In Europe, for example, there are multiple transmission system operators (TSOs), which are responsible for their own region of the grid. These TSOs must exchange power to ensure reliable operation of the whole system.
Does anyone know how the amount of power exchanged is determined? Is there some forecasting of demand in each region that gives each TSO and ballpark of how much power they need/how much excess power (generation capacity) they have?
If anyone has any reports that describe this process it would be greatly appreciated!
Edit: A reason that I'm wondering is because it seems like in some regions tie line flows (between areas) are scheduled as a set point to be maintained. Any idea how these scheduled flows are determined? Specifically the note "maintenance of the scheduled interchanges" in this link.
Best Answer
In Australia we have the National Electricity Market, which is run by the Australian Energy Market Operator. Wikipedia describes the operation of the NEM as follows:
The interchange of energy between regions is based on 'economic dispatch'. Every five minutes, each generator submits a bid to the market, i.e. "I will generate 10 MW for $10" or "I will generate 20 MW for $30". The market operator then calculates which combination of generators to run so that the total cost of meeting all customer's loads is minimised. This includes minimisation of transmission line losses and accounts for the maximum capacities of the interconnecting lines.
To answer your original question, the 'amount of power exchanged between areas' is not a controlled quantity. The electricity market is based on meeting the consumer's loads using the cheapest generators, and the power exchange between areas is a consequence of that.
You may wish to read further on 'economic dispatch' as it is a fascinating window into the generation and transmission industries.