Solar Panel Guide Discussion

zeupater

Martyn1981 wrote: »

Here's one I made earlier!

http://www.earthtechling.com/2012/02/japan-combines-solar-storage-to-beat-blackouts/2/

Quick question, if your leccy is mostly tier 1, have you thought about a company that offers a single tariff, no tiers or standing charges? I think you can find them for around 15p(ish). Any use?

Mart.

Hi

Looked at that last month when the 2011/12 supply contract expired, but I saw the best option as being a deal which locked the supplier into no price increases until late next year but no conditions on us ... that's really bought time to see how market prices change over the next few months ..... anyway, the next eco-purchase will reduce the electricity imports by another 25%, just waiting for the right time to spend the money and show the best return .....

Z

grahamc2003

zeupater wrote: »

Anyone got a spare Prius battery pack, an old inverter, circuit design experience and some time on their hands ?? :D

HTH
Z

Not sure a Prius pack would be much use - they're only 1.3kWh capacity (on the mk2, the most frequent model you see around). Even then, to get a long life, the Prius only uses the mid 20% of that capacity, so about 250Wh if you want the pack to last the life of the car (or 12 years).

The Prius works by continually storing and using the mid 20% on a second by second basis, and delivering/storing it at quite a high power of around 21kW, or 28hp.

The new Plug-in will have a bit more capacity.

ronlizpatsimon

The trouble with using batteries for mass storage is the cost of replacement ones!

zeupater

grahamc2003 wrote: »

Not sure a Prius pack would be much use - they're only 1.3kWh capacity (on the mk2, the most frequent model you see around). Even then, to get a long life, the Prius only uses the mid 20% of that capacity, so about 250Wh if you want the pack to last the life of the car (or 12 years).

The Prius works by continually storing and using the mid 20% on a second by second basis, and delivering/storing it at quite a high power of around 21kW, or 28hp.

The new Plug-in will have a bit more capacity.

Hi

It was a little tongue-in-cheek & based on the post 2009 Prius which I'm sure has a 4.4kWh Li-ion pack with an 8 year guarantee (it's on our list of possible replacements for MrsZ's 4x4 when she decides to change) ... so is pretty well matched to our average overnight usage (which will be well under 3kWh soon).

Z

Martyn1981

zeupater wrote: »

Hi

Looked at that last month when the 2011/12 supply contract expired, but I saw the best option as being a deal which locked the supplier into no price increases until late next year but no conditions on us ... that's really bought time to see how market prices change over the next few months ..... anyway, the next eco-purchase will reduce the electricity imports by another 25%, just waiting for the right time to spend the money and show the best return .....

Z

I'm in the same boat, found a nice deal with single tariff, no SC's and not for profit. £6 more than current leccy bill, but 2p more per unit than I'm paying now. So hopefully, if I cut leccy by another 400 units after extension install it works out. But ..... I'm on a fixed price deal till 2014, so probably best to watch and wait for now.

May I ask what the 'eco-purchase' is/might be? Are you looking seriously into batteries, as I remember you were doing the maths a few months ago, but it was borderline?

Mart.

zeupater

Martyn1981 wrote: »

I'm in the same boat, found a nice deal with single tariff, no SC's and not for profit. £6 more than current leccy bill, but 2p more per unit than I'm paying now. So hopefully, if I cut leccy by another 400 units after extension install it works out. But ..... I'm on a fixed price deal till 2014, so probably best to watch and wait for now.

May I ask what the 'eco-purchase' is/might be? Are you looking seriously into batteries, as I remember you were doing the maths a few months ago, but it was borderline?

Mart.

Hi

I'm not going for any storage capacity until we've reduced the imported electrical usage quite a bit more in order to minimise the size of any battery installation (& therefore cost) .... the main eco-item on the shopping list is a replacement screen (plasma to LED) for the home entertainment system, but it's got to be at the right price because the current one is perfectly good and the only reason to change is on consumption grounds. I've got my eye on some particular units which could be cost-justified at the moment, but haven't jumped yet ....

Everything is subjected to energy audit and justification in this household ....

Z

John_Pierpoint

Martyn1981 wrote: »

Try this article that looks at 4kWp PV prices in Germany with FITs, and in the USA without. $8,000 v's $20,000.

http://www.renewablesinternational.net/pv-prices-down-66-since-2006/150/510/56052/

Mart.

There is an interesting advert above the article, from Du Pont, the people who rescued General Motors between the world wars and who went on to build the A bomb for the US government (at a charge of $1).
[I recall visiting a trade stand where Du Pont was pushing a product to pack into the walls/roof of modern light weight buildings to capture the day time to "melt" it and then when the temperature dropped over night the energy would be released to "freeze" it again; thus making up for the loss of thermal mass present in historical construction techniques.]
Amongst some documentation on improving PV panel manufacturing techniques, this observation says it all:
The PV industry currently faces the greatest challenge of its 30+ year lifetime. Incentives that drove torrid industry growth over the last several years are drying up. Prices for cells and modules have dropped precipitously as a result of over-capacity and over-production. Module buyers are now becoming more selective, preferring higher-value and higher-quality modules at low prices. As a result of these dynamics, hundreds of rapidly-growing cell and module manufacturing companies that have sprung up in the last decade face a daunting challenge:

Martyn1981

John_Pierpoint wrote: »

[I recall visiting a trade stand where Du Pont was pushing a product to pack into the walls/roof of modern light weight buildings to capture the day time to "melt" it and then when the temperature dropped over night the energy would be released to "freeze" it again; thus making up for the loss of thermal mass present in historical construction techniques.]

Hiya John, I remember watching or reading something about installing phase change materials in buildings that need a lot of cooling (air conditioners), the idea being that heat is extracted during the day, then released at night. Can't remember where I saw it, but the crucial factor was choosing the right material for that application, so that it changes within the necessary temperature window(s).

Also some interesting stuff on 'zeolites' that can store heat (sort of) indefinitely if kept dry. I think aluminium alumina is similar, but may be making that bit up.

http://www.techthefuture.com/energy/zeolite-stores-thermal-energy-for-unlimited-amount-of-time/

Mart.

Martyn1981

orrery wrote: »

I'm sure that they have, but I've done my numbers too. Spread-sheeting the original pre-December 2011 tariff against a cash ISA (both tax free income), with an allowance for maintenance costs to the PV system, shows that it will take about 17 years for me to better the ISA. Those with the more recent lower tariffs are unlikely to ever break even on that calculation, even with lower cost systems. There's no way I'd go ahead with a system now.

Hiya Orrery, I've been doing some calcs for my Aunt this week as she fancies getting PV. Not an ideal install, but pretty good, 3kWp and 'better than East'.

At £5k and post Nov, she's looking at £424 (8.49%) + leccy, or pre Nov £438 (8.76%) + leccy. So a decent return. Breakeven point with savings/earnings reinvested about 10 years, or 12 with a new inverter. (3.5% interest, 3% inflation, leccy savings approx £100).

Should be able to utilise scaffolding needed for another job, reducing install cost by 5-10%.

Mart.

zeupater

John_Pierpoint wrote: »

... I recall visiting a trade stand where Du Pont was pushing a product to pack into the walls/roof of modern light weight buildings to capture the day time to "melt" it and then when the temperature dropped over night the energy would be released to "freeze" it again; thus making up for the loss of thermal mass present in historical construction techniques ...

.... I suppose that this would be similar to heating large reserves of supersaturated soduim acetate when there's excess energy and then releasing the energy by returning it to crystalline form when (exothermic) heating is required ....

Z