A sell order is a bid placed by a market participant on a connected trading platform, with the intent to sell electricity. Sell orders are part of the redispatch process, in which market participants are invited via a market message to submit buy and sell orders to help resolve intraday congestion situations.
For congestion situations expected to occur within 24 hours (intraday), the market is asked via a market message to submit flexibility bids. These consist of buy and sell orders placed on connected trading platforms. With a sell order, market participants offer to consume less electricity (or generate more) than previously agreed. The electricity that is no longer used is offered (sold) per kW or MW at a sell price determined by the market participant.
If the GOPACS algorithm can match a buy order and a sell order that together resolve the congestion situation, the sell order will be executed, and the participant with the highest bid price will see their offer accepted.
If more electricity is generated, it naturally needs to be sold. But why does electricity need to be sold when less is consumed? Here’s the reason: the consumer has already purchased electricity in advance. If they now consume less to help resolve a congestion situation, surplus electricity remains. The consumer can then offer this surplus via a sell order. If the electricity is sold at a higher price than originally paid, this results in a financial benefit.
If there is generation congestion in an area, more electricity needs to be exported than the grid can safely handle. The substations connecting the area to the medium- or high-voltage grid are overloaded. In this case, a market message will request buy orders, which encourages local participants to either consume more or generate less, meaning less electricity needs to leave the area. A local buy order must always be paired with a non-local sell order to maintain system balance.
Conversely, in a consumption congestion situation, more electricity needs to be imported into the congestion area than the grid can safely handle. In this case, sell orders are requested within the congestion area — either by reducing consumption or increasing generation. This reduces the need to import electricity into the area. These local sell orders are then paired with non-local buy orders.
| Generation Congestion | Consumption Congestion | |
|---|---|---|
| Situation | Too much electricity in the congestion area | Too little electricity in the congestion area |
| Consequence | More electricity must leave the area than can be safely transported | More electricity must enter the area than can be safely transported |
| Desired action | Reduce generation or increase consumption | Reduce consumption or increase generation |
| Inside congestion area | Buy orders | Sell orders |
| Outside congestion area | Sell orders | Buy orders |
