Solar Thermal Energy

Solar Thermal Energy (STE) – In recent years, much attention has been given to the benefits of generating electricity from solar panels. The advantages to be gained from renewable electric power sources. However, the power of the sun can also be harnessed in a more straightforward. Sometimes more efficient way, to provide energy directly for heating buildings, and for a commercial or domestic water supply. As energy prices inevitably increase, an Solar Thermal Energy installation will make increasing sense for many homes and businesses in the UK.

solar thermal energy
Image: Markel Redondo by (CC BY-NC-ND 2.0)

How Solar Thermal Energy Works

The principle is simple. STE is harvested using a panel to absorb the sun’s rays, which are used to warm a fluid, or, in some cases, air. The fluid can simply be water, or, in areas at risk of freezing temperatures, a glycol mixture similar to that used in car radiators. The warmed water is circulated, sometimes passively but usually by a controller, and generally through a heat exchanger. It can then be used as part of a heating or hot water system, or in more sophisticated applications, as part of a power generation system.

How Efficient is STE?

The materials used for solar panels have been extensively researched and developed in recent years. As a result, even in cold or cloudy weather, enough heat can be absorbed through the panels to produce a useful effect. The system may be able to pay for itself in a comparatively short period of time.

How Safe is STE?

Solar Thermal Energy installations present few risks to the user, but lightning protection, surge protection, and earthing in particular, must be considered.

Lightning Protection for STE Systems

Like any metallic equipment in an exposed position, a STE array needs lightning protection. There may be an additional hazard from induced surge currents if, for example, there are power cables nearby. In this case, the surge protection is needed even when a direct lightning strike does not occur. In either case, the lightning or surge protection will be effective only if the earthing is adequate.

What Kind of Lightning Protection and Earthing is Necessary?

If the building on which the STE array is being installed already has its own lightning protection, it may simply be necessary to ensure that the Solar Thermal Energy system is linked to it, and that the earthing is of sufficient quality. (In every king of surge protection, good earthing is crucial.) It is also possible to install lightning and surge protection specifically for the STE system. Which may make sense if, for example, it is being fitted at a distance from the building.

Installing a Safe STE System

A good solar energy engineer will ensure that lightning and surge protection, and the necessary earthing, are part of the initial installation. On very tall buildings or in particularly exposed locations, where lightning strikes are common or where overhead power cables pose additional risks, the advice of a specialist may be necessary.

Solar Energy – Saving our Planet

Solar energy could solve our need for power. With time running out to come up with a solution, Desertec Foundation have unveiled their plans to develop sustainable energy sources – primarily through solar plants in the desert.

No Control

By the year 2050 we will need THREE TIMES Earth’s natural resources to sustain ourselves.

In just 36 years we will need three Earths to sustain just one! Imagine your children and grandchildren plunged into energy focused catastrophes, darkness, war? Unfathomable.

A Ray of Light

As poets use pathetic fallacy to relate emotion to weather, scientists are starting to do the same. In true dramatic fashion the sun could save our problems.

To give you an idea, at any time the sun emits roughly 3.86 x 1026 watts of energy. In basic terms, add 24 zeros to the end and you can appreciate its sheer power! On a clear day, 1m2 of earth will absorb 1KW of that energy.

A standard swimming pool, roughly 48m2, would absorb about 288KW during six hours of midday sunlight. That is the equivalent of 10 times what the average US household uses in an entire day!

So in theory, just harness the sun’s energy and put an end to this renewable energy debate?

The Plan of Action for Solar Energy

Desertec Foundation has developed some interesting plans which aim to do just this. On their diagram below, the squares represent the size that a solar energy plant would have to be to develop the energy needed today in the World, Europe and Germany respectively. Not as large as you thought?

Earth Africa

Considering the size of inhabitable land on Earth, we could easily spare this space couldn’t we? Desertec Foundation believes deserts could be the key. Build these solar energy plants in these wastelands, out of people’s way and, without mass disruption. But who would own them? Who would have control over the Earth’s power? Is that something that one nation should control?

Putting politics to one side, Desertec have also sourced Europe’s renewable energy scope.

Desertec Renewables Map

Risks and Consequences

The links between energy sources would be large scale connectors and inter-connectors. Such HV does pose great risk however. Monitoring and understanding the flow of energy would be critical and this is where GreyMatters comes in.

Awareness of soil resistivity or protecting these energy sources from the harmful effects of lightning would be essential. Imagine the chaos if a solar energy plant was directly struck by lightning, the immense dispersion of energy… it would be pandemonium and potentially fatal!

Although this plan is a mammoth task and still in abstract form, is renewable energy not worth our time and investment? Should saving our world not be our priority? Well, I suppose we have plenty of time right … 36 years …

It’s time to act!

What is Concentrated Solar Power (CSP) And How Will CSP Benefit Us In The Future.

Understanding Concentrated Solar Power (CSP). And How Will CSP Benefit Us In The Future. So, in simple terms. Concentrated Solar Power. Or CSP is a system that uses lenses and mirrors. To concentrate a large amount of sunlight onto a small area. Electricity, produced when the captured light converts to heat. And this heat used to drive a heat engine. Normally a steam turbine, connected to an electrical power generator.

CSP South Africa
Concentrated Solar Power in Action

Advantages of CSP

The main advantages of CSP can include reduced deforestation and increased energy security. It’s sustainable energy. So, getting more power from the sun can help to slow down global warming. And it’s a reliable source of power as the sun will always rise. But, the cost attached to installing and maintaining the system, is the only real problem facing CSP.

Lightning Protection

Aside from complying with any technical regulations. An insurer may demand the installation of surge & lightning protection. An internal lightning protection system creates an equipotential bond between cables and metallic installations. So, directly connecting any metal and conducting plant component. While live cables like telephone lines and mains connections, directly connected to the ground system as part of the surge protection device.

Surge Protection

Surge protection prevents damage occurring to electrical devices by excessive voltage. Again, using equipotential bonding between connected conductors. Also, installing an earthing or grounding rod as part of the system. In this way, preventing voltage peaks so, protecting the connected device.

Growth of CSP

The system might seem pretty inefficient as there are several processes during which energy will be lost. But this is a renewable source of power that’s starting to become popular across the globe. The Concentrated Solar Power market has been rising gradually. And with countries like Spain and America at the forefront of the growth. Also, Spain now has a generating capacity of 632 MW. And the USA now has 509 MW after adding two CSP plants in 2010. Furthermore, Middle-East has also installed CSP plants and they’re planning on building the world’s largest one in Abu Dhabi.

CSP plant

CSP in the United Kingdom

How can the UK with our lack of sunlight really compete with the Middle-East, USA and Spain? Well, the UK probably can’t get involved with CSP in the same way as countries blessed with all-round sunshine. But the government is making small-scale concentrated solar power part of its drive for sustainable power.

The Carbon Trust

The Carbon Trust is currently looking to accelerate the take-up of CSP in the UK. During 2013, they produced a report that examines the potential benefits of Concentrated Solar Power to UK businesses. It shows that there is substantial growth potential in small-scale CSP for industrial process heat. The report suggests that CSP will grow by a factor of 2,500% by the year 2050. But it outlined the main barriers and market failures. That will need to be overcome before the full potential of Concentrated Solar Power realised.

Barriers for industries

The Carbon Trust report shows that the main barriers for CSP in the UK. Are low awareness of it as a potential energy source. Also, a lack of confidence that the technology will work in UK weather. Together with, conditions and the payback period that most firms feel are unattractive. Particularly in the current period of austerity.

Rest of the world

The Carbon Trust’s 2013 report shows that growth in Latin America and Africa will be far more impressive than it will be in the UK. So, with a potential growth factor of 4600% expected by 2050. Therefore, India is one of the world’s leading markets for CSP. With 70 systems installed in a range of domestic manufacturers. Chile and Kenya are also developing markets that have massive potential for the future. All three of these countries have a strong national interest in renewable energy and continual sunlight to exploit.

What Next?

If you would like to talk to GreyMatters about Solor Thermal Energy or Concentrated Solar Power, please contact us today.

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