Ever wanted to achieve super hero status? Everybody has sometime. Here’s how you can save the planet for future generations, make your facility a greener place to work, and put a smile on your CFO’s face. The best part – wearing the tights and a cape while doing it – is optional.
The conundrum aspiring super heroes face is: “How can I stop global warming when most of my time is spent finding ways to reduce costs?” The key to solving this perplexing equation is buried at the bottom of page 48 in the Environmental Protection Agency’s (EPA’s) EnergyStar® and Other Voluntary Programs 2001 Annual Report.
There, the EPA states that in 2000, a total of 1.64 pounds of carbon dioxide (CO2) was emitted into the atmosphere for every kilowatt-hour of electric generation. The EPA calculates that continuing investments in energy efficiency will reduce the marginal emission rate over time. In 2005, it drops to 1.20 lbs. CO2/kWh.
In 2010, it drops to 1.09 lbs. CO2/kWh. In short, a domino effect occurs. You save money by reducing energy consumption, which reduces CO2 emissions, which helps reduce global warming.
The Greenhouse Effect
We know that the greenhouse effect is real. Without the heat-trapping effect of water vapor, CO2, methane, and other naturally occurring greenhouse gases, our planet would be a cold, lifeless rock. As part of nature’s carbon cycle, some of these emissions are captured and stored in the oceans, forests, and agricultural land.
Over the past 200 years, the concentration of CO2 in the atmosphere has risen from 280 parts per million to a current level of 375 parts per million. It is expected to increase to 550 parts per million by 2050. This increase is the result of mankind’s use of fossil fuels, and, to a lesser degree, deforestation and other land-use changes. Consequently, both surface temperatures and sea levels have been rising for some time.
Scientists had assumed trees and plants would offset much of the global warming to come. This theory is based on two facts: Plants need carbon dioxide to grow, and experiments in greenhouses have shown that plants grow better with extra carbon dioxide in the air. This concept was supported by the phenomenon that CO2 emissions were growing faster than the actual level of CO2 in the atmosphere.
However, studies conducted by Duke University and others have concluded that existing forests are not going to solve the problem of rising carbon dioxide. While trees were growing faster, they depleted other nutrients, like nitrogen, from the soil. This accelerated growth accounts for 30 percent of the changes in carbon being stored by plants and soil in the country. Most of the carbon absorption comes from an overlooked but important fact – more trees. In the eastern United States, forests are re-growing on formerly cleared land. In the western states, aggressive fighting of forest fires has allowed forests to grow thicker than in the past.
Planting more trees is a good idea, especially in urban areas. They offer shade, help control rainwater run-off, absorb noise, and generally make cities a better place to live. That’s in addition to their ability to absorb CO2. An average, middle-aged southern pine will absorb about 100 pounds of CO2 during a year, according to William H. Schlesinger, dean of the Nicholas School of the Environment and Earth Sciences at Duke University and author of Forest Ecosystems. Of that 100 pounds, 34 pounds of CO2 will stay out of the atmosphere.
While planting trees is wonderful, it doesn’t get us to a level of net zero CO2 emission. This brings us back to making your CFO happy by reducing costs. The easiest and most efficient way to reduce energy costs is to eliminate unnecessary use, which in turn reduces CO2 emissions.
The average energy consumption for office buildings over 5,000 square feet is 19.6 kWh/sq. ft./yr., according to the EPA. Consumption drops to 12 kWh/sq. ft./yr. or less for the almost 500 office buildings that have qualified for the EnergyStar label. That’s a reduction of 40 percent!
Let’s put this in financial terms. Using data from the Building Owners and Managers Association (BOMA) International’s 2002 Experience Exchange Report, the average downtown private-sector office building comprises 334,840 square feet. Using an electricity cost of $0.08 per kWh, that’s an annual savings of $205,407 ($0.61/sq. ft.). Better yet, it increases the building’s value by $2.5 million at an 8.25-percent capitalization rate.
From the global warming perspective, this translates into an annual reduction of 2,086 tons of CO2 emissions, or the net CO2 uptake of 122,748 southern pine trees.
Best Strategies to Reduce Electric Consumption
While significant strides have been made in energy conservation, the EPA’s EnergyStar program has demonstrated one can still find energy savings. There are two basic strategies that can be employed to reduce electricity consumption:
Operating any building effectively and efficiently is difficult because of the complexity of buildings. Determining the power requirements for lighting, HVAC, and receptacle loads is a moving target based on changing factors such as weather, space use, and work schedules. The process begins with an audit to model usage and pinpoint waste. Remember, no one has found a more effective way of reducing energy costs than eliminating unneeded kWh from their electric bill. If you eliminate unnecessary usage, you can avoid costs while reducing the level of CO2 emissions.
Source: FSI Energy Engineering Services
The process begins by establishing a baseline. The following information is needed to assess consumption and system performance:
A complete set of electrical system drawings with equipment nameplate ratings.
Hourly demand-profile or monthly peak demand.
Monthly electrical usage for last three years.
Monthly electrical billing for latest 12 months.
Weather data for latest 12 months.
Your electric utility can be a source for monthly peak demand and usage data. Also, the HVAC equipment logs and three-hour temperature profiles will help in correlating the operation of the HVAC system to weather data over a 12-month period. If this data is not available, a snapshot of a typical operating period during the peak demand months may be satisfactory. However, a complete analysis cannot be done until the data is collected. Better data equals better results. This process can take six months to a year and be done by in-house staff or a consultant.
Electric use and power demand should be recorded at regular intervals. Inexpensive data loggers should be able to collect all the needed information. This equipment can be moved weekly, capturing data snapshots of a particular load. When working with motor loads, both the input power and the output of the machine or system need to be recorded at the same time.
Some equipment may only need to be monitored on a daily basis, while HVAC equipment is typically monitored on an hourly basis. Temperature and other variable data should be collected to correlate with the operation of HVAC systems. The power density (kilowatt) and energy intensity (kilowatt-hour) on a square-foot basis should be calculated and used as a baseline to compare usage and demand. If you have a campus or multiple buildings, it should be done for each building.
The process of data collection, assessment, and analyses of every major electrical and mechanical system, branch circuit, or piece of equipment can identify a number of energy-saving opportunities.
Lighting accounts for 30 to 40 percent of the total energy use for most office facilities. In industrial facilities, lighting will account for five to 10 percent of the total energy use due to the heavier process and motor loads. In either case, it is an attractive cost reduction strategy and is commonly the first option selected.
Start with a lighting audit to evaluate the current lighting systems and assess how well the systems perform compared to state-of-the-art systems. The benchmark is lighting power density (LPD), which is expressed as watts per square foot (W/ft2). A state-of-the-art T8 fluorescent lighting system in an office space is at or below 1 W/ft2. Compare that to a typical office building LPD of 2 W/ft2 or more, and one can see the savings potential.
If you think lighting upgrades are old hat, more T12 fluorescent lamps are produced each year than any other type of fluorescent lamp. Converting T12 fluorescent systems with magnetic ballasts to T8 fluorescent systems with electronic ballasts offers energy savings of 40 to 60 percent, and a 30- to 50-percent return on investment. Also consider using low mercury fluorescent lamps. They cost the same, perform as well or better than those with high levels of mercury, and are not considered hazardous waste. While mercury is a critical component for a fluorescent lamp, it isn’t needed in your tuna sandwich.
Add occupancy sensors to an upgrade from T12 to T8 fluorescent lighting and the return on investment soars to levels that will make a CFO break out into song. The logic is simple. Keep the lights off when nobody is in the room. The typical private office is empty 53 percent of the day, storerooms 56 percent, meeting rooms 66 percent, and restrooms are empty 70 percent of the time.
Daylight harvesting is another simple technology that yields high returns on investment. An office building located just a few blocks from my office was originally built to California’s stringent Title 24 standard. By upgrading the lighting system to T8 fluorescent, the LPD was reduced from 1.44 W/ft2 to 0.84 W/ft2. Daylight harvesting reduced the LPD an additional 23 percent to 0.65 W/ft2, while maintaining light levels at 50 footcandles.
Don’t forget that by reducing the lighting load you can reduce the HVAC load at the same time. One kW is equal to 3,412 BTUs and 12,000 BTUs equal one ton of air-conditioning.
Often overlooked, window film can reduce the amount of solar heat gain in a building by as much as 65 percent. This can account for one-third of a building’s cooling load depending upon locale. Single-pane, tinted glass is the most common glazing for existing office buildings. Applying window film can reduce the solar heat gain from 175 BTU/h-ft2 to 65 BTU/h-ft2. With a 10-year manufacturer’s warranty and installed cost of $3 to $4 per square foot for window film, a 40-percent return on investment is common.
Adjustable Speed Drives
Manufacturers have used adjustable speed drives (ASD) for years as a way to control large process loads effectively and efficiently. For an office building, the prime candidate is the HVAC system components, such as air-handling units, chiller compressor motors, cooling tower fans, exhaust fans, and water pumps. The typical HVAC system is operated under maximum load conditions only about one percent of the time. A total of 83 percent of the time it’s at or below 70-percent capacity. Using an ASD allows a motor to have its speed reduced by 20 percent while reducing its energy consumption 50 percent.
The cost for the equipment and installation usually has an inverse relationship with motor horsepower. Large motors typically cost less per horsepower. Motors of 100 horsepower and up typically fall into the no-brainer category when assessing an ASD upgrade. A high-efficiency motor may be a better solution on smaller motors. As with most projects, a detailed engineering review of the ASD, motor sizing, motor winding, coupling and load characteristics, and a detailed cost/benefit analysis should be done.
Over the past 20 years, there has been a substantial improvement in the efficiency of electric motors. The largest motors in an office building are commonly the chiller motors. Replacing older motors with newer, more efficient motors will yield significant savings. Today, a chiller can produce one ton of chilled water at 0.5 kW (0.5 kW/ton) or less. In 1980, it was 0.7 kW/ton or more. By 1990, it had improved to 6.5 kW/ton.
If an 800-ton chiller rated at 0.7 kW/ton was upgraded to 0.5 kW/ton, it would reduce demand by 160 kW, a 29-percent reduction. Couple this with the CFC phase-out that began in 1986; buildings with chillers that are near the end of their 20-year service life will find upgrading makes financial sense. Also, the local utility may have an incentive program available that can offset some or all of the costs.
Fan and pump motors are potential candidates for upgrades that can improve efficiency by up to 15 percent – the smaller the motor, the larger the potential for improvement. A plan can be developed to replace old motors with high-efficiency units on a set schedule or when they break down and need repair. The decision to replace or repair should be made before a motor fails because a replacement motor can take some time to obtain.
Yes, high-efficiency motors cost more, but they are worth it. The initial cost premium can often be recovered in energy savings during the first year – a 100-percent return on investment. The energy savings continue so by the end of the fifth year the total cost of the motor is recovered – a return on investment of more than 20 percent per year. The choice isn’t difficult. You can buy motors that are profit centers or cost centers. Just ask your CFO which one he or she prefers.
Energy Management Systems
These sophisticated systems have the ability to monitor almost an unlimited number of points for temperature, pressure, humidity, voltage, current, and switch or relay status throughout a single office building or college campus. They can turn systems or selected pieces of equipment on or off, based on time-of-day schedules or specific parameters, such as temperature. The data collection ability can be used to generate a variety of utilities and energy consumption reports and analyses for use in operations and maintenance planning.
Besides the ability to manage comfort, they can perform energy management functions, such as temperature setback. If a facility is served under a time-of-day rate schedule, these systems can be set to turn off major equipment or motors during peak hours, or delay their start to keep peak demand below a pre-set level. This ability to shave peak demand or employ other energy management strategies has produced electrical energy savings that have yielded return on investments of 25 to 35 percent.
Doing the Right Thing Alan Whitson, RPA (AWhitson@aol.com) is the seminar leader for the nationwide “Turning Green Into Gold” series and co-author of a book entitled, “The 365 Most Important Questions To Ask About Green Buildings.” Seminar schedule and book information can be found at (www.squarefootage.net).
This approach can create a list of projects that can reduce costs, reduce global warming, and provide return on investments that often exceed other uses of capital in your organization. Not every strategy has to be implemented. Carefully evaluate each building and choose those strategies best suited for your applications. Consider bundling several projects together, so those with highest return on investment can help pay for projects with lower ROI. Not every project needs to be complex. Simple approaches work too, such as turning off the lights when you leave the room or planting a few extra trees.