MoneySavingExpert Chair, Martin Lewis · Editor, Marcus Herbert

Solar panel efficiency

Posts: 1,288 Forumite
I have a house with a flat roof and am interested in installing solar panels. However, in principle, we do not use enough electricity to make solar panels worthwhile.
However it occurs to me that there should be a substantial increase in the "efficiency" of the panels if they are simply moved once or twice a day. Is anyone able to do the appropriate calculation ?

• Posts: 13,822 Forumite
edited 10 September 2023 at 4:52PM
The word "simply" in your opening post is doing a lot of heavy lifting!
Usig PVGIS, modelling 1kWp of panel near Coventry, I get the following outputs:
• Fixed angle: 1003kWh/yr
• Vertical axis tracking: 1288kWh/yr
• Inclined axis tracking: 1284kWh/yr
• Dual-axis tracking: 1321kWh/yr
By moving the panels once or twice a day you'll have a smaller gain than any of the tracking options, plus you'll need to have a system for moving them which will add to the installation cost and require some sort of ongoing maintenance.
N. Hampshire, he/him. Octopus Go elec & Tracker gas / Shell BB / Lyca mobi. Ripple Kirk Hill member.
2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 30MWh generated, long-term average 2.6 Os.
Taking a break, hope to be back eventually.
Ofgem cap table, Ofgem cap explainer. Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs.
• Posts: 1,288 Forumite
I was actually thinking of moving the panels manually along some sort of rails. For QrizB"s figure it sounds like I might get an extra 10-15% that way.
Perhaps the first thing to do is find out what other people have designed.
• Posts: 4,110 Forumite
I like the notion of having each panel on a motor-driven turntable that rotates to always face the sun.  With a manual change of angle to the vertical that you can alter every few weeks to suit the season.  Unless you could find a way of doing this very cheaply I imagine the cost would not justify the benefit.
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