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The complete guide to solar panels

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Everything you need to know about how energy from the sun creates clean, green electricity for homes and businesses in Northern Ireland.

Solar power provides a renewable and sustainable source of electricity in Northern Ireland. At the core of that process are solar panels, which capture the power of sunlight and use it to generate electricity.

We’re going to dive into some of the most common questions about solar panels and guide you on the best way to take advantage of the benefits of solar power in Northern Ireland.


Article contents:

  • Solar panels explained 
    • What is a solar panel?
    • How do solar panels work?
    • How much energy do solar panels produce? 
    • How efficient are solar panels? 
  • Top benefits of solar panels
  • Key considers before installing solar panels
  • Solar panel tips & tricks
  • Selling solar energy with Power NI
  • FAQs 


Solar panels explained 

What is a solar panel?
Solar panels are large, flat surfaces made from silicon or an alternative semiconductor that capture sunlight and convert the energy it contains into electricity. They can be attached to homes or business premises to generate electricity. 

The three main types of solar panels in Northern Ireland are monocrystalline, polycrystalline, and thin film.

  Monocrystalline Solar Panels Polycyrstalline Solar Panels Thin Film Solar Panels
 Appearance:  Black and uniform appearance Blue and marbled appearance Clean black appearance, which sit flat against roofs
Material: Silicon Silicon Glass or layers of photovoltaic (PV) materials
Commonly used: Suitable for all types of installations — the most common type of solar panel Suitable for low-cost residential installations Suitable for awkward spaces or buildings, where thicker solar panels not appropriate
Pros: This is the most efficient solar panel type, with the most subtle and consistent appearance This solar panel is more affordable compared to monocrystalline, and is also less wasteful to make This panel is unobtrusive, with a clean design and has the lowest installation costs
Cons: These panels have white space around individual cells and have a high cost
 These panels generate less electricity, and can have an
inconsistent/conspicuous appearance
These panels have the lowest performance and shortest lifespan

How do solar panels work?
Solar panels work by taking photons — the small packets of energy that make up sunlight — and converting that energy into electricity. Let’s take a more detailed look at how solar panels produce electricity.

  1. The sun gives off light, which travels in the form of photons. 

  2. The photons hit the photovoltaic (PV) cells of the solar panel. This creates an electrical charge.

  3. The DC current of the charge is converted into the AC current we need for our homes by an inverter within the solar panel.

  4. The AC current flows through a meter and into your home’s consumer unit.

  5. When you use electricity, it automatically comes from the free electricity you’ve generated.

  6.  Any extra electricity you generate but don’t use can be sold back to the grid.


How much energy do solar panels produce?
The amount of energy produced by solar panels depends on several factors. This includes the capacity of the solar panels, the number of solar panels in the system and the amount of sunlight, as well as the pitch and direction of the roof. An installer will be able to survey your roof and give an estimate of how much solar energy you’ll be able to generate. 

  • The average energy output for domestic solar panels is between 250 and 400 watts per hour.
  • Most domestic solar panel systems need a capacity of 4kW per hour.
  • A three-bedroom house in Northern Ireland will need around 16 solar panels.
  • The electricity generated and used is free, so your electricity bills will be lower.


How efficient are solar panels in Northern Ireland?
Although solar panels work best and create most electricity in direct sunlight, they are still effective in cloudy and even rainy conditions. Solar panels need only light to generate electricity. It’s only at night that solar panels will stop generating electricity.

The sunlight we get on a cloudy day in Northern Ireland still generates electricity, but it will be significantly less than when we’ve got clear blue skies and sunshine. Around 80% of solar power is generated between March and September.  But our rainfall can be useful: by washing away dust and dirt, rainwater helps solar panels to continue to work effectively. 


Top benefits of solar panels

There are many benefits of installing solar panels in Northern Ireland. Some of the key advantages include:

1. Environmental benefits
Solar power is a form of green, clean and renewable energy. Switching to solar energy will dramatically reduce your carbon footprint. In fact, having solar panels on your roof is estimated to save one tonne of carbon dioxide emissions every single year.

2. Save money & earn money 
With the right solar panel system, you’ll be able to generate most or all of your own electricity, particularly if you install a battery to store electricity created when you’re not at home. This will cut your energy bills. You can also earn money by selling electricity from your solar panels on days when they generate more than you need.

3. Electricity in all seasons
Solar panels work efficiently all year round. They need sunlight, not heat. Although they will generate substantially more electricity in the direct sunlight and long daylight hours of summer, solar panels continue to generate electricity on a cold winter’s day. Around 20% of the electricity from a typical solar installation will be generated between October and February. 

4. Increased property value
All of the benefits we’ve mentioned so far — especially the opportunities to generate money, reduce your carbon footprint and have greater energy efficiency — can make a property highly sought-after. As a result, installing solar panels may increase the value of your home.


Key considerations before installing solar panels 

Solar panels are a big investment so it’s important to give everything careful consideration before going ahead. There are several things to think about to help you decide whether solar power is right for your home.

Roof size & sun direction 
Do you have enough space on your roof to be able to install solar panels? 
An average installation will need around 20m2 of roof surface area. If you don’t have a roof that’s large or strong enough to accommodate the number of solar panels you need, solar power might not be feasible for your home.

Sun direction and shade are other important factors. South-facing roofs will generate the most electricity. South-facing roofs in coastal locations are among the highest generators because they also benefit from reflected sunlight from the sea. East or west-facing roofs could yield 15-20% less electricity, and north-facing roofs are not recommended. Shade from neighbouring buildings, trees or chimneys could also impact performance.

Permission & regulations 
You don’t normally need planning permission to install solar panels in Northern Ireland. But you might need to do so if you live in a conservation area or in a listed building. It’s best to double-check with your local authority’s planning office before going ahead with an installation.

All solar installations in Northern Ireland must meet Engineering Recommendation EREC G98/NI standard. After installation and commission, your installer will register your generator connection with NIE Networks to confirm that your solar panels are connected to the grid. You can then register with us for the export of the electricity you generate.

Upfront & ongoing costs
Installing solar panels is a considerable investment, usually between £4,000 and £9,000. Solar panels in Northern Ireland currently cost around £780 for each 350-watt solar panel. Unfortunately, there are no solar energy grants in Northern Ireland at the moment. That means a 10-panel system suitable for the average three-bedroom house will cost around £7,800.

Solar panels require very little maintenance, but regular cleaning by an installer and cutting back any trees that cause solar shading will ensure your system continues to generate efficiently. The inverter may need to be replaced, but no other servicing should be required within a solar panel’s 25-year lifespan. One optional extra cost is to “pigeon-proof” your solar panels by adding mesh, skirting or anti-roosting spikes. This typically costs £600-£1,000.

The Energy Saving Trust says a three-bedroom house in Belfast will save between £95 and £375 per year on its electricity bills. On top of those savings, you could make more money by selling the energy you’re not using. See the current rates.


Solar panel tips & tricks 

If you’re ready to go ahead with a solar panel installation, there are several things you can do to improve the efficiency of your solar panels and get the best return on your investment. Simply follow these solar panel tips and tricks.

Prioritise daylight hours  - Use your electrical appliances during the day to make the most of your solar panels during daylight hours. Set timers on your washing machine, dishwasher and other appliances so that their cycles run when your solar panels are generating the most electricity. That will help you to avoid paying for electricity in the evening.

Reduce electricity use (one appliance at a time) - Remember we said to set the timers on your appliance to take advantage of the daylight hours? Make sure to set them for different times so that you’re never using more electricity than your solar panels are generating. That means using only one energy-hungry appliance at a time and taking steps to reduce your electricity consumption in general.

PV diverters or battery storage systems - Installing a PV diverter might add £800 to your solar panel installation costs, but it enables you to make the most of the electricity you generate. Instead of exporting electricity back to the grid, with a PV diverter you can use it to power your immersion heater to give you hot water to use later. A solar battery is another way of capturing electricity that you don't need during daylight hours so you can use it later. 

Reduce shade - Keeping shade off your solar panels will help to maximise their efficiency. This may mean trimming trees that have grown since the system was installed (or politely asking neighbours if they would mind trimming their trees). If you can’t avoid shade, installing a micro-inverter will help to maximise output from the unshaded areas of your solar panels.  

Upgrade appliances - By upgrading to more energy-efficient appliances you can reduce your electricity consumption. This increases the likelihood of the energy generated by your solar panels being able to cover all or most of your energy use. The same principle applies to energy-saving LED bulbs.

Monitor via app - Using an app like the Power NI app helps you to monitor your electricity use in real time. You can also get apps that link to your solar panels to give you a full picture of what’s being generated and what’s being used at any time. That helps you to adjust your energy usage to get the best results.

Regular checks – Regularly monitor readings from the generation meter — a meter installed at the same time as the solar panels to track the total energy generated — will help you check the system is working properly. Sometimes systems can trip and may not automatically switch back on. 


Selling solar energy with Power NI 

We’re committed to supporting renewable energy production in Northern Ireland at every scale. If you’re generating solar energy at home, we’d be delighted to buy it from you.

If you’re creating more renewable energy than you use, you can sell the excess energy to us via Microgeneration. Our Microgen tariff sets out how much we’ll pay you for the electricity you export to the grid. This allows you to generate long-term income from your solar panels.

The rates are approved by the Utility Regulator, so you have peace of mind that you're getting a fair price. You'll also have a dedicated online account to keep track of all payments and submit meter readings.