Over an uninterrupted period of least 19 years and a day, a window or other aperture in a building can acquire a “right to light” over nearby land. Once this happens, the window owner can prevent the nearby land owner building on his land in a way that reduces the amount of light passing through the window below a reasonable minimum. No reported case has yet decided whether or not a PV panel can acquire such a right. Current law has three critical points:
- There must be a defined window or other aperture that lets light pass.
- The aperture must serve a building, and
- The reasonable minimum is what the accommodation lit by the window reasonably needs “according to the ordinary notions of mankind”, which may be less than the amount of light passing before the offending new building went up.
The clearly defined edges of a PV panel appear similar enough to a window frame to allow a Chancery Judge to decide that a PV panel meets Point 1.
Point 2 is more problematic. Churches, picture galleries, open-sided garages and domestic greenhouses, as well as conventional houses, workshops and offices etc., have been classed as buildings for this purpose. The open-sided garage case decided that a “building” (a) gives substantial shelter from the elements, (b) requires to be lit through apertures in the ordinary way and (c) is so firmly integrated into the ground that it has become legally part of the land and would pass automatically with a transfer of the land. Surmounting this hurdle looks daunting.
The reasonable minimum (Point 3) allowed to the greenhouse owner was enough to grow ordinary greenhouse crops such as tomatoes, but not enough for what the 1978 Court of Appeal Judges called “exotic purposes”. It is distinctly possible that what a PV panel operator considers the irreducible minimum (i.e. all the light there is) may be more than a Chancery Judge considers to be the reasonable minimum.
If a PV panel can acquire such a right, it must enjoy the light for at least 19 years and a day to do so. It may be several years before a PV panel owner can claim one. Litigation could arise sooner if a neighbour, concerned that a PV panel may be steadily acquiring a right to light over his land, serves a light obstruction notice. This effectively forestalls a right to light being acquired, by interrupting the 19 years and a day period.
Preserving the light reaching a PV panel may, in some limited circumstances, be a valid planning consideration, but even when it is, it may be outweighed by others in the mind of the planning authority. Private rights between separate land parcels are generally irrelevant for planning purposes.