Mrs Sun has got her hat on

So, nothing about politics today.  Schtum. Zip. Not a dickie bird. Not that anyone is reading this as you’ve all left me. I don’t blame you.

However, I do have something … something I knocked up for an old army pal of mine I had coffee with on Friday. He runs ecovision systems, a forward-looking energy business that supports domestic and industrials. If you need solar panels, ground or air-source heat pumps, or a hassle-free boiler, he’s your man. If you mention me I might get a free beer when we next meet. Anyhow, the blog is about fitting (or not) solar panels to your house.


could be the Canal du Midi

For the record we had C’s sister, Annie, down for the weekend which included a lovely walk along the Sharpness canal. If the weather stays like this, we might have to reconsider our plans to up-sticks and live on the Med? It’s a thought.

Be back mid-week. I hope you’re enjoying the weather, wherever you are.


Domestic solar panels – a decision of conscience?

Do you remember Mr Barnard’s science lessons? No? The ones with volts and amps. And whats? No, sorry. Watts. Do you remember him explaining the difference between energy and power? I think he made a lame science joke about joules not being a fashion brand, but something much, much more important: energy, I think. And then we got round to batteries and direct current (and we licked a small battery and got a shock?). Then the stuff that comes out of the wall was … I remember now: alternating current. Which was flippin dangerous and, ‘no, Jimmy, don’t put your tongue anywhere near that’.

Now fast-forward and ask yourself the question, ‘should I put solar panels on my roof?’. It’s a sensible question. After all, the planet is in the oven and browning nicely. We’re losing 50% of our insects. I haven’t seen a hedgehog since I was twelve. The Arctic is melting and, as a result, the ‘mare’ in Weston-super-Mare is soon going to take on a whole new meaning. And energy costs are only likely to go up.

Right up to date, this week somebody with a brain in government has said that in six years’ time we shouldn’t be fitting new houses with gas – a carbon rich fuel. Electricity is the future; which we can steal from the wind. And, if we remember Mr Barnard’s class, solar panels push out electricity. Although, to add to the confusion, even that is not strictly true. You can get solar panels that heat up the stuff like they use in the back of your fridge which, in turn, warms water for your showers [you don’t take baths, of course, because it’s more eco-friendly to shower].

Good. Panels it is. They’re old technology so it’s not a though we’re hanging around for the faults to be ironed out. On, on.  

So, where do we start? Well, IKEA do them – seriously; they’re flat and they come in a pack.  So do tons of other companies. Get three quotes and make a decision?

Mmm, maybe. Let’s give it a bit of thought.

First, dispel any notion that solar panels are only effective in the Sahara. (Actually solar panels become less effective if they get very hot). If the sun is up, pointing at your roof – and even in cloud – your panels will generate electricity. On a sunny day, mid-summer, listening to Jeremy Vine, a half-decent set of panels would run most of the appliances in your house – at the same time.            

In winter, output will drop considerably. In January your system will likely be only 10% as efficient as the same panels in June. But they will give you something. Free electricity generated by Mrs Sun.

And let’s skip over: they’re bog-ugly; for most homes you do not need planning permission; and the collective view is that they neither add to, nor take away from the value of your home. Buying £5k’s worth of solar stuff is not going to add £5k to your the selling price of your castle. And let’s ignore whether your roof faces the sun (you really need a south or southwest aspect), whether it is at the ‘optimum pitch’, and whether your neighbour has planted a series of towering leylandii between your roof and the fiery furnace. We’ll assume all those things work on your favour.

And we’ll ignore government subsidies (feed-in-tariffs) which they pay you for fitting panels. Because, whilst as I pen this the subsidy currently adds up to around to a measly £150 a year, they are stopping at the end of March (2019).

Instead, we’ll go back to school. But not for long as it’s crazily complicated. Panels are pretty standard, although you pay for what you get. On average a single panel delivers around 330 watts (on the second Tuesday in June, at midday). That makes an average domestic series of twelve panels about 4 kilowatts, which is a lot of watts. But, in perspective that’s only about one-two-thousandth of the output of SIzewell B – and only on the second Tuesday in June at midday. The panels deliver their electricity in direct current – DC (24 volts), which needs to be inverted via a shiny box to alternating current – AC (240 volts – the kind not to lick), before it can run your kettle, or be fed back into the National Grid to be consumed by your neighbour’s Bose sound bar. Which is keeping you up at night. That conversion loses electricity, by the way. As does the length of the wires between the panels and the shiny box. It all makes a difference.

Most companies now offer a battery to store any spare electricity that your appliances don’t use when the sun’s out. They do this so you can use that spare power to watch Midsomer Murders when the sun has gone to bed. Which is fun, although it’s not without a cost – a medium-sized battery will set you back about £2,000. Batteries are classified in kilowatt hours (kWh) – why?, they store in direct current which needs to be inverted to alternating current before you turn on your smoothie maker. But, and it’s a big but, a ‘normal’ set of panels will fill a ‘normal’-sized battery in the summer. Which is when you’re at Butlins. In the winter, when your washing machine is working overtime to clean the dog and Mrs Sun is away browning the knees of the lovely people of Rio de Janeiro, your battery will not be filled.

However, batteries are not all bad. They will save you a bit of cash and some companies will pay to steal your excess battery power/storage to contribute to a local grid, which they share … and all of a sudden you’re part of a joined-up operation that’s going out of its way to save the whales. Well done you!

Watts, kilowatts, kilowatt hours, direct current, alternating current?


You have my sympathy.

And that’s before Mr Sales-Based-On-Commission sends you all the specifications and associated charts and graphs. There’ll be a projected cost-benefit chart which will tell you that, assuming the sun doesn’t burn out, your system will pay for itself in about twelve years’ time. At which point you’ll be laughing all the way to the cashpoint, whilst planning your around-the-world cruise.

Mmm. At fifty-seven, in twelve years’ time I might not be able to make it up the gangplank. And/or, more likely, I’ll have moved and will not have asked Whites to rip the panels off my roof and somehow or other, fix them to the thatched cottage I’ve bought in the country. Notably, a few years later the panels will need replacing (after 20 years they can lose around 50% of their efficiency) and the shiny-box inverter, which has a life of around ten years, will have been replaced, delaying your trip on The Sea of Indulgence by at least a year.

Phew. So much information.

So, why bother? Why spend around £5,500 for a ‘standard’ twelve-panel array (£7,000 with a battery), which only works in the summer and will not have paid for itself before you’re in a nursing home?

Good question.


Because, and I have been very conservative with my figures, a small town of 5,000 houses each fitted with a 4 kW array and a 3 kWh battery would have the same power output as a nuclear power station. And, when it’s snowing outside, if you fill your battery from the national grid with low-cost electricity overnight (aka Economy 7) – which is getting easier and easier to do – those numbers improve.

Now, let’s mandate that, shall we? Let’s make it the law – maybe handing out new subsidies to make it happen.

There are 27 million households in the UK. If we fit just 5 million of them with a standard set of panels, the total average output would be in the order of 5 gigawatts (that’s 5,000,000 kilowatts – a flippin helluva lot of watts), with a further 11 gigawatts of storage capacity. Cost? Around £25 billion.  

How many power stations is that? Power stations come in many shapes and sizes, but if we assume that a really big station generates 500 megawatts, our panels would deliver ten really big power stations’ worth. And at £4 billion a pop for a new power station, that’s a saving of £15 billion. Which is a lot of billions.

So. In summary.

The good news for you is the cost of solar panels has halved in ten years. The bad news is the sun hasn’t got any hotter and government subsidies have run out. The result is you will not reap the financial benefits of fitting panels to your roof any time soon. And your neighbours will laugh at how ugly your house has become.

But. You will be making a difference. When burning the toast we will all use a little less gas, burn a little less coal and, if a lot of us do it, deplete a little less uranium.

And maybe, just maybe, you’ll see a hedgehog in your back garden before you die.