Solar Reporting – Sunrise Sunset
Before the Queensland State Government reduced the rate of tariff feed in, I pursued purchasing a solar array. And what a mine field it was! After reading an extensive quantity of solar install horror stories on the internet and more specifically on the whirlpool forums, I began in earnest the search for a Solar Vendor that even if they went to the wall, the equipment would be covered by the original manufacturer’s warranty. The other consideration was to find a vendor that was not a sub contractor to an “xyz” solar company. I finally found one that ran his own business, Celtic Solar. I cannot recommend this vendor highly enough, his install was impeccable. Having said all that, the inverter I chose was an SMA 4000 with 18 x German Solar 225W Panels.
Getting some statistics….
Once the install was completed, I was able to read live numbers of power generation on the inverter. It was time to get the inverter to talk. The SMA inverters have an excellent bluetooth stack, and I quickly had it talking to an old notebook I had lying around. SMA produces a windows only client at this stage, (my end goal is to virtualise it on my NAS4FREE FreeBSD Server, another story) however this suits the purpose in any case. Now I have it talking to a notebook and I can see it on a screen. The problem is it doesn’t really have any significant reporting capabilities, nor a web interface so it’s not platform agnostic either.
Pvbeancounter to the rescue, this very nifty google project talks to the SMA SunnyPortal and uploads it to a free account at PVoutput.org, it then disseminates the array data into nicely organised graphs and charts. I had quite a bit of fun with this at first, being able see energy generation patterns and how the weather would affect the output. Also being able to tie tariff information with energy generation made for an interesting ROI calculations on the capital investment. After all, this is not a toy, I invested a tidy sum to help me financially. Looking at all the power I was generating was hugely satisfying however I had no idea what my usage was. If I was using twice what I was producing it was going to be a fruitless exercise.
So then I set about getting a way to retrieve consumption data, about 8 weeks in, Energex finally installed my digital meter which allowed me to finally receive the generous feed-in tariff that the Queensland Government offered, (until 2028). I was really hoping to use the digital meter to retrieve the consumption rate, but that was not to be, Energex locked down the digital meter so that I could not retrieve any data, so this was dead-end. I finally decided upon a Watts Clever EW4009, this particular meter is natively supported by pvbeancounter. This has allowed me to push consumption data as well as the energy generation data in 5 minute increments.
This produces some particularly interesting graphs, and allows me to trim, with the help of my wonderful wife, the daily consumption patterns to maximise the return from the feed-in. Its cheaper to buy power when I’m not producing it. The trick is to minimise power usage when practical during the day, and buy it back at more than half the rate during the evening. The beauty of such a reporting solution is that I’m not tied into a Solar provider, it’s all open source as well. There is even a iOS app that I can use, easy to read and portable. PVMobile.
Real Time Energy Generation
Real Time Consumption[inline]