THIS is apropos the news item ‘Nepra advises producers to install solar-wind hybrid plants’ (Feb 10). Being a researcher in this field, I would say that such projects are like white elephants.

The capital cost of such projects will be exorbitant to say the least. It is important to understand the physics behind the construction of such power plants, and one does not need to be a rocket scientist to grasp the concepts.

Solar power plants make use of solar energy to produce electricity and are worth their cost in day time. They are good as dead at night time, while wind generators can only operate when sufficient wind is blowing.

Instead of increasing the capacity of the system we must know installing solar and wind systems will be detrimental to the entire grid system, which is already overloaded with limited short-circuit capacity.

Power engineers at the National Electric Power Regulatory Authority should ponder this out. A wise idea will be to invest in storage systems that connect to existing solar and wind power plants. The cost of their construction and maintenance will be bare minimum by comparing this idea with the construction of large power plants that work at half capacity.

Connecting flexible AC-transmission systems with these systems is another way of increasing the capacity of our already existing solar and wind systems. These devices will allow solar power plants to operate 24 hours.

Research in this area has established the point such devices are making their way in the field with excellent results. With research work in power systems next to nothing at our universities, we will always come up with such projects in the future as well.

It only takes a single search on IEEE Xplore Digital Library to look at a plethora of current research work in this area.

Syed Ahmed Raza
Canada

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THIS refers to your news report ‘Nepra advises producers to install solar-wind hybrid plants’ (Feb 10). It is good to see National Electric Power Regulatory Authority taking notice of the curtailment issue currently being faced by wind power plants in Jhimpir, Sindh, and to hold a consultative meeting with the various stakeholders.

One, however, wonders how its advice to these wind power plants of hybridising their plants with solar at their existing sites will resolve this issue. Before advising any solution, the authority should have first ascertained the actual cause behind this curtailment whether it was commercial (higher tariff of these wind power plants) or technical (constraints or bottlenecks in the system upstream).

Hybridising the two renewable resources arguably results in maximising power production from a particular site, alleviating the intermittency and variability of wind and solar, and in minimising the cost of production, but it is not clear how it will improve the off-take and lessen the chances of curtailment in the future, especially if the curtailment occurs owing to some technical constraints in the system upstream.

M. Shahid Rahim
Bahawalpur

Published in Dawn, February 19th, 2020