Miscellaneous Solar PV, batteries, tariffs etc.

[Pete Thomas]

We just had a solar install. It is 20 panels with a max potential of about 8kWh but realistically in UK and shading not going to get that)

5k Inverter and 19kW battery system

Why such a large battery storage you ask? Well the idea was to be able to store the cheap overnight rate from Octopus (9.5p per kWh for 4 hours) plus we use a lot of electric due to ASHP.

But I have to admit my research wasa bit off because I now find the 5k inverter is limited to 3.7 output so can only charge the battery to about 75% in 4 hours which I had mistakenly presumed would be 100% at 5kWh). But all is better if I can get onto Octopuse Intelligent that gives 6 hours of cheap electricity.

Bit of a minefield, but just wondered who else is delving into this solar malarkey and any advice. Seems to be changing all the time now there is Octopius Intelligent Flux.

 

[thomsax]

Interesting, but what is ASHP?

I'm interested to have 4-6 solar panels and a small wind turbine. Just enough to charge a small battery so I can run the wood pellet burner and the circulation pump on the boiler. Just 175-200 W.

Solar panels are popular in Sweden. Long and cold nights when we need the energy 😉. We had a good energy system in Sweden. Water power and nuclear power. Stabile energy at 50 Hz.

 

[mizmar]

what is ASHP?

air source heat pump - varmepumpe ... Less common in the UK than Scandinavia

 

[dexdex]

We have 19 panels (7kW peak) since September. No battery, it isn’t yet economic here. The electricity company buys back the production surplus.
In September and October we were able to charge our EV and cover our daily domestic consumption. November has been rainy/cloudy, so only a miserable contribution from our roof.

 

[DaveT]

I have had 8 solar panels giving a max 2.5kW on my roof for 4 years now. I'm in the UK.
Being a sad old engineer I have recorded daily generation and daily electricity usage for 6 months - September to March.
On a good sunny day it will do 8kW, on a grey rainy day it will do 10 WATTS, even zero Watts, no power generation at all.
Does better in summer of course!
I fancy getting a big battery system so I can go off-grid for electricity. 5kWh would be cutting it a bit fine. 10kWh should do it. Old Nissan Leaf batteries too far gone to be used on an electrical vehicle are reckoned to be good and cheap for home use.

thomsax: buy the best panels you can find. You should be able to get about 300W from one panel if you moved 1,000 miles south! The EU have a website that lets you calculate what power you can expect based on your longitude, tells you the best angle to mount them too. Needing 200 Watts per hour to run your wood pellet burner and the circulation pump starts adding up. Mid-winter will need a lot of battery backup, and the batteries don't like the cold! Two panels and a big battery would do it in the UK.

 

[LostCircuits]

I installed solar in Jan 2016. Total cost ~US$12.000 after the tax credit. I paid it off right away to eliminate the "money factor" / interest payments and 7 years into it I well broke even. There are all those tricks that they power companies are playing, like you get a refund on Dec 31st for what you over-produced but then they start billing you for January/February when you are net negative. The conversion rate is 5:1 so they still make a profit. On the other hand. my refund of $30.- at the end of the year amounts to 1500 kWh and now that I got an electric vehicle with an average of 3.6 miles/kWh. that's about 5000 miles at the cost of $30 that I would otherwise spend on 4 beers in a pub.

 

[thomsax]

thomsax: buy the best panels you can find. You should be able to get about 300W from one panel if you moved 1,000 miles south! The EU have a website that lets you calculate what power you can expect based on your longitude, tells you the best angle to mount them too. Needing 200 Watts per hour to run your wood pellet burner and the circulation pump starts adding up. Mid-winter will need a lot of battery backup, and the batteries don't like the cold! Two panels and a big battery would do it in the UK.

I try to be positive to solar panels, wind mills/power .... but I think it's just a chimera. Lastest november a big solar panel installation on the roof at my brothers house gave zero energy. Cloudy/dark and winther (cold and snow) came early as well. He have to pay twice for this. First the cost for the panels and work and he also pay via taxes for the subsidieces for solar panels. I have big trees in my garden and they doing more for the clima than solar panels on my roof. A tree is binding carbon and gives us a good micro climate as well. I have to cut down our trees to have the sun to shine at the roof.

 

[thomsax]

I bought a new bike for some months ago. So now I have three; one MTB, one practical and one cargo bike. No battery car or bike.

 

[stom]

I’ve had a solar system put on our house this summer. It was installed in May. 6.6kw output from 18 panels with a 6kwh battery on an unshaded south west facing roof.. December will be the first month that we’ve had to pay for electricity. Jun-Oct we’ve been paid more than any energy we’ve used to top up the battery overnight. Nov was exactly equal in energy credit vs overnight battery chathing. We’re on Octopus Flux, top up the battery at cheap rates overnight and sell excess at the same price during the day. 6years break even is what I’ve calculated for our system at a £12k install price. The system outputs in the summer 40kwh+ on a cloudless day!

I did the calcs on buying a 6kwh battery expansion pack and force discharging to the grid at peak hours. It’s an 8year+ payback so not really worth the effort as in 8 years time I expect battery tech to have moved on significantly.

 

[mizmar]

thomsax: buy the best panels you can find.

Depends where he lives... Sweden

I think it's just a chimera

Probably, in much of the Nordics, at this state of the technology.
The difference useful sunlight between the equator, temperate and northern parts can be a factor of 2-4 or more, yet pv technology is - like oil - a global community. So you're going to need several times the area, at several times the cost... Added to which, a lot of the time the sun is low in the sky, so buildings, trees and mountains can be a problem. Added to which the Nordics can be very cold and very dark at the some time! Conversely in Norway, anyway, in the summer electricity can become -ve cost (they sell it to Sweden and the UK)... So maybe no buyback when the sunshines longest.
There's not many pv installations in Trondheim!

 

[thomsax]

Many energy companies, distributers, are not dealing with energy from pv installations. It makes our national system unstable.The energy system in Sweden is based on water- and nuclear- power. The system is built on 50 Hz rotation. pv and wind energy need to be stabilized. Huge investments and it's Swedish tax payers and private energy consumers that have to pay, even if most of the money comes from EU. But we pay a lot to EU, more than we get back.

I think we are in the same situation as we were in the mid 1850. The new time is poking but this time we can relay on the mistakes we have done for over 100 years ago. We pretty much know what we want and what we should out from. Politicians, venture capitalists, different organizations ... have made a hugh marshmallow. Huge, fluffy and colored ... but the content is more or less just air.

"Mycket skrik för lite ull, sa månskensbonden som klippte grisen" ( "A lot of shouting for a little wool, said the moonlight farmer who sheared the pig" )

 

[Targa]

The new time is poking but this time we can relay on the mistakes we have done for over 100 years ago.

'relay', a typo for 'rely'?
Then could be a freudian slip humans being what they are.

 

[Ivan]

I think we are in the same situation as we were in the mid 1850

Plus ça change

 

[Ivan]

"Mycket skrik för lite ull, sa månskensbonden som klippte grisen" ( "A lot of shouting for a little wool, said the moonlight farmer who sheared the pig" )

Café Sax Aphorism of The Year

 

[mizmar]

Café Sax Aphorism of The Year

Luckily the year is almost over!

 

[LostCircuits]

Many energy companies, distributers, are not dealing with energy from pv installations. It makes our national system unstable.The energy system in Sweden is based on water- and nuclear- power. The system is built on 50 Hz rotation. pv and wind energy need to be stabilized. Huge investments and it's Swedish tax payers and private energy consumers that have to pay, even if most of the money comes from EU. But we pay a lot to EU, more than we get back.

That's an interesting perspective. In the US the situation is quite the opposite. If it were not for some legislative hurdles where private households need to stay within the net-zero envelope, solar power could be used to mitigate many of the infrastructure problems by establishing micro cells/micro grids which are only near distance and because it is a distributed power system rather than a single point of origin, would require a lot less copper. Especially in urban areas like the big cities, these grids could be used to absorb the majority of the demand from AC during hot days with a lot of sun and then only the net deficit would need to be pushed through the main power grid.

It is coming, though. Despite the electric companies who originally opposed and lobbied against it. But with the recent power line-caused wildfires and litigation and the consequent increased safety requirements and necessary infrastructure updates (power lines under ground etc.) it is cheaper for those companies to embrace the distributed idea, even if it may cause a dip in short term revenue (that's the idiotic part, the expenditures can be written off ...)

I am pretty sure that the next 5 years will bring a major change-over - with the caveat of who's going to run the country.