Concentrated Solar Thermal Power

Concentrated solar thermal power, a renewable energy source which utilises the heat of the sun to generate power, is just one of many forms of sustainable energy - sustainable energy that is growing in popularity. As more and more of the population do their part for the environment and switch to renewable and sustainable fuels, carbon emissions are beginning to drop. In fact, 2010 saw a 7% reduction in carbon emissions, while renewable energy systems in use rose by 35%.

The United Kingdom government has imposed strict guidelines with regard to renewable energy and has set a target of producing at least 15% of all power within the UK from sustainable fuels by the year 2020. With ongoing promotion of renewable energy sources, the start of government funded grants and the promises of many more incentives due to be launched over the next few years, it has been suggested that the UK could actually far surpass its original guideline and hit a percentage more than twice that of the target. While just over 25,000 gigawatt hours of energy generated from sustainable sources were used in the UK in 2010, studies show that if power sources such as concentrated solar thermal continue to grow at the rate they currently are, this figure could rise to a gigantic 197,000 by 2020.

How Does Concentrated Solar Thermal Power Work?

While solar thermal power is energy generated through solar collectors such as photovoltaic panels, concentrated solar thermal power differs in that it is generated through the use of mirrors and lenses, thereby concentrating a large amount of the alternative fuel source onto a small absorption area. In much the same way as the sun's rays passing through a strategically placed magnifying glass can cause a piece of paper to heat up enough to ignite, concentrated solar thermal power works by using the magnified solar energy to heat a liquid, producing steam to power turbines similar to those found in conventional fossil fuel power stations.

There are two commonly used methods of concentrating solar energy; traditional parabolic troughs and the more modern 'power towers'. Parabolic troughs are so named due to their trough-like shape. They are highly reflective and are able to intensify solar energy by up to 60 times its original power. The troughs are set upon a moveable base, allowing the reflectors to track the sun's movement throughout the day and focus the energy onto tubes and pipes filled with a liquid, usually oil.

1. Traditional parabolic troughs

2. Solar power towers

Power towers work in a similar fashion, but large, flat mirrors are used to focus the solar energy onto an absorption plate at the top of a purpose built tower. The tower contains a large tube which is heated to produce steam. While early power towers were filled with oil similar to that used in the parabolic trough method, later designs have incorporated molten nitrate salt due to its heat retentive qualities. This molten salt technique was first used in 2010 at the Archimede solar power plant in Sicily.

Solar Thermal Versus Concentrated Solar Thermal: Which is Best?

Solar thermal and concentrated solar thermal, although both generate energy from the same sustainable fuel, are very different and each has its advantages over the other depending on circumstances. Whereas individual solar thermal panels are ideal for generating power for a single home or business, it is obviously incredibly impractical to mount an entire power tower onto a domestic rooftop. Concentrated solar thermal plants are designed on a much larger scale and use such magnified fuel that this form of sustainable energy system is much better at providing power to a wider field such as a complete power grid. Concentrated solar thermal plants are also designed with far greater means of energy storage.

Is there a Future for Concentrated Solar Thermal Power in the UK?

The first concentrated solar thermal power plant, recognisable as such today, was built in Italy in 1968 so this form of renewable energy system has already stood the test of time and is popular in many countries throughout the world. This is particularly true of those with sunnier climates such as Spain, Italy and certain parts of North America such as the West Coast and the Mojave Desert. But what about the UK? Is Great Britain keeping up with the latest environmental trends?

As of 2012, with Spain leading the way and setting the precedent for concentrated solar thermal power, and the USA coming in a close second, here in Britain, according to the Committee on Climate Change, "Concentrated solar power is not suitable... as it requires intense sunshine and little cloud cover to be economic." That said, there are currently no concentrated solar thermal plants in the United Kingdom.

The Committee on Climate Change does, however, acknowledge that Britain could benefit from concentrated solar thermal power and has suggested buying solar energy from nearby sunnier climates such as North Africa or other parts of Europe. This suggestion has been deemed quite controversial and has been met with disdain from many renewable energy advocates. The Renewable Energy Association's Ray Noble, for one, has criticised the Committee of Climate Change for "missing a great opportunity to support Britain's solar generation".