With an installed generation capacity of 100 MW, the Shams 1 concentrated solar power (CSP) project is one of the largest solar power projects in the world.
However, several aspects, apart from its size, make the concentrated solar power project unique and a technological benchmark in the solar thermal power sector.
The managers of the Shams 1 project regard the power plant as a critical milestone in the learning curve of large-scale development of CSP projects around the world. While interacting with the engineers, one realises that the project was intended as a demonstration to test solar thermal power technologies in the harshest of environmental conditions.
The three main challenges that the Shams 1 project faces on a daily basis are high-velocity winds, sand, and water scarcity. The project engineers explained to me in a recent site visit how they managed to overcome all of these challenges, delivering solutions that are proving to be critical lessons for all CSP projects around the world.
High-velocity winds can be a major threat to the integrity of the mounting structures of the reflectors. This is an issue project developers have to deal with in case of solar photovoltaic power projects as well, especially if thin-film solar panels are being used. The wind speeds around utility-scale projects are much higher as they are typically located in remote areas with no natural or human-made features to counter wind speeds.
The Shams 1 project site is surrounded by a 7-metre-high wall to keep the high-velocity winds in check and away from the parabolic trough reflectors and their mounting structures.
Sand, flown in with wind, deposited on reflecting mirrors can adversely affect their optical efficiency and reflectivity. This, in turn, would reduce the solar radiation incident on the absorber tubes and the heat transfer fluid (oil, in this case) would not heated up to the optimum level to generate the desired electricity in the steam turbine.
To overcome this issue, the project engineers use robotic cleaners. The cleaning process is optimised so as to maintain a balance between efficient plant operation and maintenance costs.
A view from underneath the air-cooled condensers at Shams 1 project
Water is an essential part of the power generation cycle at any CSP project. Major consumption of water takes place in the recycling of steam into water for reuse in the heat exchanger. According to the plant engineers, every other CSP project in the world uses water-based condensers to recycle the low-pressure steam coming out of the turbine. Shams 1, however, uses air-cooled condensers to overcome the challenge of water scarcity. Air-cooled condensers help the plant save 2 million gallons of water every year. However, they also cost more.
Representatives from several countries visit Shams 1 project every year to learn the innovative solutions implemented to overcome some fundamental but ever-present challenges. A number of representatives from the neighbouring Gulf countries have visited the project and are now looking to develop similar projects back home.
Some of the solutions implemented at Shams 1 are already being replicated at other project sites. SolarReserve and Saudi Arabia’s International Company for Water and Power Projects (ACWA Power) recently secured a bid to develop a 100 MW CSP project in South Africa. The project will have 12-hour storage capacity and will have an air-cooled condenser to minimise water consumption.
Heat transfer fluid (HTF) booster heaters at Shams 1 project
When the Shams 1 project was being contemplated, storage solutions for utility-scale power projects had not been commercialised. Thus, to ensure smooth and efficient operation, the project developers decided to hybridise CSP with gas-based power generation. On an overcast day, gas (imported from Qatar) is used to superheat the heat transfer fluid (HTF) to a much higher temperature than achieved through solar heating. This super heater HTF then generates steam of high temperature and pressure in the heat exchanger, which, in turn, increases the power generation.
The project engineers stated that, in oil-rich countries, hybrid CSP project make a much stronger economic case than adding storage, thus hinting that despite the commercialisation of storage solutions, the project may not incorporate them.
The project is believed to be among the most expensive CSP projects in the world, in terms of capital investment as well as levelized cost of generation (even though the terms of power purchase agreement have not been disclosed). But the fact remains that the Shams 1 project is the first, and currently the largest, CSP project in the Middle East region. The harsh climatic conditions have not deterred the project developers to set up this project, which has successfully incorporated path-breaking innovations which are now being replicated in similar projects around the world.
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