So far we've looked at ways to reduce the amount of energy we use (eg turning off lights or installing smart thermostats). But what about those "heavy" chores around the house or business that must be done?
The clothes need to be washed, the pool needs to be cleaned by the pump, the electric car needs to be charged and the water needs to be heated. You can't ask the water heater to burn 1000W instead of 4000W, nor can you "dim" it like a light bulb. The amount of energy (kWh) required for these jobs is fixed.
So since we can't change how much we burn, the engineers' solution is to change when we burn it. This strategy is called Load Shifting and is the most powerful saving "weapon" in the era of modern electricity tariffs.
The logic is extremely simple: We transfer the operation of energy-intensive devices from Peak Hours, where electricity is very expensive, to Off-Peak Hours, where electricity is cheap or even free.
Not all devices can be upgraded. You can't say "I won't cook now that I'm hungry, I'll cook at 03:00 in the morning because electricity is cheap", nor can you switch the TV on.
Ideal loads for Load Shifting are those that produce an effect that can be stored (thermally, chemically, or practically) for future use:
Gone are the days when you set an alarm to get up to press the water heater button. Heterochronization should be done automatically.
All modern washing machines and dishwashers have a Delay Timer button. You prepare the bin with clothes and detergent at 19:00 in the evening (peak time). Instead of pressing "Start", you select "Start in 6 hours". The machine will wake itself up at 01:00 at night and work on the cheap night power.
For devices that do not have their own brain (like the water heater or the pool pump), we use Smart Relays (eg Shelly Pro, Sonoff) in the electrical panel, as we saw in the previous chapters. Within the app, we make simple weekly schedules: "Turn on the pool pump every day from 02:00 AM to 05:00 AM."
This is where the price-driven automations we saw in Home Assistant come in. If you are on a dynamic (Orange) tariff, the night program is not enough, because the prices change. The smart home scans the energy market prices for the next day, finds which are the 3 cheapest times in a row (which on Monday might be 03:00 AM and Tuesday 14:00 PM) and automatically moves the operation of the water heater or car charger to the correct time "window"!
Let's make a hypothetical comparison for an electric car that needs 40 kWh to fill up, using a dynamic tariff.
We are talking about a saving of almost 70%, without changing anything at all in the way you live (since in the morning the car will be just as full).
Load Shifting is the practical application of the proverb "the smart admits, the cunning excuses". We don't fight our energy needs, we just learn to satisfy them when the market sells us energy at the lowest possible price. Proper use of "smart" relays and Delay Start can reduce your bill dramatically by making the most of modern tariffs.
Next Step: Synchronization shifts the loads to save you money on the kilowatt hour price. But what happens when too many devices turn on at the same time and the building risks "throwing" the main switch or being fined by grid operator due to huge demand?
We continue to the next technical guide, which mainly concerns professionals and large installations: Peak Shaving: What it is, how network overloads are avoided and why it concerns large installations.
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