Four things household batteries can do


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Published 6 January, 2016 by Swell

"Oh the things you can find when you don’t stay behind!

Dr Seuss"

We get a lot of questions about what batteries can do. Used correctly they can be an amazingly powerful addition to our electricity grid – as well as to your home. Here are four things a battery can do. But first - think beyond the battery. Consider your whole 'home energy system'. That’s your solar panels, battery and appliances, all working together as a system.

Thing 1. Charging from solar and supplying back when grid tariffs are high

This is the obvious thing right? Adding a battery to your home’s energy system helps you use more of your solar in your house by charging up during the sunny hours and discharging later in the day. It relies on some good optimisation software to do this well.

Thing 2. Be a power station

Your home energy system can also be a mini power station. Many of the world's wholesale electricity markets are volatile, with prices soaring from time-to-time when demand is particularly high. This is certainly true in Australia. Many power stations only run during these price spikes, it is the only way they can be profitable. They use power sources that are fast to start, like gas, diesel and hydro. But a good home energy system is even faster, and can switch over to ‘export mode’, selling your stored energy back to the grid when prices are spiking within seconds. You just need a utility who will buy clean energy from you instead of just buying from power stations. The good news is many progressive energy companies are starting to do just that.

Thing 3. Be a power line

If power lines are overloaded, they melt. Of course we don't let this happen. Experts spend a lot of time predicting worst case scenarios and making sure we build power lines big enough to cope. But this is a major investment in ‘just in case’ metal that hardly ever gets used. There is a better way. A smart home energy system reduces the amount of power it pulls during peak times. It can even start pushing energy back up the line to keep it cool. In recent times 'poles and wires' companies have begun to offer money to large consumers who reduce consumption at peak times.

Thing 4. Be a balancer

Electricity systems are a giant balancing act. Electricity generators push energy into the system, and consumers take energy out. If the balance is off - for instance if consumers are drawing out more than the generators are putting in - there will soon be a black out. If consumers slowly change consumption then the generators have time to adjust the valves and keep things balanced. But what if a big power station blows a boiler or big factory fails without warning? Balance is lost, and the first anyone knows about it is when the frequency of the AC electricity changes. It should be 50 cycles per second in Australia, but this rises if generators are putting in too much energy and falls if they are not keeping up with demand. There are special markets for power stations capable of detecting these frequency deviations and responding within seconds to correct the problem. In Australia, these are part of the 'ancillary market' while elsewhere they are often called 'reserve markets’. You know where I am going with this. Home energy systems are great at detecting these frequency deviations and responding fast.

So there you have it: four things a battery can do for smarter home energy use and a cleaner, balanced grid. What do you think? We love your questions, leave a comment for us.