be established, it could take on the task of calculating the appropriate wheeling charges, and potentially even the collection and distribution of the fees. Again, however, this is not a necessary first step.

From international experience, wheeling charges tend to evolve over time. Wheeling methodologies are an effective tool to ensure that transmission owners provide capacity for multilateral trading, since the value of providing the capacity is known in advance for the transmission owners. Wheeling charges can evolve to become more sophisticated or harmonised over time. When market models change it may also be appropriate to change the way transmission owners are compensated. In highly integrated markets such as in the primary model, proposed in later sections, wheeling charges may change to congestion rents. Congestion rents offer the transmission owner compensation based on the short-term value of the grid, and is as such not known in advance; this coupled with connection tariffs is typically the way highly integrated markets compensate the utilisation of transmission grids. Since the ASEAN region is in the early stages of creating multilateral power trading, wheeling charges are an important tool in succeeding with establishing multilateral power trading.

Data and information sharing requirements

Multilateral trading requires some level of data and information sharing. This is another area where the presence of a central, responsible organisation can be extremely helpful, as it can take on responsibility for receiving and distributing information to and from relevant ASEAN stakeholders using a central IT and communications platform. For example, such an institution would be able to receive transmission system data from the transmission owners, and it could in turn send back information on traded volumes.

The sharing of power system operations and planning information will inevitably raise concerns over data confidentiality.18 It is not unusual for data to be considered too sensitive to share, or there may even be legislative or regulatory obstacles to data sharing. It is possible, therefore, that some AMS will need to change relevant national legislation or add specific exceptions to existing regulations in order to allow these data to be shared with a regional co-ordination body.

As a starting point, though, it is worth bearing in mind that the initial data sharing requirements may be minimal. For example, before the development of a regional institution, data will need to be shared on a bilateral or multilateral basis among limited groups of AMS. These countries could decide among themselves what data requirements are necessary, and how to share these data in a secure manner.

Ideally, however, data sharing methods and requirements should be harmonised as early as possible. Over time the data sharing requirements will certainly change, in particular as multilateral trading in ASEAN develops into a more organised regional market. At a minimum, therefore, any agreements defining data requirements should be easy to amend and update.

Information that will need to be exchanged will primarily be focused on items that directly relate to cross-border power trade. A high-level list of future potential market informationsharing requirements includes:

aggregate and/or calculate ATC

18 This section draws on work done as part of the ATSO institution study, which is currently not publicly available.

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