The concept of backup power has been around for a very long time, but people have not taken it seriously as a reliable source of power for several reasons. In the earlier days of 2015, though, Tesla came up with a new device known as the “Powerwall” that could change the way we think about consumer-level electricity. The company has been entering the energy storage market for some time already, and it looks like it’s very serious about trying to bring about a very solid change in battery technology that could make more affordable and reliable rechargeable units in the near future. But is the Powerwall able to live up to expectations, and – more importantly – can we actually power a house with a battery at all?
Analyzing a House’s Power Needs
For a decent large apartment, the average consumption of electricity can be anywhere from 100 kWh to 800 kWh, depending on what devices are installed and the habits of its inhabitants. This is kind of why it’s very difficult to gauge exactly how much electricity we must account for when determining the amount each person needs. When in doubt, it’s better to stick to the maximum in the range if you are designing a battery that can power it for a particular period of time. Tesla’s Powerwall battery has a maximum capacity of 10 kWh.
According to the Energy Information Administration, the average American consumes roughly 10908 kWh each year, which is roughly 909 kWh per month. Per day, that would be around 31 kWh. Worldwide, that average is around 3,500 kWh per year, which is around 9.58 kWh per day.
Take note, however, that these are averages and don’t necessarily properly represent each household. Given this data, we can conclude that the Powerwall battery might be appropriate to power a house for one day in certain circumstances, but many households would only be able to use it as a backup unit for a few hours in case of a loss of power.
So far, we’ve only spoken about storage capacity, but there are other hurdles that a fully-functional house battery would need to overcome.
Addressing Other Challenges
Whenever we talk about electrical infrastructure inside of a home, it’s important to address the particular nominal power capacity of its setup. Can the wires handle the demand from the appliances connected to them? Assessing a battery is no different. Tesla’s Powerwall has a current capacity of 5.8 amps, with a peak output of 8.6 amps. That’s very typical of lithium-ion batteries, and it’s sufficient if you plan to run a toaster. But if you want to turn on an oven that has a heating element with 2.4 kW of nominal power while you’re washing clothing and browsing the Web on a desktop computer, the battery is practically toast.
At this point, given the current capabilities of supplementary power supply technology, I don’t necessarily see its viability at present. For batteries to have a convincing impact in the way houses are powered, we would need to apply a different type of chemistry with a higher drain capacity. Circuit breakers are often capable of handling up to 32 amps of current, but the best lithium-ion technology can give us is roughly 15 amps of drain capability. Batteries aren’t built with houses in mind, which means that we’d have to reinvent them completely.
Yes, you could run two or even three of Tesla’s batteries together, but there is yet another problem: Each battery will have a different rate of decay, and when one is drained completely, the other might still have power left. Since you can’t tell which one has decayed more over time, you might end up speeding up the process of decay by powering the house with both batteries at the same time when only one of the batteries has any amount of power left. Asking for power from an already-drained lithium-ion battery is very detrimental for its health.
Don’t misinterpret this harsh analysis for a definite “no” on the technology, though. This is a stepping stone towards creating a very versatile and worthwhile backup power solution that could inspire people to install renewable energy in their homes. What do you think? Is this even a proper pursuit? Let us know in the comments!