Logging electric/gas usage and solar generation... Anybody else done it over years?

samcat · 16 Mar 2022 at 11:51

Been a project since we moved house, trying to better understand usage and generation and the impacts of any changes.

We originally had 1kWp of solar, upped to 2kWp July 2019.

This is my SEG (solar electric and gas) logging from the last 6 years, an overly complex excel sheet I created for myself:

I also chart sun hours (2nd axis) against the solar and electric (as it directly influences solar generation averages). Average temperature (2nd axis) is mapped against gas usage (again, directly influences it).
July 2019 we increased from 1kWp to 2kWp of solar, hence the jump in generation.

Last years power usage was anomalous but expected.

New boiler early 2021 which has reduced gas usage a bit.
We are booked in to have the (leaky) double glazing replaced, which should again help keep the house warmer.
Ewi is being discussed this summer, as the green building people have said time and time again - Insulate insulate insulate!
We are also in discussion around adding lots more solar and a battery, the maths seems to stack up, would be looking to around 8-10kWp total (SE/SW split 65:35)

Does anyone else log/monitor it against changes? Always interested in seeing how others tackle this, and how real world changes/improvements stack up.

dirtychinchilla · 16 Mar 2022 at 12:05

That's very interesting. I'm logging our gas and electricity usage, but we don't have any renewables. Unfortunately I only started doing it a few months ago, so no particularly exciting data to show.

However, in the summer I plan to install some PITRVs on all our rads and return temperature limiters on the towel rails, so I'm hoping to have a nice comparison between before and after.

samcat · 16 Mar 2022 at 12:13

dirtychinchilla said:
That's very interesting. I'm logging our gas and electricity usage, but we don't have any renewables. Unfortunately I only started doing it a few months ago, so no particularly exciting data to show.

However, in the summer I plan to install some PITRVs on all our rads and return temperature limiters on the towel rails, so I'm hoping to have a nice comparison between before and after.

Nice!

A tip for you, keep as much granular data as you can.. I have daily data saved (so can see how much energy we produced or consumed on any given day).. I *wish* I had hung onto the 5 minute data from years back when it was available, but didnt... And now its gone, can only get the newer stuff.
Its easy to have the data and not use it, its impossible to get it again once its gone.

Learn some python and get it to hook into your energy provider, pull the data down and save it that way.. Much easier! And keep a simple log of what you change on your house and when (simple date and what changed), at least then you can correlate changes and see any relationships.

Enjoy the journey, its fun!

Journey · 16 Mar 2022 at 12:21

Very nice data set, I have some data so far but nothing worth doing anything yet, although I will hang on to it and try to make something as useful as what you have shown. I'll probably need to plot EV mileage for each year and mpkWh against it as well, otherwise it could make the usage look off.

SDK^ · 16 Mar 2022 at 13:24

I've just signed up to Octopus Go which provides electricity usage data every 30 minutes into a downloadable CSV file from their customer website portal. I also have a couple of plug usage monitors tracking the power use of my two 300w aquarium heaters.
Will be interesting to see the winter vs summer usage at the end of the year.

samcat said:

What was the spike on your March 21 Electricity use?

samcat · 16 Mar 2022 at 13:54

SDK^ said:
I've just signed up to Octopus Go which provides electricity usage data every 30 minutes into a downloadable CSV file from their customer website portal. I also have a couple of plug usage monitors tracking the power use of my two 300w aquarium heaters.
Will be interesting to see the winter vs summer usage at the end of the year.

What was the spike on your March 21 Electricity use?

We had some heating issues so had to chuck oil filled rads on.. air leaky detatched house. So yeah, ouch.

dirtychinchilla · 16 Mar 2022 at 14:43

samcat said:
Nice!

A tip for you, keep as much granular data as you can.. I have daily data saved (so can see how much energy we produced or consumed on any given day).. I *wish* I had hung onto the 5 minute data from years back when it was available, but didnt... And now its gone, can only get the newer stuff.
Its easy to have the data and not use it, its impossible to get it again once its gone.

Learn some python and get it to hook into your energy provider, pull the data down and save it that way.. Much easier! And keep a simple log of what you change on your house and when (simple date and what changed), at least then you can correlate changes and see any relationships.

Enjoy the journey, its fun!

Hah I would love that, but I'd have to read the meter myself every date. Ovo Energy does give me granular electricity data, but not gas. I don't honestly think I'd do anything with it if I could.

Funnily enough, I'm in the process of launching an building energy portfolio management tool at work, which would ideally give you all that granularity.

So are you reading everything from an API? Could you go into a bit of detail because it's something we'll be facing with this new tool.

samcat · 16 Mar 2022 at 15:19

dirtychinchilla said:
Hah I would love that, but I'd have to read the meter myself every date. Ovo Energy does give me granular electricity data, but not gas. I don't honestly think I'd do anything with it if I could.

Funnily enough, I'm in the process of launching an building energy portfolio management tool at work, which would ideally give you all that granularity.

So are you reading everything from an API? Could you go into a bit of detail because it's something we'll be facing with this new tool.

Growatt inverter for the solar, got into it using the API on their own website, bit of probing/logging what it does and mimicking it in my own python.
Exactly the same with Ovo.

They dont do anything clever, and replicating the api calls/behavior works until they change something and break it (ie its their own API, and not something publicly published)

dirtychinchilla · 16 Mar 2022 at 15:21

samcat said:
Growatt inverter for the solar, got into it using the API on their own website, bit of probing/logging what it does and mimicking it in my own python.
Exactly the same with Ovo.

They dont do anything clever, and replicating the api calls/behavior works until they change something and break it (ie its their own API, and not something publicly published)

Very good. I would have absolutely no idea what I was doing. Do I need granular data? I'm not sure what benefit it would give me at this time.

samcat · 16 Mar 2022 at 15:38

dirtychinchilla said:
Very good. I would have absolutely no idea what I was doing. Do I need granular data? I'm not sure what benefit it would give me at this time.

Daily/Hourly/more granular can show you specifics/bad habits/something odd etc whereas the daily/monthly shows you trends.
The problem with the more granular data is its noisy.

Gas and Electric 2022 to date:

You can see the noisy nature of it, and thats only daily data. But the very nature of granular data lets you spot that something odd happened:

(thats electric bill column, 'Someone' switched on and left on an oil filled radiator )

Swings and roundabouts. Daily detail is probably enough for most uses/needs around gas/electric.

Solar is different.. 14/03/2022:

This shows solar generation by 5 minute interval... You can see where our panels are located a very specific 'switch on' time.. Its useful knowing this as it lets us time our electric loads that can be timed (washing, drying, dehumidifier etc).

You can also see the builders over the road did something that caused a momentary power outage.

dirtychinchilla · 16 Mar 2022 at 16:01

OK I can see how that might be useful! I wonder if you'd be able to connect any of your appliances to automatically react to this signalling.

In the wider industry, it's something that's under development i.e. prioritising heat pumps when the grid has a low carbon intensity to charge thermal stores. If you do have stored hot water, you could be using excess solar energy to heat water, unless you are fortunate enough to have an export tarrif.

samcat · 16 Mar 2022 at 18:35

dirtychinchilla said:
OK I can see how that might be useful! I wonder if you'd be able to connect any of your appliances to automatically react to this signalling.

In the wider industry, it's something that's under development i.e. prioritising heat pumps when the grid has a low carbon intensity to charge thermal stores. If you do have stored hot water, you could be using excess solar energy to heat water, unless you are fortunate enough to have an export tarrif.

Got a solar immersion booster in place already, so immersion takes us down to approx 50 Watts export, rest used as low grade energy (hot water) reducing our gas bill a bit.

Working on a simple pi based energy monitor, plan is to feed that into ifttt to make choices around the home.. Switching on aircon/laptop chargers, turning on mining/changing card profiles/energy limits etc.

Troop · 16 Mar 2022 at 22:19

Victon Venus web portal logs your data day/week/month etc.(yesterdays data)

Semple · 17 Mar 2022 at 06:51

dirtychinchilla said:
OK I can see how that might be useful! I wonder if you'd be able to connect any of your appliances to automatically react to this signalling.

That's the general premise of a smart home

, having the house decide when to power stuff up based on consumption/generation.

samcat said:
Working on a simple pi based energy monitor, plan is to feed that into ifttt to make choices around the home.. Switching on aircon/laptop chargers, turning on mining/changing card profiles/energy limits etc.

I'd suggest looking at something like Home Assistant for triggering your automations. Ifttt is a bit... basic.
There's been a heavy focus on energy management over the last 6 months, so they've got some nice dashboards and ways of displaying energy data.

john_smith · 17 Mar 2022 at 07:07

I've recorded my solar generation and electric consumption, monthly, since 2011.

dirtychinchilla · 17 Mar 2022 at 08:04

Semple said:
That's the general premise of a smart home , having the house decide when to power stuff up based on consumption/generation.

Yes, but virtually no one is doing it. Commercial heat pumps, for example, don't really run like that yet.

b0rn2sk8 · 17 Mar 2022 at 08:13

I’ve got my meter reading a going back to when I first bought our house. While they are not consistent in terms of the frequency, they are good enough to track usage.

It’s quite interesting looking back, I can see that we are consistently using at least 10kwh/day less gas than last year. It’s amazing what a bit of insulation and turning off a radiator in the spare room will do to your bills. I still have about 1/3 of the loft to do which is boarded directly onto joists so it’s bigger job.

Electric on the other hand has gone up significantly but that’s due to an EV purchase.

samcat · 17 Mar 2022 at 08:13

dirtychinchilla said:
Yes, but virtually no one is doing it. Commercial heat pumps, for example, don't really run like that yet.

Always thought the grid is missing a trick, should have specified that the grid can talk to inverters so the grid can manage the amount of export wanted (simply my shunting it around the MPPT curve you can vary generation/export. Obviously cant add, but can always reduce).
At times they have excess supply which can cause issues.

gc123 · 17 Mar 2022 at 18:50

slightly off topic but noticed today , martin lewis is recomending reading your meters on the 31st (for us non smart).
so when the cap goes up we dont get sneakily charged for energy at the new rate we already used.......