Method for controlling at least one electrical installation, the installation comprising at least one electrical energy source and/or at least one electrical energy sink and being coupled to a power grid, wherein - a future time period is specified with a start time and duration; - an upward flexibility is determined for the time period, wherein the upward flexibility comprises a predicted maximum feed-in power increase and/or a predicted maximum feed-out power decrease; - a downward flexibility is determined for the time period, wherein the downward flexibility comprises a predicted maximum exit power increase and/or a predicted maximum feed-in power decrease; - a sales threshold price is set for the time period; - a purchase threshold price is set for the time period; - at least one electricity trading transaction is entered into for the time period, the electricity trading transaction comprising a base value, a base quantity, a base price, a date on or by which the electricity trading transaction must be conducted, and the obligation to physically settle during that time period; - the base value comprises a positive or negative power on demand; - the date is the start time; - physical fulfillment includes that the base value is delivered in the amount of the base quantity; - in case of positive power on demand, ALp ≤ Fo and BPp ≥ Pv applies, wherein ALp is the base quantity of positive power on demand, Fo is the upward flexibility, BPp is the base price of positive power on demand, and Pv is the sales threshold price; - in case of negative power on demand, ALn ≤ Fu and BPn ≤ Pe applies, wherein ALn is the base quantity of negative power on demand, Fu is the downward flexibility, BPn is the base price of negative power on demand, and Pe is the purchase threshold price; - on or up to the date the installation is controlled in such a way that the installation supplies the base value in the amount of the base quantity during the time period. - a future time period is specified with a start time and duration; - an upward flexibility is determined for the time period, wherein the upward flexibility comprises a predicted maximum feed-in power increase and/or a predicted maximum feed-out power decrease; - a downward flexibility is determined for the time period, wherein the downward flexibility comprises a predicted maximum exit power increase and/or a predicted maximum feed-in power decrease; - a sales threshold price is set for the time period; - a purchase threshold price is set for the time period; - at least one electricity trading transaction is entered into for the time period, the electricity trading transaction comprising a base value, a base quantity, a base price, a date on or by which the electricity trading transaction must be conducted, and the obligation to physically settle during that time period; - the base value comprises a positive or negative power on demand; - the date is the start time; - physical fulfillment includes that the base value is delivered in the amount of the base quantity; - in case of positive power on demand, ALp ≤ Fo and BPp ≥ Pv applies, wherein ALp is the base quantity of positive power on demand, Fo is the upward flexibility, BPp is the base price of positive power on demand, and Pv is the sales threshold price; - in case of negative power on demand, ALn ≤ Fu and BPn ≤ Pe applies, wherein ALn is the base quantity of negative power on demand, Fu is the downward flexibility, BPn is the base price of negative power on demand, and Pe is the purchase threshold price; - on or up to the date the installation is controlled in such a way that the installation supplies the base value in the amount of the base quantity during the time period.