Green Building Forum - Maximising solar PV utilisation Wed, 29 Apr 2026 13:13:27 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131479#Comment_131479 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131479#Comment_131479 Sun, 22 Jan 2012 20:28:52 +0000 Gavin_A Posted By: bot de paillehttp://www.britishgas.co.uk/business/products-and-services/energy-management/smart-metering.html
erm yeah, the link was referring to an electricity smart meter.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131542#Comment_131542 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131542#Comment_131542 Mon, 23 Jan 2012 09:27:12 +0000 Seret
Arduino based:
http://openenergymonitor.org/emon/node/217

Bit more rough-and-ready:
http://www.yougen.co.uk/blog-entry/1737/Auto+control+enables+use+of+solar+PV+for+immersion+heater/

To my mind there's nothing wrong with doing this. The pricing structure implies minimising your export, and you'd be mad not to really. Ideally we'd be able to store excess electricity, but the economics of battery storage are marginal at best according to my calculations. I really think there's a huge gap in the market for a practical home storage system for on-grid PV. Perhaps as current batteries continue to improve it will come, but I wouldn't be surprised to see it come from out of left field either.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131556#Comment_131556 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131556#Comment_131556 Mon, 23 Jan 2012 10:36:08 +0000 SteamyTea Posted By: Seretbut I wouldn't be surprised to see it come from out of left field either.

Will almost certainly be a resistive load such as water or space heating as that has virtually zero electrical losses. That is the trouble with the grid being pretty good at delivering electrons.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131580#Comment_131580 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131580#Comment_131580 Mon, 23 Jan 2012 13:38:13 +0000 Seret
Until then, storing your excess electricity as heat seems like the simplest and most economic solution for a homeowner.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131592#Comment_131592 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131592#Comment_131592 Mon, 23 Jan 2012 14:50:08 +0000 DamonHD
With a typical swing in generation intensity (kgCO2/kWh) in the GB grid of (say) 20% as of now, it is just possible that a good inverter/charger with Li-chemistry batteries could have an energy loss of significantly less than 20% round-trip and actually lower a typical house's carbon footprint. But only just, and not in winter when we seme to run coal generation pretty-much flat out for now. Not possible at all so far as I can see with lead-acid batteries (round-trip losses at least 20% themselves), even ignoring any emboddied costs.

Rgds

Damon]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131641#Comment_131641 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131641#Comment_131641 Mon, 23 Jan 2012 17:44:38 +0000 fostertom Posted By: Seretthere's a huge gap in the market for a practical home storage system for on-grid PVElectric car]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131642#Comment_131642 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131642#Comment_131642 Mon, 23 Jan 2012 17:45:42 +0000 fostertom Posted By: Seretstoring your excess electricity as heatElectric (night store) Aga]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131648#Comment_131648 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131648#Comment_131648 Mon, 23 Jan 2012 17:56:22 +0000 skyewright Posted By: fostertom
Posted By: Seretstoring your excess electricity as heat
Electric (night store) Aga
At the risk of stating the obvious it seems likely that for most installs, most of any "excess" occurs outwith the heating season...]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131652#Comment_131652 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131652#Comment_131652 Mon, 23 Jan 2012 18:01:01 +0000 SteamyTea ]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131653#Comment_131653 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131653#Comment_131653 Mon, 23 Jan 2012 18:04:36 +0000 fostertom Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131709#Comment_131709 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131709#Comment_131709 Tue, 24 Jan 2012 01:16:59 +0000 Phil.Chaddah-Duke Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131710#Comment_131710 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131710#Comment_131710 Tue, 24 Jan 2012 07:52:23 +0000 Sprocket
OK, I feel a bit better about the idea now.

> electric car >most of any "excess" occurs outwith

I had also been seriously considering this.
As long as I can work around a car that has to be parked at home in the sunny part of the summer day.
Shame there is no sensible storage for this... two cars to swap is pushing it a bit.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131745#Comment_131745 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131745#Comment_131745 Tue, 24 Jan 2012 11:24:43 +0000 skyewright Posted By: SeretThe pricing structure implies minimising your export
Perhaps, unintentionally entices rather than implies?

Posted By: SeretUntil then, storing your excess electricity as heat seems like the simplest and most economic solution for a homeowner.

Depending on:
a) The cost of the "maximisation" technology.
b) The available "excess" that you actually have a use for (and the value that can save, compared to other sources for that usage).
c) The technology &/or implementation being smart enough to avoid accidental increased import.

Ethical issues aside, unless those factors combine to produce a realistic payback for the "maximisation" process, the most economic solution is to be happy with the generous FIT and let the excess out into the grid...

[aside]
One problem with the current system is that without an export meter (which applies to most installs) the owner not only doesn't know how much they are actually exporting (making it difficult to assess the maximisation potential), they don't know exactly how much they are using (as opposed to importing) either!
[/aside]]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131752#Comment_131752 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131752#Comment_131752 Tue, 24 Jan 2012 11:56:26 +0000 Seret
Ethical issues aside, unless those factors combine to produce a realistic payback for the "maximisation" process, the most economic solution is to be happy with the generous FIT and let the excess out into the grid...


Dumping the power into an existing immersion heater can satisfy all of that for about £100, so the break-even point would seem to be at about 2500kWh compared to gas or 800kWh compared to electric. How quickly you hit that is obviously going to depend on how big your array is, what other loads you're meeting, and (as you say) how efficient your dump load system is.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131767#Comment_131767 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131767#Comment_131767 Tue, 24 Jan 2012 13:23:19 +0000 skyewright Posted By: SeretDumping the power into an existing immersion heater can satisfy all of that for about £100, so the break-even point would seem to be at about 2500kWh compared to gas or 800kWh compared to electric.
With just a standard immersion as the dump (and without spending extra on 110V transformers, etc.) isn't maximisation only available when generation is above houseload + 3kW, squeezing the annual potential yield notably?]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131769#Comment_131769 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131769#Comment_131769 Tue, 24 Jan 2012 13:28:24 +0000 SteamyTea ]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131773#Comment_131773 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=131773#Comment_131773 Tue, 24 Jan 2012 13:49:44 +0000 Seret Posted By: skyewright
With just a standard immersion as the dump (and without spending extra on 110V transformers, etc.) isn't maximisation only available when generation is above houseload + 3kW, squeezing the annual potential yield notably?

Yes, it wouldn't be at all practical without limiting the power going to the heater. You can of course get 1kW immersion heaters, but they're upwards of £50 anyway, so you'd be better off trying to control the power properly IMO.

Obviously the ideal system would accurately monitor the excess power available, and trim the output to the heater to match. The Arduino system could do this, but the parts to pull off this kind of power electronics are fairly expensive. It's probably more cost effective to just cut in relays at 500W and 1kW like the bloke I linked to.]]> Maximising solar PV utilisation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=154794#Comment_154794 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8456&Focus=154794#Comment_154794 Thu, 23 Aug 2012 17:35:14 +0100 jamesw http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=9487]]>