Can you make solar power work when the sun goes down? You can, and Dubai is about to run a city that way.

• A new concentrated solar plant is under construction in Dubai.

• When it opens next year, it will be the largest plant of its kind on Earth.
  

• Concentrated solar power solves the problem of how to store electricity in ways that solar pannels cannot.
  

A Saudi power company will soon begin construction on the world's largest concentrated solar plant. Situated in the United Arab Emirates, the plant will have an estimated capacity of 700 megawatts and a power storage system that will keep the lights of Dubai shining for up to 15 hours after sunset.

Dubai goes solar

Noor Energy 1, as the project is called, will also include a vast solar panel array for good measure. When it is completed in 2020, it will provide Dubai with 24-hour access to clean energy. It will dwarf the current record holder, Noor-Ouarzazate CSP in Morocco.

The project is part of Dubai's plan to reach 75 percent renewable energy by 2050. The designers will also gain insights which may help Saudi Arabia on its plans to diversify its energy portfolio.

Concentrated solar power (CSP) is a bit different than the solar power most people are familiar with. While solar panels are well known and increasingly popular as a source of energy, concentrated solar power has yet to capture the popular imagination in the same way. This is a shame.

Abdulhameed Al-Muhaidib, the director of asset management at Saudi Arabia's ACWA Power, explained the difference between typical solar panels and this technology to Arab News:

"It's a completely different technology because you have to do a heat exchange and (use) steam turbines, a process that makes it more expensive than solar PV, the main benefit is storage because you can store heat, while in panels you can't and lithium batteries are still expensive."

Because storing heat is a bit easier than storing huge amounts of electric power, these plants can be more desirable than large solar panel arrays when the problem of providing energy after dark needs to be solved. However, while photovoltaic cells can produce a fair amount of power when the sun isn't shining, concentrated solar plants generate practically nothing when weather conditions aren't favorable.

How does it work?

The picture at the top shows an artist's impression of the soon to be built facility. The little objects in a circle around the tower you see are not solar panels but mirrors that reflect sunlight onto a tiny point in the central tower. The concentrated light is then used as a heat source for an otherwise conventional steam driven power plant.

The plant in Dubai will not use water to store the sun's heat. Instead, the concentrated sunlight will heat molten salt. This is because molten salt retains its heat longer than water does. This will allow for the energy to be stored long after the sunsets at a fraction of the cost of lithium-ion batteries.

When Dubai needs electricity, the heated salt will be pumped out of storage and used to boil water to make steam. When it has cooled, it can be recycled and used again.

While concentrated solar power remains largely unknown to the general public, it will soon be lighting up one of the most magnificent cities in the world. Will this prove to be the project that makes CSP mainstream and competitive with photovoltaic cells? Time will tell.

Upcoming CSP events:

4th Annual CSP Focus MENA 2019（Jun.26-27, Dubai）

3rd CSP Focus Innovation 2019（Oct.24-25, China）

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