Three things about plug-in solar that are not in the coverage

1. A second instrument lands the same day, and nobody is reporting it

Coverage of 27 August 2026 concentrates onSI 2026/848, which makes plug-in solar legal to connect. A second order comes into force on exactly the same day:the Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026.

It writes plug-in solar into planning law for the first time, then removes permitted development rights in two cases. For equipment on a building:

in the case of plug-in solar, where any part of the plug-in solar would be installed on a wooden wall, balcony or enclosure or on any part of the exterior of a block of flats which is clad in timber

And for free-standing equipment:

in the case of plug-in solar, any part of the plug-in solar would be installed on a wooden fence, gate, wall or other means of enclosure

Why it matters. A wooden balcony and a garden fence are the two places a renter would naturally put a panel. Both leave the permitted development route on the day the product becomes legal. It is not a ban; it means a planning application, which on a £400 kit is usually decisive.

Check it: open the order, article 3(d) for buildings and article 4(1)(d) for free-standing. Article 1(2) gives the commencement date. England and Wales only.

2. The industry tells people the opposite of what the regulation says

Regulation 22(2)(c) of the Electricity Safety, Quality and Continuity Regulations 2002 requires that the distributor is advised

before, or at the time of, commissioning the source

The Energy Networks Association's current Distributed Generation Connection Guide: G98 & G99, version 3.0 of March 2026, summarises the process as "fit and inform" and has the installer notify within 28 daysafter commissioning. Its earlier summary guide states plainly that you do not need to talk to your operator before the equipment is running.

Why it matters. Notification is not a standalone duty you can be late on. It is one of three conditions in regulation 22(2) that exempt you from having to agree specific requirements with the operator. There is also a gap the guidance does not anticipate: every step of the G98 process assumes an accredited installer, and a tenant plugging in a certified kit does not have one.

Check it: regulation 22(1)(d) sets the demanding route, 22(2) removes it subject to three conditions, and (c) is the timing one.

3. A panel flat against a railing beats a tilted one in winter

We modelled an 800 W kit in London withPVGIS, the European Commission's irradiance system, at two angles.

Why it matters. In midwinter the British sun barely clears 15 degrees, so an upright panel points at it while a tilted one points past it. The upright panel also varies only 1.8 times across the year against 3.8 times for a tilted one. Since winter output is far more likely to be used rather than exported for nothing, the gap in money is narrower than the gap in kilowatt hours. The mounting most renters are stuck with is the one that handles winter best.

Method: 0.8 kWp, 14% system losses, due south, London coordinates, PVGIS v5.3 queried 12 August 2026. Modelled, not measured. We have not metered a panel over a winter and say so.

Using this

All of it is free to use. Attribution is welcome but not required; the underlying documents are public and you should cite those. If you want the figures for a different city, or the full twelve-city dataset, ask and we will send it.

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Contact

hello@flatwatt.co.uk. We answer quickly and we would rather be corrected than quoted wrongly.