Solar Together

[DrFfybes]

So after 34 days (572Kwh) I have recouped 1% of the capital cost of my system. It is early days and I am yet to work out the benefit of leaving the immersion switch on and not using gas for water heating. For the last two weeks we have been near to 100% self sufficient for our electric needs, some days courtesy of our 20Kwh battery set up.

If you have battery then simply get a timer and set the HW on a timer to suit - we have 2-4pm and 10-11:30pm. makes no difference if your store your energy as heat or in the battery, although when you get your export up and running it might make sense to heat it in the afternoon from sunlight or overnight on cheap reate depending on the tariff.

Waiting on paperwork before sorting out which energy provider to go with and get my feed in up and running.

Considering 4 more panels on a North West facing portion.......

I'm astounded you haven't had the electronic copies of the certs - mine took 4 days. You only need the electronic ones, as you attach them to an online application to the provider.

Oh, and why are you waiting to decide? - rates have just changed so get looking

Paul (March export 404p less than import, including standing charge )

[flyer61]

Paul

I still haven't paid...ergo no paperwork but the rest of it I will pull finger....

[the0ni0nking]

Looking back now on the month of March - installation was completed on the 13th so first full day of "solar" was the 14th.

Inclduing standing charge the 1st to the 13th electric bill worked out at £3.90/day - with 14.23kwH per day of grid usage

The 14th to the 31st electric bill worked out at £1.31/day - with 2.88kwH per day of grid usage. This equates to a reduction of £2.59/day.

Additionally, the total kwH exported to the grid came in at 67.3kwH - which at the SEG tariff rate for British Gas (15p) would be 56p per day (average daily export of 3.74kwH).

When looking at the modelling from the quotation, March should have seen an average bill reduction of £95 compared to pre-solar and my pro-rata calcs suggest it would have come in at £97.70.

The way it seems to be working is - now using April times given the clocks have changed - the 7 West "ish" facing panels start generating around 6.45am and are generally covering the load by half 7 to 8am. Their production generally peaks over the hours of 10-12. The 8 East "ish" facing panels start ticking up from about 10am, peaking between 2-4pm and declining to close to 0 around 6-7pm. If the weather is sufficient to charge the 10kW battery to 100% then it would generall cover the load overnight until the panels kick in again.

I suspect the weather at the back end of March was slightly more favourable than normal but I don't have any historic data to compare to.

[UncleEbenezer]

The way it seems to be working is - now using April times given the clocks have changed - the 7 West "ish" facing panels start generating around 6.45am and are generally covering the load by half 7 to 8am. Their production generally peaks over the hours of 10-12. The 8 East "ish" facing panels start ticking up from about 10am, peaking between 2-4pm and declining to close to 0 around 6-7pm.

Is it your panels that put you in a mirror-image world?

[the0ni0nking]

One thing I’ve noticed in respect of the battery is that once it reaches full charge and while the panels are still generating more than enough to cover the domestic load, the battery starts to provide a very minor amount of the power (like 10w or so) which results in the export being 10w or so higher.

I’m no tech expert but I assume there is a reason for the battery to behave like this? The amount is so small generally it’s still at either 99% or 100% power when the solar generation falls below the load. I assume it’s a built in part of the battery system to improve its longevity but have no real idea?

[BullDog]

Looking back now on the month of March - installation was completed on the 13th so first full day of "solar" was the 14th.

Inclduing standing charge the 1st to the 13th electric bill worked out at £3.90/day - with 14.23kwH per day of grid usage

The 14th to the 31st electric bill worked out at £1.31/day - with 2.88kwH per day of grid usage. This equates to a reduction of £2.59/day.

Additionally, the total kwH exported to the grid came in at 67.3kwH - which at the SEG tariff rate for British Gas (15p) would be 56p per day (average daily export of 3.74kwH).

When looking at the modelling from the quotation, March should have seen an average bill reduction of £95 compared to pre-solar and my pro-rata calcs suggest it would have come in at £97.70.

The way it seems to be working is - now using April times given the clocks have changed - the 7 West "ish" facing panels start generating around 6.45am and are generally covering the load by half 7 to 8am. Their production generally peaks over the hours of 10-12. The 8 East "ish" facing panels start ticking up from about 10am, peaking between 2-4pm and declining to close to 0 around 6-7pm. If the weather is sufficient to charge the 10kW battery to 100% then it would generall cover the load overnight until the panels kick in again.

I suspect the weather at the back end of March was slightly more favourable than normal but I don't have any historic data to compare to.

Thanks, that's very interesting reading. So you're presently getting around 12 hours useful generation every day it seems. I have south eastish and north westish roof surfaces and I've always resisted the idea of solar panels. Perhaps the price, especially with battery storage, is getting to the point I should revisit my thinking. I'm pretty certain that even without solar generation I could timeshift all my electricity consumption to the low tariff I have overnight with a ~10kw hr battery. Solar generation would be a bonus in addition to that.

[flyer61]

Well after 78 days of generation since installation we have produced our first 1Mwh (1000Kwh). Sadly the grid has snaffled 175Kwh of production. Interestingly we have used 170Kwh from the grid in that period. So in the lovely conditions we have been enjoying almost total self sufficiency and 'saved' about £230 in electricity costs, nearly £3 per day on average. I am yet to analyse the effects of having the electric immersion on all the time versus our gas consumption.

Just waiting for the paperwork to get my feed in tariff sorted.

[the0ni0nking]

Thanks, that's very interesting reading. So you're presently getting around 12 hours useful generation every day it seems. I have south eastish and north westish roof surfaces and I've always resisted the idea of solar panels. Perhaps the price, especially with battery storage, is getting to the point I should revisit my thinking. I'm pretty certain that even without solar generation I could timeshift all my electricity consumption to the low tariff I have overnight with a ~10kw hr battery. Solar generation would be a bonus in addition to that.

I think I should clarify this as I think it varies significantly on whether or not it is a sunny day (noting that I am not in the UK to be able to monitor the weather each day).

On a day where there is sunshine, the E & W facing panels both generated electric which graphically looks like a flattened parabola over the course of the day. The E facing starts off say at 0630 and declines to close to 0 around 1600. The W facing starts off say at 0900 and declines to close to 0 around 1900. The drop off on the W facing panels seems more severe than the E probably coinciding with the sun going behind the houses on the other side of the road.

On a cloudy day, the performance of the panels are obviously lower but much more closely aligned graphically and the both graphs are a very very much flatter looking parabola.

I'm guessing April so far has been clear and fresh in Yorkshire - so far this month only 4.1kWh have been drawn from the grid against 202.4kWh exported (at time of writing).

For the 2nd half of March which basically coincides with the date of install 13/3 and working from 14/3, import was 46.5kWh versus export of 67.3kWh.

British Gas still haven't advised me of the detail re export (I've had one email saying they're setting it all up). I pay the electric and gas bill at that property (part of the rental arrangement) so the DD to them is still £250/month which is ok as it's therefore included in the Santander Edge account which pays me a % back on household bills etc - currently the amount paid back is more than the monthly fee so it's worth continuing that account for the moment and I'd likely have difficulty opening any new one given my non-resident status in the UK.

[flyer61]

I should of said 51 days for my 1000kwh.........doh!!