What Is Home Energy Storage? The Power Behind Your Outage

What is home energy storage - featured image

Did you know there are a number of ways in which you can benefit from home energy storage or home batteries? In this post and video we will discuss all of them.

To see how home battery can profit you the most we will briefly look at the prices of some of the popular batteries in the market, and lastly we will tell you about an option that is low cost, not well known but is extremely beneficial. Now there are at least five ways the batteries can benefit you, so let’s look at them one by one.

Home energy storage is the use of a battery bank, typically lithium-based, as a store of energy that can be be used during power outage. Home energy storage is particularly useful for maximising the output from a solar PV system, when electricity can be stored during the day and used at night when there is no solar production. Home batteries can also be charge from the grid and used during power outages.

What are the benefits of home energy storage?

Number one is maximizing your solar or wind installation output. Say you have a solar installation on your roof. It turns out that you are generating most electricity during part of the day when you’re not at home. If you have a grid-tied system that extra electricity would go to feed the grid, because the generated electricity is not being utilized.

When you come home in the later half of the day solar isn’t producing anything and you have to buy electricity from the grid. Now that doesn’t make sense, does it?

Even if you sell electricity to the grid, chances are that you’ll be buying back at a higher prices, so the best option is to utilize energy that you have generated to fill your own needs first before you export it. A battery allows you to do exactly that.

Benefit number two is buying electricity from the grid when it’s cheap. True home battery systems one can buy maximum units of electricity from the grid when they are low in price. For example, in the UK off-peak energy can be purchased for as low as 8 pence per unit, whereas energy during the peak times is as high as 22 pence per kilowatt hours.

This is if you’re on an electricity tariff plan like economy 10, or economy 7. Why do we have cheaper tariffs? It is because some power plants, especially coal and nuclear, cannot be completely shut down and they keep producing electricity in the late hours of the night when the demand is extremely low.

Utility companies incentivize the use of this off-peak electricity by offering much cheaper tariffs on it during those times. Through home battery use one can buy cheap electricity and even sell it back to the grid during peak times.

What is home energy storage?

Of course, you will have to ask the local utility company to ensure that this practice is applicable as rules are different in different parts of the world. Also, make sure that the battery pack provides this functionality in its software.

Benefit number three is monitoring energy usage. New home battery systems come with great tools that allow you to monitor:

  • what you are currently consuming
  • what you’re currently generating
  • how much of the electricity is going to your home or your car, and
  • how much you are using from the grid

The availability of this information alone on your phone 24/7 can help you optimize your energy usage. You can cut down drastically the consumption of electricity just by being aware and by taking simple steps.

For example, you can reduce the usage of appliances that cause a spike in your energy charge, like only boil enough water that you need, or you charge your electric car when it’s more feasible to do so. Also selecting the best source for it, that is grid or battery.

Use home batteries to help the grid

Benefit number four is that batteries help the grid, which in turn helps you. The future of electricity will be based on a smart grid, for which the presence of home energy storage is very important. When you plug in your home battery you are in a way helping the grid to increase the electricity buffer, as you might be aware, for the national grid.

Power plants try to generate energy as it is needed. This keeps the grid frequency of electricity in check and also reduces the wastage. However, it poses another problem, because sometimes it’s difficult to keep with instantaneous demands that are out of the normal pattern.

What is a V2G bidirectional charger?

Batteries in this case can help the power generation sector by providing electricity when the grid needs it. They take the edge off the sudden increases in demand. In fact, even electric car battery packs can be used for this purpose.

Use lectric car(EV) as a home battery
V2G – using electric cars to store energy

The vehicle to grid systems, or V2G, as it’s called, is already in place in at least four countries. The charger of vehicles used for V2G are two-way chargers. As we know, automobiles spend 95 percent of their time being idle – this idle time can now benefit the grid.

It’s a revolutionary idea that will make a grid system much more efficient. Furthermore, we tend to switch off our large wind farms when they’re producing too much. A grid that is connected to thousands of battery packs can allow that energy to be stored.

Home battery backup power

Benefit number five is backup power. Last but not the least, batteries can provide you power in case of grid failure. This may not be a huge advantage for those living in urban areas but it can be a lifeline for people who live in remote corners of the globe.

Grid failures are frequent in such areas. A great example of this is the Isle of Eigg in Scotland, which was one of the first island to go for 100% renewable energy. They now have two whole days of backup power, thanks to the battery systems becoming affordable and robust over time.

Those are the five ways in which home energy system can benefit you. It has to be mentioned that if you own a electric car, then the gains of the home battery are even more pronounced, as your consumption of electricity is much higher.

Are powerwalls worth it?

If you look at some of the top-of-the-line lithium-ion battery packs in the market, from the power wall to the LG Chem 6.4, the Solax Hybrid X1 and the Powerwall 3. The Tesla Powerwall is a cut above the rest when it comes to value.

Not only it has the lowest price per kilowatt hour but there’s also a warranty period of 10 years. The upfront cost, however, is very high. This apparently makes a compelling case for deep-cycle lead-acid batteries, for their low upfront cost is at least 4 times lower in price per kilowatt-hour.

But do remember they only have a fifth of life and their round trip efficiency is also poor. If you put one kilowatt into a lead acid battery you get back approximately 0.8 kilowatt hours. Whereas with lithium-ion you get around 0.95 kilowatt hours back.

The only thing that undercuts Tesla in price are Chinese companies. Their lithium ion battery packs are, believe it or not, less than half the price per kilowatt hour when compared to Tesla Powerwall. The functionality, however, of these Chinese batteries is limited, and also the warranty period is short.

Finally, as promised, I want to tell you something exciting that has only recently arrived in the energy market. It is the thermal battery. The idea here is instead of storing electricity we store heat and use it when we need heating. How can this be a game-changer? Well, in cold climate areas more than 50% of our energy use goes into space and water heating.

Say you have excess energy from solar panels that has nowhere to go. Well, now you can store that energy as heat. The system is even more efficient if we charge the thermal battery through a solar water heater.

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