Solar Panal info req for domestic use

[The Natural Philosopher]

Indeed. So why don't you?

[The Natural Philosopher]

Yes, now do the 'maths' mary - you may need to take of your socks, because the numbers sometimes go above ten, and see how MUCH you really saved.

Indeed!

[The Natural Philosopher]

Longish in what terms?

a decade or two?

>

[The Natural Philosopher]

Gosh, you have summed your position up in a nutshell Dave.

[The Natural Philosopher]

Knitting a jumper.

Payback time probably under a winter.

[Andy Hall]

OK, so are you here making the connection that I think you are? i.e.

- Solar panels = "reduced carbon" energy

- Therefore reduction in carbon emission

- Therefore less climate change

- Therefore less flooding of low lying areas

This is shortening, simplifying and perhaps not in the order that you might present it.

I'm not going to counter it with the teaspoon and Titanic argument either.

However, let's assume that the prospective purchaser believes that buying a solar panel for his hot water affects the "cost" for the poor sods living in low lying areas.

This is actually falling into the feel good category because the money spent is being considered as affecting the well being of others, present and future as opposed to benefiting the spender directly. It could then be considered on the same basis as charitable giving to flood relief to Bangladesh for example. Then one has to wonder whether the £5000 spent on the solar panel system would have been put to better use as a charitable donation, especially when grossed up with the tax contribution.

Could it be that the solar panel represents an enormous and lasting equivalent to the paper sticker I get when I put money in the collecting tin in the high street?

[David Hansen]

On Mon, 28 Jan 2008 09:18:54 +0000 someone who may be The Natural Philosopher wrote this:-

Excellent, personal abuse.

[David Hansen]

On Mon, 28 Jan 2008 09:16:54 +0000 someone who may be The Natural Philosopher wrote this:-

It is certainly true that the peak output of solar PV panels does not coincide with peak electrical demand. However, that does not mean they are pointless.

You appear to be mixing up PV and hot water panels. Whether this is accidental or deliberate I leave for others to decide.

[Mary Fisher]

Well, I wouldn't have seen it if you hadn't replied :-)

(I always read your posts)

Mary

>

[Mary Fisher]

Early motor cars were neither. Those who bought them were pleased with them - and more R&D was done on the back of that.

It might happen again :-)

By the way, we live on the state pension but could afford a dhw panel. They're not that expensive.

Mary

[Mary Fisher]

I suspect that most people who get a solar dhw system change the rest of their lifestyle to suit. That would include adjusting 'heating periods', surely.

[The Natural Philosopher]

Ditto.

After your hilarious comments about 'religion'

This whole topic is too important to be left to touchy feely qualitative analysis.

If people can't do the maths and the real analysis, they shouldn't comment.

Its like going into the supermarket, and buying tow to get one free..and then letting it rot in the cupboard. That isn't saving money. That's being a gullible fool.

Which by and large is what most people who buy so called 'green' products, are.

BECAUSE its something I consider important I HAVE spent a total of several MONTHS looking into 'green' technology and the like, doing a LOT of sums, and double checking the results.

Using strict cost benefit analysis both in cash and energy terms.

And frankly the answers are depressing and scary. Almost none of it makes a measurable difference to overall carbon footprint, and a lot of it actually makes things worse, and the one thing that actually DOES have the potential to make a real positive difference is shouted down by religious greenies. On QUALITATIVE grounds. It makes them FEEL BAD.

Let's take solar power.

The UK is about 30M hectares in surface area.

A hectare is 10K square meters, so thats 300G meters square.

WE have a peak winter energy consumption as a nation, of around 300GW.

In winter, the average insolation is less than 600Wh per day, or 25W/sq meter.

That means we need to totally cover the entire area of the UK with solar panels at 4% efficiency, to generate our energy needs.

In summer, when we don't need the energy, its a lot less. But that's no great help is it?

In terms of cost, a decent nuclear power stations is around £1000 a Kw.

So unless that one meter square solar panel is actually costing less than around £2.50 (at 10% efficiency)..its money better spent elsewhere.

Its also rank hypocrisy, or naivete of the first order to claim that you personally are 'green' when everything you use , eat buy and consume, is produced by a system that isn't.

As I pointed out to the woman in the checkout at the 'green' till in Waitrose, that the plastic used in one carton of cream was ten times the amount in the plastic bags used to carry the shopping home in. Howevr all I got was teh blank incomprehension of those that don't like to be told that they are basically involved in a futile feel good marketing exercise, and their cherished beliefs have no more chance of stopping global warming than fitting a CFL bulb does.

Its only by doing the nummbers, that you can actually whittle down the bullshit to what really actually DOES save energy and works.

We have juts had a thread on wood burning, and the US contributor and I both came to a reasonably similar figure that 5-10 acres per house is what it takes to heat a small home, sustainably.

There are about 30M households in the UK.Pretty staggering for a country of 60M people, but that's apparently the way it is. 10 acres is arond 4 hectares, so we would need to devote something like 120M hectares to wood growing just to heat our houses. Thats 4 times the total land area of the united kingdom. Right. Great idea.

The latest greatest windmill projcet, a '1GW' windfarm at a cost of £1.5bn, won't actually produce 1Gw at all. Since thats its PEAK output, when the wind is exactly the right strength. Typically it will produce about 15% of that. Average. Which makes it about 4 times as expensive AT LEAST as a nuclear power station. To do the total country copmplete energy needs, we need about 1800 windfarms JUST like it. A staggering conclusion.

Never mind the cost issues of maintaing all those windmills out there in the sea..

Whereas we can run the WHOLE COUNTRY, on just 100 5GW nuclear power stations.

The simple answer is this. You need a staggering amount of kit - often exceeding the total area of the country, to collect the very low energy density energy from 'renewable' energy. I.e. energy from the sunlight we get, whether its biofuel or direct solar. Or windmills, or water power. We are a society that actually uses something like 10% of the equivalent energy it gets from all the sunlight falling on it, to keep itself running. Whilst with excruciatingly expensive technology we might reduce that a little, we cannot slash it in half, or anything like it, at the population density we have. Nor can we contemplate slashing the population in half either.

We have built this society by using energy - energy borrowed from natures piggy bank of fossil fuels. It's running out. If it is NOT replaced, we will revert to the sort of lifestyles and population levels of - say - Tudor England.

No renewable energy source has the sort of levels of energy we need to counteract this: we have no geothermal energy to speak of, we have some possibility of using some tidal energy, but at massive adverse and unknowable effects on tidal ecosystems.

Using natures Stellar piggy bank and raiding the fusion store, gives us a few hundred billion years of energy, but we cant yet do it economically, if ever.

The ONLY thing we have left is a couple of million years of nuclear fission energy.

Its not the best solution. Its the ONLY solution.

Nothing else can replace fossil fuels in the UK. Not one other technology has a *prayer*, even. Windmills are a distant ugly and hugely expensive second best. Maybe in practice they might to 10% of the job at enormous expense and totally transform the whole nature of the seascapes and landscape in so doing.

Solar power has its place in sunnier climes. Stuck in a low population low latitude desert, it starts to make sense. Not a lot, but some.

I don't have any axe to grind in this apart from simply not wanting to be involved in the sort of chaos and civil war that would accompany the return of the UK to a pre industrial society. I have no involvement with the power generation industry, or any other industry, I am not part of any lobby or group.

I simply did the sums, using the facts as available, not as wishful thinking. I wish we did NOT have to contemplate nuclear power. But at least its problems are practicably soluble, Whereas that doesn't ring true for any other way to crack the nut.

Certainly not any technology that relies on direct or indirect solar energy falling on the UK landmass. There isn't enough of it.

In fact, there is a puzzle, in that the earths actual temperature is more than can be accounted for by the solar radioation and its initial temperature post formation, leading to a lot of speculation that it is in fact a large fission reactor in its own right.

So you may owe the life of the planet to nuclear reactions anyway. Makes it a bit stupid to worry about siphoning off a little to heat your tootsies doesn't it?

[Mike Scott]

The Natural Philosopher wrote: ...

Isn't there a large molten iron core that makes up the difference? Been there since year dot, or thereabouts, cooling all the time.

But out of curiosity, what happened to all the research into fusion reactors? Anyone else remember ZETA?

[David Hansen]

On Mon, 28 Jan 2008 11:41:08 +0000 someone who may be The Natural Philosopher wrote this:-

Indeed.

Some may claim to have spent months doing calculations. However, if it was a mine's bigger then yours competition they should realise that some have spent years and decades doing the same.

[Mary Fisher]

There are other theories now.

There was a programme about it last week on R4.

I remember ZETA well, the problem was containing the temperature.

Mary

[The Natural Philosopher]

yes, there is, but the surface temps don't match that. Hence speculation about fission being in the mix somewhere.

- There certainly HAVE been natural reactors in the past. (Gabon)

- The concentrations of Uranium isotopes today, show that by and large there was a LOT of fission going on to leave what's left. How much heat this priduced nd where is ..debated.

- cheock out 'georactor' in google for a theory that isn;t that respactable, and nowhere near esastblished thinking, but is inetersting to say the least.

Still going on. The last gasp of the last torus was actually significantly energy positive,and a new thing is being built in France IIRC too go one step furher..only about another 9 steps to a commercial proposition.

[The Natural Philosopher]

Shame they haven;yt come up with the right answers then.

I note you have failed to summarise them for all to criticise, and you haven't actually refuted mine.

[The Natural Philosopher]

Well in a touchy feely qualitaive way, thats approximately correct.

In the same way that its kind of hard to fit the sun into a plastic bag...

[Huge]

The Earth is still warmer than it "should" be.

Have you been paying attention? Apparently not!

[tom.harrigan]

Actually the commercial demonstration reactor will be the one after the one in Provence.

T