how to consume less? Solar, EcoJoko, batteries?

The principle? During the day, you pay the night rate (between 13 and 16 cents), but for 22 days a year, the kilowatt hour increases to 76 cents. These are usually the coldest days of the year, between November and March, and it starts tomorrow December 3, 2024!

Tempo Rouge: 76 cents per kWh

From 6 a.m., the kWh therefore approaches 1€. For a consumption of 20 to 30kWh, this costs between 15 and 20€ per day. -nothing serious, for a one-off oversight, but over 1 or 2 weeks, the bill can quickly add up. Note that red days are often consecutive, for a whole week for example – but never on weekends.

If you plug in your electric car, it's easy to consume an additional 20 to 80 kWh! And plein of a Tesla (80 kWh) then costs almost €60, or twice the price of a SuperCharger!

How to consume less?

The first step, obviously, consists of avoid using any appliances that consume a lot of energy, especially :

Obviously, a few minutes of microwave will have almost no impact. On the other hand, 2 to 3 hours in the oven (5 to 10 kWh, or between €3 and €7 per quiche!) can quickly add up to the bill!

There is also these small devices which continuously consume fairly modest amounts of powerbut over a day, this can increase the bill. For example, a StarLink dish consumes between 50 and 100W permanently, or between 1 and 2kWh per day – or around €2/day during RED periods.

Think about it: your soundbar, the television, the 5 internet terminals at the other end of the house, …Maybe on certain days we can turn off a few devices, and save a few kWh (and therefore a few euros) per day!

How do I know my consumption?

How do I know how much my house consumes? EDF and its suppliers do not, by default, offer a system for displaying consumption in real time.

However, this value is essential! If your house like 1500W continuously (24 kWh per day), it is not at all the same thing as if it requires 300/400. If you do not use a heat pump, air conditioning, or electric car and you see your consumption soaring, there may be greedy devices that consume all day (a swimming pool pump for example or an electric heating system) which it would be good to stop or delay.

However, he is possible to know the consumption in real time quite easily, in 2 possible ways:

• On the Linky by pressing the “+” key on the device until you see the index in VA displayed
• With measuring devices type EcoJoko (see our test) or even a Shelly

I really like these accessories, which are often more useful for saving money quickly, than solar panels : they allow you to become aware of your consumption and identify energy-consuming devices. At EcoJoko, we even draw up a map of the most energy-consuming devices:

But more empirically, it is very telling to see the needle fly when you turn on a small heater or a hairdryer. We can see straight away when a water heater turns on or when the car is charging: powers between 10 and 20x higher than a television for example!

Solar panels, a solution?

If you have been following our EcoTech series for more than a year, you have read this article which takes stock of the performance of plug&play solar panels (to install yourself).

Concretely, these inexpensive and easy to install kits make it possible to easily erase its consumer stub. During a Red Tempo day, even if you are careful, you will always have between 100 and 500W of permanent consumption, that's the famous heel.

By investing between 400 and 600€you can produce between 300 and 400W when the weather is nice and around 50/60W if the sky is overcast. Obviously, in winter, the production window is between 8 a.m. and 3/4 p.m.while in summer, we can last until 8 p.m.!

By increasing your production capacity (for example between 1500 and 2500W), you can even run machines, an air conditioner, your electric car or a small electric heater during the day without it costing you a cent! Despite everything, let's be honest, it's mainly in the evening that we consume, and solar power will then be of little use.

To truly be independent in this area, you need large roof installations.. We have also published a very comprehensive article on a 10kWp installation allowing you to charge your car, without paying a cent to your electricity supplier.

Finally, there is also mobile solar solutions, we had fun loading an ID.Buzz with Jackery portable panels : it works, but it's not very fast!

Batteries, really profitable?

Last solution to save a few kilowatt hours: batteries!

Today there are two types of batteries:

Nomadic batteries are in fact small portable generatorswhich can power tools, a vacuum cleaner, camping gear (kettle, hob, etc.). They charge on conventional current, or on solar panels.

Generally, they are quite expensive, 800 to 1000€/kWh, i.e. around 35 cents per kilowatt hour stored. This remains cheaper than a Red Tempo day (double), but much more expensive than a kWh at peak/off-peak rate (between 18 and 23 cents) or blue/white Tempo (between 13 and 16 cents).

It remains that if you absolutely need to use a vacuum cleaner, washing machineor an energy-intensive device during red days, they can provide several hours at high power (between 1000 and 3000W for 1 to 3 hours for the most powerful). Then simply recharge them at night…

Today, we find batteries at very reasonable pricesbut I especially recommend them if you have several uses: for doing work in places without an electrical outlet, vacuuming in the cellar, for camping… and obviously, for using gourmet appliances during the Rouge Tempo reds .

Solar storage batteries

Another type of battery has undergone a revolution in recent months: solar storage.

To put it simply, these batteries are placed between your panels and the house : they store the solar surplus and return it to your house in the evening. The idea is to come erase your heel from consumption all day long and not only during sunny periods. Ingenious, no?

With much longer lifespans (6000 cycles), the stored kWh costs between 13 and 16 cents, less expensive than EDF's lowest rates.

On paper, it's a great idea : during the day, you store current in the batteries and in the evening, you recover your investment in the house. This still requires a little intelligence, and the systems that we have tested (like the EcoFlow PowerStream) are still not very profitable, because the batteries are too expensive. You also need good power (at least 4 to 6 panels) to fill the batteries while powering the house at a minimum.

Anker Solix's solution is already more profitable, we will test it soon, just like Zenduretwo systems with 6000 cycles (only 3000 at EcoFlow) and less electronics (no inverter on the batteries, which remain in direct current), which allows lower kWh costs.