So I went up
to the balcony to try to help some of the snow down. I have a plastic
snow shovel, good for snow, and a metal spade, good for ice. The spade
helped some of the snow above the bottom row coming down.

When the first row of panels was clear, I went back to check and the
generation had gone up from 2.5 to 2.9. Of course this difference may
have been due to the higher angle of the sun, as this had taken about
half an hour, clearing the ice and snow off the balcony too, and may
have had nothing to do with my work. I went back up again with the
snow shovel, which has a longer handle and is less likely to smash the
panels, and this got some of the snow off the second row of panels.

I went back to check the generation and it had gone up from 2.9 to
3.2. At first sight this seemed a pretty poor return for my work.
Financially speaking I would have been better off spending the time
giving out tissues in front of the station. Also, this seemed a poor reward
for the risk of falling off the balcony and breaking my neck, or
accidentally putting the spade through the panels and causing them
permanent damage. But then, a few minutes later, there was a rumble
and a crash as half the snow slid off the roof. The generation shot up to 6
kW, and then over 7 when a second load of snow crashed down from the
middle of the roof. The panels at the bottom had heated up, in turn
heating up the air passing under the panels. After clearing the bottom
of the roof, I noticed it was over 25 degrees in the air channel. This
must have helped melt the snow further up the roof. Or perhaps this
was going to happen anyway, whether I'd been clearing snow or not. I
like to think that this bit of snow clearing was not entirely
pointless. Ironically, if we had less roof insulation, the snow would
have melted much quicker.

But this kind of snowfall is pretty rare so it's hardly
worth worrying about anyway, unless the climate shifts significantly
and snow starts getting over the protective ring of mountains and
falling more heavily and more regularly, or unless we get to a
situation where there's no grid and we have to rely on our own
electricity. There's a lot to be said for connecting to solar panels
and going off the grid if you're in a sparsely populated area or have
unreliable generation, but where we are, we stand to gain a lot more from
being connected.

Winter's coming, but not too close!

The temperatures are starting to drop below zero every night, and the other day it was trying to snow outside.  The garden is often tinted with frost as we look out over breakfast. On clear evenings the moon reflects on the snowy tops of the mountains, under a starry sky that seems to suck heat from your face as you look up.

November has come and gone and winter is definitely here, destined to get colder and colder for the next couple of months. Meanwhile, inside the house, we haven't put the heating on yet but the low temperatures are still a degree or two over 20. When the sun shines, it gets into the high 20s around midday with all that solar radiation.

On the last day of November, we put away the thin blankets we've been using since summer and got out the winter futons. In the old house, the stoves came out and the thick futons went on at the beginning of October. By now we would probably have added a blanket on top, and hot water bottles inside. We'd be facing icy corridors, and a real struggle to get out of our warm cocoons in the morning. In the new house, the kids sometimes jump out of bed before the sun even comes up. 

Let it snow!

I love snow.

In England when it snows everything stops. People miss school and don't go to work. Traffic systems close down and people can't get to the airport to go on their skiing holidays. Sometimes power cables are brought down and the food in people's freezers is spoiled.

Here in Japan people are used to snow. Matsumoto is not in Snow Country, but is surrounded by it. The snowiest city in the world is apparently Aomori, where it comes in from the sea like waves over the winter. In Hokkaido they have a different front door upstairs, and neighbourhood battles go on as people clear snow into each other's parking spaces as soon as they vacate them.

Clearing snow here, for the most part seems to me a waste of time, although everyone gets very busy doing it. Sooner or later it's going to melt, so why bother? While it's snowing, you can walk on it or drive in it as everyone changes into snow tires from some time in early November when the first hint of white hits the highest mountain peaks. I don't really like driving in snow, so I don't unless I really have to. Like if I'm going skiing. Usually I don't really have to drive. I cycle to work, but can walk or get a bus if necessary.

As a house owner, my view of snow should have changed a little from this childish enthusiasm, but it hasn't yet. My house is effectively at the end of a cul-de-sac, so I don't have any responsibility to clear the thoroughfare in front of it. The biggest worry is the roof and the balcony on the south. Snow is rather heavy. It may be much lighter than water, but you don't get fifty centimetres of water building up all across the top of a house. Actually we don't get snow building up over our roof either, so far. It slides off the southern solar roof well. Some of it does hit the balcony on the way down making a ridge there that seems to sit happily, although most of if falls straight onto the terrace below. Probably a good idea to clear that off in the interest of balcony longevity, but it is not doing too much harm, and we wouldn't need to worry if it snowed while we were out of the country. 

Snow is more likely to stay on the north roof as it's shallower, and part of it is in the shade. Snow goes through a melting freezing cycle, and bits of ice come crashing down to where we keep the bicycles. 

Obviously snow impedes the performance of the solar panels. When the roof panels are covered, not much sunlight gets through, although of course the radiation that does get through heats the panels, melts the snow on top of it, and helps the snow slide off. Also, when it's actually snowing, few rays get through the clouds and snow. Even so, it was producing something while it was snowing. Admittedly only a hundred watts or so--in the battery charger ball park--and half the 200 watts that the house seems to consume even when everything is switched off. Over a day when it snowed pretty much all the time, we still made 2.3 kWh, which is about 10% of what we used. 

I was hoping we'd hit 1000 kWh within the first month of living in the house, but it's snowing again today, so it's looking unlikely.

Ne'er cast a clout till May is out

Not that that has much to do with the pictures. It was a glorious day when they poured concrete, and they were worried it would be too hot and dry too quickly. There's been a fair bit of rain since, reminding me of the old Yorkshire saying in the title. This is a little ambiguous, as "May" could mean the month or the flower, but either way, it's best not to get all your clothes off just yet. It hasn't really got hot yet this year, and the rainy season has already started. I think it's a little earlier than usual. Then there's been a typhoon and the rivers are all close to bursting their banks, filled with chocolatey water gushing down where we have barbecues.

This is what the concrete pouring looked like, anyway: