The saying goes that the last decade was about deployment of renewables and this decade is going to be about storage, but why.? Storage made sense if you had an electric vehicle and this was the early usage, charge the storage during the day and then charge the car overnight but this is evolving and you are now seeing Telsa saying that will not deploy solar without storage. What we are talking about here is edge storage.
In the UK the cost paid by the utilities for renewable electricity is something of the order of 4p to 6p which is roughly a 1/5 or a 1/4 of what it will cost you to buy electricity and this is based on an estimate as the technology is not deployed to support actual delivery. The ability to assess the true situation must wait on Elexon to complete its new system that will offer 1/2 hour billing so in the meantime if you can store energy during the day you can use this to offset your usage when you need it, at night or in the morning and reduce your need to import electricity later in the day.
One of the main drives has been the evolution of battery chemistry. Deploying Li for storage didn’t really may sense due to the high cost and lower life cycle but we now have seen LiFePO4 become readily available and these are much better suited to this use. What LiFePO4 offers is lower cost and higher cycle capacity, the order of 3000 or so. Their weight penalty is not really a penalty when it comes to station use and these seem a much better fit. This is why we are seeing them become the dominant chemistry for stationary storage.
As the sun doesn’t just shine for a couple of hours and the wind doesn’t blow based on a schedule this is more of an issue at grid scale and this leads to what is called curtailment, where the utilities ask the renewable providers to go offline. The issue with this is that they have to pay for this and the cost of this have been in the 100s millions over the last couple of years. This is a separate issue requiring grid-scale storage.
Longer term (or even now) we are starting to see distributed power stations which puts the distributed energy storage under the control of the utility. They can then use it to offset peaks which we’ve seen has been very effective in California this summer in contrast to the UK where they were forced to rely on importing energy to keep the lights on in London.
This is important from two perspectives: the first is that the development of true micro-grids is some time off although you are starting to see these in Australia. The other is that areas like London are becoming constrained by the existing infrastructure. The ability to use local storage and distributed power stations eases this based on the existing infrastructure and provides the time to address the wider issues.
It is not only the main infrastructure that is constrained but we are also seeing this where electric vehicles need to be charged in remote locations such as service stations but there is an infrastructure constrained. Instead of upgrading the power feed, a battery can be deployed and ‘trickle’ charged, which is charged at a lower rate and then used to charge vehicles at a much higher rate. Such an approach can be used in the home making use of low overnight tariffs supporting a reduction in curtailment to charge the house system in order to improve the overall efficiency while also lowering the cost to the consumer.
So the ability to shift store energy so it can be used later is going to be really important — the cost of solar has come down significantly over the last decade but also the rapid evolution of battery chemistry now makes this practical.
PS a friend recently pointed out that batteries are not the only option for energy storage and water can also be used for storage. There are now several options in this space and some also remove the need for a water storage tank.