Solar PV … Free Renewable Energy from the Sun

Solar PV Photovoltaic), is a technology that converts sunlight into electricity As the world continues to transition towards sustainable energy, the use of Solar PV (photovoltaic) technology is becoming an increasingly popular choice for homeowners, businesses, and farmers to generate their electricity, reduce their carbon footprint, save on energy bills and even help to power electric vehicles.

Originally developed to power satellites in space, modern PV cells are now affordable enough to be combined with solar panels and used to generate electricity for our homes and business. Solar PV systems are now one of the cheapest ways to generate electricity and they provide an energy source that is sustainable, clean, and free.

Every second of the day, the Sun converts more than 4 million tons of its mass into energy-producing solar radiation. In just 90 minutes enough sunlight strikes the Earth to provide the entire planet’s energy needs for one year!(-source SEAI learning hub)

What is Solar PV?

The term solar panel is often used interchangeably to describe the panels that generate electricity and those used to generate hot water.
Solar thermal collectors are used to produce hot water, while Solar PV panels are used to generate electricity and are referred to as solar photovoltaic panels (Solar PV).

How does Solar PV work?

Solar PV systems use cells consisting of one or two layers of semiconducting material, to convert solar radiation into electricity. Solar PV works by using solar panels to capture energy from sunlight and convert it into direct current (DC) electricity.

An inverter then converts the DC electricity into alternating current (AC) electricity, which is what powers your home. The electricity generated by your solar panels can either be used immediately, stored in a battery, or fed back into the grid.

Is Solar PV an option for your home?

Several factors need to be considered to assess whether Solar PV is suitable for your home:

• Panel location – usually panels are placed on the roof of the building. These roofs are usually pitched, but solar panels can also be installed on flat roofs, and also at ground level.
• Orientation – The best performance is obtained when the solar panels are facing due south, but southwest and southeast also provide good performance. East and West orientations also work but will produce less electricity. Any other orientation could fail to provide enough electricity to make an installation economically viable.
• Tilt – The tilt angle is also important. To get the best performance the panel should be perpendicular to the Sun. The pitch angle of your roof will determine the panel tilt angle. Lower tilt angles give better Summer performance as the Sun is higher in the sky. Higher angles give better winter performance as the Sun stays lower.
• Obstruction & Shading –  You need to check if there is shading or obstruction from trees, other buildings, or structures. Just one shaded panel will affect the performance of the entire array.
• Roof Structure – You’ll need to check that the structure is able to take the weight of the panels. Most pitched roofs should be suitable but a structural survey will be required before an installation goes ahead.
• Electricity Requirements, Budget & SEAI Grants – You need to work out how much electricity you need to generate. You will need to weigh up your objectives, the amount of electricity you require, the cost of installation, and then look at the SEAI grant allowances for Solar PV to see if this is a viable option for you.

A Home Energy Assessment is the best way to have your home professionally assessed. 

A Note on Flat Roof & Ground Installations

Flat Roof Installations

Panels can be installed on flat roofs but will need a frame to provide a tilt. On flat roofs, it’s usually possible to orientate the panels so they face due south or as close to due South. as possible. The frame also requires ballast to ensure that it remains secure in high winds and this can add substantial weight so not all flat roofs will be suitable.

Ground Installations

Panels can also be installed at ground level but again a frame is required to provide a suitable tilt angle. Ballast may also be required unless the frame is fixed to firm concrete foundations.

How Many Solar Panels Will Be Required

A typical domestic installation could require between 4 – 7 panels, which forms what is referred to as an ‘array’. Solar Panels are normally manufactured in standard sizes, the most common size is 1 m x 1.7m. In order to assess how many solar PV panels are right for your home, a detailed assessment of your needs, as well as the other points mentioned above would need to be taken into consideration for an accurate calculation.

A Home Energy Assessment is the best way to have your home professionally assessed. 

Will Solar Panels work on cloudy days?

Yes, solar panels work well on cloudy days. Obviously, the sunnier or brighter it is the more electricity a solar PV system will generate, the orientation and tilt will also play a part, but yes, the system will generate electricity on a cloudy day.

In Summertime – Solar PV works really well and generally can produce more electricity than is required for immediate use. When the sun is shining each panel can generate between 250 W and 350 W depending on the type of panel used.

In Wintertime – Solar PV works less well but because the panels work even on cloudy days they can still generate enough electricity to meet many household needs.

During average weather conditions in Ireland, you can expect 1 kW of panels (4 panels at 250W) to generate between 700 and 900 kWh of electricity per year. Comparing your annual electricity consumption with how much electricity you can generate on-site will give you an idea of how much electricity will still need to come from the great.

For systems larger than 2 kW, some form of storage should be considered to increase self-consumption. A Home Energy Assessment will help analyse your needs and size your installation accordingly.

What Is Needed to Create a Functional Solar PV System

To create a functional Solar PV system a number of components are required.

1. Solar PV panels – a sufficient number of panels to serve your needs.

2. Monitoring Display (optional) – Most solar systems will have a display panel that shows you how much power is been generated. This can be wired or wireless and some can even provide data via an app on your smartphone.

3. Inverter – The solar panels produce direct current electricity (DC) which needs to be converted to alternating current (AC) to operate appliances in your home or business. The inverter performs this task as well as smoothing the power to the distribution box and providing information to the monitoring display on how the panels are performing throughout the day.

4. AC Distribution Unit – The electricity from the inverter is fed into your AC distribution box where it is then used instead of electricity from the grid.
On dull days and at night the distribution unit will use electricity from the grid unless you have some battery storage in which case that can be used before switching to the grid.

5. Battery Storage (additional option) – A Solar battery stores the energy generated during sunlight hours and makes it available for use at night or on cloudy days. It is an additional cost in the solar system but provides flexibility and means that electricity is not wasted during periods when the panels are producing the maximum output.

Is Planning Permission Required for Solar PV Panels?

For solar panel installation on houses: there is no limit to the area of solar panels which can be installed on rooftops of homes, anywhere in the country.

Solar installations will be able to cover the entire roof of the house. The 12 sqm² – 50% roof limit which was previously applied to houses has been removed nationwide. You will need to inform the ESB of your installation.

What if your system produces more electricity than you need?
Then you have a few options:

• Battery Storage – you can store excess electricity using special batteries. There are a number of different products on the market, but keep in mind, this will add to the cost of the overall system installation.
• Heat Hot Water – a hot water immersion diverter can be used to divert excess electricity to an electric immersion in your water tank to heat hot water. These are a relatively inexpensive addition to a solar PV system though you will need a hot water tank with an immersion heater.
• Charge an EV – with electric vehicles becoming more popular, once you have a charging station installed at home, you can charge your vehicle with the excess electricity generated.

Types of Solar Panels

There are two main types of Solar Panels. Both are manufactured using silicon as the semi-conducting material, but the construction is slightly different. Each type has advantages and disadvantages.

1. Monocrystalline panels – have higher efficiencies and sleeker aesthetics they are black so they tend to blend in better with dark roofs but they cost more to manufacture. Panel efficiency ranges from 17% to 22% which means that you may need fewer panels to produce the same amount of electricity as if you were using polycrystalline panels.

2. Polycrystalline panels – have lower efficiency than monocrystalline panels but cost less to manufacture. Panel efficiencies range from 15% to 17% which means that you may need more panels to produce the same amount of electricity as monocrystalline panels.

What is the Cost of Installing a Solar PV System in Ireland?

The cost of installing a solar PV system in Ireland depends on various factors, including the type of panels, size of the system, monitoring equipment, and the complexity of the installation. However, the cost has been decreasing in recent years, making it more affordable for homeowners and businesses and the SEAI provide grants to help with the cost of this home energy upgrade.

Grants offered are provided by the Government of Ireland through the Sustainable Energy Authority of Ireland (SEAI).

Solar Farming in Ireland 

Solar Farming is becoming a popular choice for some business owners to generate their own power and get electricity directly from ‘farm’ to factory. It is a cost-effective, sustainable way to generate clean energy as well as create jobs and additional income streams for landowners

Solar Farms in  Co. Tyrone, and Eli Lilly Pharmaceutical plant in Cork, now have solar farms to send electricity direct from their own solar farm to the factory.

In the case of Eli Lilly, they have the farm installed on their own land, using a ‘direct wire’ system. that literally sends electricity over the fence to the manufacturing site, just 200 metres away! The ground panels are placed high enough off the ground to allow sheep to under graze, creating a mutually beneficial sustainable set-up.

Read more about Solar Farms in our news section. 

Video Credits:

Thank you to RTE Nationwide, and reporter Niall Martin and the businesses showcased in this informative and exciting piece showcasing how Irish business owners are being innovative and making the most of renewable solar power, taking it from farm to factory direct.

This episode of Nationwide aired Wed 26 April 2023

SEAI Grants – Grants offered are provided by the Government of Ireland through the Sustainable Energy Authority of Ireland (SEAI).

INSULEX is registered with SEAI as a One Stop Shop for Home Energy Upgrades.