This is the title of an interesting article by Finn Peacock, an industry consultant and strong advocate of solar energy. The following is a much shortened version. The link to the original article is given below.
The top 6 battery myths
Myth #1: Batteries improve the economics of solar power
Many Solar PV owners look at the feed-in tariff, and mistakenly consider this a rip-off and incorrectly conclude that Solar can’t pay for itself without a battery. They refuse to virtually give their electricity away to the ‘evil’ grid!”
The truth is that at current prices, for the vast majority of Australian homeowners, batteries will not pay for themselves before the warranty expires. And when buying a solar power system, if you add batteries, you’ll make the payback of the system as a whole worse – not better.
Myth #2: Grid-connected batteries save you the full cost of buying grid electricity
Q: How much do you save, per kWh, if you store your solar energy in a battery and then use it at night?
A: Although you save 30c (or whatever your usage tariff is), by not drawing a kWh from the grid, you are, obviously, not now exporting that kWh to the grid. So you are losing the feed-in tariff on that kWh. In fact, it’s a bit worse because every time you charge and discharge the battery, you lose ten to thirty per cent of your energy to battery inefficiencies. (Note: there are also significant additional costs in the way batteries actually operate).
Myth #3: Batteries reduce your carbon footprint
If you have a grid-connected solar power system that exports surplus solar electricity to the grid and you add batteries, you actually increase your home’s carbon footprint.
If you don’t have batteries, any excess solar energy gets exported to the grid. While you may be disappointed with the feed-in tariff this pays you, the environmental benefits of your exported solar electricity are very real. Each kWh you export means that the grid has to generate a kWh less from fossil fuels. You should feel good about that.
However, if you have batteries on your home, every kWh you put into the battery is one less that goes into the grid. So although your stored solar means that you have to import one less kWh, it also means that you’ve exported one less kWh. So there is no net environmental benefit.
In fact, because a battery system is only seventy to ninety per cent efficient2, you are offsetting ten to thirty per cent less CO2. And you also have to repay the large amount of CO2 emitted in the manufacture, delivery and installation of the battery and battery inverter.
Myth #4: All batteries can provide blackout protection
Running a home without the grid is quite a complicated task, because you need to:
- Isolate the house safely from the grid, so you don’t send electricity into the grid and kill lineworkers trying to fix it.
- Balance all the generation and loads so that you match supply and demand at all times.
- Ensure that the battery is never overloaded by the house loads.
- Ensure that the battery is never overcharged from the solar.
All this functionality comes at a cost. So if you are buying a battery and want blackout protection, be sure you are getting a system that will actually do that3
Before you do that, however, you should have a think about how big a problem blackouts are for you, and consider other, much cheaper, solutions such a diesel or petrol gen-set
Myth #5: You need a specially designed solar system to add batteries in the future
If you are thinking that a ‘battery ready’ solar system might be a good idea, that is a great idea. And the good news is that every grid-connect solar power system ever sold in Australia is ‘battery ready’.
Myth #6: Adding batteries to your solar is sticking one finger up to the electricity companies
You may not realise there are actually up to four companies that are responsible for getting electricity to your house and they all get paid from your bill. Let’s explore who they are and see which ones we really have the bad feelings for.
The 4 companies that you pay through your electricity bill. Image credit: SAPN
Generators own the power generation fleet, be they coal-fired power stations, wind farms, gas power stations or hydroelectric systems.
Examples are AGL Energy (who are also a retailer), who own lots of coal, gas and wind, Origin (also a retailer), Snowy Hydro and a handful of others. These earn an average of 22% of your total electricity bill.
Transmission networks get about eight per cent of your bill. They are the companies that build and maintain those big pylons that carry electricity from the big generators to the big substations near population centres. Their formal name is transmission network service providers
Below are the details of local TNSPs:
They are a large part of ‘the grid’ and enable coal-fired power stations to distribute their power, but they also make wind and solar farms and the snowy hydro scheme viable.
Once the electricity leaves the transmission network, it uses the distribution network to get to your home. The companies that own and operate the distribution network are called the distribution network service providers (DNSPs). These guys get about thirty per cent of your bill.
Below are the details of your local DNSPs:
The last company in the line is the Electricity retailer, (Note: which includes Pooled Energy, which is the only retailer that actively works to reduce your electricity and chemical use, and labour costs associated with the pool.)
Conclusion: Should you add batteries?
Not yet. The technology, the capacity and the costs are not there yet
The full article by Finn is here https://www.solarquotes.com.au/blog/solar-battery-myths/
Overall, the Pooled Energy system looks to the Grid like a vast distributed battery at a tiny fraction of the cost. There is no more efficient thing than saving energy and Pooled Energy both saves it and manages it.