Double-action solar tower promises clean energy all day and night, but comes with ecological challenges

Standing at an impressive height of 200 meters, a double-action solar updraft/downdraft tower holds the potential to generate clean energy consistently, offering a 24/7 power supply in the context of a hot and arid desert environment. However, this innovative energy solution does not come without its set of ecological challenges. The towering structure and its operations may impact the local ecosystem and biodiversity, necessitating a careful examination of the potential environmental consequences. As we explore and embrace new technologies for sustainable energy generation, it becomes imperative to strike a balance between the undeniable benefits of clean energy production and the preservation of the delicate ecological equilibrium. This underscores the importance of conducting thorough environmental impact assessments and adopting responsible practices in the deployment of such advanced energy infrastructure to ensure a harmonious coexistence with the surrounding environment.

Ecological Benefits

The double-action solar tower has the potential to generate more than twice as much energy as a standard solar updraft tower, which means that it could help to reduce our reliance on fossil fuels.
The tower could also help to improve air quality by capturing and converting carbon dioxide into electricity.

Ecological Challenges

The tower is large and tall, which means that it could have a negative impact on the local environment. For example, it could disturb wildlife habitat and change the microclimate.
The tower uses water to cool the air, which could be a problem in areas where water is scarce.

Overall, the double-action solar tower stands out as an innovative and promising technology, offering the prospect of a continuous and clean energy supply around the clock. The capability to harness solar power for both updraft and downdraft processes marks a significant advancement in sustainable energy solutions. This technology’s potential to operate consistently is particularly noteworthy, addressing the intermittency issues often associated with renewable energy sources. However, amid the optimism surrounding its energy-generating prowess, it is equally crucial to approach the deployment of these towers with a discerning eye on the potential ecological challenges they may pose. Balancing the imperative for clean energy with the need to safeguard the local environment is paramount. Therefore, a comprehensive assessment of the ecological impact is imperative to ensure that the benefits of this innovative technology are realized without compromising the delicate balance of the ecosystem. By conscientiously addressing these ecological considerations, we can harness the full potential of double-action solar towers while maintaining a commitment to environmental sustainability.

A 200 metre tall, double-action solar updraft/downdraft tower could generate clean energy 24/7 in a hot, dry desert area

Researchers in Jordan and Qatar have come up with a remarkable design for a “twin technology solar system” (TTSS) capable of generating clean energy 24/7. This double-action design promises more than twice as much energy as a standard solar updraft tower. As its name suggests, the TTSS combines two tower-style technologies into a single design: a solar updraft tower and a cooling downdraft tower. These are integrated into a single tower, with the updraft tower coming up through the middle. A solar updraft system works by heating up the air at ground level, then using the fact that hot air rises to funnel that air up a tall tower with turbines in it. The air is heated under a large roof covering a vast collection area, made from a greenhouse-type material designed to trap as much heat as possible.

These have been built at experimental scale, but not yet at a commercial scale, since they’re typically very large, tall structures to ensure a good temperature differential. Thus, capital costs are high and they’re viewed as risky.

A cooling downdraft tower, on the other hand, forces air downwards to turn another turbine. In this design, that’s accomplished by spraying a fine mist of water into the ambient air at the top of the tower, making it both cooler and heavier and sending it downward.

The TTSS design places an updraft tower in the middle, and surrounds it with 10 downdraft towers running around the outside, such that it can operate in both updraft and downdraft modes simultaneously.

The research team, from Jordan’s Al Hussein Technical University and Qatar University, modeled a TTSS tower some 200 m (656 ft) tall and 13.6 m (45 ft) in diameter, with a 250-m (820-ft) diameter collector underneath it. The inner cooling tower’s diameter was 10 m (33 ft), leaving a 1.8-m (5.9-ft) gap all the way around. This gap was partitioned into 10 separate downdraft towers, with water misting systems at the top and turbines at the bottom. The location chosen was near Riyadh City – hot, dry desert areas are ideal for these designs.

In simulation testing using local weather data, the team estimated that such a system would generate a total of around 753 megawatt-hours of energy annually, with the external downdraft towers running around the clock to deliver about 400 megawatt-hours, and the updraft tower working more efficiently under the hot sun to contribute around 350 MWh.

These figures, according to the research team, were 2.14 times as much as similar updraft-only designs – which makes sense given the updraft/downdraft splits above. They could also go some way toward addressing the offset between energy supply and demand that you can get with most solar projects.

The team refrained from calculating the Levelized Cost of Electricity (LCoE) at this juncture and didn’t draw direct cost comparisons, such as juxtaposing it against a solar photovoltaic array coupled with battery energy storage. They acknowledged that, in the geographical regions where the TTSS system could be most effective—hot, arid desert cities—securing a sufficient water supply for the downdraft system might pose a challenge. Despite these considerations, the concept remains captivating and serves as a demonstration of the multitude of approaches available for driving turbines to generate electricity. This exploration showcases the innovative spirit within the realm of energy generation, encouraging the exploration of diverse and unconventional methods to meet the ever-growing global demand for sustainable power solutions.

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