4 FM quick reads on demand response
1. Things to Know Before Beginning Demsand-Response
Demand-response programs offer maintenance and engineering managers opportunities to deliver energy efficiency and savings to their organizations. And as institutional and commercial facilities continue to search for bottom-line benefits, such incentive programs from utilities have become more popular.
Before making the decision to take part in a demand-response program, managers need to weigh a number of factors. Among them are the program's technology requirements, ensuring effective communication with the utility and within the facility, and monitoring the program to ensure the program delivers the intended benefits.
The East Meadow School District in Westbury, N.Y., has participated in a demand-response program since 2008, focusing its savings efforts mostly on corridor lighting, lighting in non-essential areas, and the air-conditioning system.
The situation is a win-win for the school district, which was asked to reduce its kilowatt (kW) use by 30,000 per megawatt (mW) per year, which breaks down to 20,000 mW in summer and 10 mW in the winter. If it hits those targets, the total annual benefit is more than $3,000. However, the school district does not incur any penalties if it does not meet its targets, which makes participation in the program more appealing.
Managers should not make the decision to take part in a demand-response program lightly, considering all the factors involved, such as downtime and the impact a demand-response event can have on occupants and staff.
Before the East Meadow school district opted to participate, director of operations Patrick Pizzo conducted research and made recommendations to district officials regarding the way the program would directly and tangibly affect building occupants. After doing the research, he took his findings to a committee that made the final decision. As he says, in a school setting, anything that is going to necessitate a change in the building's operation should be initially investigated in collaboration with occupants who will be affected.
2. What You Need To Know When Calculating Demand Charges
Calculating demand charges on your electric bill can be tricky if you're not an expert. Here's what you need to know when calculating demand charges.
1. Understand the electric tariff(s) for your account(s). It may be seen on the bill as an alphanumeric (e.g., EL 8). Your utility account rep should be able to break out all demand charges, which may appear separately for generation, transmission, and distribution.
2. Review a year of bills and cull out the dollars charged for demand. Divide that annual cost by the total electric spend to derive the percentage cost of demand. If that number is under 20 percent, using average electric rates for all upgrades may be acceptable. If greater than 20 percent, make it a rule that all calculations of dollar savings be performed using real tariff rates instead of average pricing.
3. View your hourly load profiles for at least one hot day, a cold day, and an intermediate day. Many meters now report usage in the short time intervals needed to do this. Your utility may even offer web access to that data. If not, various methods exist to meter demand on your own. Doing so will show when peaks occur, and help find ways to control them. Various types of real-time dashboard software and services are also available to do this for a fee. A web-based course on load profile analysis is offered by the Association of Energy Engineers (www.aeeprograms.com).
If you're looking for ways to cut demand, train facility personnel to avoid unnecessary demands (e.g., equipment testing) during peak hours. Where feasible, adjust operating schedules to minimize or shift activities during peak load hours. In industrial facilities that use electrically-powered fork lifts, for example, the units are plugged in for charging at the 3 p.m. end of a shift, but a timer and relay postpone the charge cycle until 10 p.m., thus shifting about 50 kW of peak load.
3. Understand How Rates Change To Manage Electricity Costs
Electric rates continue to rise, and to mitigate the impact, smart facility managers are examining options for controlling their usage. Care is needed, however, in the economic analysis of such upgrades. Some efficiency choices may reduce consumption more than peak electric demand, and using average electric rates to evaluate them may result in disappointment. Understanding how rates are changing may go a long way to navigating those changes.
Unlike residential electric rates that charge only for the kilowatt-hours (kWh) used each month, commercial facilities may be billed for both consumption and for how quickly they consume electricity, also known as demand. That speed of electric use is measured in kilowatts (kW), or in kilovolt-amps (kVA). Think of a kW as a kWh per hour: Your peak kW demand is the fastest rate of electricity use during a monthly billing period.
Demand charges are typically based on the highest peak kW seen each month. Depending on the tariff, that peak may either occur at any time, or be based on a time window such as 8 a.m. to 6 p.m. on weekdays. It is not, however, based on the very brief instantaneous demand spike that occurs when a motor or light is first started. Instead, it's often calculated as the highest kWh consumed in a 15-, 30-, or 60-minute period during a month. That consumption is divided by the length of the time interval to derive the peak billed demand.
This means that a single rapid usage, such as running all chillers for 15 minutes at one time during a hot spell, perhaps only once in a month, could set the peak demand charge for that month. Where a ratchet (also called "contract demand") charge exists, such a spike could also set a charge that would be levied each month for an entire year.
4. What Is Smart Grid, Precisely?
Today's tip is about how you can best prepare your buildings for the new smart grid.
But first, facility managers need to understand what smart grid is, and what it isn't.
Basically, "smart grid" describes increased capabilities in the nation's energy grid that will allow for two-way communications between facilities (and even devices) and the utility. The smart grid will also provide better power reliability and quality, and better efficiency in transmission.
Facility managers have been hearing for years that smart grid is coming, and there's been tons of advice from vendors, consultants, utilities, and other industry experts about how facility managers should prepare to best reap the benefits. But here's a little secret: Smart grid, in large part, is here!
One of the sure signs that smart grid is here is the increase in automated demand response programs. There's even a credit in the new version of LEED - LEED v4 - for demand response. Even though many facility managers may not immediately recognize this as taking advantage of smart grid, an ADR is, in fact, exactly what a smart grid provides. Smart energy management systems that ratchet building systems up and down automatically during peak demand periods are commonplace now. Here's one simplified example: A smart meter can send a signal to the BAS so that a variable speed drive is slowed by 20 percent for 10 minutes. This reduces the motor's energy use by 40 percent. Once the 10 minutes are up, the VFD goes back to full speed and a different VFD is slowed. Occupants are unlikely to notice the change, and peak load is reduced. Small changes like this could add up to huge savings once facility managers become adept at looking for the many energy-saving opportunities smart grid provides.
The next evolution of what we're commonly calling smart grid - if we define smart grid as a s sort of catch-all term to refer to how utilities and facilities will interact - is real-time pricing. Facility managers will be able to program energy management systems to optimize how the facility uses energy when energy is the cheapest. They may not necessarily save a tremendous amount of kilowatt hours, but they'll certainly save cost.
While many of the overarching benefits of smart grid accrue to the utilities, these advantages are ones facility managers can take advantage of now. Explore these options with your local utility, if you haven't already.
QUICK Sign-up - Membership Includes:New Content and Magazine Article Updates
Educational Webcast Alerts
Building Products/Technology Notices
Complete Library of Reports, Webcasts, Salary and Exclusive Member Content
click here for more member info.
Press Release Archives
Our Content On Your Site
FM Online Tools
- Content Directory
- Site Map
Other Online Resources