One interesting approach to demand reduction is the idea or demand response, or “DR” programs. The New York Times recently had this article on Idaho Power’s approach to DR. The article includes this explanation of what DR is:
This concept, called demand response, has gained traction in utility circles. In essence, it involves paying users to make small sacrifices when there is an urgent need for extra power (the “peak”). The utility can then rely on cutting some demand on its system at crucial times — and, in theory, avoid the cost of building a new plant just to meet those peak needs.
There are many opportunities for demand response in data centers. EMI did a process evaluation for the California Emerging Technologies Program (ETP). During this project, EMI prepared a number of case studies on different technologies assessed by the ETP. One such case study was on an “Auto-DR” technology. My colleague who worked on this passed on this report on a joint effort between PG&E and LBNL’s Demand Response Research Center (DRRC) on an a similar Auto-DR pilot program in the summer of 2006. During the pilot program, they setup locally participating businesses to have automated controls to lower their energy consumption in response to demand response signals from PG&E. Of the 24 facilities that participated in the pilot, an office/data center had highest achieved demand reduction for a single event at 363 kW and highest average for 294 kW. In this instance the the DR strategies used at the data center site included: duct static pressure increase, Supply Air Temp (SAT) increase, fan VFD limit, chilled water (CHW) temp increase, and cooling valve limit. The chart below from the report shows how high the demand savings was for the office/data center (all the way on the left) compared to other sites.
The office data center also had the lowest payback period at 0.4 years for implementing the Auto-DR.
Following the project, the DRRC published this data sheet with information on the DR potential of data centers. The sheet makes some interesting points including that “savings can be higher than those in other industries because reducing server loads simultaneously reduces cooling and other equipment loads.”
Here are some of the other methods the DRRC recommends in their fact sheet:
– Dynamically shift load onto fewer servers using virtualization.
– Migration of load to another location (i.e. another data center).
– Temporarily raise set-point temperatures.
– Use backup reserves such as ice storage or chilled-water storage for cooling.
PG&E is still running the Auto-DR program along with the other large California IOUs which also have programs.
Tags: Data Center, Demand Reduction, Demand Response, Emerging Technologies, EMI, Energy Market Innovations, ETP, Load Shifting, PG&E, Pilot Programs
