World’s tallest solar tower to be built in Dubai

The Mohammed bin Rashid Al Maktoum solar park, named after the Emir of Dubai, is one of the world’s largest renewable energy projects and forms part of Dubai’s strategic vision of reaching 75% use of renewable energy by 2050. For a total investment of 50 billion dirhams (12 billion euros) the complex will by 2030 have an installed capacity of 5000 MW.

Launched in 2013, the project currently comprises three sections (phases 1, 2 and 3) entirely dedicated to photovoltaic power. The foundation stone of phase 4 was laid in March 2018. This phase of the project is dedicated to concentrated solar power, CSP.

The heat transfer fluid used for this array, molten salt, reaches very high temperatures, 560+°C. Its significant advantage is that it can help to render large-scale energy storage more competitive than PV technology. The molten salts at high temperature are accumulated in tanks at the base of the tower, the tanks being large enough to create an energy reserve sufficient to feed the power station throughout the night, thereby enabling it to operate 24 hours a day.

Phase 4 includes a 100 MW solar tower, receiving the sunlight from thousands of mirrors mounted on motorised supports spread over several square kilometres, and shifting their orientation to follow the sun. The central receiver, made by CMI, will be positioned on top of the tower where what is described as an ultra-modern heat exchanger capable of absorbing the huge energy flows from all these mirrors will transfer the heat to the molten salt.

This solar receiver is a metal cylinder more than 30m high and with a diameter of more than 20m. Molten salt continuously circulates around its periphery, in special alloy tubes designed to withstand the temperatures imposed by the solar flux

coming from the mirrors below. Inside is a complex system of piping and tanks with temperature and pressure probes, and maintenance platforms and other access ladders that will enable the maintenance team to gain access to any point within it. The installation as a whole will be supported by a metal framework weighing over 1500 tonnes.

The 4th phase is better known as the DEWA project, after the Dubai Electricity and Water Authority, which has been at its the centre throughout. It has been dubbed the ‘project of the year’ for the global CSP industry. After intense competition ACWA Power won the 14 billion dirhams (over 3.3 billion euros) contract to construct it. ACWA Power is one of the world’s largest developers of CSP solar power plants, and currently has the Noor 1, 2 and 3 power plants under construction in Morocco. It worked in collaboration with the Chinese group Shanghai Electric in the role of EPC contractor (Engineering Procurement and Construction) on the DEWA project.