Solar panels for farm buildings
Most modern farm sheds in Ireland can take solar panels. A box-profile steel roof is ideal, each kWp needs 4 to 5 m² of roof, and panels on a farm building roof are exempt from planning permission in most cases. Asbestos roofs cannot take panels.
Which shed roofs suit solar panels
| Roof | Suits panels? | What to know |
|---|---|---|
| Box-profile steel | Yes | The standard modern shed roof. Panels fix to the purlins, and the roof usually carries the load without reinforcement. |
| Fibre-cement | Case by case | The sheets are brittle, so fixings go into the purlins, never the sheet alone. An older roof is better re-sheeted first. |
| Asbestos-cement | No | Common on sheds built before the 1990s. Installers will not drill or mount on it. It has to be professionally stripped and replaced first. |
Older sheds can have light purlins. Ask the installer to confirm the roof can carry the load before you agree a price.
How much roof you need
- Per kWp: 4 to 5 m² of roof, generating about 860 kWh a year
- Typical farm buildings: 200 to 1,000 m² of roof
- One hay shed: room for a 50 to 100 kWp system
- Panel weight: about 12 to 15 kg per m²
Pitch and direction
- Pitch: 10 to 35 degrees is ideal
- South: the highest output across the year
- East and west: lower peak, but generation is spread across the day, which suits morning and evening milking
Planning permission for panels on farm buildings
| Where the panels go | Planning | Conditions |
|---|---|---|
| On a farm building roof | Exempt, no cap on area | Within 15 cm of a pitched roof, at least 50 cm in from the edge, and not above the ridge |
| On a roof inside a Solar Safeguarding Zone | Exempt up to 300 m² | Tell the council in writing within 4 weeks of starting |
| On a farm building wall | Exempt up to 75 m² | Within 15 cm of the wall and 50 cm in from its edge |
| Ground-mounted in the yard | Exempt up to 75 m² | No more than 2.5 m high, and not in front of the nearest farm building to the road |
| Solar farm exporting to the grid | Permission needed | The exemptions only cover power mainly used on the holding |
The exemptions apply when most of the electricity, over 50%, is used on the holding. A protected structure always needs permission. There are 43 Solar Safeguarding Zones in Ireland, so check with your county council whether the farm is inside one.
Things specific to the building
- Pig units: ammonia and dust corrode fixings and cabling, so ask for suitably rated mounting, isolators and enclosures
- Separate meters: if the yard and the house have their own electricity supplies, the array goes on the one with the biggest daytime load
- Export: a smart meter is needed to be paid for surplus power
- Grant: TAMS 3 pays 60% of the cost of a system on a farm building. See farm solar grants