5/14/2009 10:00 AM
The benefits of an energy audit
The last article reviewed the certainty of increased power bills. Upcoming new regulations regarding how power is generated could result in power bills increasing by almost 20 percent. In addition, corporations are receiving increased pressure to become better citizens and consumers of power and natural resources.
All of these factors are combining to create a perfect storm of higher power bills. About all broadcasters and content producers can do is mitigate their own usage. Fortunately, that’s not as hard as it may first seem.
There is a wealth of resource on the Internet. In fact, you’ll probably be overwhelmed with the hits that come back to you. To help you get started, here’s a list of beginning resources:
• The Green Grid.org
• Energy Right.com
• EPA, Mercury spills
Conduct an energy audit
The first step in reducing your power consumption is to better understand where it’s now going. That requires a survey. Before we look at the process, let’s review some generally-accepted categories of facility power usage. This will help target the largest uses of power.
Figure 1 illustrates where power is consumed within facilities. When it comes to using electricity, HVAC systems are usually the most power-hungry. The chart shows that a building’s HVAC system represents about one-third of its electricity consumption. For the typical TV station, that figure may increase when the studios are used because of lighting and the need for additional cooling. The figure goes down when production isn’t taking place. However, other than the changes in HVAC demand brought on by the use of studio lights or outside temperatures, a content production center’s power consumption is relatively constant. Power companies love these kinds of customers.
The second highest demand area for power is the technical infrastructure. This includes all video/audio production equipment, cameras, switchers, signal processing, racks and studio microwave equipment. This digital equipment accounts for about 30 percent of a facility’s power needs.
Office lighting and desktop business computers account for another 21 percent of a station’s power bill. For our survey purposes, we’re going to ignore the remaining support areas like snack machines, water coolers, etc.
A broadcaster’s digital infrastructure operates 24/7/365. In my 20-plus years of broadcast work, I’ve never seen a studio engineer turn “off” any piece of equipment. In fact, you would probably be hard pressed to find the on/off switch on much of today’s signal processing equipment. These devices are expected to be powered up and left that way. If that’s so, can anything be done to reduce the power they consume? The quick answer is yes. The more complete answer is yes, but it takes some work. Let’s examine the process behind an energy audit.
Finding power hogs
In an effort to better understand where power might be saved, it’s worthwhile to conduct an energy audit. Simply put, this is a report on what devices operate and how much power they consume. It’s often best to develop a simple spreadsheet so you can track consumption by device and by room. The more detailed the list, the more likely you’ll be able identify energy-robbing devices and then develop methods to rein in those costs.
The first step is to assign responsibility. This may be the perfect opportunity to train a new person about a facility’s operations. Survey tasks include reviewing building spaces, recording square footages, verifying the location of doors and windows and hours of operation. This may be a perfect task for that new engineer, who would benefit from a better understanding of a facility’s spaces.
Once all the data has been recorded, this person can prepare a report summarizing his or her efforts. At this stage, the audit merely details consumption. Recommendations and implementation of changes to reduce power usage is a separate process, which may require a senior staff meeting.
The audit should record the type of lighting used in each room and the number of hours per day it must be used. Describe the type and quantity of lighting used by room. If available, measure the amount of light used in the office spaces. Tests often reveal that these areas have too much lighting. One clue to this problem is finding a light shield taped to any computer monitor.
The HVAC should be the first area examined because it consumes most of the power. Note the volume of air moved and motor sizes for all components in the HVAC system. Especially important is the age of the system. Check the condition of all fan belts. Note how often the filters are changed. A more complete HVAC power audit may require someone with expertise in such systems.
The auditor should record for each space, the hours and days of the week the area is used along with types of lighting and the equipment in the area. In business spaces, list the computers, monitors, printers, copiers, fax machines and any other business equipment in use. Log the amount of power each device consumes. It is important to note all of these details as we’ll see later, even little numbers can add up to a large power bill.
Technical spaces will be more difficult to audit. One method is to list each rack along with a brief description of the gear housed there. Then, using a clamp-on ammeter, measure the current being drawn by rack and then calculate power consumption on a rack-by-rack basis.
Stand-alone devices, such as tape machines, monitor walls, etc., should be assigned to the room in which they reside along with calculated or measured power requirements. List every device as either a 24/7 or occasional power requirement. If the device isn’t operated 24/7, estimate how often it is used, and log that data. The auditor should carefully look for devices that could be turned off when not needed, and note that in the record.
Don’t forget to audit commons areas: lobbies, hallways and lunchrooms. Add to that refrigerated water fountains, cola and snack machines, and water heaters (if electric). Include all TV sets located throughout the station. Include outside displays, marquees and satellite dishes.
Because much of the equipment in a broadcast/video facility is composed of rack-filled cages, actual power calculations are difficult. Also, some devices like outside display signs won’t have a UL plate listing power consumption. It often will be easier to just measure actual power consumption with a clamp-on ammeter. Now it’s time to calculate some power loads.
Table 1 to the right illustrates some data, which may apply to the typical office space.
Yearly work hours, occupied 10hr/day, 5day/wk, 52wk/yr = 2600hr/yr
Total number of hr/yr 24*365=8760hr/yr
Total overnight/weekend hours = 8760-2600= 6160hr/yr
Cost per kWh = $0.10
Now let’s calculate some costs.
As the table shows, a yearly savings of $1203.82 was possible by changing only a few parameters.
First, the original T12 fluorescent lamps at 40W each were replaced with smaller T8 lamps, which draw only 25W. Second, the automatic sleep mode was enabled on the Vista computer. This causes the computer to significantly reduce power consumption when it’s not needed. This results in as much as an 85 percent reduction in power consumption. How many computers are in your station? Third, a motion was installed in place of the overhead light switch. This ensures the lights are turned off when no one is in the office. The total out-of-pocket cost is about $30. And you'll receive a total ROI in less than two weeks.
Now, let’s see how a similar solution might affect a little-used technical space. Table 2 to the left illustrates the simple addition of a motion sensor to control the lighting in an equipment room. The result is a savings of about $500, which is certainly worth the time, effort and cost to install a motion sensor.
These two scenarios were presented to emphasize the cost of human spaces. Technical areas typically draw constant power. It’s the locations where people gather and work that have changing workloads. For that reason, these spaces should be examined carefully for low-hanging fruit energy savings. The simple addition of a motion detector to control lights, as shown above, saved more than 100X its installation cost. And these savings continue.
The complexity of these lists and calculations by space will vary widely, but the goal should now be obvious — get operational spaces to require less power. Using the above data, ask these key questions about each space and device:
• What equipment can be turned off? If so, how/when?
• Can the level of lighting be reduced? If so, how/when?
• Can these tasks be automated? People forget; computers don’t.
While the calculations are fundamental, the audit may require hundreds, so make a spreadsheet.
Help is available
There are even more thorough ways to save through energy use reductions, but you may wish to seek a professional energy audit to identify them. Sometimes, the local power company will even help cover the cost of a professional auditor. For instance, the Shakopee, MN, power company will contribute up to 75 percent of the audit cost, based on the client’s power consumption. Check with your power company to see what services it may offer.
Experts say companies can save up to 75 percent on their power bills through careful implementation of energy audits and controls. Some of the solutions are quick, easy and require little cost. Getting the maximum benefit often requires investments in replacing older HVAC systems and implementing better environment controls.
However, there are even ways to reduce the CAPEX cost of these replacement systems. Some power companies offer contributions, offsets or lower rates. There may be tax benefits to installing more efficient systems. Consult proper advisers for specific benefits that may apply to your situation.
Any company that implements an efficiency program now will benefit immediately in lower OPEX. More importantly, as electrical costs increase from the mandate of cap and trade, the cost of new power plants and increased local and state taxes, the value of becoming an efficiently-run business increases.
The next column will examine some specific lighting technology and the rules surrounding its implementation.
Energy crisis on campus
Energy audit form