SOLAR POWER

There are two main types of solar panel in Ireland; solar thermal and solar photovoltaic (PV).

Although we don't receive much sun, Ireland can still benefit from solar power. It does not need to be sunny to generate power!

A reduction in our carbon emissions will rely heavily on the widespread implementation of all forms of renewable energy.

Solar power will be a key player in Ireland's changing energy scene.

Solar Power in Ireland

Solar PV capacity in Ireland is one of the lowest in Europe. Currently, Ireland has a total capacity of 15.7 MW, consisting of 11.9 MW residential capacity and 3.8 MW commercial capacity.

Solar PV only accounts for 0.1% of renewable electricity in Ireland and is the least utilised of the established renewable electricity sources. 

The cost of solar power has decreased rapidly in recent years. Solar power is quickly becoming the easiest and cheapest option to start producing your own green electricity in Ireland.

There are no large-scale solar farms in Ireland at the moment, although many are planned for the future. 86 developments were granted planning permission between 2015 and 2018. Commercial solar farms are currently more expensive than commercial wind farms in Ireland and so their wide-scale installation is still a few years off.

There is a desired 1.5 GW of grid-scale solar energy by 2030 as part of Ireland's Climate Action Plan. The Government have pledged to continue the long established grant programme, which is detailed below.

Solar Thermal

Solar thermal panels harness the sun's energy to produce hot water for a household or business.

They use the sun's rays to heat a water/glycol mixture that runs through the panel. This heat is then exchanged with water in a hot water tank.

This water is then pumped throughout the building to provide heat.

They only produce 5% of all renewable heat energy in Ireland.

Solar thermal panels cost less than PV panels and can provide 70-80% of hot water requirements. Their lifespan is 25-30 years.

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Solar Photovoltaic

Solar photovoltaic panels harness and convert the sun's energy into electricity to power homes and businesses.

They produce <1% of all renewable electricity in Ireland, although demand is rapidly increasing.

Their costs range from 3000 - 10000, providing up to 50% of electricity demand. Some companies quote higher figures. Lifespan is approximately 25-30 years, with panel efficiency decreasing around this time.

It is the cheapest and best grant-supported route to renewable energy micro-generation, allowing you to gain independence from the grid.

 

Solar Panel Home
Image by Vivint Solar

A solar thermal system consists of several individual components. The actual panels are referred to as collectors as they 'collect' heat energy. There are two types of collectors; flat plate and evacuated tube collectors.

Flat plate collectors are the cheapest solar thermal option available. The panels are flat and unobtrusive.

 

Evacuated tube collectors are more expensive but have increased efficiency and perform better in colder climates. The conical tubes have a greater surface area exposed to the sun than flat plate collectors. Evacuated tube collectors can also be tilted to take advantage of the winter sun due to the gaps between the tubes allowing wind to pass through. If flat plate panels were tilted, high winds could pull them off the roof.

A mixture of water and glycol flows through the panels. The glycol prevents the water from freezing during low temperatures. This mixture is heated by the sun and sent to a heat exchanger which is located inside a water cylinder. The heat exchanger transfers the heat to water within the cylinder, with the end result being usable hot water which is then pumped throughout your home or business.

The mixture returns to the panels to resume the collection of solar heat.

You should be aware that many companies have stopped supplying solar thermal panels due to reduced demand and the their disadvantages e.g. solar thermal panels are less useful when you have electric heating. Therefore, it can be difficult to find a registered installer.

A solar PV system consists of two main components; the panels and an inverter. The solar panels produce direct current (DC) electricity which is converted to alternating current (AC) electricity for use in our homes and businesses.

 

Solar PV generates electricity by converting the sun's light energy into electricity using photovoltaic cells, which are cells that produce electricity via the photovoltaic effect. We give a brief explanation of the process in a silicon cell below.

A silicon solar cell is essentially a sandwich of silicon doped/mixed with different materials to give them an affinity towards positively or negatively charged particles. These layers are separated by a single 'gap' known as a junction. When photons of light energy from the sun hits one layer of this sandwich, negatively charged electrons are knocked out of the layer. These electrons travel to the second layer which attracts these electrons. In short, the transfer of these electrons over the junction between these two layers generates an electric field. This is explained in more detail in the above video.

Solar PV Efficiency

The highest solar cell efficiency reported is 46% using non-commercial multi-junction solar cells.

Typical solar farms use panels with an efficiency of 15-20%. The maximum theoretical efficiency of a  single junction silicon solar cell is 33.7% and is known as the Shockley-Queisser limit. That is, under the best possible conditions, only 33.7% of all sunlight hitting a PV panel can be converted into useable electricity. Various natural factors which limit the absorbance of sunlight decide this maximum limit.

Even with such a low efficiency in comparison to other generation methods, the sun still produces enough energy to meet the entire world's energy demands many times over.

Solar Power Grants

Solar Thermal                               1200

Solar PV (per kWp)                        900
(to a maximum of 2 kWp)

Solar PV (per kWp)                   
     300
(2 - 4 kWp)

Total Available PV grant              2400
(4 kWp system)
                 

The government has committed to extending the grant scheme as part of the Climate Action Plan. The Sustainable Energy Authority of Ireland is the government body responsible for grant applications. Please follow the link below for more information on the grants available and how much you could save by installing solar panels.

 

There exists a long-established grant scheme through the SEAI available to homes built and occupied before the 31st of December 2020.

A grant of up to €2400 is available for the installation costs of solar PV panels and batteries for electricity storage.

For Solar PV, the grant amount is calculated based on the output of the solar panels. An applicant can receive €900 per kWp capacity up to 2 kWp, and then €300 per kWp from 2-4 kWp. Therefore, the total grant available for a 4 kWp system is €2400.

For solar thermal a grant of up to €1200 is available.

kW and kWp

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The average PV solar panel is ~300-400 watts.

Multiple panels are linked to give the total maximum output.

A Kilowatt peak (kWp) is the rate at which a panel generates electricity at peak performance.

A 3 kWp system consisting of 10 panels can generate 2800 kWp per annum.

The average consumption of an Irish household is 4200 kWp per annum.

Planning Permission

Planning permission is not required if the solar panels take up less than 50% of your home's roof. This equates to about 6 individual panels.

If your planned solar system falls outside these limits, is on a protected structure, or is located in a protected area then you should speak with your local council regarding planning permission.

Solar panels ideally require south-facing roofs for maximum output.

The roof should not be obstructed by trees or similar obstacles.

As solar panels have a long lifespan your chosen installer should ensure that your roof is in a suitable condition to support the panels. Wooden supports will be built onto your roof to support the panels.

As expected, some areas of the country are more suited to solar panels.

Solar Thermal panels require more direct sunlight than solar PV.

What Happens to Excess Energy?

Under the Climate Action Plan, the government introduced meters to every household in Ireland to allow the sale of excess renewable power to the grid. The Roll-out of these meters is scheduled to begin next year. Currently, any excess power that you do not use is sent to the grid resulting in no income for the owner.

There are a few options for the excess power if you do not want to provide energy companies with free electricity. The excess electricity can be diverted and used with an immersion heater to provide hot water for your home. This can result in water being heated unecassarily however, which should be avoided if possible.

Other than this you can store the electricity for future use using a battery, with a grant for this offered by SEAI.

There is no use for any excess hot water produced by solar thermal panels.

How can Grian help you?

Solar PV is currently the cheapest and most established option for personal renewable energy generation. Solar thermal is also widely employed in Irish households. There has never been a better time to install solar energy systems in your home.

 

Grian will determine using local solar data how much kWp a standard system could be expected to produce once installed, while also calculating the potential savings.

We will then contact Solar thermal and PV providers to determine what's the best option for you.

 

Recycling Solar Panels

PV recycling process statistics - useful info on what can be recycled from solar panels and the future of PV waste management.

PV Cycle - Global organisation set up to sustainably manage the future influx of PV waste.

Widespread implementation of solar panels would be pointless if there was no recycling system in place to deal with end-of life-panels. This is an important issue as there will be an estimated 60 million tonnes of solar PV waste by 2050.

As more solar panels begin to be decommissioned it remains to be seen if the recycling methods in place are both practical and sustainable. If the correct procedure is not in place then the world will face a new waste crisis to deal with the influx of end-of-life panels, dealing an ironic blow to our attempt to reduce our carbon footprint.

It is not currently economically viable in many countries to recycle solar panels. Hopefully, this will change as the market for solar panel recycling inevitably grows. Thankfully many countries require end-of-life panels to be recycled by law.

We have included some useful links below related to solar panel recycling.

Recycling In Ireland

Under EU law end-of-life solar panels in Ireland must be recycled. As solar power is relatively new in Ireland there are not many recycling services available.

WEEE Ireland announced a partnership in 2017 with PV Cycle, a non-profit membership-led organisation that deals with PV module waste collection and disposal. The benefit of this partnership should be realized in the coming years.

We have found two businesses currently catering to solar power recycling in Ireland, mainly damaged panels in need of replacement. We have included links below.

WE RECYCLE IT

RECYCLESOLAR.IE