[SallyintNorth]

Glad it's not just me, then. Not oil lamps but other non-electric alternatives to what we use now, like hand-cranked mincers.

No, not just you.  I saw, at a scything festival, a pedal-powered smoothie-maker and was inspired.  Sadly the inspiration can't make me able to create anything like that, but I just love the idea of using pedal power (or I wouldn't mind getting me a turnspit dog!) to do things we now think need a 13A plug.  In my dreams, someone makes and markets the adapted exercise bike with a universal connector thingy and we can all use it to churn our butter, liquidise our soups, etc etc etc.

One of my green thinker friends uses the reversal of, "We used to use horses walking round and round to mill our flour, now we plug in an electric horse walker to exercise our horses", to demonstrate just how far we have gone in the wrong direction.  Sadly I can see on the faces of the people who hear this that the only ones who 'get it' are those of a green bent already.

[suziequeue]

I have a book called The Human-powered Home by Tamara Dean - published by New Society Publishers.

It's really interesting.

I am keen to make a pedal-powered apple scratter

[Norfolk Newby]

I am sceptical about the current range of solar cells. On the one hand they are very expensive for the electricity they produce and on the other, their life expectancy can be short.

Research is making them more efficient (20% is possible) and/or cheaper to make. There are two main sorts. One is called polycrystalline and the other amorphous silicon.

If you want a high performance long life solar panel it is better to be polycrystalline silicon. This is what is used on satellites. It give the most power and has the best life but it is expensive (OK on a satellite but expensive for the roof). On satellites they last for about 10 years with some degradation along the way. Space is a very aggressive environment so this is understandable. On Earth they might last 20 years before being reduced to junk.

The amorphous silicon are cheaper to make but life can be short - less than 10 years.

All this is from me looking around the internet etc. So it may not be 100% and the cells are getting better as new manufacturing techniques come along so don't let me put you off the idea if you have mortgaged the farm to get some installed.

For me, I might get a small panel put in as a test sometime in the next 5 years. Meanwhile, I have a 2Kw petrol generator as a standby.

[ambriel]

Meanwhile, I have a 2Kw petrol generator as a standby.

Likewise, but petrol ain't getting any cheaper...

As a nation we need to drastically reduce our electricity consumption. I'm as bad as anyone - there are four PCs here and in my office that are *never* turned off. I suppose if I had to I could reduce that to two - that's in addition to the laptop I'm using now, btw.

Look at motorway lights - do we really need them all? Cars have been equipped with headlights for as long as there have been cars, after all. Do the streetlights stay on all night? I'll have to check.

[mab]

If you're looking into an on-grid 'feed in tariff' system I probably can't tell you much.

I've got a home built off-grid system and know a bit about solar panels, but I don't think you need to know much about the panels for an on-grid system.

For info there's another type of panel: Monocrystalline - these generally have the highest output per unit area, followed by polycrystalline, and then amorphous/thin-film. In terms of price per watt: mono was highest and amorphous lowest about 2 years ago, but mono have come down in price by a factor of two since then. Some of the amorphous are poor quality and best avoided; others are guaranteed as long as the crystalline types. The picture (if it has attached ok), shows my panels. the two inner ones are thin-film type, 64 watt each and guaranteed for 20 years; the outer two are monocrystalline 80watt each.

I'm not totally off-grid, but I try to stay within my solar supply - my mains electricity bill for last winter was £28  (cooker, immersion & washing machine).

mab

PS. Ambriel, a PC typically uses between 100 and 200w (not including the monitor, printer routers or anything else). taking 120w for a small one and 15p/unit that's 2 units/ day = £220 per year per PC  . You might want to re-consider turning them off - or replace them with laptops - or, next time you upgrade one, ask for a high efficiency PSU.

[SallyintNorth]

mab, that was fascinating!  How much power does a laptop consume (if left plugged in and turned on)?

[Dizzycow]

Does anyone know of a reputable scottish firm who will do the pv under the 'rent my roof' system?

[ellisr]

I work for a company that makes the only solar slate in the UK and they cannot be seen on the roof. They are fitted like slates and are now being allowed in heritage sites where before no solar technology was allowed unless it could be completely hidden out of site.

[mab]

How much power does a laptop consume (if left plugged in and turned on)?

Hmm, well that does depend very much on what size and processor spec and what it's doing;

My 17" 1.6GHz acer laptop uses about 28w when on and idle. The actual power also depends a lot on what it's doing - using the processor intensively and operating the hard drive can raise the consumption by 30% (e.g. viruscan). If I turn off the display backlight it goes down by about 8W. The mains power supply (which I rarely use) uses an additional 5w which comes out as heat.

Hypothetically, if it was left on 24/7 doing random things I would guess it would consume about 40W average (including mains adaptor) = £73/year (at the above rate); If the backlight was turned off for much of the time it was left that might bring the cost down to £45ish.

I also have a 2GHz 13" macbook - this uses 25-50w depending on what it's doing. turning off the airport (wireless card) saves about 3W. If the macbook's turned off but the power supply is left plugged in (with the battery fully charged) it uses 4.5w and just the PSU disconnected from the macbook uses 3w.

the router uses ~6w; if left on 24/7 that would be about £11/year.

small notebook type units with small displays and long battery life might be significantly better, but I don't have one to test.

mab

[SallyintNorth]

Wow, thanks for all of that, mab. 

I am disgusted that the manufacturers are still allowed to make PSUs that consume when not being used, but my laptop is pretty much either turned off at the mains or on and connected to the mains, so that won't affect me.

I keep my wireless off so that will help but despite good intentions do not very often turn off overnight and just keep it plugged into the mains.  Mind, I am very good at always putting the laptop in 'sleep' mode when I leave it and I nearly always remember to unplug the internet connection.  Antivirus will still do things but otherwise it should be quiet while I am not actively using it.

[bucketman]

The has guy been round and we're looking at a 12k investment with a £1250 per yr return. The real figures work out about 11.6% so about 8.5 and 9 yrs to pay for its self then £1250 for the rest of the 25yrs all indexed linked. So at todays prices its £12k outlay and 300 months x £104 = £31400 return not bad. wonder what the banks would give
rob

[shearling]

Mmmm. We are on FITs and have been waiting nearly a year for the first payment. The reason change of ownership of the house. very interesting process. Also the electric firms ask for quarterly readings and then pay - so they say - within 90 days.

[doganjo]

The has guy been round and we're looking at a 12k investment with a £1250 per yr return. The real figures work out about 11.6% so about 8.5 and 9 yrs to pay for its self then £1250 for the rest of the 25yrs all indexed linked. So at todays prices its £12k outlay and 300 months x £104 = £31400 return not bad. wonder what the banks would give
rob

Don't know what they said to you, but I was told the scheme started a couple of years go and that now the remaining number of years guaranteed by the Government is down to 22.

[bucketman]

Don't know what they said to you, but I was told the scheme started a couple of years go and that now the remaining number of years guaranteed by the Government is down to 22

Spoke to them and both of us are half right
1 what ever year you sign up you get that tariff for 25 yrs indexed linked
but
2 the latter you sign up you get a smaller tariff so if you left it for 23 yrs you would only get free electice and a small pay back for any leccy you don't use
The FITS is to get people to sign up sooner rather than latter.
rob

[ambriel]

Yes that sounds about right, mab. The electrickery bill for the office runs to around £230/quarter. I do switch off the printers and monitors but two of the PCs have to stay on because they're receiving data 24/7. I might try and consolidate them into one PC when I get some spare time.