Harvesting Sunlight With Salt

Projects, such as Shams 1 and Noor 1, are aiding the solar industry’s evolution. North Africa, specifically the Mena region, and the Middle East are hoping to supply Europe with reliable electricity. To achieve this, the two regions need a solar energy system that is virtually infallible: continues to provide electricity when it’s cloudy and throughout the night.

Fortunately, concentrated solar power appears to be a perfect solution. Concentrated solar power, or CSP, differs slightly from conventional solar techniques. Instead of converting the sun’s rays into electricity, CSP harnesses the heat generated on contact.

To capture the energy in this manner, mirrors are used to focus direct sunlight into a thin beam, which is pointed to a storage unit filled with salt.

Sharpening the focus of the sun’s rays onto the sodium over time can raise the salt’s temperature to approximately 500 degrees Celsius if the conditions are right. This stored heat can then be utilized to generate steam and vicariously electricity.

One of the major advantages CSP has is the duration of time that salt can retain heat. Typically, sodium can maintain its temperature approximately 24-hours, meaning CSP can produce energy throughout the night or on cloudy days. Due to this, the energy storage potential of a CSP plant could feasibly provide long lasting energy regardless of the weather.

CSP projects, such as Abu Dhabi’s Shams 1 and Morocco’s Noor 1, are paving the way for the promising solar technology. With the cost of building a CSP system steadily falling, the solar solution may become less expensive to construct than its renewable energy counterparts.

According to Paddy Padmanathan, the chief executive at Acwa Power, “I expect concentrated-solar power, within 18 months, to be head-to-head with combined-cycle gas, if not more competitive”. He went on to say that “The focus has been on PV and batteries, but there’s a limit on how long they can hold a charge for. We’re proving that CSP can work through the night.”

To date, a large portion of the Mena region relies on gas and oil to produce energy. Countries in this area, such as Morocco, typically spend over $3 billion USD each year to import electricity and fuel. This annual expense is expected to grow as Morocco continues to expand its electrical grid. On average, Morocco’s energy demands are increasing at about 6.5% annually. In order to meet the growing demand, Morocco brought their CSP plant on line last year, dubbed the Noor 1. Morocco aims to utilize the plant to reduce its reliance on energy and fuel imports, as well as participate in Europe’s energy market. Presently, the Noor 1 is connected to Spain via two underwater power lines. As of last year, Morocco and Portugal were actively discussing the construction of a new undersea link to connect them.

The region of Mena is not alone in the quest for exporting renewable energy. Australia is also seeking a way to utilize excess solar power. The country is researching the prospects of transporting renewable energy to Indonesia. To accomplish this task, Australia hopes to connect two 2000-kilometre power cables from its Kimberley and Pilbara regions to Indonesia’s Java.

Unfortunately, implementing these underwater power links come with a major drawback. Any damage inflicted upon the cables may result in significant power outages that last for several months. Tasmania, for example, endured a 6-month power outage. This devastating event occurred in 2015 when the island’s electricity interconnector simply failed.

In addition to underwater power cables, Australia is researching other feasible solutions for solar technology. Australia’s energy team is looking into converting ocean water into hydrogen with solar energy. The process involves splitting water molecules at the atomic level and harvesting the hydrogen particles. Afterward, the molecules are converted into energy via a specially designed fuel cell. Each of these energy cells is capable of generating electricity, by invoking a chemical reaction with the harvested hydrogen molecules. A few bonuses to using this renewable energy solution include the fact that the process does not produce waste or emissions.

As one of the major users of this type of solar technology, Japan has started to refer to their energy market as a “hydrogen economy”. Due to the energy demands required to split hydrogen from water, however, the technique is unpopular in other nations. Nevertheless, Japan and Australia are discussing the development of several massive solar-hydrogen projects. The ultimate goal is to create significant amounts of hydrogen gas for exportation.

With the age of oil subsiding, it appears that viable solar energy solutions are ready to meet our growing electrical demands.