Solar panels and energy crunch forum

Myth 1 - We do not get enough sun in the UK for solar panels?

This is incorrect because the UK receives 60% of the solar energy that the equator regions do. This gives plenty of energy to harvest even in the winter months.

Solar panels as a technology is not new and have been around for over 120 years. Solar panel technology has markedly improved especially over the last 5 years, giving even greater performance figures, but the end of cheap energy (75% of our gas and oil will come from Russia) making solar panels a real necessity over the long 30 + years lifespan.

Please feel free to browse and add your know how for the benefits of others.

Welcome to the solar century

Err... the myth is quasi-true and so is the bust of the myth...

The message is:

Spend the money where it is going to reduce consumption in the first place (heat less water, heat it to a lower temperature, turn down the room thermostats, insulate the house). Even if I could generate all my electrical power needs from solar, it would still only represent around 10% of my total energy usage.

I saved about 20 kw h per day by turning the gas heating thermostat down to 14C at nights and use an electric radiator in the bedroom that burned 2 kw h. Use an instant heating electric shower or boil a kettle. Most of the time there's tepid (20-25C) water left over for the next day until lunchtime and that is suitable for doing dishes - do not just do your laundry at 30C, do all washing with tepid water rather than hot.

Thanks for your input but you are missing the point.

The myth was that the UK does not have enough solar energy for solar panels to work. It does. Simple Fact, absolute myth busted.

Not everyone lives the same life you live. Somehow I cannot imagine my busy family life using the same hot water amount or energy consumption you use. Something tells me, you live alone.

To get back to the original point, Yes the UK does have enough solar radiation for solar panels to work.

Interesting...

I'll hold up my hands and admit that I am an electronic engineer... a happily married one.

As well as my own test 264 Wp off-grid solar system at home, my sister-in-law and father-in-law have both installed grid-tie systems of 1 kWp and 5kWp respectively and report the same findings as my test system. Large reductions in grid bought electricity in the summer and smaller reductions in the darkest winter months.

In particular, I was interested by my father-in-law's 5kWp system as it makes use of the latest high efficiency hybrid panels but still I only saw a maximum of 2.8kW output at the daily solar maximum hour on clear, sunny days in early November with a few hundred Watts at best on cloudy days.

I am sorry about the singleton jibe, below the belt I admit. You are talking about PV solar panels, which is only a very tiny percentage of solar installations done in the UK.

Your data are misleading, because most people are interested in solar hot water systems which has efficiency of between 60 - 70%, as opposed to 12 - 15% with electric, solar panels. Yes, PV solar panels are not for the majority of people, but misleading people into thinking all solar technologies do not work well in the UK is incorrect, and wrong.

Very interesting this read. Handbags at dawn me thinks.

Just to put my two peneth into this debate. I have had evacuated tubes systems installed since 2004 and i am very happy with its performance and was surprised to see them working in winter, even recently through these snowy days. So as to prevent a handbag assault, I can confirm that solar panels do work, they work well, so solar radiation is ambundent enough in the UK for solar panels purposes.

Hi Adrian,

Now that we can have a proper conversation, I did make it clear in my post that I was referring to PV Solar systems. I thought the forum was not purely dedicated to water heating solar systems so it is right to discuss PV system performance here.

Water systems will fare much better with efficiencies of up to 70% than electric solar panels.

The average electric immersion heater is 3kW and takes 1.74 hours to raise 100L of water from 15C to 60C in a perfectly insulated tank.

If we assume, a 6m2 (3m x 2M) solar panel active collection area and 70% efficiency you should see something like these performances:

On a clear, sunny winter day, you'll see a peak of around 530Wm-2 and the collector would provide 530x6x70% = 2.2kW for an hour at the solar maximum, enough to raise the same 100L of water by 19C to 34C. With 70% of that output either side of that peak hour you could get up 60C. But with an average of 1 sunny hour per day in December it's going to be tough to achieve on average. You could do it with 14m2 of collector.

On a dull, overcast day with only 50Wm-2 radiation, you are only going to reach a maximum heating power of 6x50x70% = 210W - enough to raise the 100L of water by just short of 2C per hour. You could heat your water to 60C even on a cloudy day if you had a 60m2 collector.

In mid-summer on a clear day, the same 6m2 collector sitting in 900Wm-2 will make nearly 3.8kW and easily heat your tank up to 60C in about 80 minutes (less as your tap water would be coming in warmer in the summer).

The figures are still skewed towards the summer months, as said in the original post.

I started experimenting with PV because I started to work at home and have to use a laptop. Co-incidentally, at the same time I saw Maplins doing a discounted amorphous 12W PV panel for £40. So I began an experiment to see if I could run my work laptop on solar power. How hard could it be to reliably solar power a 30W load for 8 hours a day? "Quite hard" is the answer.

Hello again

Thanks very much for your inept information.

On this category, the subject was about if the uK has enough solar radiation to work solar panels. A common misconception is that it does not, but just like Germany, which has a similar climate to the UK Germany, has and does have the biggest solar take up.

To someone who knows nothing about solar panels and confuses the PV and hot water systems, your information could lead them to think we dont have enough solar radiation, when we do.

No one is claiming solar can do all a domestic, household needs, but it does contribute allot to it.

With PV, this is dependent on your households consumption rate and system size installed i.e. 1kw, 2kw, 3kw etc etc

With solar hot water, I think this is a no brainier to install if possible.

Any workings out you do as to the financial feasability will be outdated within months, with the trend of higher and higher energy prices. The cost of installing is being forced higher and higher by aforementioned energy issues, British pound problems and with the lower bank interest rates.

These are interesting times, and as time goes on solar is becoming more and more of a no-brainer proposition.

These are fascinating times, and as time goes on solar is becoming more and more of a no-brainer proposition.

Amen to that.

Having worked those numbers on water heating last night, I think I've talked myself into buying some evacuated tubes ... just as soon as replace the roof. No point in putting them up there when the roof will need replacing soon. My house has a lovely do south facing sloped roof and no nearby trees. I might go half and half as it would be beneficial to have some PV, as well.

I'm waiting for the rumoured market commoditisation of PV panels that supposed to happen this year as many of the cell producers ramp up production. Thin film panels that can be "printed" on continuous rolls make substantial reductions in prices compared to the traditionally grown crystal cells that are so labour (and energy) intensive to make. Amorphous silicon evaporated on glass panels already undercut polycrystalline types by 50% in the Pound per Watt stakes, and the next generation are being printed on, UV stable plastics, to make them lighter, more robust and cheaper.

Thin film is not the absolute holy grail it is supposed to be. Bearing in mind that standard PV solar panels now are 15% efficient at the moment. Thin film is only 7% efficient, so you are still going to need twice the square metre coverage to match todays figures. Yes it will be cheaper to produce, but I got a sneaky suspicion, that it will be more costly to install, thus cancelling out any savings.

Everyone waiting for the miracle technology to arrive, but I suspect (like everything else in life) it will be disappointing. I doubt too it will be cheaper than solar hot water to install at around £3 grand.

The answer to the original question is:

800 KW/sq m in Scotland
900 KW/sq m in North England
1000 KW/sq m in Midlands
1100 KW/sq m in London
1200 KW/sq m in South England
1300 KW/sq m in Cornwall

This is enough solar radiation hitting your roof to install solar panels a viable option.