Jeremy Harris Posted July 20, 2019 Posted July 20, 2019 Nice sunny day today. Hot water was recharged for free by 9 am. Washing machine ran for free after that this morning, then, when I came back from the supermarket run we were still exporting over 4 Kw, so I decided to charge the car. It finished charging about half an hour ago, with around 100 miles range gained for next to sod all (best I can estimate is that ~100 miles cost me around 5p). I read the meter this afternoon, and since January 15th we've used about 1,800 kWh, including charging my car.
MikeSharp01 Posted July 20, 2019 Posted July 20, 2019 Is that imported or a mix of home grown and imported KWh?
Jeremy Harris Posted July 20, 2019 Author Posted July 20, 2019 12 minutes ago, MikeSharp01 said: Is that imported or a mix of home grown and imported KWh? That;s all self-generated, except for about 0.35 kWh of import. I can live with paying about 5p for the day, given that I charged the car, did the washing and topped up our hot water for that. It also includes cooking two meals and few cups of tea. Bit of a cheap day.
MikeSharp01 Posted July 20, 2019 Posted July 20, 2019 Great news you are almost 'off grid' but I suppose we should also look at the capital cost for a comparison with on grid. I think you have talked about payback times before.
Jeremy Harris Posted July 20, 2019 Author Posted July 20, 2019 5 minutes ago, MikeSharp01 said: Great news you are almost 'off grid' but I suppose we should also look at the capital cost for a comparison with on grid. I think you have talked about payback times before. We're about a year away from the system having repaid its investment. It's generated around 33 MWh so far.
MrMagic Posted July 20, 2019 Posted July 20, 2019 (edited) Probably about 40miles from @JSHarris and was an 'average' day here....although saying that, looks like I crossed the 1MWh mark today, small victories. https://pvoutput.org/intraday.jsp?id=69928&sid=62139&dt=20190720 Oh to have more roofspace, less clouds and a neighbour without trees!! Edited July 20, 2019 by MrMagic
Ferdinand Posted July 21, 2019 Posted July 21, 2019 10 hours ago, JSHarris said: We're about a year away from the system having repaid its investment. It's generated around 33 MWh so far. Interesting the differences from orientation, position and trees. My rather larger array has general 16MWh since Feb 2016. I think Jeremy’s was put in in spring 2014.
ProDave Posted July 21, 2019 Posted July 21, 2019 Just had 2 weeks away leaving the house to look after itself. PV generation over that fortnight was a bit down on expectation. But not surprising, there has been a lot of rain here while we were away, it was on the news while away that the centre of Dingwall 12 miles from us flooded again (it last flooded in 2006 when they said that was a 1 in 100 year event) The PV panels kept the HW tank topped up, the ASHP used just 3KWh in addition to the solar PV power sent to the immersion heater. In that fortnight, we exported 24KWh which is roughly 4 times what we normally export. That will no doubt be when the immersion thermostat cut out and no more could be diverted to hot water.
SteamyTea Posted July 21, 2019 Posted July 21, 2019 55 minutes ago, ProDave said: the ASHP used just 3KWh in addition to the solar PV power sent to the immersion heater. You kept those on while away, why?
ProDave Posted July 21, 2019 Posted July 21, 2019 6 minutes ago, SteamyTea said: You kept those on while away, why? Yes. Don't want all that electricity getting all unwanted and exported now do we.
MrMagic Posted July 23, 2019 Posted July 23, 2019 O/T but thought it would be good to share the impact of shading...it really is shocking just how much of a difference it makes.
Jeremy Harris Posted July 23, 2019 Author Posted July 23, 2019 We're generating about 5.9 kW at the moment, down a bit because of the heat, I think (it's 31.8°C outside and still rising). Luckily we have no shade:
jack Posted July 23, 2019 Posted July 23, 2019 5.9kW for us as well. Our panel angles knock the top end off a bit, but we do get a good spread of generation across the day. I also need to spend a morning scrubbing the panels. I was up there last week and there's some minor algal growth on some of them that won't be helping matters.
K78 Posted July 23, 2019 Posted July 23, 2019 If it was like this everyday I would clad my house with PV panels.
SteamyTea Posted July 23, 2019 Posted July 23, 2019 1 hour ago, MrMagic said: the impact of shading...it really is shocking just how much of a difference it makes. Not really. Shading, in effect, turns a module into a resistor. I often wonder how shading impacts the longevity of modules, but a decent inverter should minimise that. Individual inverters on shaded modules is the best method.
MrMagic Posted July 23, 2019 Posted July 23, 2019 50 minutes ago, SteamyTea said: Not really. Shading, in effect, turns a module into a resistor. I often wonder how shading impacts the longevity of modules, but a decent inverter should minimise that. Individual inverters on shaded modules is the best method. I guess from a layman/simple-person like me it's surprising! I've got Tigo 'optimisers' on the panels, hence the panel level monitoring, so it's not so much of an issue.
ProDave Posted July 23, 2019 Posted July 23, 2019 3 hours ago, MrMagic said: O/T but thought it would be good to share the impact of shading...it really is shocking just how much of a difference it makes. Sorry to appear dumb, but can you explain what that picture is showing me?
MrMagic Posted July 23, 2019 Posted July 23, 2019 (edited) @ProDave No need to appear dumb... I didn't really give any context! Due to having a small roof I've essentially got two separate PV systems. One on the office (you can see in the background picture) and one on the main house roof. Each inverter is represented by the box with the squiggle on (technical term) - the number being the current output, i.e. 519 watts and 1176 watts. Each of the larger solar panel looking squares represents a solar panel - and the large number being the current watt output of that individual panel, the lighter the green the more output. These are all 300w max output panels. In this setup, due to shading mainly, Wagner installed Tigo optimisers on each panel - this gives the per-panel statistics + helps bypass the panel when shaded by the neighbours silver birch and all kinds of other stuff that I don't pretend to understand. Oh, and the point for posting was to show the difference between the unshaded panels producing ~225w and a shaded panel producing just 31 watts (top row). Hope that helps! Edited July 23, 2019 by MrMagic 1
ProDave Posted July 23, 2019 Posted July 23, 2019 7 minutes ago, MrMagic said: ach inverter is represented by the box with the squiggle on (technical term) - the number being the current output, i.e. 519 watts and 1176 watts. Each of the larger solar panel looking squares represents a solar panel - and the large number being the current watt output of that individual panel, the lighter the green the more output. These are all 300w max output panels. In this setup, due to shading mainly, Wagner installed Tigo optimisers on each panel - this gives the per-panel statistics + helps bypass the panel when shaded by the neighbours silver birch and all kinds of other stuff that I don't pretend to understand. Oh, and the point for posting was to show the difference between the unshaded panels producing ~225w and a shaded panel producing just 31 watts (top row). Hope that helps! Thanks. I thought it was trying to show power Vs time of day or sun elevation but with no scale. That makes a lot more sense now.
SteamyTea Posted July 23, 2019 Posted July 23, 2019 The main thing is that the optimised modules are giving out about the same power. This shows that the system is working as well as it can. 1
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