Made in Japan (part 2)

This time we're in Miharu in the prefecture of Fukushima to the NNE of Tokyo by some 200km.

If you keep hitting (+) on the map it will zoom in and show Miharu (eventually!).

My father-in-law's house has two arrays on the South and West facing roof slopes and luckily even though it is in a quite steep valley, the valley runs East to West and his house is on the North side so it gets a fair bit of sun even in the winter.

The panels are made by Hitachi and are their newest hybrid crystalline amorphous type that have layers that give excellent wide spectrum responsiveness on cloudy days but the high output of crystalline panels on sunny days. The Sharp ones used on the house in Tokyo were a common crystalline type. On the South roof there are 18 panels and another 13 on the West roof.

All the power conversion kit is made by Sanyo.

As the array is split into unequal strings of 18 and 13 panels, they work at two different DC voltages. So outside on the wall is a voltage converter / combiner that converts the two different DC supplies into one at a common voltage that then goes into the inverter indoors.

A single DC cable goes to the power conditioner in the house where it is converted to mains. It's a less elaborate unit than the Sharp one and just has a single display that toggles between current kW output and the lifetime kWh generated. The information plate says it is rated for 70-380V DC input and 5.5kW output at 200VAC with an efficiency of 95%.

Outside, the utility company has fitted two digital electric meters, again one for power used and another for surplus power sold to the grid.

The inverter appears to be putting out 200V rather than the house 100V, so either it's designed to be split phase (100-0-100) relative to earth or it actually doesn't feed the house directly but just the grid through the separate meter so that the household usage bill is offset by the generating credits.

My father-in-law said that in the summer and up until September it generates a net surplus to the household requirements but by November it doesn't quite make enough to completely offset their usage.  On the clear sunny day shown here, the inverter reported making 3.0kW for a short while around mid-day but 2.1 to 2.6kW for the bulk of the day. The sun was quite low in the sky even at noon and as it moved round to the West, the output declined a bit.  In summer it was probably ok with the sun much higher in the sky and on cloudy days it probably doesn't make much difference either having part of the array facing west.

Another novel feature of their house is a Sanyo air source heat pump (ASHP) that heats water by extracting heat from the outside air (usually hot and humid). Using a sort of reverse air conditioner it pumps the heat into an insulated hot water tank. 

It uses about 60-70% less electricity than a resistive heater. The Japanese call it an Eco-Cute. It doesn't mean "cute" though... "kyu" is a kanji in Japanese than means "to heat water". The difference between an ordinary air conditioner compressor and these water heaters is that the refrigerant is at a much higher pressure in this system to more efficiently extract heat and it's only in recent years that they've been made small enough and cheaply enough for home use.

Inside the house is the large hot water tank and compressor. A digital display shows the water temperature and how "full" the hot tank is as a bar graph.

The system also controls the heating of the bath to a constant temperature - very important for Japanese.  You take a shower and wash and then sit in the tub just to relax and get warm while the system cycles the water.  You could sit in it all evening.

He also had the kitchen refitted and they changed from a gas hob for cooking to electric induction.  This wastes a lot less energy (95% of the energy goes into heating the pan rather than the hob or the air) but did have the drawback that they had to replace most of their cookware.  Induction hobs only work on ferrous metal pans, so the typical aluminium or stainless steel with copper bottoms don't work well.  As they generate quite a large surplus of electricity, it made sense to change from gas to electric for cooking.

Made in Japan (part 1)

It's not just me in my family that has solar power, no sireee.  It was actually my in-laws that started things off.

My wife is Japanese and her sister lives in the suburbs of Tokyo.  Back in 2008 they installed a grid tied 3.07kWp Sun Vista system by Sharp.  

Sharp call the inverter a "power conditioner" and it has a control and info panel near the utility breaker panel indoors.  It lights up different colours during the day to indicate the power level.  Blue means the system is generating a surplus and is selling electricity to the grid and yellow means it is generating but grid power is being used as well.

The panels are mounted on both sides of the roof but the slopes face sort of east and west so one half of the array is always sub-optimal. The sun doesn't make such a low angle in winter in Tokyo when compared to the south of the UK so the variation of day hours are less extreme and Japanese Autumns and Winters are characterised by clear sunny days (very unlike the UK). In the summer the sun goes mostly directly overhead so it's not such a problem.

Their house is the one at the back of the white one - you can just see the panels on the roof.  The houses are terraced back to back.

The installers mounted the inverter on the outside wall and then ran a wire to the remote control panel inside.

The mains is fed to two meters outside that the utility company installed.  The digital one on the left measures grid power drawn and the old school mechanical one on the right measures solar power sold to the grid.

The remote panel in the house displays an estimate of power being generated as well as the proportion being used or sold and the lifetime kWh. Flicking through the menus you can pull up generating history graphs for the last hour, day, week, or month.

It's about 11am in this shot and it's just started to make a surplus now that we are done with breakfast and have stopped using the kettle.  The sun is a bit hazy today. 

They tend to sell a lot of power during the weekdays when they are out at work but then buy it back at the weekends when they use the air conditioning and clothes dryer.

The whole system is a kit made by Sharp but a local installation company fitted it.

PV in Germany

I knew that solar was more popular in Germany than the UK but this set of pictures gives you some idea just how far ahead they are compared to us in the UK...

I wasn't intending to go on holiday in Germany but fate (or rather volcanic ash) interceded and we had our flights to Japan cancelled.  So, not wanting to spend the whole of the four weeks I'd booked off sitting in our back yard, we caught the ferry to France and drove across to Germany.  We went to Seiffen near the Czech border and up to Berlin and across to the Nurburgring (but I couldn't drive on it as my insurance excludes it by name!).

Along the way, we were amazed by how many houses had solar PV or thermal (sometimes both) and here is a sample of what we saw.  The biggest array by far was one in the "back yard" of Amazon's warehouse in the middle of nowhere in the middle of Germany.  Absolutely huge it was.... a whole field of trackers.

Some like this one are communal, shared somehow by the residents of a block of flats.  This one has 121 panels and at a typical 180Wp per panel that's about 21.7kWp

Many businesses install very big arrays on their warehouses or factories.

This was one pair we saw from the window of our castle hotel at Neuhausen near Seiffen that specialises in wooden toys and other intricate wooden decorations.  You can see the 88 panel array on the house but also a bigger one on the barn just peeking over the hills behind.  This house had in the region of 15.8kWp installed.  And this is quite common in Germany.

These two we saw in another castle town, Wernigerode, where we stayed at a ski hotel.  This house must get through a lot of hot water! It has a massive thermal solar panel.

This one not only has panels all over the roof but also on angles all over two garages / sheds to the left of the house.

Driving in the scenic valleys to the North of Kassel, we saw a solar showroom.  A big ex-supermarket type building with a large car park.  Could solar be so popular that they have something akin to a car showroom for selling installations?  A helpful woman enquired if I needed help.  I looked at a selection of example panels they had in different powers and styles (including black framed ones and big amorphous ones).  They stocked some brands but she pointed out that they also made their own brand too.

Driving on through that town we started to see more and more installed PV systems... Obviously, the showroom had been doing plenty of deals for the 'Burghers.

Driving along the 80 towards the fairytale town of Hameln (as in the Pied Piper of), we were stopped in our tracks by the sight of this village (Oedelsheim) with its numerous houses with big PV arrays.

The farmhouse on the far left having some 264 modules installed on the upper and lower roof! I did notice on my travels that mostly the Germans seem to go for poly panels rather than mono types.  Maybe they're a lot cheaper or perhaps the German made ones are predominantly poly types?

The neighbours were keen to keep up with the Johans in some arms race to see who could have the biggest array.

Hameln Banhof (train station) has this bus station with see-though panels specially made to make power and act as a sun shade. They are not so different to normal panels just the cells are spaced out a bit and a clear backing used instead of the usual white / blue EVA.

Treysa in Schwalmstadt to the SE of Kassel has a walled old town and from the ruin of the church you can see this school complex with a massive PV array on several buildings.

This office, visible from the old town wall has 198 panels (~35.6kWp) installed.  By now this looks "average" as installations go.

Even some of the old timbered houses in the town have been kitted out.  Not sure massive solar arrays on quaint English Tudor houses would sit well with the parish council but the Germans don't seem to mind.

Just outside the nearby castle village of Ziegenhain (supposedly the town of Red Riding Hood) some nutter has put a 5x5 module tracker on his shed...

Ferienhof Todenhausen wins the award for the most solar systems installed in one village though...  It's not that big a place but it has a crazy amount of PV installed.

I counted 14 PV / thermal installations on different houses in this close-up shot alone.

And someone went mad on the far right of this shot where they installed PV all over the two enormous grey sheds with specially designed sloping roofs!

All the excitement went to me head and I bought the used 50W panel and 5x new 80W panels off of eBay for me home brew setup when we came back home.

On the way to Yorkshire to pick up the 80W panels, I noticed plenty of large buildings (offices, warehouses, farm buildings, homes) that were all ideal candidates for massive PV arrays that would almost certainly had one if they were in Germany... Not a sausage here.  Pitiful.