To talk about our approach to energy management properly, we have to – whether we like it or not – brush up on a few basic terms in order to understand everything that is to follow. We need to learn to play with these concepts to see how we can collectively manage energy in the future. Some readers might now be beginning to regret the fact that they spent their physics classes daydreaming instead of listening...
Disclaimer: this article does not aspire to be 100% scientifically correct. Some readers will argue (deservedly so) that this author is on a hiding to nothing. But don't fret: I'm not preaching anything new here.[
Here's a tip: put the 80s hit 'Electricity' by OMD on in the background while reading the uplifting words in this article.
First things first: back to school to understand a few key terms
Power: ‘What can it do?’ or: the potential amount of energy that can be supplied per time unit by a consumer (such as a device, e.g. a toaster). Power is expressed in watts (W) or kilowatts (kW). A toaster has a power rating of 920 W.
Consumption: 'What does it do?', or: the amount of energy that a consumer uses per hour while in operation. Consumption is expressed in kilowatt hours (kWh). If we toast some bread for two minutes, our toaster will have used 920 W / 30 = 0.03 kWh If you're still hungry: toasting a single slice of bread will cost you 0.03 kWh x 27 cents = €0.008.
Ampere: (A) is the unit of electric current. Electric current measures the electron flow rate through a cable (kind of like how water flows through a garden hose).
Volt: (V) is the unit of voltage that indicates how quickly electrons flow through a wire (kind of like the pressure in a garden hose...okay, so this comparison isn't the best one).
Now let's ramp things up a bit
The ampere and the volt are used to determine the power. This is why power is sometimes also expressed as VA (it's also to make people pull their hair out). If you really want to shine it on, keep saying KVA (pronounce it as kaaveeyaa) instead of kW. Power (W) = V x A. A 4 A toaster with a rated voltage of 230 V has a power rating of 4 A x 230 V = 920 W.
Keeping up? It's about to get interesting. As we know now: W = V x A
If you have a minute, go and take a look at your electricity meter. You'll see the main fuse in there somewhere. On it, it'll say how large your connected load is. Mine is 40 A. If you multiply that 40 A by 230 V, you'll see that my installation can cope with up to 9,200 W or 9.2 kW of power.
Here comes the magic
In a year, that amounts to 8.76 hours (h). Suppose you were to run it at full power for a whole year with your connected load of 40 A, this means: 40 A x 230V = 9.2 kW x 8.760 h = 80.592 kWh How about that?[Einde van tekstterugloop]You could also see it this way: I consume 4,000 kWh and if I divide that by my power (9.2 kW), that gives me the number of hours that my installation makes full use of the connected load: 4,000 kWh / 9.2 kW = 434.78 h (5% of the time).
What does this all mean?
In the distributed electricity system of the future, we will increasingly rely on renewable energy sources. We know that production of these types of energy can fluctuate. To be able to align the supply of electricity with demand during periods of fluctuation, it's very important to consume energy at the right time – when renewable production is at its peak.[Einde van tekstterugloop]In other words: drink merrily when it's raining!
In practice, however, what's happening is that I'm sitting at work eating my lunch, while at home my solar panels are busy producing energy. I'm not using the energy I generate myself. I can get around this by installing a battery for my own energy consumption needs. That's definitely drinking while it's raining. While my battery is charging in the afternoon, it becomes the consumer of the energy produced by my solar panels – so if I wanted to, I could come home in the evening and turn on all the hobs plus the oven.
You can also charge a home battery with electricity from the grid at times when this is beneficial for the grid, i.e. if there is a surplus of energy and the system has to be 'relieved' to bring it back into balance. The new legislation on setting tariffs will reward those users who connect their assets to the grid in a manner that benefits the system with the best price. You've probably heard of the famous negative prices that apply if you produce too much renewable energy.
This presents home batteries in a different light
Based on this line of thinking, a home battery system allows for a smart, ever-changing combination of the following:
- Maximum private consumption of locally generated energy (with your own solar panels)
- Avoidance of peaks in the grid (in times of peak demand, you can help to smooth it out by using your battery rather than the grid)
- Off-takes from the grid at times when the system directs it to do so (dynamic price setting reflects the conditions of the system to encourage consumers to behave appropriately). You can do this by charging your battery when you have no other need for it.
- Prevention of taking energy from or supplying it to the grid via your solar panels or battery if this is beneficial for this system
Don't worry: this entire process is intended to be fully automatic and controlled by a (home) energy management system – a component installed in your fuse box that contains smart software (that's where those familiar terms 'AI' and 'machine learning' come into play). This software serves as the basis for an energy IoT system in your home and ensures everything that needs to happen gets done. And that's all thanks to kW, kWh, A and V.