The Strategist

Concentrated solar power: what does the future hold for solar energy?

03/15/2016 - 17:01

Despite several years of stagnation, solar market takes off again thanks to technologies which achieved maturity threshold while being less and less expensive to use. Among these technologies, concentrated solar power (CSP) appears as a promising solution for those looking for the perfect match between reliability and modularity.

Last year photovoltaic issue with Chinese manufacturers of solar panels turned the industry’s views upside down. In 2010, the Chinese government, concerned about the high level of air pollution, decided to make a turn in the direction of solar energy and give support to its producers. Having just begun to develop, the industry received $ 42 billion in subsidized loans and turned into a huge market (not only domestic, but also an export one) within only two years.

Everything was fine until the moment when the industry became highly dependent on exports. In 2011-2012, more than 90 percent of panels made in China were exported abroad, rather than being installed within the country. To its cost, the USA became the top customer.  Shortly, American energy companies’ warehouses got literally stocked up with cheap Chinese solar panels. This resulted in dumping of US manufacturers and floated market, what had extremely negative impact on domestic producers and the industry in general.

The problems did not stop there. In 2014, a new study from Northwestern University and the US Department of Energy's Argonne National Laboratory revealed a dark side. Solar panels made in China have a higher overall carbon footprint and are likely to use substantially more energy during manufacturing than those made in Europe. To put it simply, the production of environmentally clean solar panels in China is a dirty industry. Let’s remind that six of the 10 manufacturers ranked by IHS are Chinese (and we shouldn’t forget about a huge number of small industrial companies). Given this, one can only imagine how huge the negative impact is, not only on the environment but also on the economy in general.

Utilization of photocells is another environmental problem. Modern photovoltaic cells have a life span of 30-50 years on average. After this period, such disposal method as land filling is unacceptable since the cells contain cadmium and silicon. Affordable and environmentally friendly method of photocells disposal has not been discovered yet.

All of the above-mentioned makes one think if solar power in general is as such an advanced and environmentally friendly technology as its producers characterize it.

We might need to turn this issue other way round.

Today, concentrated solar energy is used as an alternative method of solar energy converting, because it’s able to smooth out some of the photovoltaic drawbacks. The method consists in focusing the sunlight on a vessel with water to its further use in heating or steam generators. Energy focusing can be made by different ways. That’s why CSP systems are a separate branch of solar thermal energetic.

In early September 2013, unusual reports of a London skyscraper «Walkie-talkie» decorated by glass panels began to appear in media. The building was literally melting cars on nearby streets and causing damage to surrounding cafes’ property. It also resulted in light burn injuries of passers-by and builders. The locals, however, found the problem as a reason to laugh - the British learnt how to fry omelette on the burning hot asphalt. 

The London skyscraper case demonstrates the operation principle of CSP supremely well. The concave surface of the building naturally focused the sunlight on the opposite street, heating it to the limit.

In contrast to rather costly and waste-full silicon production of photovoltaics, CSP uses relatively cheap and recyclable materials such as glass, steel and oil (parabolic troughs) or water (Fresnel technology).

Now, CSP producers are trying to ride the wave of common enthusiasm of green technologies. The main arguments in their favor are their low cost, relatively easy maintenance and, of course, environmental friendliness. Is it really so?

Let's look at some distinctive disadvantages of CSP.

1. CSP devices are less profitable in the high latitudes. This may be a reason of rather low incidence of CSPs in the world. In this regard, CSP manufacturers are dependent from export, possibly even in a greater degree compared to PV. Think, for instance, of the French company Sun CNIM. Relying on large background experience, the company opened its first solar farm in 2010. Now, Sun CNIM specializes in exporting, mainly in North Africa, and is planning to further expand the market. One of the company’s projects (CNIM eCare) is situated in Morocco.

2. Solar concentrators produce large-area shading of land, which leads to drastic changes in soil conditions, vegetation, etc. From this point of view, the most appropriate becomes use of compact linear Fresnel reflectors. Hans Christian Schröder of German TÜV SÜD Industrie Service writes: "The simplified design (of CLFR) minimizes costs while improving environmental compatibility, i.e. more efficient land use."

3. Use of low-boiling liquids (synthetic thermal oil in concave parabolic collectors) and possible leaks in the solar power systems during their prolonged use may lead to significant pollution of drinking water. Additional strengthening of pipes and nodes system can be the solution in this case. However, this increases the total cost. The problem can be solved by use of alternative fluids (e.g. demineralized water).

It is clear that some technical issues remain open. Despite the fact that generally CSP have been well developed and commercialized, traditional power plants keep a tight reign. In this regard, the technology still gives place to its older brother - photovoltaics.

At the same time, we can suggest that CSP will be developing rapidly in the future, being an alternative to photovoltaic in relevant regions. According to a research report released by Transparency Market Research, the global concentrated solar power market is growing rapidly to reach US $ 8.67 bln by 2020, after being recorded around US $ 2.51 bln at the end of 2013. Basing on these figures, we can assume that CSP has a bright future.

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