Paddy Rose, Renewable Energy Manger at Advanced Heating & Energy Systems Ltd explains some of benefits of a Solar PV system and why it’s very much the way of the future. Paddy has over 15 years experience with renewable energy, primarily with solar thermal. He is also a part-time lecturer at CIT Cork on solar thermal and PV.
What is Solar Photovoltaic and how does it work?
Translated literally Photovoltaic means lights-electricity. Solar Photovoltaic (PV) technology converts sunlight directly to electricity by means of PV cells made of semiconductor materials.
The amount of panels equates to a certain kw output, for example a 2kw system, 3kw system or 4kw system but we will come back to that…
The different components of a PV system include PV modules, which are commonly called PV panels; one or more batteries; a charge regulator or controller for a stand-alone system; an inverter for a utility-grid-connected system and wiring; and mounting hardware or a framework.
The direct current is isolated with switches and is then sent to an inverter; the inverter changes the direct current to alternating current, which we use in our homes and factories.
We size a PV system in an existing building from the amount of electricity used annually. Other factors that determine what size system is suitable is the system’s compatibility with the building in question, whether it’s domestic or commercial, single phase or three phase and so on.
What is the difference between Solar Photovoltaic and Solar Thermal Panels?
The principle behind both technologies is the same – they use solar radiation (energy from the sun) to create usable energy.
Solar thermal transfers this energy through a solar panel, either flat plate solar or tubed solar, to the water cylinder in a house, heating the water.
Solar PV uses the sun’s raw energy to create electricity, which is used first, before grid electricity, to support any Item in the building that is drawing power. It can also be diverted to assist with hot water production.
How well does Solar PV work in the Irish climate?
We are always reliant on the weather conditions when it comes to renewable energy. However, in general we have good results from Ireland. We always explain to customers that a PV system is dependent on the climatic conditions, and clearly outline how production will vary based on this, so the customer will understand how their system will be of benefit to them.
My house is 10 years old and is heated by oil. If I get Solar Photovoltaic panels on my home, will they work in conjunction with the oil burner or will I have to change my heating system completely.
Solar PV has nothing to do with the heating and the oil boiler/gas boiler. In this particular instance the PV system has the capability based on design to be diverted to heat the domestic hot water cylinder. However to support heating with PV is not really possible. Some heat pumps can be supported by PV (electricity) in cost reduction, but again this is based on the design of the system
What will adding Solar PV panels to my home do for my energy rating?
Yes, it does improve your energy rating. A BER assessor is the right person to advise on how much it can change for the better
What kind of cost am I looking at?
A system can start from €3000 upwards. The electricity you use annually will determine the system size to install.
My electricity is approx €120 every two months and I spend approx €500-€600 a year. €What kind of savings can I make to my electricity and my heating bills?
Different rates may apply but if you take a cost of a unit of electricity as being .15 cent without the VAT, then If you spend €120 per two months that is about 800 units per two months. 800 units per two months over one year is approx. 4800 units per year. So if you install a 4kw system, it will give you approx. 3700 units per year and 3700 units per year at .15 cent is €555 in potential savings!
I say potential savings because there are a lot of variations to be taken into account from the weather conditions to how we live in the house. For example when a system is producing 3kw per hour and if during that time no one is in the house and only one kw is being used by the standby energy in the house, the problem is that 2 kw goes back to the grid wasted.
We have a solar diverter, which is used to heat domestic hot water in case this happens but you will still have losses, as we may not always be capable of using the free electricity.