How solar thermal energy systems work and why they are worth installing

Solar energy has many advantages. Installing a solar thermal energy system, for instance, will save you money on your bills, protect the environment and provide you with hot water even when the grid is experiencing problems

Published on 13 January 2020

Functioning and advantages of a solar thermal energy system - Enel X

How is it possible that a visionary genius like Leonardo da Vinci failed to think of something as intuitive as using the heat of the sun to produce hot water? The answer is simple: he did actually think of it but, like many of his projects, the idea remained on paper. Only after the Industrial Revolution was it possible to turn it into reality. Indeed, the first commercial solar-powered hot water system was patented in 1891 by an American inventor, Clarence Kemp.

Solar energy has several advantages. Unlike fossil fuels, it is will never run out – well, not in the next five billion years, at least. This is why it is referred to as a “renewable source.” Furthermore, solar energy production does not release greenhouse gases into the atmosphere and is thus an important tool in combating climate change, the greatest environmental problem the planet is facing.

Another hugely important positive aspect of solar energy is its versatility as it can be used in different ways and for different purposes. Photovoltaic systems, for instance, use sunlight to generate electricity for private use (using now increasingly common panels on home roofs) or for commercial purposes (large photovoltaic farms managed by electricity companies). The panel helps cover the electricity requirements of a family unit or a building, thus significantly reducing electricity bill costs. Not only that, self-production guarantees re-supply of electricity in the case of blackouts or grid problems. In an increasingly flexible electricity system, this turns consumers into producers of electricity which can be fed back into the grid.  

Solar thermal energy systems, on the other hand, are mainly used for producing hot water for domestic use and, to a lesser extent, for heating. Underpinning the mechanism are solar panels which, unlike their photovoltaic counterparts, do not produce electricity. Rather they collect solar energy in the form of heat which is then transmitted to a fluid which in turn transfers it to household water.  There are two main categories of solar thermal energy systems: the simpler, natural circulation version, which is recommended for individual families, and “pumped” circulation systems which can produce large quantities of hot water, thanks to the use of a pump.

Installing a solar thermal energy system is worthwhile from many points of view. First and foremost, it helps cover the hot water requirements of a family unit or building. In summer, this can rise to nearly 100%, in actual fact.The initial financial investment will pay for itself very quickly through savings on electricity and gas bills. And, by producing zero-miles heat, you are also reducing the environmental impact relating to transportation of raw materials and energy.  

But that is not all. Solar energy – like other renewable sources – is always more financially competitive: this is why it is one of the driving forces of the current energy transition to a safer, more sustainable system. According to the 2019 New Energy Outlook 2019 published by BNEF (Bloomberg New Energy Finance), which is widely considered one of the most authoritative studies on the global energy market, solar and wind power will be supplying almost half of the electricity grid requirements by 2050. At the same time, thermal power stations will be supplying just 21% of electricity. From the standpoint of installed capacity, we will see a move from the current 57% accounted for by fossil fuel sources to two-thirds clean energy. The future will only get more renewable as time goes on, in other words.

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