Solar

 

The typical cloudy weather of Ireland often makes its inhabitants doubt that solar energy can be used on the Emerald Island. However, Ireland does get enough sun to harvest a fair amount of energy from it.

Ireland’s solar potential is as good as Paris and 70% as good as the Mediterranean coast! Its solar energy is provided by both direct sunlight (40%) and indirect sunlight (60%). Even when the sky is cloudy, solar radiation can be converted into useful heat by solar panels. If Ireland manages it right, solar energy could represent 10% of the energy it produces by 2020

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 The International Energy Agency states that: “In 90 minutes, enough sunlight strikes the earth to provide the entire planet’s energy needs for one year”.

 Solar energy, through different technologies, can help produce energy or heat buildings and water.

 

SOLAR HEATING SYSTEMS

There are two main types of systems able to create heating and hot water: flat plane solar thermal and evacuated tube.

Flat solar collectors can often be seen on roof tops or as part of them. They are heavy, rigid, and robust plane structures that look like boxes. They are adapted to structures that do not need very high temperatures; such as regular houses.

Evacuated Tube Collectors look like several tubes put together on a roof. They are light so they cannot be part of roofs as flat collectors can be, but they are far more efficient than them. They can provide approximately 20% more energy than flat collectors. Consequently, they do not take up as much room. They can operate with just a little light and they can create high temperatures. Some people find them less visually attractive than the flat collectors, but it is simply a matter of taste.

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Picture of both evacuated tubes and flat panels taken from the blog “Alternative Power Distribution” – Link: https://alternativepowerdistribution.wordpress.com/2011/03/16/using-evacuated-tube-solar-collectors-guidelines-for-plumbing-contractors/

SOLAR POWER GENERATING SYSTEMS

Solar energy often uses devices with complex names, such as photovoltaics (PV) and Concentrated Solar Power (CSP). They are devices that capture the heat from the sun and use it to create electricity.

  • PV panels directly convert the light into electricity;
  • CSP uses mirrors to redirect the sunlight towards a small area, either a tube or a solar power tower. A solar power tower receives a lot of sunlight from the mirrors around it and uses it to heat the water it contains. The steam produced by this phenomenon runs a turbine and a generator to create electricity.

 

… And if it is cloudy?

Solar power generating panels work both on sunny and cloudy days. They do not need direct sunlight; diffused light on the cloudy days is enough and will allow them to create as much electricity as on a sunny day.

 … And at night?

 It is the same for wind turbines when wind is not blowing, energy needs to be stored to be used when its source is missing. Please refer yourself to the “WIND” section of our website – right next to this one – in order to know more about how energy storage works.

 … Would it save money for me?

 PV panels could produce almost half of the annual electricity consumption for a regular house.

A solar thermal system can provide hot water all year round: 90 to 100% in summer, 60 to 70 % in spring and autumn and 10 to 20% in winter. So, they allow their owners to save up to 60% or 70% of their hot water bill each year.

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Solar panels in Belfast – credits to Katsiaryna Trusova

The payback comes quickly too. For example, if an Irish household of 5 people is replacing an oil or gas water-heating system, solar installations have a payback in about 6 to 8 years. If the heating system is electric, the payback is between 4 to 5 years.

Their other advantages are that the resource (light from the sun) is free, clean and unlimited. As the panels can be placed on the buildings, no extra space is needed for them. They require very few maintenance and can be installed anywhere: from a completely isolated house which have troubles accessing the electric grid to any city.

Opponents of solar energy can say that the way they are built is not as green as the energy they produce. Almost half of the world’s photovoltaic panels are produced in China, where those industries do not give a lot of importance to actually protecting the environment and its workers. If the solar panel industries could make efforts not only to focus on the final product they sell but also on the way they are built, this market could have more clients, who want to be sustainable from an environmental but also from a social point of view. The prices of the panels may rise, but protecting our planet and the workers’ rights is probably worth it.

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Putting solar panels in Senegal; credits to “Bread for the World”. Picture found in “policy innovations” website, in article: “Send salads to Ethopia, and Solar Panles to Senegal”: http://www.policyinnovations.org/ideas/commentary/data/000250

 

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