High-efficiency inverters key to solar success in Bangladesh: Expert

A good quality inverter can help efficiently convert and manage solar energy, allowing excess power to be sent back to the grid, said Rezwan Khan, executive director of the Institute for Advanced Research.

“Grid-tied systems connect the photovoltaic (PV) output to the grid via a grid-tied inverter. This connection allows the export of power when internal demand is lower than PV output. A good quality inverter can have an efficiency greater than 95%,” he said at a programme titled “Renewable Energy in Bangladesh: Prospects and Challenges” today.

An inverter is an electronic device or circuitry that changes direct current to alternating current.

He discussed ongoing research into better battery storage solutions to handle the variable nature of solar energy and highlighted the potential benefits of using solar power for other applications, such as cooking.

Rezwan Khan explained the importance of storage batteries, which can store energy during sunny hours for use at night.

Two types of batteries are used for large-scale PV energy storage: lead-acid batteries and lithium-ion batteries. Lithium is a rare earth element with limited availability. Research is ongoing to use sodium or potassium instead of lithium, he said.

In his keynote speech at the programme, Rezwan also discussed the potential of PV applications beyond energy storage.

He said, “The introduction of net-metering in Bangladesh is set to optimise the utilisation of PV outputs by allowing the export of excess power back to the grid, thereby maximising energy efficiency and supporting the country’s sustainable energy goals.”

He introduced the concept of clean electric cooking using inverterless PV-grid DC link, which could achieve up to 90% efficiency compared to the 40-45% efficiency of gas cookers.

Underscoring that, “Heat does not cook; it is the temperature that cooks,” he said insulated cooking pans can significantly reduce energy consumption.

The decreasing cost of PV has made PV power cheaper than grid power, opening up new innovative applications. However, large-scale integration of PV (25-30%) can cause system instability due to the intermittent nature of sunshine.

Therefore, new low-cost battery technologies and supercapacitors are being researched for short-term storage of electrical energy, Rezwan concluded.

The event was organised by the United International University’s School of Business and Economics as part of the Bangladesh Corpus: Public Lecture Series 2024.

UIU School of Business and Economics Professor Dr Muhammad Fouzul Kabir Khan was present as the guest of honour at the event held at the university campus.