Residential Solar Panel Confusion

In late 2018, under Amendment VC149, the State Government changed Clauses 54 and 55 and included new Decision Guidelines requiring consideration of the impact of overshadowing from new development, on existing rooftop solar energy systems, on neighbouring lots in residential zones. At the same time Planning Practice Note 88, Planning considerations for existing residential rooftop solar energy facilities, was released providing guidance on the new provisions to applicants and decision makers.

In a previous article we provided the following summary of VCAT decisions that have provided useful interpretations of the VC149 changes:

Mellas v Hobsons Bay CC [2019] VCAT 400 involved the construction of three double storey dwellings in the General Residential Zone. A neighbour appealed Council’s decision, raising concerns about overshadowing to solar panels (among other matters).

The Tribunal found that the extent of shadowing to neighbours’ solar panels was reasonable because:

  • A lower row of the neighbours’ panels on a single storey dwelling in an area where the Planning Scheme permits development up to 11 metres in height (General Residential Zone) was not ideally located to provide protection from shadow.
  • The complete avoidance of new shadow to the existing solar panels at the objector’s land would unreasonably constrain the development of the application site.

Cameron v Port Phillip CC [2019] VCAT 298 involved the construction of a dwelling in the General Residential Zone. The neighbour had an eight panel solar facility adjoining the subject site. The Tribunal made an interim order and required further information, including:

  • When the energy facility was erected on the subject building.
  • The model and type of energy facility (including whether the facility is ‘multiple string’ or ‘single string’, or if the facility uses a ‘feed-in’ or ‘battery storage’ installation).
  • Any other system features of the energy facility, such as micro inverters or bypass diodes, that assist operations of the facility in partial shading.
  • The maximum power generated from the energy facility and details of typical solar power generated during a 24-hour day – over a 12-month period.
  • The estimated loss of energy efficiency from the facility that may arise from overshadowing of the panels from the proposed development on the review site.

In this instance the neighbour’s solar system was an older ‘single string’ system. It was submitted that, in these systems, shading of any one of the panels would ‘significantly’ diminish energy output from the system. In its decision the Tribunal found that:

… the availability of an alternative location for the solar energy facility on the applicant’s property, including the age and use of single string panel technology, are all relevant considerations…


…an alternative location exists on the applicant’s site … [to] ensure unfettered access to sunlight throughout the day.

The Tribunal considered that the facility was outdated and suggested the applicant relocate the solar facility or upgrade the system.

Hall v Moreland CC [2018] VCAT 2022 involved the construction of a dwelling in the Neighbourhood Residential Zone. The neighbour was concerned about the impact on his solar (single stream) system during the warm months of the year.

The Tribunal noted that the zone provided for a dwelling height up to 9 metres and two storeys and that the construction of a single stream solar system was unsatisfactory in those circumstances, and also that overshadowing of the system could occur from other circumstances such as vegetation growth or other structures not requiring a planning permit. It was indicated that while it may be unfeasible to modify the system, that issue needs to be balanced against whether it is unreasonable to constrain or compromise a modest redevelopment on an adjoining lot.

Beal v Yarra CC [2019] VCAT 411 involved the construction of a two storey extension to a dwelling in the Neighbourhood Residential Zone. The dwelling to the south of the proposal had a bank of 12 solar panels on the north facing roof plane.  In the appeal made by neighbours, the Tribunal was not able to properly assess the impacts on the appellant’s solar system as the appellant had not provided details of the age, quality and type of system, it’s maximum capacity and extent of loss of energy efficiency. The Tribunal found that the appellant’s panels had not been installed in an optimal location.

Clause 1 Planning has also previously noted that we have been receiving requests for the following types of information, from Councils who are looking to assess the shadowing impacts on roof top solar systems:

  • 3D shadow or sectional shadow drawings to show the extent of shadow cast over the existing solar panels on the adjoining property. Shadow drawings must include the following times (daylight hours which provide function to solar panels):
    • winter solstice 22 June between 8am and 5pm
    • equinox 22 September between 7am and 5pm
    • summer solstice 22 December between 7am to 7pm
  • If solar panels are overshadowed, details (if possible) of the type of the existing rooftop solar energy facility e.g. single string or multiple string / or any other system features such as micro inverters or bypass diodes which can operate with partial shading.
  • An outline of how overshadowing of any existing rooftop solar energy facility is proposed to be mitigated.

Although the VCAT interpretations and list of the types of information Council’s are likely to seek (above) are of some assistance to permit applicants, there remains a significant lack of clarity on exactly how the impact on roof top solar systems should be assessed. In a more recent VCAT decision,  Ramjee v Manningham CC (Red Dot) [2020] VCAT 1 (5 February 2020),  the Tribunal has highlighted the inadequacy of the current situation and called for a more stringent state-wide assessment framework to assist permit applicants, affected parties and decision makers understand when overshadowing impacts are appropriate and when they are not. In Ramjee the Tribunal has noted:

Where assessments are undertaken of overshadowing impacts as in this case and others, the Tribunal’s findings are frequently and superficially limited to the net change in shadow impacts rather than the actual effects on a system’s performance – that is, the net change to a system’s energy output.

The introduction of a suitable methodology (such as the time of year and spread of hours) during which assessments are to be taken and clearer guidance on what constitutes an acceptable loss of a system’s overall performance at specified times would be of assistance to all stakeholders. The decision also notes that contextual considerations such as the strategic context of sites and the orientation of solar panels should preferably be incorporated into any newly developed methodology/provisions.

The absence of timely access to and ready availability of information about the type and operating characteristics of existing rooftop solar energy systems presents very real challenges for permit applicants formulating proposals and for decision makers tasked with assessing their effects. The introduction of a suitable framework facilitating access to such information and assessment guidance in circumstances where this information is absent may be beneficial.

For now, permit applicants should continue to rely on the principles contained in the cases listed above (Mellas, Cameron, Hall and Beal) for guidance on the impacts of overshadowing on roof top solar systems – however, we expect more stringent and clearer guidelines might not be too far away.

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