Energy monitoring - going beyond smart meters...

I can’t help with modbus, but see that it’s mentioned by a fair few users of the Open Energy Monitor system on their forum.

A separate thread on energy monitoring could perhaps start by looking at OEM (if there would be any interest here...)

And @Simon1D do you and transparent mean something separate than what’s been outlined here:

Or would this be more specific to generation? @knight @ArundaleP and @cybermaggedon, might be interested if something gets discussed relating to this ^^^

Thanks for picking this @Tim_OVO 

That Home Assistant topic is different to what I’m raising here.

I’m looking at using digital metering to provide data which can be stored and analysed. That data should enable ‘us’ to develop home-based energy usage devices which

• optimise the proportion of renewables in the mix
• decrease the overall household energy budget
• provide a framework on which future Time Of Use tariffs could be based
• reduce losses on the Distribution Grid due to Phase-imbalance and Harmonics

That’s not the same as the ‘Smart Home’ devices which enable a light to be turned on with a voice command or charge your EV with enough electricity for your trip the next morning. Users with Smart Home devices tend not to know (or care) what affect it has on their energy budget. They are persuaded by slick marketing rather than joule-counting.

The Open Energy Monitor forum link which @Simon1D has given us is spot on!

… I just need time to get stuck into it. 

But we need to avoid expanding on that subject within this topic.

I have more to post here about PV Inverters and I don’t think it wise to swamp such useful information by surrounding it with discussions on energy monitors.

Yes, Open Energy Monitor is separate from Home Assistant, and it’s not specific to generation. There is a huge amount of information about OEM on their website, which I won’t try to repeat, but perhaps a few images will give some idea. It monitors supply voltage using its AC mains adaptor and combines this with readings from a current transformer to obtain an estimate of power drawn, every 10 seconds, and my history from setup looks like this:

Zooming in a few times:

The only other sensor I have counts the LED pulses on the SMETS2 meter:

That’s 1000 pulses per kWh, so this is like a high resolution plot of meter reading (in Wh) vs time. It also has 10 second resolution:

The power drawn then was…

So far, so boring. OEM users with solar panels, batteries, heat pumps, etc. (I have none of these) can add more sensors and keep track of what those are up to.

Potentially, it gives far more insight than mere smart meters ever can. And, of course, those who are into home automation can link this  into their Home Assistant, Node Red, or whatever else they might have.

The key to it all is that both hardware and software are open source (free as in freedom), and if you don’t feel up to building hardware yourself, it’s all available to buy in their online shop. So it gets more difficult if your battery from Tesla is resolutely proprietary and non-open, but those who try seem able to get something out even from them.

I’ll stop here, partly because I don’t want this to turn into a sales pitch, but mainly because the system is very new to me. It’s been in development for nearly 10 years and (evidently) the community of users have a lot of both good ideas and competence.

The monitoring thing:

 talks to a Raspberry Pi over RF, (this was an Rpi3 that I already had - I only had to buy the RF add-on) which is what does all the server stuff and is accessible over WiFi.

If nothing else, it’s like having a souped up IHD that works anywhere.

At which point, @Tim_OVO please move this energy monitoring content into a separate topic. I may not yet have time to get stuck into it immediately, but we really must keep this topic here for PV stuff which can be easily assimilated!

I’ve just started a thread already, @Tim_OVO 

New thread now combined with related comments. In case this is missed, @knight @ArundaleP @cybermaggedon @Blastoise186 you may be interested to see what Simon’s been up to here ^^

Thanks for the info @Simon1D, this is really cool.  Shame it’s not possible to get the information straight out of the smart meter or IHD, but… anyway, really cool, and the devices don’t appear to be expensive at all.

I noticed there’s a forecast.solar integration for Home Assistant which predicts an estimate of your solar capture just using your location and some internet-based metereological service.  This isn’t monitoring, it’s predicting.

Perfect. Many thanks for moving that exchange of comments, @Tim_OVO!

I can procrastinate no longer. I have a little to-do list of steps needed to finish off the setting up of my OEM system. Full disclosure (not that I’m putting pressure on myself, or anything):

• Write a Python script that does an “input/bulk” of my historic smart meter reading data (I already have these data scraped from My Ovo). Both electricity and gas meter data, for what that’s worth. (ok. I admit I’ve actually done this already, but the early Ovo gas meter data are still contaminated by those MAXINT nonsense values, and I need to clean those out intelligently. Haha - I’ll end up “estimating readings to replace missing data”. What chance I can make a better job of it than Ovo?)
• Write another script that will scrape the latest day’s data and do the input/bulk so automatically keeping the actual smart meter data up to date.
• Look into why the OEM pulse counting isn’t perfect: I assume it’s noise in the electrical signal from the optical pulse sensor, but am surprised that the spurious pulses are as many as 0.5% of the actual pulses. I took a quick look at the electrical signal, and it seems pretty clean to me. I expect that the “signal conditioning” leaves something to be desired, and I don’t see why the pulse counting can’t be essentially perfect.
• Once pulses are being counted correctly, I can more easily check and correct the calibration of the power measurement.
• Once the sensing is correct and calibrated, I’ll sort out the data “feeds” and learn how to process (analyse) them the way I prefer.

What I haven’t looked into yet is setting up the MyElectric “app” that presents a souped up IHD-like display on a web page or mobile device (smartphone, etc). This is the kind of thing that the utility company would provide, and which would change whenever one switches supplier. No longer - it would present the information I want, not what they think I want.