Energy storage controller with battery life model
An electrical energy storage system includes a battery configured to store and discharge electric power to an energy grid, a power inverter configured to use battery power setpoints to control an amount of the electric power stored or discharged from the battery, the battery power setpoints comprising at least one of frequency regulation power setpoints and ramp rate control power setpoints, and a controller. The controller is configured to use a battery life model to generate the battery power setpoints for the power inverter. The battery life model includes one or more variables that depend on the battery power setpoints.
1. An electrical energy storage system comprising:
a battery configured to store and discharge electric power to an energy grid;
a power inverter configured to use battery power setpoints to control an amount of the electric power stored or discharged from the battery, the battery power setpoints comprising at least one of frequency regulation power setpoints and ramp rate control power setpoints; and
a controller configured to use a battery life model to generate the battery power setpoints for the power inverter, the battery life model comprising one or more variables that depend on the battery power setpoints.
2. The system of claim 1 , wherein the battery power setpoints comprise both the frequency regulation power setpoints and the ramp rate control power setpoints;
wherein the controller is configured to:
generate the frequency regulation power setpoints based on a frequency of the energy grid;
generate the ramp rate control power setpoints based on a power output of a photovoltaic field; and
combine the frequency regulation power setpoints and the ramp rate control power setpoints to generate the battery power setpoints.
3. The system of claim 1 , wherein the one or more variables that depend on the battery power setpoints comprise at least one of:
a temperature of the battery;
a state-of-charge of the battery;
a depth of discharge of the battery;
a power ratio of the battery; and
an effort ratio of the battery.
4. The system of claim 1 , wherein the controller is configured to determine a relationship between each of the variables of the battery life model and one or more variables manipulated by the controller.
5. The system of claim 1 , wherein the controller is configured to use the battery life model to estimate an amount of battery degradation that will result from the battery power setpoints.
6. The system of claim 5 , wherein the controller is configured to use the estimated amount of battery degradation to estimate a cost of the battery degradation that will result from the battery power setpoints.
7. The system of claim 6 , wherein the controller is configured to:
estimate an amount of frequency response revenue that will result from the battery power setpoints; and
generate the battery power setpoints as a function of both the estimated cost of battery degradation and the estimated amount of frequency response revenue that will result from the battery power setpoints.
8. The system of claim 1 , wherein the battery life model is a parametric model comprising a regression coefficient for each of the one or more variables in the battery life model;
wherein the controller is configured to perform a curve fitting process to determine values for the regression coefficients.
9. A method for operating an electrical energy storage system, the method comprising:
storing electric power in a battery and discharging the stored electric power to an energy grid;
using battery power setpoints to control an amount of the electric power stored or discharged from the battery, the battery power setpoints comprising at least one of frequency regulation power setpoints and ramp rate control power setpoints; and
using a battery life model to generate the battery power setpoints, the battery life model comprising one or more variables that depend on the battery power setpoints.
10. The method of claim 9 , wherein the battery power setpoints comprise both the frequency regulation power setpoints and the ramp rate control power setpoints;
the method further comprising:
generating the frequency regulation power setpoints based on a frequency of the energy grid;
generating the ramp rate control power setpoints based on a power output of a photovoltaic field; and
combining the frequency regulation power setpoints and the ramp rate control power setpoints to generate the battery power setpoints.
11. The method of claim 9 , wherein the one or more variables that depend on the battery power setpoints comprise at least one of:
a temperature of the battery;
a state-of-charge of the battery;
a depth of discharge of the battery;
a power ratio of the battery; and
an effort ratio of the battery.
12. The method of claim 9 , further comprising determining a relationship between each of the variables of the battery life model and one or more variables manipulated by a controller.
13. The method of claim 9 , further comprising using the battery life model to estimate an amount of battery degradation that will result from the battery power setpoints.
14. The method of claim 13 , further comprising using the estimated amount of battery degradation to estimate a cost of the battery degradation that will result from the battery power setpoints.
15. The method of claim 14 , further comprising:
estimating an amount of frequency response revenue that will result from the battery power setpoints; and
generating the battery power setpoints as a function of both the estimated cost of battery degradation and the estimated amount of frequency response revenue that will result from the battery power setpoints.
16. The method of claim 9 , wherein the battery life model is a parametric model comprising a regression coefficient for each of the one or more variables in the battery life model;
the method further comprising performing a curve fitting process to determine values for the regression coefficients.
17. A controller for an electrical energy storage system, the controller comprising:
a processing circuit configured to:
use a battery life model to generate battery power setpoints, the battery life model comprising one or more variables that depend on the battery power setpoints; and
use the battery power setpoints to control an amount of electric power stored or discharged from a battery, the battery power setpoints comprising at least one of frequency regulation power setpoints and ramp rate control power setpoints.
18. The controller of claim 17 , wherein the battery power setpoints comprise both the frequency regulation power setpoints and the ramp rate control power setpoints;
wherein the processing circuit is further configured to:
generate the frequency regulation power setpoints based on a frequency of the energy grid;
generate the ramp rate control power setpoints based on a power output of a photovoltaic field; and
combine the frequency regulation power setpoints and the ramp rate control power setpoints to generate the battery power setpoints.
19. The controller of claim 17 , wherein the one or more variables that depend on the battery power setpoints comprise at least one of:
a temperature of the battery;
a state-of-charge of the battery;
a depth of discharge of the battery;
a power ratio of the battery; and
an effort ratio of the battery.
20. The controller of claim 17 , wherein the processing circuit is further configured to:
use the battery life model to estimate an amount of battery degradation that will result from the battery power setpoints; and
use the estimated amount of battery degradation to estimate a cost of the battery degradation that will result from the battery power setpoints.