Two-tier battery solution for data center backup

1. A system, comprising:

a plurality of first batteries, each first battery respectively electrically coupled to a respective server rack in a plurality of server racks and having a respective capacity to provide power to the respective server rack for a first power anomaly for up to a first duration;

a second battery electrically coupled to the plurality of server racks and having a capacity to provide power to the plurality of respective server racks for a second power anomaly for up to a second duration, wherein the second duration is longer than the first duration, wherein each power anomaly is a deviation of mains power from one or more of a nominal supply voltage and frequency; and

a power control system operable to perform operations comprising:

determining, for the plurality of server racks and based on observed power anomalies, a power anomaly profile that describes historical statistics of the observed power anomalies;

determining, for the plurality of server racks and based on the power anomaly profile, a likelihood threshold that quantifies a likelihood of any future power anomaly exceeding the second duration; and

selecting the capacity of the second battery based on the historical statistics of the observed power anomalies and power consumption statistic for the plurality of server racks such that a likelihood of the second battery to provide power to the plurality of server racks for a duration of any future power anomaly meets the determined likelihood threshold.

2. The system of claim 1 , wherein the power control system is further operable to perform operations comprising:

determining that the first power anomaly is occurring; and

in response to determining that the first power anomaly is occurring, enabling, within the first duration, the second battery to provide power to the plurality of respective server racks.

3. The system of claim 2 , wherein the power control system is further operable to perform operations comprising:

determining a response time of the power control system to cause the second battery to provide power to the plurality of respective server racks; and

selecting the first duration based, in part, on the response time.

4. The system of claim 1 , wherein the second battery has a battery capacity of at least one mega-watt hours.

5. The system of claim 1 , wherein the power control system is further operable to perform operations comprising:

determining that a demand response condition for a power grid providing power to the mains power is met; and

in response to determining that the demand response condition is met, causing the second battery to provide at least a portion of power to the plurality of server racks to shed a load from the power grid that is at least equal to the portion of power provided by the second battery.

6. The system of claim 1 , further comprising a switch to electrically couple the second battery to the power grid, wherein the power control system is further operable to perform operations comprising:

determining that the first power anomaly is occurring; and

in response to determining that the first power anomaly is occurring, enabling the switch to enable the second battery to provide power to the power grid.

7. The system of claim 1 , wherein each power anomaly includes a power grid frequency imbalance, a voltage drop on the power grid, or a lack of adequate current within the power provided by the power grid.

8. A system, comprising:

a plurality of first batteries, each first battery respectively electrically coupled to a respective server rack in a plurality of server racks and having a respective capacity to provide power to the respective server rack for a first power anomaly for up to a first duration;

a second battery electrically coupled to the plurality of server racks and having a capacity to provide power to the plurality of respective server racks for a second power anomaly for up to a second duration, wherein the second duration is longer than the first duration, wherein each power anomaly is a deviation of mains power from one or more of a nominal supply voltage and frequency; and

a power control system operable to perform operations comprising:

determining, for the plurality of server racks and based on observed power anomalies, a power anomaly profile that describes historical statistics of the observed power anomalies; and

selecting a capacity of the second battery based on the historical statistics of the observed power anomalies such that a likelihood of the second battery to provide power to the plurality of server racks for a duration of any future power anomaly meets a likelihood threshold;

wherein selecting the capacity of the second battery based on the historical statistics comprises:

determining a power consumption statistic for the plurality of server racks;

selecting the likelihood threshold;

determining, based on the historical statistics, a modeled second duration having a likelihood of occurring equal to the likelihood threshold;

determining, based on the modeled second duration and the power consumption statistic, a modeled capacity; and

selecting the modeled capacity as the capacity for the second battery.

9. A method, comprising:

providing a plurality of first batteries, each first battery respectively electrically coupled to a respective server rack in a plurality of server racks and having a respective capacity to provide power to the respective server rack for a first power anomaly for up to a first duration;

providing a second battery electrically coupled to the plurality of server racks and having a capacity to provide power to the plurality of server racks for a second power anomaly for up to a second duration, wherein the second duration is longer than the first duration, wherein each power anomaly is a deviation of mains power from one or more of a nominal supply voltage and frequency;

determining, for the plurality of server racks and based on observed power anomalies, a power anomaly profile that describes historical statistics of the observed power anomalies;

determining, for the plurality of server racks and based on the power anomaly profile, a likelihood threshold that quantifies a likelihood of any future power anomaly exceeding the second duration; and

selecting the capacity of the second battery based on the historical statistics of the observed power anomalies and power consumption statistic for the plurality of server racks such that a likelihood of the second battery to provide power to the plurality of server racks for a duration of any future power anomaly meets the determined likelihood threshold.

10. The method of claim 9 , further comprising:

determining that the first power anomaly is occurring; and

in response to determining that the first power anomaly is occurring, enabling, within the first duration, the second battery to provide power to the plurality of respective server racks.

11. The method of claim 10 , further comprising:

determining a response time of a power control system to cause the second battery to provide power to the plurality of respective server racks; and

selecting the first duration based, in part, on the response time.

12. The method of claim 9 , wherein the second battery has a battery capacity of at least one mega-watt hours.

13. The method of claim 9 , further comprising:

determining that a demand response condition for a power grid providing power to the mains power is met; and

in response to determining that the demand response condition is met, causing the second battery to provide at least a portion of power to the plurality of server racks to shed a load from the power grid that is at least equal to the portion of power provided by the second battery.

14. The method of claim 9 , further comprising:

determining that the first power anomaly is occurring; and

in response to determining that the first power anomaly is occurring, enabling a switch to enable the second battery to provide power to the power grid, wherein the switch electrically couples the second battery to the power grid.

15. The method of claim 9 , wherein each power anomaly includes a power grid frequency imbalance, a voltage drop on the power grid, or a lack of adequate current within the power provided by the power grid.

16. A method, comprising:

providing a plurality of first batteries, each first battery respectively electrically coupled to a respective server rack in a plurality of server racks and having a respective capacity to provide power to the respective server rack for a first power anomaly for up to a first duration;

providing a second battery electrically coupled to the plurality of server racks and having a capacity to provide power to the plurality of server racks for a second power anomaly for up to a second duration, wherein the second duration is longer than the first duration, wherein each power anomaly is a deviation of mains power from one or more of a nominal supply voltage and frequency;

determining, for the plurality of server racks and based on observed power anomalies, a power anomaly profile that describes historical statistics of the observed power anomalies; and

selecting the capacity of the second battery based on the historical statistics of the observed power anomalies such that a likelihood of the second battery to provide power to the plurality of server racks for a duration of any future power anomaly meets a likelihood threshold;

wherein selecting the capacity of the second battery based on the historical statistics comprises:

determining a power consumption statistic for the plurality of server racks;

selecting the likelihood threshold;

determining, based on the historical statistics, a modeled second duration having a likelihood of occurring equal to the likelihood threshold;

determining, based on the modeled second duration and the power consumption statistic, a modeled capacity; and

selecting the modeled capacity as the capacity for the second battery.