SEC FAQ

Solar panels that transform light into electricity are known as solar photovoltaic (PV) panels. “Mono-crystalline silicon panels” are considered the most efficient type of solar PV panels at converting light into electricity and the most widely deployed type of rooftop solar worldwide.

At the point where sunlight strikes a solar PV panel, DC (Direct Current) electrical power is generated. This DC power then travels to an inverter where it is converted to usable AC (Alternating Current) power for use with any electrical devices such as TVs, phone chargers, microwaves, refrigerators, etc.

A solar PV system is typically made up of:

• Solar panels on the roof which generate DC (direct current).
• A mounting system which is the frame mounted to your roof to hold the solar panels.
• An inverter which converts this DC into AC (alternating current – to power your kettle, toaster, TV, etc).
• Optional – a diverter switch to use any surplus energy to heat your water.
• Optional – A battery storage system to save surplus energy generated during daylight hours for later use (night-time for example).

Yes they do. It is visible light that drives solar PV cells, not the heat from the sun. Therefore Ireland’s climate is much more favourable to solar PV than many people realise, allowing it to still function on cloudy or rainy days, (although not at the peak performance achieved on cloudless days).

The amount of electricity generated annually will depend on a range of factors including the hardware chosen, size of system, roof slope and the direction in which the panels are installed. Typically a 3kW (3 kilowatt) solar PV system would generate around 2,600 – 3000 kWh (kilowatt-hours) of electricity a year if well-located, about 50% of the annual electricity demand of an average Irish home. 

For perspective, an electric oven uses about 2.3 kWh for 1 hour of cooking while a 50” LED TV uses around 0.016 kWh for 1 hour of use.[1]

There are two main considerations when determining whether or not solar panels are right for you – (a) whether you have a suitable roof on which to install your panels and (b) what your pattern of energy usage is. 

Roof Suitability:

To determine if your roof is suitable for solar PV, you need to consider its age and condition, its slope and orientation, and if there is any potential shading from nearby trees or buildings. The best rooftops for maximising electricity generation are those with sufficient space to accommodate the required number of panels, have a 35 degree slope, a south-facing aspect, in good condition and have minimal shading. (However, the best aspect to maximise solar generation for your particular situation may be East or West depending on your pattern of energy usage – see below).

Pattern of Energy Usage:

As solar PV systems generate electricity only during daylight hours and predominantly around the middle of the day when you may be at work, you need to consider how much of the generated electricity you will use in your home. Without any additional systems, a lot of the generated electricity can be fed back to the grid. While electric utility providers will pay you a wholesale price for this excess solar electricity you provide them, you will save more by using it to meet your electricity needs rather than selling it to them.

1. Powering Your Home – The first destination for the electricity generated by your solar panels goes to meeting the power requirements of any electrical heating, lighting or running appliances you have operating at that time.
2. Charging the Battery (if applicable) –  Next, any surplus power will go towards charging your storage battery, (if you have one installed).
3. Hot Water Diverter (if applicable) – If your home has a MyEnergi EDDI hot water diverter installed, the system will then send surplus solar electricity to the immersion in your hot water tank to heat your water.
4. Smart EV Charger (if applicable) – Some chargers like the MyEnergi ZAPPI can be integrated into your solar PV system to use surplus power available to start charging your electric vehicle.
5. Exporting Power to the Grid – Finally, if there’s still excess electricity after other priorities have been addressed, it will be automatically fed back to the national grid and you will receive a wholesale payment for it. The payment rates vary by electricity supplier and you can export up to €400 annually without having to pay income tax on this revenue.

At certain times of the day or certain times of the year, solar systems may produce energy to be used in the home, stored in a solar battery for later use, or exported to the grid.

Conversely, there will be times when the power from the panels is not sufficient to export, store or use immediately. At these times, electricity will be automatically drawn from the battery (if part of the system) or imported from the grid to meet your needs.

It usually takes less than a day to install a domestic solar PV system. While the final size of the system depends on the household’s electricity demand and the availability of suitable roof space, below is a rough estimation of system size using 410W panels:

System Size Solar Panel Array

• 2 kWp (for small 2-bed home) ~9m2 area (~5 panels)
• 3.0 kWp (for larger 2-bed home) ~14m2 area (~8 panels)
• 3.5 kWp (for standard 3-bed home) ~16m2 area (~9 panels)
• 4 kWp (for larger 3-bed home) ~18m2 area (~10 panels)
• 5 kWp (for 4-bed detached home) ~22m2 area (~12 panels)
• 6.5 kWp (for 6-bed detached home) ~29m2 area (~16 panels)
• Please note: if you also wish to charge your electric vehicle (in addition to powering your house) with generated solar electricity, you will require more panels than the examples listed above

Generally, you will not need planning permission for solar panels. Solar installations can now cover the entire roof of a house, subject to minor setback distances from the edge of the roof (and from other roof structures like Velux windows and chimneys). However, ask your local authority for guidance about planning permission if your home is a protected structure or is located in a protected area, (e.g. an architectural conservation area).

The overall trend has been a considerable reduction in the cost of purchasing and installing solar panels over the last 10 years.

Broadly speaking home PV systems should range from around  €1,000 – €2,000 per kWp installed (ex VAT), but prices will vary depending on the hardware chosen, size of system, accessibility of the roof or site, and installer used.

Despite the upfront cost, it is worth remembering that there is a guaranteed return on investment with an average payback within 5-8 years (with the SEAI grant). After this time, you will be generating free electricity for the remainder of your system’s lifespan (25+ years).

Yes, there is an obligation for energy suppliers to pay their domestic customers for the excess electricity they generate with their solar panels that is exported back out to the national grid. Officially this is called the Clean Export Guarantee (CEG) tariff. To find out what rate you will receive, contact your current electricity supplier.

In a slightly different system to homeowners, businesses will be paid for surplus energy sold back to the grid through a Clean Export Premium (CEP) feed-in tariff.

Currently in October 2024, Pinergy pays the most for exported energy at 25 cents/kWh, followed closely by Energia at 24 cents/kWh. However, like their electricity price plans, suppliers may change these feed-in rates too, so the best now may not be the best in 6 months time.

The current rates as of October 2024 are:

• Pinergy 25 cents/kWh
• Energia 24 cents/kWh
• Electric Ireland 21 cents/kWh
• Flogas 20 cents/kWh
• SSE Airtricity 19.5 cents/kWh
• Bord Gais 18.5 cents/kWh
• Yuno Energy 15.89 cents/kWh

Income from exporting surplus solar energy to the grid is generally considered taxable. However, from 1 January 2024 until 31 December 2025 if you sell your electricity back to the national grid, you qualify for a tax exemption of €400 per year on this income. In other words, earning €400 or less from your exported energy will not be subject to income tax.

Here are a few ways to ensure you don’t exceed this €400 threshold:

1. Optimise Usage at Home: Maximise your own use of solar energy to reduce the amount exported to the grid. For example, run heavy demand appliances (like tumble dryers and electric showers) to consume more energy at peak solar generation times.

2. Monitor Your Exports: If possible, monitor your export amounts so that your income from exported energy remains within the €400 exemption limit. You can keep track of this in your bi-monthly bills from your electricity supplier. (Some suppliers may only list this in your bills every 6 months). If still exporting too much, consider shifting things you run exclusively on the cheaper night rate to the peak solar generating time instead, (heating your water or some charging of an EV for example).

3. Invest in Battery Storage: By storing excess energy instead of exporting it, you increase your self-consumption and reduce the chance of having to pay income tax on any additional earnings above the €400 annual exemption.

The solar PV system should be designed to supply a sizeable amount of electricity a household needs at the time of day it is needed so as to reduce spill of excess solar-generated electricity back onto the grid. 

For example, a house with regular daytime occupancy should use all energy-thirsty appliances during the peak solar generating hours of 10am-4pm. Examples of power hungry appliances include the tumble dryer, electric oven, washing machine, dishwasher, electric hob and electric shower.

For those who use the majority of electricity in the mornings, an east-facing panel array would make the most of the morning sun. Likewise, if you only use electricity in the evenings, a west-facing array may save you more money. If using most electricity at night between coming home from work and going to bed, consider adding battery storage to save the solar energy generated during the day to use at this time.

A solar optimiser is a device attached to each solar panel to maximise output by adjusting the voltage and current for optimal energy flow.

Optimisers allow each panel to produce at its maximum capacity regardless of the performance of surrounding panels. If one panel is soiled or is shaded by your chimney, nearby buildings or trees at certain times during the day for example, optimisers prevent it from reducing the output of the others and thus help increase overall system efficiency. An added benefit is that many optimisers also offer panel-level monitoring, allowing homeowners to track performance and identify issues more easily.

Your installer can tell you if the proposed roof space for your panels will require optimisers, and if so, how many.

Installing a ‘diverter switch’ like a MyEnergy EDDI will monitor the solar power generated by your system and the electricity demand in the home. If there is any excess generated, it is diverted to heat your hot water in your immersion tank which you can use later.

It can be a worthwhile investment for those who do not have a smart meter, pay a 24 hour electricity standard rate, generate regular excess solar power and need hot water daily.

However, if you have a smart meter/tariff, a diverter may not be as attractive an investment. Instead you could sell excess solar electricity to the grid at the export rate during the day, (earning 20c per kWh for example), and buy it back cheaper overnight to heat your water before 8am (paying 14c per kWh for example).

Other instances where a diverter switch may not be worth it are if you have a heat pump, (more efficient for heating hot water), if you have low hot water demand from your cylinder (as you use electric showers & don’t take many baths), or if you have other priorities for your excess solar such as charging a solar battery or electric vehicle for example.

Adding a battery may also help maximise use of solar electricity generated. For example, if not home during the day, the battery can store the solar power and allow you to use it at a time that best suits you.

In addition, if you have a smart meter/tariff, a great way to use the battery is to charge it up overnight on a cheap night rate, use that to power your morning routine, let the solar panels recharge the battery during the day and then use that to power your evening/night routine. In this way you are avoiding the use of expensive day rate electricity. 

Battery storage will add to the installation and maintenance cost of your PV system as it requires a hybrid inverter, battery pack and additional wiring, but it is certainly worth considering. To find out how much you can save by incorporating a storage battery into your solar system, use this handy battery calculator.

However, if not ready for battery storage yet, you can ask the installer to set up the necessary infrastructure now to easily incorporate it in the future.

The SEAI solar panel grant is available for all houses built before 2021 where no previous funding for Solar PV has been awarded for this address. It is based on the size of the system you install – i.e. more panels means a higher grant, but only to a maximum of €2,100.

System Size (Grant Value – based on 2024 values)

• 2 kWp solar PV system (€1,600)
• 3.0 kWp solar PV system (€1,850)
• 3.5 kWp solar PV system (€1,975)
• 4 kWp solar PV system (€2,100)
• 5 kWp solar PV system (€2,100)

Remember that if you install more than 4kW of solar, you will still only get a €2,100 grant. Other things you get installed (such as batteries and immersion diverters) do not affect the amount of the grant. The grant takes the form of a once-off payment to a homeowner once all work has been completed and a post work BER assessment has been done.

Several criteria must be met to avail of the grant –

• The grant is available for private residences built and occupied before 31st December 2020 and the grant applicant must be the owner. Besides owner-occupiers, private landlords can also apply. Note: Your electricity meter’s installation date determines your property’s construction date. Each property can only claim the solar grant once.
• Systems must be installed by an SEAI-registered solar company to qualify.
• Only new equipment is eligible, including solar PV panels, inverter, and mounting hardware. Work done must meet SEAI’s required standards.
• After installation, the home’s BER (Building Energy Rating) assessment must be carried out by a BER assessor from SEAI’s National Register.

For the Solar Meitheal programme, GDSEC will only engage SEAI registered installers who provide new equipment installed to SEAI approved standards.

You can apply for the SEAI solar grant by filling out the form on the SEAI Application Portal. You can find a complete guide to the process in this SEAI Solar PV Scheme Application Guide For Homeowners. Grant offer approval is very fast and only takes minutes in many cases.

Please Note: Wait for your transition to the winning Solar Meitheal installer and signed contract before applying for your solar grant. The installer will be able to talk you through the process if you are unsure. Then wait for your grant offer before you start the works. Do not start the installation of your solar system until you receive the grant offer.

After your solar panels are installed, you have to get a Building Energy Rating (BER) assessment of your property carried out. Without this BER, you will not be able to receive SEAI’s solar grant.

PV systems are very low-maintenance, but require occasional monitoring. The inverter should be checked routinely to make sure the system is operating with no errors. Also, it is good to get an idea of how much electricity your PV system could generate yearly from the installer and compare this with how much your system generates. If there is a huge gap between expected vs. actual, this is likely a failure in the inverter which might need replacement at some point. The solar panels themselves are extremely robust and usually have a 25 year+ lifespan, but consideration should be given to cleaning them every 6 months to a year in order to maintain optimum performance.