Minimizing grid consumption (2024 evaluation)

2024 is over. Welcome to 2025!

In October 2024 I analyzed the data YTD: Minimizing grid consumption (2). In the days after NYE I had another look at the data and noticed some irregularities. The algorithm that calculated the direct consumption percentage didn’t match with the values registered by my energy meters. I updated the algorithm and recalculated the data from 2024 to make it consistent with the values registered by the energy meters.

The good news is that things look better compared to analysis I did in October:

I closed the year with a direct consumption of 34.1%. This is a huge leap forward from the 19% in 2023! However, unfortunately I did not achieve my goal (40%).

First things first: where is the improvement coming from? As I mentioned in the previous blog, I spend my time on improving two things: car charging and heatpump planning.

Car charging

In total the car consumed roughly 6400kWh in 2024, of which 1730kWh were produced by solar energy.

At this moment I’m planning the charging of the car based on an ON/OFF mechanism. The car is charged when most solar energy is expected. Then it will charge at 11kW (full speed). What I can still improve is to take the amount of expected solar energy into account, and adjust the charging speed accordingly. This will lengthen the charge and spread it out over the day, and probably result in a higher direct consumption, especially in the summer months.

Heatpump planning

The planning of the generation of domestic hot water was already operational for a longer time. I improved some small things in the algorithm, for example, setting the maximum power consumption of the boiler at disinfection runs depending on the availability of solar energy.

In total the heatpump consumed 2650kWh in 2024, of which 739kWh where produced by solar energy.

In the last months of the year I made some minor adjustments to the planning of heating the house. As the isolation of our house is modern I can turn off the heatpump for a couple of hours without noticeable impact on the inside temperature. I’m reducing the set temperature during the night and turn off the heatpump during the six hours the EPEX energy prices are at their peak. As the heatpump is consuming a lot of energy during the winter period, when there isn’t a lot of solar energy anyway, I don’t think this will actually contribute to my main goal.

Conclusion

Unfortunately I wasn’t able to achieve my target, but I made a good step in the right direction. I made some small adjustments to the goals, hoping I can still achieve 50% direct consumption without using a battery system. As the “salderingsregeling” will end in 2027, it should still give me enough time to evaluate if there is a need for a battery system before 2027 starts.