By offering cheap energy storage, concentrating solar energy has enormous potential. However, international standards are needed to become a competitive market proposition.
Solar thermal energy, also called concentrated solar energy (CSP), is a renewable energy that uses the sun’s heat captured by various types of focusing mirrors. The energy from the concentrated sunlight heats a high-temperature fluid in a receiver, travels to a heat exchanger and ultimately drives a steam or gas turbine to produce electricity.
The CSP market was a promising renewable energy source in the 1990s, but in recent years the CSP market has failed to take off. plants Being built around the world, especially in China, prices have not fallen enough to make it economically viable. Installing and maintaining concentrated solar collector fields in harsh, often desert-like conditions is too often more expensive than other forms of renewable energy, such as solar photovoltaics (PV) and wind energy.
Store energy cheaply
“Competition from solar energy has taken market share away from more complex solar thermal technology because solar panel prices have fallen so much over the last fifteen years and they are so easy to install, literally plug-and-play. However, solar thermal energy has an important advantage over solar energy: cheap energy storage,” explains Eckhard Lüpfert, chairman of IEC TC 117, the IEC committee which prepares standards for solar thermal power plants.
The typical thermal storage systems consist of insulated storage vessels filled with hot molten salt, with pumps and heat exchangers. According to Lüpfert, the price of thermal storage is much cheaper than that of lithium-ion batteries, which are currently one of the most widely used forms of energy storage. “Battery performance is improving, but thermal energy storage has a significant advantage and is still about a hundred times cheaper,” he says.
An article published in Science directly emphasizes that “in areas with high levels of solar energy, CSP can play a crucial role and thus significant progress is being made to increase competitiveness through the improvement of energy storage systems integrated with CSP”. The article highlights the potential of CSP thermal energy storage to stabilize the electricity grid by “being able to generate power during hours of high demand (periods of high prices, morning and evening), and store energy efficiently , when the demand for electricity is low, but renewable. energy is available in abundance (low price periods, midday)”. The idea is that CSP is combined with other renewable energy sources, such as solar energy, and that energy storage is offered at grid scale. (To learn more, read about the different storage systems and technologies used in CSP here.)
CSP for industrial process heat
Another selling point for CSP is its use in industries that rely on a large amount of energy for heating processes, commonly described as industrial process heat. This includes petroleum refining, chemical manufacturing, iron and steel, cement and the food and beverage industry.
For example, to make cement, raw materials such as limestone and clay are ground into a fine powder, which is then heated in a cement kiln to a temperature of 1,450 °C. The heating process depends on energy from fossil fuels, which cause enormous CO2 emissions. Pressure is mounting from all quarters to decarbonize the economy. Although some research focuses on materials that require less heating, the concentrated sunlight used to heat fluids in CSP can be used to reach the high temperatures needed.
CSP can also be used for solar energy fuels, which are gaining increasing interest. (For more information about this application, read: Understanding solar-powered fuels | IEC e-tech).
The absolute need for standards
IEC TC 117 published its first standards in 2017 and in recent years has developed important benchmarks for the industry, all of which are crucial to stabilize the quality of components and installations and to help reduce the costs of the various CSP technologies, making them become better competitive. Standards also guarantee the security and reliability of CSP systems used around the world. “A CSP installation is not just an electrical installation, it is almost a chemical process installation. These are hazardous materials, such as organic liquids, that are heated at very high temperatures. Ensuring the safety of employees and the factory environment is therefore of the utmost importance and one of the main focuses for our standards,” describes Lüpfert.
Looking to the future, standards will be needed in another area that are precisely related to the use of CSP for niche applications, such as industrial process heat. According to Lüpfert: “We can take the lessons and achievements of STE plants and apply them to industrial process heat applications. We need to broaden the applications of the TC 117 standards. It is often a matter of scaling back what we have already achieved in terms of performance and reliability.”
One of the biggest challenges in the coming years will be attracting the right kind of experts to participate in the standardization work. “We have many scientists and researchers, but we need more people involved on the ground and experts from the industry,” Lüpfert indicates.
But there is also hope. “Since COVID, we have changed the way we work, and meeting online has been a blessing. Thanks to online tools, we have started to attract people who are better qualified for the work we need, especially from the industrial sector. We also use forums such as SolarPACESa technology collaboration platform that allows us to discuss pressing issues related to CSP before we experience the formal limitations of standardization,” he says.
As the race to reach zero carbon emissions targets continues to accelerate, focusing on solar energy technologies can play an important role in ensuring we reach that goal, with the help of international IEC standards.
Author: Catherine Bischofberger
The International Electrotechnical Commission (IEC) is a global non-profit membership organization that unites 174 countries and coordinates the work of 30,000 experts worldwide. International IEC standards and conformity assessment are the basis of international trade in electrical and electronic goods. They facilitate access to electricity and verify the safety, performance and interoperability of electrical and electronic devices and systems, including, for example, consumer equipment such as mobile phones or refrigerators, office and medical equipment, information technology, electricity generation and much more.
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