The local planning department has an exemption specifically for the installation of Solar Panels.

The document ‘Land Planning and Development (Exemptions) Ordinance 2007’ can be found on this link.

Land Planning and Development (Exemptions) Ordinance 2007

The section on the exemption for solar panels states the following:

Where the panel is mounted on a roof:
• it is installed parallel to the plane of the roof slope
• it projects no more than 30 centimetres from that plane
• the panel is not installed on any roof slope facing a highway

Where the solar panel is mounted on the ground:
• Where the panel is mounted on the ground, no part of it is located forward of any elevation of the dwelling-house that faces a highway
• it does not exceed 2 metres in height
• the total area of the panel to be installed, or of that panel together with any other panel mounted on the ground within the curtilage, does not exceed 10 square metres
• it is not located more than 30 metres from the dwelling-house

The size of the panel is only restricted when it is placed on the ground, therefore we do not need to consider the size of the existing solar hot water panel. Better yet the additional PV Panels are covered under the same exemption used to install the solar hot water collector.