Paul Kenny, chief executive of Tipperary Energy Agency, presented the key steps involved in setting up a renewable electricity system in a farmyard and house context at the Energy in Agriculture event on Tuesday.
While this power cannot currently be sold into the grid, it can offset a significant portion of your electricity bills and grants are now available if the panels are installed on a domestic building.
1 Measure your consumption
The load needed to power your farm will determine the amount of energy you need to generate. If you have a recent ESB meter, its screen offers options to display this data. External devices are also available to measure loads. Take readings at different times of day.
It also pays to consider other loads you could convert to electricity before generating your free power, Kenny said. Would an electric car suit you? Do you have a bottled gas stove you could replace with an electric one?
2 Solar or wind?
Solar and wind options are available for self-consumption, but Kenny said solar is preferable in most cases. While large windfarms can achieve costs as low as €1,000 per kW capacity installed, this is closer to €6,000 for small setups, he warned.
"Small wind is very hard to make pay, but it will work if the site is very windy, with a large load such as heat pumps and a big enough turbine," he said.
3 Size your system
In Ireland, solar panels generate on average 4.5kWh per kW of capacity installed, but this can peak at 7kWh on summer sunny days, with regional variations.
"Aim for your load to be between the average and the peak," Kenny said. If your load is, for example, 10kW, solar panels with a capacity of 13kW to 15kW would be suitable. These will end up covering 10% to 15% of your electricity needs, Kenny said.
You can install more capacity and divert the extra electricity to a dump such as a water heater or to battery storage. In this case, solar can economically generate up to 30% of your electricity.
It is not economical to design a system that would cover your peak needs because much of the power would go unused at other times and there is currently no option to sell it to the network.
4 Face the sun
Solar panels should be south-facing for maximum efficiency. However, having some panels facing more towards the east and others westwards will spread power generation evenly from morning to evening, Kenny said. This may be more suitable to your needs and will not necessarily increase costs proprotionally, as each panel will generate less electricity and the cabling and inverter can be sized accordingly.
5 Choose your components
Solar units require:
Photovoltaic (PV) panels, which Kenny said do not vary significantly in price from one supplier to the next.A mounting system, which can range from cheap aluminium rails on a roof already oriented in the right direction to more costly ground-mounted systems.An inverter to convert DC power from the panels to DC power used by appliances.Cabling and a breaker on the fuse board.The installation must be connected to the grid to switch on and off between your solar and mains supplies.
"You can't use solar PV in your house as an off-grid system," Kenny said. The system will also switch off if the ESB supply is cut off to protect any maintenance staff working on your outside line.
6 Battery or not?
"Batteries used to be expensive, but they are falling rapidly in cost," Kenny said, adding that they would form a standard part of solar installations in two to three years. Their current price is €300/kWh. Size wise, "the sweet spot is usually between 10% and 15% of the electricity you produce," he added.
7 Planning permission
Solar panels are exempt from planning permission under 50m², which represents 12kW capacity, but Kenny hopes this will be increased soon. In the meantime, he advised that they should be included in any planning application for a new building at no extra cost – just in case.
Read more
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Paul Kenny, chief executive of Tipperary Energy Agency, presented the key steps involved in setting up a renewable electricity system in a farmyard and house context at the Energy in Agriculture event on Tuesday.
While this power cannot currently be sold into the grid, it can offset a significant portion of your electricity bills and grants are now available if the panels are installed on a domestic building.
1 Measure your consumption
The load needed to power your farm will determine the amount of energy you need to generate. If you have a recent ESB meter, its screen offers options to display this data. External devices are also available to measure loads. Take readings at different times of day.
It also pays to consider other loads you could convert to electricity before generating your free power, Kenny said. Would an electric car suit you? Do you have a bottled gas stove you could replace with an electric one?
2 Solar or wind?
Solar and wind options are available for self-consumption, but Kenny said solar is preferable in most cases. While large windfarms can achieve costs as low as €1,000 per kW capacity installed, this is closer to €6,000 for small setups, he warned.
"Small wind is very hard to make pay, but it will work if the site is very windy, with a large load such as heat pumps and a big enough turbine," he said.
3 Size your system
In Ireland, solar panels generate on average 4.5kWh per kW of capacity installed, but this can peak at 7kWh on summer sunny days, with regional variations.
"Aim for your load to be between the average and the peak," Kenny said. If your load is, for example, 10kW, solar panels with a capacity of 13kW to 15kW would be suitable. These will end up covering 10% to 15% of your electricity needs, Kenny said.
You can install more capacity and divert the extra electricity to a dump such as a water heater or to battery storage. In this case, solar can economically generate up to 30% of your electricity.
It is not economical to design a system that would cover your peak needs because much of the power would go unused at other times and there is currently no option to sell it to the network.
4 Face the sun
Solar panels should be south-facing for maximum efficiency. However, having some panels facing more towards the east and others westwards will spread power generation evenly from morning to evening, Kenny said. This may be more suitable to your needs and will not necessarily increase costs proprotionally, as each panel will generate less electricity and the cabling and inverter can be sized accordingly.
5 Choose your components
Solar units require:
Photovoltaic (PV) panels, which Kenny said do not vary significantly in price from one supplier to the next.A mounting system, which can range from cheap aluminium rails on a roof already oriented in the right direction to more costly ground-mounted systems.An inverter to convert DC power from the panels to DC power used by appliances.Cabling and a breaker on the fuse board.The installation must be connected to the grid to switch on and off between your solar and mains supplies.
"You can't use solar PV in your house as an off-grid system," Kenny said. The system will also switch off if the ESB supply is cut off to protect any maintenance staff working on your outside line.
6 Battery or not?
"Batteries used to be expensive, but they are falling rapidly in cost," Kenny said, adding that they would form a standard part of solar installations in two to three years. Their current price is €300/kWh. Size wise, "the sweet spot is usually between 10% and 15% of the electricity you produce," he added.
7 Planning permission
Solar panels are exempt from planning permission under 50m², which represents 12kW capacity, but Kenny hopes this will be increased soon. In the meantime, he advised that they should be included in any planning application for a new building at no extra cost – just in case.
Read more
Big players prioritised over farmers in renewable energy acceleration
Downey and Smith back in (solar) power
Dempsey at Large: energy is where it's at
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