Solar Battery Storage - My experience

About 7 years ago I did a post looking into the costings of buying battery storage to go with our solar panels. I came to the conclusion that the cost of batteries would have to halve before they would pay for themselves.

Since then the cost of batteries have continued to come down and the cost of electric has gone up (Thanks to the Russians invading Ukraine). So, nearly 3 years ago (2023), I decided to get some through a scheme which aimed to cut the cost of buying and installing batteries via a bulk buy initiative.

In the end, I got two Pylontech US3000 batteries installed with a total usable capacity of 6.4 kWh plus a Solis inverter for £5000. Still not cheap, but just manageable.

[Note: Both Pylontech and Solis are Chinese companies - A sign of the times]. 

Based on the energy savings we got in the first year of use over the previous year we saved about £410. So, assuming everything stays the same, it'd take just over 12 years for them pay for themselves. That's not bad, as long as they exceed their 10 year warranty of course.

Batteries, as my previous post pointed out, are the answer to the annoying fact that it's often impossible to use all the energy your solar panel generate, so you end up selling the excess back to the grid for a pitiful rate (Currently just over 5 pence a kWh) when compare to what they charge us (Currently over 28 pence).

Of course, that assumes your batteries can store all the excess....we probably use about 6 kWh a day and the batteries can store about 6.4 kWh, which basically means anything more than 12.5 kWh of solar energy in a day still finds it's way back to the grid. On a good day, that's up to 6 kWh.

Anyway, back to the money saving aspects. 

A little known fact about these systems is that you can program the inverter to get the batteries to store electric from the grid when the price is cheaper. For example, we have an Economy 7 plan, which means we get electric at a cheaper rate at certain hours during the night. We can therefore tell the inverter to use any spare capacity in the batteries to store that cheaper rate electric.

Now, that's not such a clever idea in the summer because you'd rather be storing the free  electric coming from your panels, but it's great for the gloomy winter months. I worked out that we can save a further £51 over the winter, which brings the pay back time down to just under 11 years.

Whether that trick is possible with all inverters, I don't know. It also assumes you're sufficiently tech savvy to do the necessary setup. Solis provide manuals and, more importantly, videos that take you through the process.

I've been looking at current battery prices and a US3000 would now cost around £820. You'd also have to get an inverter and an installer, but I'd guess that a similar system would now cost between £3k to £4k. Even better value.

When you factor in the volatility of energy prices these days - As I write this, the US and Israel are attacking Iran, pushing up natural gas prices - Solar battery storage is certainly something to consider if you can afford the upfront cost.

My EV Journey

It's been about 4 years since I last did a post here. Much has happened on the global carbon reduction front but, frustratingly, the progress hasn't been fast enough. It looks like we're going to go through the internationally agreed limit of +1.5C and, even if all countries stick to their current pledges, we're going to end up with +2.4C, which will be bad for all of us.

Two areas where there has been significant progress are a) That China, long used by western politicians to do nothing as their carbon footprint dwarfs any other country's, are making serious inroads into their CO2 production and may have peaked it already, 5 years ahead of schedule; and b) Globally, 1 in 4 new car sales are electric.

Which leads me to the subject of this post: I've just bought a used electric car.

It's a 2021 Kia Niro 3: 

Ever since I got the Toyota Prius back in 2008 (?), I've promised myself the next one would be an EV. So, I've been holding out until either new or used prices came down to reasonable levels.

The Niro wouldn't have been my first choice in terms of looks or the fact it's an SUV but there you go. The fact is, the motor industry is mostly making larger models, small car choices are limited (The good news is that small cars are on their way).

Anyway, 6 months on from buying it, here are my thoughts.

It's a good drive: It's obviously very quiet. No engine noise drowning out conversation or the very nice stereo system. It gives you instant power when you need it. No annoying delay when you put your foot down, or the long build up to full speed from, say, coming out into traffic, that you'd get from a petrol/diesel engine.

Charging: Charging from a 3 pin socket is possible but very, very slow, taking over 30 hours to charge from zero to full. So, I got a charger installed as soon as possible. They're not cheap, costing over £1000, but they make life a lot easier (10 hours to full charge if you get the usual 7kWh charger), and often add to the price of your house. UK energy companies offer special EV rates for their electric. Ovo give me 7p a kW, which is considerably cheaper than usual peak/off peak rates.

So, if you don't do long journeys, getting about is very cheap. My car gives me 4.4 miles per kW or 1.6 pence a mile. By contrast, the Prius would cost me around 11 to 15 pence per mile at today's prices.

The cost and aggravation comes in if you need to do a long journey which requires you to charge at a public charger. [Note: To keep your car's battery in good condition, you are advised to keep the battery between 20 and 80% full, which tends to force your hand a bit]. 

I tried this out on 450 mile round trip. I started with a 100% battery (Kia advise you to charge to 100% on a home charger once a month), and that got me to where I was going with 27% left. I then used a public charger for 49p/kWh which works out at around 11p per mile. Okay, I guess. However, in the UK, you have to download an app and enter your details, including credit card to do this. It's not just a swipe your card and go deal which would be much easier. As you know, you don't always get a phone signal, and technology doesn't always just work. In this case, the QR code that provided the charger's ID didn't work, so I had to find a workaround.

In the UK, there are dozens of charging networks, most requiring that you download their app even if the charger is contactless. As it turned out, I had to charge 3 times, and each was on a different network, requiring me to download 3 different apps. All 3 chargers gave me problems. The second one took an age to download the app, the ID had to be searched for, and, despite allegedly being able to charge at a rate similar to my home charger, provided me with the equivalent of a 3 pin socket, giving me an extra 40 miles after charging for 5.5 hours. The third was a fast charger and the app lost my credit card details and provided no way to add it again. In the end, I used contactless, and it worked. It was very fast to charge but cost 89p/kWh or over 20p a mile! It was a motorway service station but, I suspect, any fast charger would be expensive.

The lessons I've learnt from this are: a) plan your longer journeys in terms of where you'll charge using something like Zapmap; b) Build in contingencies in case the chargers are occupied or out of order; c) Download all apps in advance of travelling. 

This should make life easier and, hopefully, charging cheaper.

I do wonder how it's got like this though. It's like the wild west out there. Maybe the previous government thought allowing a free-for-all amongst networks would create competition and drive down prices but it's not my experience. Using Zapmap to check prices, they seem remarkably uniform, almost as if they're all checking the competition's prices to see how much they can get away with. Maybe, just maybe, this would be okay if the tech just worked but, from my limited experience and reading Zapmap reviews, it doesn't in every case. As ever, it seems to be a rush to market with flakey hardware and software, and I hate to think what the security is like for our data.

Maybe one day the cowboys will be driven out of Dodge, until then I'm going to enjoy my EV and limit the number of long journeys. 

Why zero carbon by 2050 may not be enough

 

For years now, climate scientists have been saying annual global carbon emissions need to level off by 2020 and fall sharply thereafter until it reaches zero by 2050. This is to give us a chance of avoiding catastrophic climate change.

But I get the impression that all world leaders have been hearing is “Do something by 2020, blah, blah, blah, reach zero by 2050”.

Certainly, there doesn’t seem to have been any attempt to level off emissions by 2020 (although Covid may have achieved that temporarily), there also seems to be no sense of urgency about cutting emissions sharply during the 2020’s (just more promises, and no action), but they do all agree they want net-zero by a distant 2050 (by which time they’ll all be retired or dead).

So, what if we do get to net-zero by 2050 somehow? Is that it? Job done, regardless of how we get there?

Not necessarily. Let me explain:

Look at the following graph. It attempts to show global carbon emissions from 1980 to 2050 in billions of tonnes. Up to 2020, it’s a simplified line based on actual emissions at the beginning of each decade (2020 is an estimate). Between 2030 and 2050, the line is based on what I believe the climate scientists say we need.

 

Now look at this second graph. It’s the same sort of thing but gives a potential scenario where the World takes a more leisurely pathway to net-zero.

 

What’s wrong with that? Plenty.

Let me overlay the two graphs:

The area shaded in yellow shows the difference between the two lines. Still wondering what the problem is? After all, we’re still reaching zero in 2050.

Okay, we’re agreed the lines are based on total CO2 emissions aren’t we? E.g. 19 billion tonnes in 1980, 22.5 in 1990, etc.

It follows that the area under each line in the first two graphs broadly represents the total CO2 emissions between 1980 and 2050. So the yellow shaded area represents a whole chunk of extra CO2 going into the atmosphere between 2020 and 2050 if the world’s leaders take a more laid-back approach.

But we’re still reaching zero by 2050, so that’s okay isn’t it? No.

You see, the line beyond 2020 in the first graph is based on what’s known as a “Carbon budget”. Scientists have worked out how much CO2 we can afford to add to the atmosphere before we risk catastrophic climate change. This is the total Carbon Budget. So they say we have to cut our 2020 emissions by half during the 2020’s to stay within this budget, and keep cutting as hard as we can until we reach zero by 2050.

So that yellow shaded area effectively breaks that carbon budget.

Get it? Because I don’t think the politicians do yet.