Okay, here are my numbers that I promised @timo12357 to share.
| Month | kWh | Market avg | Our avg | Diff | Diff % | Ref 1, EUR | Ref 2, EUR | Actual EUR | Diff to ref 1 | Diff to ref 2 |
|---|---|---|---|---|---|---|---|---|---|---|
| 2022-08 | 518 | 32,4 | 22,5 | -9,9 | -31 % | 204 | 119 | 25 | -178 | -93 |
| 2022-09 | 625 | 26,6 | 18,6 | -8 | -30 % | 202 | 119 | 43 | -160 | -76 |
| 2022-10 | 873 | 14,1 | 8,9 | -5,2 | -37 % | 152 | 81 | 84 | -68 | 3 |
| 2022-11 | 1034 | 24,2 | 20,2 | -4 | -17 % | 305 | 213 | 112 | -193 | -101 |
| 2022-12 | 1503 | 27,1 | 24,2 | -2,9 | -11 % | 496 | 369 | 179 | -317 | -191 |
| 2023-01 | 1369 | 8,9 | 6,9 | -2 | -22 % | 152 | 100 | 175 | 23 | 76 |
| 2023-02 | 1570 | 8,82 | 6,02 | -2,8 | -32 % | 173 | 100 | 188 | 15 | 88 |
| 2023-03 | 1723 | 8,16 | 5,76 | -2,4 | -29 % | 177 | 106 | 214 | 37 | 108 |
| 2023-04 | 975 | 6,66 | 4,66 | -2 | -30 % | 82 | 49 | 125 | 42 | 76 |
| 2023-05 | 890 | 3,28 | 2,18 | -1,1 | -34 % | 73 | 49 | 109 | 36 | 60 |
| -762 | -51 |
So this is all about optimizing the electricity usage with the same solution that Timo uses. It’s documented here, if somebody has not found the thread earlier: Control a water heater and ground source heat pump based on cheap hours of spot priced electricity - #13 by masipila
Explanation of the table above.
- The first two columns are obvious, it’s the month and our consumption in kWh on that month
- The third column is the monthly average price in Finland.
- The fourth column is showing what our actual average has been on that month compared to the market average. In other words, we have been consuming most of our electricity during hours that are cheaper that the monthly average.
- The consumption factor is the difference between the market avg and our actual avg. For example, in 2022-08 market avg was 32,4 c/kWh and our actual avg was 22,5 c/kWh so the “consumption factor” was -9.9 c/kWh.
Then to the original question “how much money have you saved”. It of course depends on where do you compare to, so I calculated a couple of scenarios.
Reference cost 1 has the following assumptions:
- I would have a dynamic tariff / spot price contract with 0,38 c/kWh margin (this is the cheapest margin that I was able to find today when I quick compared the dealers)
- I would not have any scheduling for the consumption so our monthly average would be 20% above the market average because most of the consumption would happen during the day when the spot prices are usually above the monthly average.
- I have no idea if this 20% is the correct factor for this since I’ve never had a spot price contract without doing schedule optimization.
Reference cost 2 has the following assumptions:
- I would have a dynamic tariff / spot price contract with 0,38 c/kWh margin
- Our consumption is optimized to the cheapest hours like it has been since last summer
Our actual cost is with the Väre Välkky contract type
- With this contract type I share the price risk with the dealer so that our price is 14,8 c/kWh +/- consumption factor
- In other words, if we consume electricity during an hour where the spot price is below the monthly market average, we get discount for the whole month’s consumption. If we consume electricity during an hour where the spot price is above the monthly average, our price / kWh for the whole month increases.
- Väre was the only company having this contract type last summer but now also Helen has this same contract type (Helen Fiksusähkö) and Fortum has it (Fortum Duo)
So how much have we saved… Compared to reference cost 1, our cumulative saving so far is 762 EUR. Compared to reference cost 2, we are still on the saving side by 51 EUR.
Now that the prices are back to normalish, we will most probably end up losing against reference cost 2 in the 24 month contract period that we have, but I consider that as the price of the “insurance” that we decided to take last summer when the hell broke loose in the energy market. When the 24 month contract ends in a year from now, we will for sure go to a pure spot price contract and continue the schedule optimization.
Edit: I forgot to mention that we got an electric vehicle in 2023-02 so the consumption went up.
Edit 2: Table formatting
Edit 3: Fixed copy-paste error from May 2023