The Tonga Energy Commission (the Commission) has approved an increase to the electricity tariff, effective from 1 May 2026. The Regulated Tariff will increase from 89.58 seniti per kilowatt-hour (seniti/kWh) to 121.63. seniti/kWh, an increase of 35.8%.
The increase is the direct result of a significant rise in the global price of diesel fuel. The wholesale price of Automotive Diesel Oil (ADO) for power generation in Tonga increased by 59% on 1 April 2026 and a further 16% on 1 May 2026 . Diesel fuel is the primary input for electricity generation in Tonga, and changes in the diesel price flow directly through to the cost of generating electricity.
The diesel price increase has been driven by the conflict in the Middle East and the resulting disruption to shipping through the Strait of Hormuz, a major global oil transit route. These events have affected fuel prices across the Pacific region and globally.
Regulatory Framework
The electricity tariff in Tonga is set under the Regulatory Addendum to the Third Electricity Concession Contract between the Government and Tonga Power Limited (TPL). The tariff includes a Fuel and Renewable Energy cost component that is adjusted periodically to reflect changes in the cost of diesel for power generation.
The standard mechanism adjusts the fuel component of the tariff each quarter. However, the Regulatory Addendum also provides for adjustments where there is an extraordinary change in fuel prices within a quarter. The Commission determined that the significant increases in the ADO price from April constitutes an extraordinary spike and has approved an adjustment so that the tariff reflects the actual cost of fuel from1 May 2026.
Impact on Electricity Bills
Electricity consumers will see the revised tariff reflected in their electricity bills from 1 May 2026 onwards.
The Commission recognises that this is a significant increase and understands the financial pressure it places on households and businesses across Tonga. The increase is not within the Commission's control — it is a direct consequence of global fuel prices due to the Middle East conflict. The Commission's role is to verify that the tariff accurately reflects the actual cost of fuel and is calculated correctly under the regulatory framework.
The Commission encourages all electricity consumers to take steps to reduce electricity usage where possible. Turning off appliances when not in use, using energy-efficient lighting, and managing air conditioning and refrigeration settings can help to reduce electricity bills.
The Commission's Role
The Tonga Energy Commission is the independent regulatory body responsible for overseeing the energy sector in Tonga. The Commission's primary functions include setting and approving electricity tariffs under the Concession Contract framework, monitoring the performance of the TPL, and protecting the interests of electricity consumers.
The Commission assessed TPL's application using verified actual diesel prices and the realistic view of likely prices across through to June 2026.
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Matangi Tonga Online ref. #9232 Tonga Electricity Commission 9 May 2026
