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2015/04/24

Power generation - performance report

Our solar sharing power plant has generated a lot of electricity since it started operation 5 months ago - precisely 22 952 kilowatt hours in the period from November 27, 22014 (start) to April 24, 2015 (today). That's not bad for an installed capacity of 40 kilowatts.

We use a monitoring service "Solar Monitor" that allows us to check real-time generation status online. Being able to check it anytime anywhere (that is, "anywhere with internet connection") is extremely convenient, and on sunny days it's also quite fun.
Picture below is Solar Monitor screen shot from today April 24, 2015, taken at 17:21. In the circle on the left you can see that the plant was still producing 2 kilowatts of power despite the late hour. That's one of the good things about days getting longer towards summer. From the screen you can see that today a total of 200.4 kWh was generated (for the record, it slightly increased to 201.9 kWh at the end of the day.)

20150424_17h21m_2kw_cutforblog

For English explanation check an older screen shot below (click for enlargement):

20150131_12h17m_374kw_cutwithnotes

By the way, the mechanism that allows us to change the panel angle (tilt) has been - as expected - a major contribution to performance.
I never noticed it before but the position of the sun on the sky is really different in winter and in summer. I do remember learning at elementary school that sun is low in winter and high in summer, but I never quite observed the sky to see how different "low" and "high" actually is. Until recently.
In terms of solar power generation, the position of sun has great implications. It means that while in winter you want to lean the panels into very steep tilt (as much as 60 degrees), in summer you want to put them in almost horizontal position (as little as 3 degrees). This greatly affects the amount of electricity produced.
Thanks to the panel adjustment mechanism, we're doing exactly this - optimizing the tilt every few days (or weeks) according to the seasonal height of the sun.
Graph below shows optimal angle of solar panels for each month of the year. The graph is for the location of Hachiouji (Western Tokyo), which is some 100 km from here, but it's the same Kanto region so the data roughly apply to our place as well (observation-confirmed). According to this graph, optimal tilt is 60 degrees in January, 34.5 degrees in March, 2.6 in June and 40.8 in October.

Nedo_panel_angle

You can find the original graph here:

This was a quick performance report.

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2015/04/02

Our solar power plant construction in 4 minutes

Here's Part 2 of the video summarizing construction of our solar sharing power plant in Tsukuba.  Given that construction was finished in November last year and now it's already April, the video is badly overdue.

There was another video covering the same topic, which I posted in February, but it was so poorly edited that I eventually decided to remake it. This is the result.

Why was making Part 2 so much more difficult than Part 1? Here's a metaphor to explain it. If we compare construction of a power plant to building a house, Part 1 of this video shows how the very building of a house was made - brick walls, window holes, a roof. At first glance it's a complete house, but in fact it's not habitable yet. It has the shape of a house but there's nothing inside. Part 2 shows how the house is equipped with all the basic amenities that make it a real, habitable house: water supply, heating, electricity, furniture.

Part 1 shows the form, Part 2 adds the substance.

The thing is, form is much easier to convey in a video than the substance.

When a building is rising in front of our eyes, it's very comprehensible to our brains. It's interesting to watch.  When some cables are added here and some boxes there, but nothing new is really growing in front of our eyes, it's not very fun to watch.

Anyway I did try my best to convey the substance in Part 2.

Part 2, showing the construction in October and November 2014, is here:

Part 1, showing the construction in August - September 2014, is here:

Enjoy watching and let me know if you have any comments or questions!

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