The Component Electricity_Tariff_Balancing_Power
The Electricity_Tariff_Balancing_Power component represents a simple tariff for participating in the balancing power market. A unit in the power system can provide positive and/or negative balancing power.
Component Template
The Electricity_Tariff_Balancing_Power.e-ctpl component template is located in the Component template library folder Electricity Supply.
Integration Into a Scheme
The following scheme bases on the tutorial 04. It shows the additional integration of the component Electricity_Tariff_Balancing_Power.
Tutorial 111 demonstrates the use of the Electricity_Tariff_Balancing_Power component to optimize marketing of the energy provided by an electricity storage system on the day-ahead and control energy market.
How the Component Works
The component Electricity_Tariff_Balancing_Power represents the participation in the balancing power market. The capacity of the respective unit is held in reserve for the provision of control energy and remunerated with a price. By holding back the power, the marketed unit cannot be used for other purposes in the energy system because it is blocked for the balancing power market. When positive balancing power is held in reserve, the unit must be able to ramp up at any time. When providing negative balancing power, the unit must be able to shut down at any time. The operating range of the unit is restricted accordingly (see following figure).
The component takes into account the time constraints of the market with six time slices per day for which balancing power can be marketed. These time slices of 4 h each are defined by the following periods: 0:00 – 4:00 a.m, 4 – 8 a.m., 8 a.m. – noon, noon – 4 p.m., 4 p.m. – 8 p.m., and 8 p.m. – midnight.
The optimization during the simulation decides on the basis of the price whether participation in the balancing power market with the provision of the power is worthwhile for each point in time in the year. If this is the case, the capacity is blocked for the balancing power market. After the simulation, the Electricity_Tariff_Balancing_Power provides information on the reserved positive and negative balancing power and the respective revenues.
Calls for Balancing Power
The call-off of balancing power is not calculated explicitly, because this requires a complex two-stage solution algorithm. The potential revenue from balancing energy calls that arise when participating in the balancing energy market for the secondary and minute reserve can be taken into account by means of an additional contribution in the price of the input data. For this purpose, a constant price component can be added to the respective input values for the Price of balancing power. This additional price component must be estimated on the basis of call-off probabilities and possible energy price bids for the respective system type. This approach allows the economic influencing factors of the balancing energy market and the call-offs to be taken into account in the model when deciding whether participation in the balancing power market is worthwhile.
Input Data
The Input data form of the component is divided into the tabs Power supply, Power demand, Power storage, and Counter regulation.
Under the input value Reference to unit, select the unit that is to participate in the balancing power market. Under the tab Power supply, electricity generators can be selected; under the tab Power demand, electricity consumers can be selected; and under the tab Power storage, electricity storages can be assigned as storages. In the subsections Positive balancing power and Negative balancing power, you can specify the Maximum positive and negative power offered with the respective price of the power reserve. In the model, the remuneration of the reserve power (Price of the balancing power) refers to the blocked power. It is specified in EUR/(h MW). You can enter an appropriately adjusted price here in order to furthermore take into account the entire market, e.g., also call-offs and thus the balancing energy market.
In addition, you can enter the Minimum bid, the smallest possible power that can be offered on the market. As a rule, the minimum bid is 1 MW. Smaller capacities can also be marketed by a combination of plants via service providers as a pool.
In the following, the Input data of the component are presented in detail.
Minimum Activation Period (only for electricity storages)
The Minimum activation period specifies for how long the storage facility can supply balancing power at least without interruption. For example, an electricity storage with a capacity of 1 MWh with a minimum activation period of 30 minutes can provide the following capacities to the market: 2 MW of positive power, 2 MW of negative power, or 1 MW of positive and 1 MW of negative power simultaneously. A minimum activation period of 15 to 30 minutes depending on the storage configuration is scheduled for electricity storages marketing primary balancing power to ensure the operational reliability of the electrical grid in Germany in 2023.
Quick Start Capability
A unit with quick start ability can respond to control power calls at any time, even if the plant has to be started up from standstill for this purpose. If the function Quick start ability of the unit is selected, the balancing power can be offered in the entire power range, even below the minimum partial load (see the following figure).
A unit without quick start ability cannot react to balancing power calls with a sudden start-up from standstill (positive balancing power) or a fast shutdown (negative balancing power). These units can only react flexibly to balancing power calls during operation above the minimum partial load. For example, at a minimum partial load of 50 % for a unit that is not able to start quickly, only 50 % of the unit’s capacity is offered on the balancing power market (see the following figure).
Symmetrical Marketing (primary control reserve)
In the case of Symmetrical marketing, positive and negative balancing power with identical quantities is provided at the same time. Accordingly, the Maximum and Minimum capacity offered, as well as the Price at which the balancing power is provided, can only be found once in the Input data. Symmetrical marketing is used in Germany for the marketing of primary control reserve.
Counter Regulation
In the case of coupled units, the power reserve for control energy must also guarantee a power reserve for the second form of energy produced by the unit, such as heat, cold, or steam. The reserve of the second form of energy is necessary to ensure that the call of balancing power in the energy system is possible or can be counter regulated. For example, it must be guaranteed for a CHP unit that positive balancing power calls (CHP unit ramps up) are also possible at any time when positive balancing power is marketed. For this purpose, the energy system must be able to absorb the the second form of energy, in this case heat. In the component Electricity_Tariff_Balancing_Power, the option Consider counter regulation can be checked to take into account the aforementioned power reserve or counter control of the second form of energy.
After checking the Consider counter regulation option, select the Kind of energy (heat, cold, steam, or fuel) that needs to be counter regulated from the drop-down list.
Conversion factor
The conversion factor represents the ratio of the heat, cooling, steam, or fuel power provided by an energy conversion system (e.g., a fuel cell or power-to-heat system) for counter regulation to the electrical power provided as balancing power. It indicates the ratio of the power reserve of the second form of energy to the electrical power reserve for the balancing energy market.
The conversion factor is positive for the supply of counter regulating power (energy generation) and negative for the consumption of counter regulating power (energy consumption).
For example, enter a positive conversion factor for the counter regulation with a power-to-heat system with reserved heat generation and a negative conversion factor for the counter regulation with a fuel cell with reserved fuel consumption. In the example of the CHP, this conversion factor is the power ratio (electricity coefficient) of the unit, which is determined from the ratio of the electrical power to the thermal (heat) power.
Systems for Counter Regulation
In the form under the tab Counter regulation, select the units that are available for counter regulation of the selected form of energy in the energy system (see following figure).
The example shows the marketing of a CHP in the balancing power market in an energy system from tutorial 4 (see figure above: Integration into a scheme). In the case of coupled plants, when reserve power is provided for control energy, reserve power must also be guaranteed for the second form of energy produced, in this case heat. This reserve or counter control of the second form of energy is necessary to ensure that the call of control energy in the energy system is possible or can be counter controlled. When positive control energy is marketed, it must be guaranteed for the CHP that positive control energy calls are possible at any time, i.e., that the CHP can start up at any time. For this purpose, the energy system must have the capacity to absorb the second form of energy, in this case heat. Equivalently, it must be possible to shut down the CHP for a control energy call in order to provide negative control energy. In this case, other plants may have to be started up to compensate for the missing heat output.
For illustration purposes, the simulation results for the CHP unit are shown below once without and once with the setting of a Counter regulation.
The results of the simulation without the use of a counter regulation for the CHP unit with the nominal electric power of 30 kW are shown in the following figure.
This shows that both positive and negative balancing power is marketed in the period shown. However, the marketing of positive balancing power in this model is problematic because a possible balancing power call cannot be counteracted: The additional heat generated by the CHP in the event of such a call cannot be delivered because there is no Emergency_Cooler in the model (see figure above under Integration into a scheme) and the heat demand is already covered by the CHP (see the following figure).
The results of the simulation with the use of a counter regulation for the CHP are shown in the following figure. In the period shown, no positive balancing power is offered because a possible call cannot be counter regulated.
In this system, to counter regulate the heat, the boiler is assigned as the system to be counter regulated under the Counter regulation tab (see following figure).
