G’day, Dr Karl here.

We are currently in a state of Energy Flux. Electricity supply is shifting to renewable sources, so batteries are becoming very important. It’s still early days for batteries, and a few weird situations are popping-up. For example, can you believe that it might be cheaper to power your whole house from your electric car battery, rather than buying batteries specifically designed for houses?

A battery supplies electrical power, thanks to chemical reactions. These reactions start with high-energy chemicals, and convert them to lower-energy chemicals. Some of the difference in chemical energy is turned into electrical energy.

The word “battery” was coined by Benjamin Franklin in 1749. He used the word “battery”, in the military sense of a bunch of weapons working together.

The word “battery” can mean either an individual electric cell, or a group of electric cells linked together.

The first electro-chemical battery was developed by the Italian physicist, Alessandro Volta, in the year 1800. It was a stack of zinc and copper plates, separated by paper soaked in salt water. These batteries were not very practical.

By 1836, John Frederic Daniell invented the first practical battery - it was reliable enough to power the electric telegraph networks. The Daniell cell had a copper sulphate solution inside a copper pot, which in turn, sat inside a container filled with sulphuric acid and a zinc electrode.

Electric battery technology had advanced enough that by the early 1900s, some of the early mass-produced motor vehicles were powered by electric batteries. But liquid fossil fuels had a much greater energy density, which was a huge advantage.

A kilogram of petrol holds about 46 MJ of energy. That’s about 25 times more than a kilogram of lithium metal battery, which holds only 1.8 MJ of energy.

Raw energy is one thing, but efficiency is another. With petrol, only about one third of the energy in the petrol ends up pushing the car down the road – the rest is wasted as heat.

But with an electric battery, about 90% of its energy will drive the car – that’s a three times increase in efficiency.

Let’s say that it takes about 100 kWh to run a house for about 10 days. And now let’s talk about powering that house with batteries.

If you buy a set of popular home batteries with roughly 100 kWh capacity, that would cost you about USD $73,000. That’s a lot.

But say instead you buy a ute, specifically the best-selling car in America for the last 4 decades, that just now has been released in a fully electric version. This ute comes with a 100 kWh battery, but costs only about USD $42,000. It’s also set up for V2G (standing for Vehicle-To-Grid), which means that the car can both recharge from the grid, as well as send electricity to your house to power it.

So for USD $30,000 less than the dedicated home batteries, you get enough battery to run the house and a twin cab ute thrown in for free.

Of course, you would need some re-wiring to your house, which would cost another USD $6,000. But you would still be USD $25,000 ahead of buying the dedicated home batteries.

The car company is overwhelmed with orders for their electric ute, and has sold them all until the end of 2023.

Now the car company has to be making a profit. And the home battery company? Well, they must be making a huge profit – perhaps more than just a reasonable one.

On one hand, with Economies of Scale kicking in, electric batteries are going to become much cheaper. Plus at the same time, new technology has already made laboratory prototype lithium batteries that are much more powerful in terms of energy-per-weight, and also other lithium batteries that have much shorter recharge times. And the latest surprise finding is not only can the lithium batteries be recycled very efficiently, but that the recycled batteries actually perform better than the original batteries made from virgin lithium.

So … floor the ute, and heat the floor – all from the same car battery – it might be why they’re called a ‘utility’ vehicle.

Electricity supply is shifting to renewables, so batteries are important.  It might even be cheaper to power your house with the battery from your electric car, rather than batteries specifically designed for houses.

Published: 26 Jul 2022Tue 26 Jul 2022 at 11:15pm / with Dr Karl Kruszelnicki

Published: 19 Jul 2022Tue 19 Jul 2022 at 4:56am / with Dr Karl Kruszelnicki

Published: 13 Jul 2022Wed 13 Jul 2022 at 3:39am / with Dr Karl Kruszelnicki

Published: 4 Jul 2022Mon 4 Jul 2022 at 4:12am / with Dr Karl Kruszelnicki

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