Utilities created demand response programs as a way to manage the growing demand on the electrical grid, offering customers financial incentives for reducing electricity usage during peak periods. In order for a customer to even consider participating in a demand response program, the building must be equipped to receive and respond to the demand response signal sent by the local utility.
This demand-responsive capability is increasingly becoming a requisite for code-compliant design. As new technologies and product solutions launch into the marketplace, the design community is beginning to demand clarity on demand response.
Code-required and incentivized demand response
The 2008 Title 24 marked the first time that demand response requirements appeared in Title 24, and the measures were limited to lighting control systems in large retail buildings (with sales floor areas greater than 50,000ft2). In 2013, Title 24 expanded the non-residential application of demand response to include buildings larger than 10,000ft2 and added HVAC system and outdoor sign lighting provisions. The latest iteration, 2016 Title 24 (scheduled to go into effect January 1, 2017) left the demand response lighting requirements essentially the same. Buildings larger than 10,000ft2, excluding spaces with a lighting power density of 0.5 watts per square foot or less, must be able to automatically reduce lighting power in response to a demand response signal by a minimum of 15 percent below the total installed lighting power.
California buildings smaller than 10,000ft2 can also benefit from demand-responsive lighting control systems, because demand responsive control is recognized as a power adjustment factor (PAF) in both the 2013 and 2016 versions of Title 24. This means that incorporating demand responsive controls in these buildings earns a 5 percent lighting power allowance credit.
While not yet required by the broader ASHRAE 90.1 or IECC building energy codes, the LEED™ v4 green building rating system awards credits for equipping a project to participate in demand response, regardless of whether or not a program is available; utilities throughout the nation are now offering demand response programs where buildings of all sizes can reduce energy costs and alleviate stress on their local energy grid.
Options for satisfying Title 24 2016 demand response
Today, there are a number of solutions that can be used to make lighting systems capable of receiving and responding to a demand response signal. These systems differ in the size of the system they are designed to support, expense and ease of implementation.
Large, networked lighting control systems can be designed to receive the demand response signal directly from the utility or indirectly, from the HVAC system receiving the signal and relaying the demand response command to the lighting system through the building automation network (BACnet). Direct communication between the utility and the lighting system is generally preferred from a standpoint of simplified system management. In larger buildings, the lighting system and HVAC system are often managed by different teams, and direct communication with each system team is the more effective and efficient method of system control.
Networked lighting systems can receive the demand response signal directly through a system accessory designated as a certified virtual end node, often connected through a contact closure, or by using a central system software that is designed to receive secure web signals from the utility. The biggest difference between these networked solutions is the amount of programming necessary to get the system to respond appropriately when the signal is received. Most systems require additional information to react appropriately to the demand response signal. There are room-based systems that connect to an accessory via a contact closure that require zero programming. For these systems, the lighting energy reduction level (20 percent, 30 percent or 40 percent) is set on a DIP Switch during installation, and the system will respond appropriately to the demand response signal with no additional programming.
Smaller, stand-alone lighting systems can also be designed to participate in demand response programs. Expense is often the biggest differentiator, as most available solutions require a demand-responsive accessory for each individual lighting panel or controller as well as an investment in parts, labor, and programming. Look for demand-responsive controls that allow the demand-responsive accessory to be daisy-chained to multiple controllers and do not require programming. These lighting control systems offer a significantly more cost-effective solution and improved design response to demand response.