Vietnam Electricity (EVN) has called for a clearer assessment of the effectiveness of battery energy storage systems (BESS), arguing that incorporating storage into solar power projects increases electricity costs while the overall benefits to the power system remain uncertain.

The utility recently submitted comments to the Electricity Authority under the Ministry of Industry and Trade regarding the proposed 2026 electricity generation price framework for ground-mounted and floating solar power projects equipped with battery energy storage systems.

According to EVN, the cost of installing energy storage systems is included in the overall investment cost of a project, resulting in higher electricity price ceilings for solar plants combined with BESS compared with conventional solar projects without storage.

As a result, electricity buyers may be required to pay higher prices for projects equipped with storage systems, while the investment efficiency and broader benefits to the power system have yet to be clearly demonstrated.

EVN therefore proposed that before the Ministry of Industry and Trade approves the 2026 pricing framework for solar projects incorporating BESS, regulations should be supplemented and clarified regarding operational control rights and responsibilities, installation objectives, dispatch mechanisms and investor obligations related to the availability of storage systems.

The utility also recommended evaluating actual grid requirements for energy storage installations at solar and wind power projects before permitting such systems, in order to avoid oversupply situations similar to those seen in several neighboring countries.

According to EVN's calculations, the 2026 electricity price framework for ground-mounted solar projects equipped with BESS would range from VND1,104.43 to VND1,549.7 per kWh, depending on the region - northern, central or southern Vietnam - and the methodology used to determine storage investment costs.

The lowest proposed rate, VND1,104.43 per kWh, applies to ground-mounted solar projects in southern Vietnam, while the highest rate of VND1,549.7 per kWh applies to projects in the north.

For floating solar projects combined with BESS, the proposed price range is VND1,298.73-1,822.63 per kWh. The highest rate applies to floating solar projects in northern Vietnam, while the lowest applies to those in the south.

To develop the pricing framework, EVN assumed that storage systems would have a capacity equivalent to 10% of the associated solar plant's capacity. Investment costs for BESS were based on tender results from Hanoi Power Corporation, Northern Power Corporation, the Chinese market and global average benchmarks.

EVN noted that several of the input parameters used in the calculations remain preliminary and should be regarded as reference values only.

To ensure objectivity before final approval of the pricing framework, EVN proposed that the Electricity Authority seek additional feedback from consulting firms and independent international organizations with relevant experience in regional and global energy markets.

Amid ongoing administrative boundary adjustments across provinces and cities, EVN also urged the Ministry of Industry and Trade to issue guidance on how provinces should be classified into northern, central and southern regions when applying regional electricity pricing frameworks, in order to avoid implementation difficulties.

Tam An