On Tuesday, the panels and wiring got installed. On Friday, the utility installed the second meter to count the electricity we generate and sell. Today, Saturday, at 10 in the morning, the utility inspector came, measured the system and declared it good to go. Switch on, wait 300 seconds (5 minutes!) for the power conditioner to count down and - electricity started flowing back to the grid. On this sunny morning, we read up to 2.4 kW. Green power as we had planned! Great Day! My wife and I looked at each other and decided this day will end with champagne.
(one celebration, two disappointments, conclusion for the day)
Celebrating our first solar kWh produced
There it is, about half an hour after switching on: the first kWh on the power conditioner readout. On the HEMS, it took a bit longer, but hey, we are producing electricity and selling it. This is the first hour of 13 years until the system has hopefully paid back its investment. Champagne will be in order...
First disappointment: buggy software
The Toshiba Feminity (its real name in Japan) home energy management system comes with IT sensor unit NWDNP-BX02 and the home gateway BTR-3005AZ which communicate via Bluetooth. The gateway's server interface is specified only for Internet Explorer 7, not compatible with other modern browsers. Firefox no good, Safari no good. Some of the readouts remain zero, like the power consumption in W. Strangely, accumulated energy in kWh does display on all browsers, even mobile Safari, Mercury, or Atomic Lite on the iPhone. Power in W only shows in Internet Explorer, and in Google Chrome.
Look carefully, the power values do not sum up correctly [update] differ by a few watts. This destroys trust in was explained by thre browser script sampling the readings. (Calls for another blog post.) As for usability, they tried to keep the interface simple, but the bar arrangement confuses (red: consumption, blue: generation, purple: feeding the grid). The orange bars represent the eight circuits we can measure with this system, however, they are shown out of proportion to the main bars. After a few minutes a few of the orange bars get misaligned and mess up the display.
Also, the slow data refresh once every 30 seconds is not what you wish for when you want to quickly find which of your home appliances waste energy (the biggie in our case: outdoor gas boilers with their electric antifreeze heating). Here, a quicker refresh, say every 5 seconds or so, would help you see how shutting devices off reduces the power reading.
All this makes me wonder how this particular brand of HEMS ever qualified for government subsidies.
Why did we not select the alternative, Panasonic Lifinity HEMS? That one would require replacing the entire circuit breaker box, while the Toshiba's power sensor rings just slip over the existing wires.
My wife checked on the internet - where else - and found METI (the Ministry for Economics, Trade and Industry) works on standardizing HEMS for mutual compatibility. About time. The proprietary approach once again fails the paying customer, or in this case the subsidizing taxpayer. As we saw with the PC in the '80s, markets develop much faster with interchangeable components and open competition. Everyone benefits as the deals get better.
Great disappoinment: too much noise, must shut down
While we were enjoying the emergent reality of going greener, our son complained of high-pitched noise. We found it came from this power conditioner, Sanyo SSI-TL40A4. The hiss [update: 17.4kHz] got on his nerves. He claimed he could even hear it back in his room, away fom the service room and its electrics. We do not fully close the doors because our cat likes to roam. Out of consideration for his final school exam preparation, we shut down the unit. Going solar in Yokohama ended after only 2 hours.
Our contractor had just been there, seen the buggy software and we reminded him of the initial agreement that we see the same data as are going out to Toshiba and Yokohama City. He admitted he did not know how we can get our consumption/generation data as a table, all we an curentl see is instant readout on the screen. He also noted our prior request was not filled, that the electrician seal the gaps in the wall openings he made for cables (and insects) not only from outside, but also from inside. There we noticed cold air infiltration. We sent him a mail about the inverter noise and that we had to shut down the unit until it can be fixed, sorry.
Power conditioner defective?
We found the installation company (Matabee) had failed to give us the operation manual. Is that not on their checklist? Anyway, fired up the unit again (wait 5 minutes). Measured with the iAudioInterface: up to 88dB (unweighted) near the enclosure at 2 kW output. Later, measured at 1 kW output, about 48db(A-weighted) at 1 m away and 0.8 m below the unit, where the specifications say 34dB (A).
For the photo, we put the microphone closer to the unit, about 50cm away, which results in a higher reading.
In their FAQ, Sanyo writes about 40-50dB operation noise, we measured over 60dB (unweighted). Fibbing specs, or maybe we got a lemon? We reported this to Sanyo on-line and expect quick action from customer service, as is common in Japan.
Conclusion for the day:
Solar technology is not yet thrivable, as the buggy old software and inverter noise demonstrate. Home facilities still suffer from leftovers of a 20th century industrial model. Could be summed up as: deliver what is promised for as low cost as the consumers let you get away with. Trouble is, consumers now share their experience.
Could we have avoided this disappoinment over our investment (it's a new car's worth) by doing more research before? Yes, lots of solar forums in the U.S., and micro-inverters appear to be the best currently available technology. But not in Japan, where the products and systems must appear on qualified lists before subsidy is approved. Test-drive? Hardly think so, it would mean to visit someone's home. As for appliances and devices consumers buy by the millions in a year, enough people review and share for would-be buyers to quickly get a second or third opinion. Much less so with home installations, which are selling a few thousands in a year, or which are selected by contractors who never have to live with what they chose. Through search engines we did not find a single personal review or blog post on the companies or devices we were about to select. Only seller's pages popped up on search engines. We hope to change that a little here.
With consumers sharing more of their experience as word-of-mouth, only companies that can deliver thick value, can thrive. Others, we'll see about it. On blogs and forums ;-)