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Dr._Shoe

Ooh how about a telephonic type system. Line rental and usage as seperate bills?

Martyn1981

Generali wrote: »

with that, we go back to a grid system of course. Australia has millions of acres of land that has nil value that could be covered in solar panels very simply. This may not be the solution for a damp, dark island in Northern Europe but for a massive island in the sun it's pretty compelling. I don't need to save solar in my summer for my winter: the sun comes out most days and I don't have days with 6 hours of daylight. Long, hot summer days is when I use electricity the most. I heat my house for about 40 days each year.

Hiya. I chat with quite of lot of off-gridders and on-gridders experimenting with batteries. One of the latter lives in Spain, so more like Aus than UK with a flatter and more predictable generation curve through the year. He recently mentioned that he is using his batteries (charged from excess PV) to run his heat pump. :cool:

Also, of course, there are already a large number of plug n play PV/hybrid inverter/battery systems on the market, but they're still far too expensive for me, but will watch with interest, particularly with the large Tesla battery factory being built.

Many of the 'battery players' have explained and priced systems for me at the cheaper end, using diversionary switches, charge controllers and additional inverters, but these 'cheaper' systems rely on lead acid batteries, and I don't have a suitable/safe storage area for that product, especially if hydrogen gas is given off. Plus my import is just too low (approx 1,600kWh pa) to justify any experimentation at this point in time.

Mart.

Martyn1981

Generali wrote: »

I don't need to save solar in my summer for my winter: the sun comes out most days and I don't have days with 6 hours of daylight. Long, hot summer days is when I use electricity the most. I heat my house for about 40 days each year.

Doh! Just realised I'm teaching granny to suck eggs. Do you have A/C? In which case is it an inverter type that is also used as a heat pump? In which case, thanks for humouring me!

Mart.

Generali

Martyn1981 wrote: »

Doh! Just realised I'm teaching granny to suck eggs. Do you have A/C? In which case is it an inverter type that is also used as a heat pump? In which case, thanks for humouring me!

Mart.

At present I only have solar hot water. The conversation came about from an anecdote from a mate who is buying solar panels on credit and the price of the electricity produced means he can pay all his interest and electricity bills and still make a profit.

I plan to solar myself up to the eyeballs once I build a home which I hope to do in 2015. It depends where it is but some land I've looked at would cost $100,000 to link to utilities which would pay for an awful lot of alternatives!

cells

Generali wrote: »

I get your point cells but at present the capital costs of electricity infrastructure are mostly charged in the unit price for electricity rather than a realistic fixed charge. That means that by going solar I can avoid paying my fair share of the infrastructure so that charge falls on fewer people.

As capital costs remain about the same but fewer people are paying them, the costs per person will increase making solar more attractive.

If electricity companies try to split the fixed costs more equitably and a lot of people have already bought solar panels, the incentives to store the electricity locally increase as people remove themselves from the grid entirely.

http://arstechnica.com/science/2015/02/future-batteries-need-to-triple-capacity-cut-price-by-67/

Battery technology is improving quickly:

A 4kwp system can generate as much energy as the average house uses, if you are off grid and no seasonal batteries you need to install a 20kWp system to meet winter needs but then produce too much in the summer with nowhere to put or use it

So you need some 5x as much PV if you are off grid, or a very expensive very heavy very huge seasonal battery. Right now the 5x as much PV is more realistic than the seasonal battery. That means a £20k investment....

The figures for Australia might be a little better but there is still a big difference between winter sunlight and summer sunlight hours

whatever the case the current system works and costs a whopping £1 per day

Martyn1981

cells wrote: »

A 4kwp system can generate as much energy as the average house uses, if you are off grid and no seasonal batteries you need to install a 20kWp system to meet winter needs but then produce too much in the summer with nowhere to put or use it

So you need some 5x as much PV if you are off grid, or a very expensive very heavy very huge seasonal battery. Right now the 5x as much PV is more realistic than the seasonal battery. That means a £20k investment....

The figures for Australia might be a little better but there is still a big difference between winter sunlight and summer sunlight hours

whatever the case the current system works and costs a whopping £1 per day

Your numbers and 'facts' are getting sillier and sillier now.

Where on earth are you getting that 5x figure from? The only months that would be a problem are December and January, and 8kWp of south facing panels at a 50d pitch would provide 275kWh and 288kWh even in darkest Cardiff. Nov and Feb would be pushing 400kWh.

That's about £4k in panels, then add about £2k more for all the rest of the kit, assuming a cheap DIY scaffolding pole ground mount. Alternatively build a basic shed come A-frame and use it to store wood for the wood burning heating system!

If you wanted you could add about £2k worth of batts, possibly fork-lift jobbies.

For £20k you could get (or have gotten a year or so back) a full off-grid kit, with large PV, wind turbine, huge battery bank and back-up generator for emergencies. All installed for you by a professional. I recall looking at some great photo shots of systems installed in Greece, by a guy who now lives in the UK. Since then PV prices have dropped even further.

Perhaps you should have a read/chat of the info on the renewables sites where the off-gridders reside. These chaps/chapesses love PV as it's so simple and cheap these days. But don't need anything like the amount you suggest.

Mart.

cells

Martyn1981 wrote: »

Your numbers and 'facts' are getting sillier and sillier now.

Where on earth are you getting that 5x figure from? The only months that would be a problem are December and January, and 8kWp of south facing panels at a 50d pitch would provide 275kWh and 288kWh even in darkest Cardiff. Nov and Feb would be pushing 400kWh.

That's about £4k in panels, then add about £2k more for all the rest of the kit, assuming a cheap DIY scaffolding pole ground mount. Alternatively build a basic shed come A-frame and use it to store wood for the wood burning heating system!

If you wanted you could add about £2k worth of batts, possibly fork-lift jobbies.

For £20k you could get (or have gotten a year or so back) a full off-grid kit, with large PV, wind turbine, huge battery bank and back-up generator for emergencies. All installed for you by a professional. I recall looking at some great photo shots of systems installed in Greece, by a guy who now lives in the UK. Since then PV prices have dropped even further.

Perhaps you should have a read/chat of the info on the renewables sites where the off-gridders reside. These chaps/chapesses love PV as it's so simple and cheap these days. But don't need anything like the amount you suggest.

Mart.

Daily winter electricity need for a typical home is about 15kWh

I looked up how much kWp of panels you would need to generate that and found a website for daily output from a 1.7KWp system which for jan was 1.5kwh so multiplied by 10

But if you want to share your data from your own 5.58KWp system we can update it. So what was your lowest Jan output in KWh and be honest.

cells

Martyn1981 wrote: »

Your numbers and 'facts' are getting sillier and sillier now.

Where on earth are you getting that 5x figure from? The only months that would be a problem are December and January, and 8kWp of south facing panels at a 50d pitch would provide 275kWh and 288kWh even in darkest Cardiff. Nov and Feb would be pushing 400kWh.
Mart.

Ok mart, 275KWh from an 8KWp system

we only have an overnight battery not a monthly one so whats the one or two lpwest production days?

Then we can try to work out how big a system you need to give you 99.9% reliability.


If its 5KWh for a 8KWp system for the lowest day and you need 15KWh that means you need a 24KWp system to guarantee you the 15KWh we need

if 6KWh is your lowest we need a 20KWp system
if 7KWh is your lowest we beed a 17.1Kwp system

I know its going to be 7kWh or lower as you posted 275kWh for the whole month

so that means you are talking about 17KWp plus system


and as you correctly point out, at all other times its excess requirement and no grid to dump it onto

Generali

cells wrote: »

A 4kwp system can generate as much energy as the average house uses, if you are off grid and no seasonal batteries you need to install a 20kWp system to meet winter needs but then produce too much in the summer with nowhere to put or use it

So you need some 5x as much PV if you are off grid, or a very expensive very heavy very huge seasonal battery. Right now the 5x as much PV is more realistic than the seasonal battery. That means a £20k investment....

The figures for Australia might be a little better but there is still a big difference between winter sunlight and summer sunlight hours

whatever the case the current system works and costs a whopping £1 per day

The winter day is 10 hours long (21 June 2014) and the summer is 14 hours (21 December 2014) in Sydney. As you go further north, the difference between the summer and winter day shrinks. Don't forget that the solar panels work more efficiently in winter too.

This is the SMH's take on the economics of solar in Sydney:

http://www.smh.com.au/money/planning/can-you-ever-make-cash-off-a-hot-tin-roof-20140121-315co.html

cells

Generali wrote: »

The winter day is 10 hours long (21 June 2014) and the summer is 14 hours (21 December 2014) in Sydney. As you go further north, the difference between the summer and winter day shrinks. Don't forget that the solar panels work more efficiently in winter too.

This is the SMH's take on the economics of solar in Sydney:

http://www.smh.com.au/money/planning/can-you-ever-make-cash-off-a-hot-tin-roof-20140121-315co.html

Its a long article which is comparing subsidy and accounting not technology.

It suggests the average CF in Australia is 17.5% which is better than the UK at 11%

From that alone you can work out annual generation.

A 1KWp system will produce 1530 KWh

The true vakue of a KWh of non controlable energy is about 5 Australian cents giving a true value of $75USD / year / 1KWp


30 year life assuming no degrade and 5% interest gives a capital cost of $1100AUD or $1.10 per peak watt for it to truly work as a technology rather than an accounting transfer


So if PV prices fall to $1.10 all included places like Australia will install them subsidy free in very large scale


The same for the UK gets a figure of ~£0.40/watt for it to work on its own merits unsubsidised un-accounting-tricks


PS even your own link says dont buy if you expect to export most the power which translates to what I keep saying....accounting tricks