fix 2024-07-16-energy.md

content/posts/2024-07-16-energy.md

@@ -225,3 +225,54 @@ Is that bad?
 We consumed 33.9 kWh. 
 Overall, we returned 4.92 kWh to the grid,
 but we actually put 29.7 kWh into the grid and took 24.8 kWh out of the grid at other times.*
+
+This was a sunny day.
+While we have been drawing almost 25 kWh from the grid (we use around 10 kWh on normal days),
+we also fed almost 30 kWh into the grid, for a surplus of almost 5 kWh.
+That is, despite the 2.5-fold higher power consumption than normal, we have provided a net power surplus to the grid.
+We also pulled power from the grid around noon, when solar power is usually available in abundance,
+and the hourly energy prices are lowest.
+
+# TL;DR
+
+Find a way to 
+[measure power and energy consumption](https://www.amazon.de/dp/B0054PSIDW)
+so that you know and do not have to guess.
+Collect and visialize that data using
+[Home Assistant](https://www.home-assistant.io/)
+or similar.
+
+Media power consumption is meaningless in the grander scheme of things.
+
+Household heat matters.
+- Get rid of gas, get a heat pump.
+- Cook electrically, not using gas.
+- Make sure your household devices working with heat are state of the art:
+  - Get a decent washing machine.
+  - Do not use a tumble dryer, dry on a clothes horse.
+  - Get a decent fridge/freezer combo. Make sure it is de-iced and efficient.
+- Watch out for always-on devices, but be sure to relate their energy use to the rest of the household
+
+Mobility matters even more than household heat: Driving uses way more energy than living in a place.
+- Work from home.
+- When moving, do not use a car, use a bike. Or public transport.
+- When using a car, use a small car. Weight matters.
+- When using a car, drive energy efficiently: Going 130 km/h instead of 100 km/h uses 50% more energy.
+- If you have to use a car, get rid of a combustion engine car, drive an electric car.
+  It uses 1/3 the energy of a combustion engine car.
+
+Make energy.
+Cover every surface in solar cells.
+
+Store energy.
+- Get a battery that can provide enough power for your household.
+  Power (Watt) are often a function of the number of cells, which also provide capacity.
+  A 5 kWh LFP battery often can only provide 3000 W.
+  Only larger batteries can provide sufficient power.
+- To get a household to self-sufficiency, surprisingly small batteries are needed.
+  The minimum of around 1/2 the daily power consumption,
+  or the production of a day in March or October should be sufficient. 
+  You may want more, but that is because of power, not energy content.
+- In any case, ~10 kWh LFP should be fine for most households.
+  Having more than you can fill on an early spring/late autumn day is useless, and you won't fill it Nov-Feb anyway.
+  Having giant capacities in summer is useless, because you won't empty the battery.