What is solar energy?
Solar power is energy from the sun that is converted into thermal or electrical energy. Solar energy is the cleanest and most abundant renewable energy source available.
Does Ireland get enough sun?
Ireland’s solar climate is as good as Paris and 70% of the solar climate on the Mediterranean coast. In Ireland a horizontal surface of 1sq.meter receives an average of approximately 1100 Kilowatt-hours (kWh) of solar energy per year (the equivalent of 120 liters of oil). Solar energy in Ireland is provided by both direct sunlight (40%) and indirect sunlight (60%). So, even when the sky is overcast, its radiation (light) is available at ground level and can be converted into useful heat by a solar water heater. With the right policy framework, solar energy could account for 10% of renewable energy generation capacity by 2020 – representing 500MW of installed generation capacity (ISEA).
What types of Solar Power Systems exist?
Solar panel electricity systems, also known as photovoltaics (PV), capture the sun’s energy using photovoltaic cells. The cells convert the sunlight into electricity. These cells don’t need direct sunlight to work – they can still generate some electricity on a cloudy day.
Solar thermal systems
Solar heat, also called solar thermal energy, describes the conversion of solar energy into a technically usable heat. Solar thermal heat is trapped using the greenhouse effect; a reflective surface transmits short wave radiation and reflect long wave radiation. Heat and infrared radiation (IR) are produced when short wave radiation light hits the absorber plate, which is then trapped inside the collector. Fluid, usually water, in the absorber tubes collect the trapped heat and transfer it to a heat storage vault. What can solar thermal systems be used for?
Solar water heating systems use free heat from the sun to warm domestic hot water. Solar panels heat water that is delivered to a storage tank. A conventional boiler or immersion heater can be used to make the water hotter, or to provide hot water when solar energy is unavailable.
Another option is collects the energy of the sun to heat water or air for direct use in solar home heating.
What happens when it is cloudy?
Solar panels work both on sunny and cloudy days. They not only harness direct sunlight when the sky is clear but also diffused light on the cloudy days, so you will still be generating electricity thought not as much as on a sunny day.
How can solar energy be stored for later use?
One of the problems with solar energy is that it can be intermittent, depending on the climate or time: sunny or not, day or night. The solution to this is energy storage and although it is still a new topic we can see many advances in this area of research. Today, energy storage is done through batteries and they can range from a simple car battery to more sophisticated backup systems. Another solution is ‘net-metering’. In general terms this means using the electricity grid as a storage option. So, owners of solar panels can feed the extra electricity generated during sunny days into the electricity grid and then, during the night or on cloudy days, use electricity from the grid. The downside of this is that the grid supply is generally from power plants using fossil fuels.
You can read GEAI’s position paper on solar energy (available soon).