The Case for Energy Conservation: Look to Lighting
Conserving energy on the factory floor cuts costs, reduces energy dependency and helps the environment. A lighting retrofit is an effective way to do that.
The U.S. business/industrial community is the best place to start cutting greenhouse-gas emissions. Why? Seventy percent of all electricity is consumed by this sector. Couple this with the fact that power plants are the nation's largest single polluter, the opportunity to accelerate greenhouse-gas reductions at the plant and facility level becomes obvious. And it can be done without government mandate or legislative interference.
Plant-level efforts, such as the use of energy-efficient lighting and other equipment, as well as on-site power generation, will become more critical as the traditional method of meeting power demands - building new power plants - becomes less feasible. Economic, environmental and community resistance to new plants, for example, has helped push the average age of U.S. power plants to nearly 40 years. At the same time, electricity use continues to grow. According to the federal Energy Information Administration (EIA), electricity consumption grew at a 2.2% annual rate over the last decade, while annual generating capacity grew only at 0.8%. The EIA expects national demand to surge another 36%, or 1.8% per year, over the next two decades.
To meet both this growth in electricity demand and planned plant retirements will require 355,000 megawatts (mw) of additional capacity, says the EIA, the equivalent of 355 1,000-mw power plants. But according to the EIA, more than 350 power-generating projects were delayed or cancelled last year. The only factor that has prevented this from creating serious electricity shortages, says the agency, has been the effects of the recession of 2001-2002. The frequency of shortages has also been reduced by the use of peaker plants: smaller power plants that are quicker and cheaper to build than base-load capacity plants, and are used to supplement the electrical grid.
The choices to ensure that the nation is not plagued by electrical shortages are obvious: increase output, cut usage or both. As noted, increasing output will continue to be a challenge, despite the use of peaker plants and renewable resources such as wind, biomass, solar and geothermal.
Generating on-site power is an important power-insurance and cost-cutting option for manufacturers that, with the advancement of hydrogen fuel-cell technology, is becoming more feasible every day. Dow Co., for example, announced in May it would begin testing fuel cells made by General Motors to generate electricity at Dow's manufacturing complex in Freeport, TX. Dow said it could eventually use up to 35 mw of power generated by 500 fuel cells.
But perhaps the quickest way for most commercial and industrial facilities to address their power concerns is to conserve energy. There are a variety of ways to do this, but most involve heating, cooling and lighting. Of these, the simplest approach is often to install new, energy-efficient lighting fixtures.
According to the U.S. Department of Energy (DOE), lighting accounts for as much as 25% of all electricity consumed in the U.S., costing more than $37 billion annually. While an average household spends 5% to 10% of its energy budget on lighting, commercial and industrial users spend up to 30% for lighting. The DOE estimates that most lighting installations, both residential and commercial, waste 50% or more of the energy they consume due to obsolete equipment, inadequate maintenance or inefficient use.
One manufacturer working to trim this number is Quad/Graphics, a multi-plant, global printing company headquartered in Pewaukee, WI. The company recently completed an energy- efficient lighting project for its eight U.S. printing facilities. The lighting initiative is expected to save the company more than 30 million kilowatts hours (kWh) and $2 million annually. As a result, the printer will take 3.5 mw of power off the electrical grid - enough to power 3,750 homes or a community of 16,800 people, according to the EPA.
The company's project centered around replacing its high-intensity-discharge (HID) lights with highly efficient fluorescent fixtures. It is expected to have a profound environmental impact over 20 years: the equivalent of removing 114,697 cars from the road or saving more than 73,000,000 gallons of gas. Specifically, this will aid the environment by preventing the release of 459,180 tons of carbon dioxide, 125,220 tons of carbon, 1,680 tons of sulfur dioxide, 3,920 tons of nitrous oxides, and 70.8 lbs. of mercury.
An added benefit is that the lighting improved the printer's workspaces. The company was able to increase foot-candle readings on average over 50% with full-spectrum light, an important consideration for Quad/Graphics' line of work. The average bulb temperature of the new fixtures is 120 degrees - significantly less that that of the HID lights, which burned at 1,200 degrees.
"Quad/Graphics has long believed that what's good for business is good for the environment," says Thomas Quadracci, company president and CEO, "and this project is proof positive. Our employees benefit from better-quality light and the community benefits from a reduction in electrical use and its associated impacts."
With careful stewardship, the U.S. has an opportunity to conserve natural resources, reduce pollution, save money, and enhance the reliability of its electric supply by promoting the use of energy-efficient lighting. For more details about how to make accurate lighting choices, see the attached sidebar. Stephen Heins is Director of Communications & Marketing for Orion Energy Systems, a Plymouth, WI-based manufacturer and marketer of energy-efficient lighting solutions for manufacturing, distribution, warehouse, commercial and school markets. Contact him at: email@example.com.
Lighting Basics and BackgroundTo choose the best facility lighting option, become familiar with the following categories and terminology.
A lumen is a measure of light output from a lamp (bulb). All lamps are rated in lumens. A 100-watt incandescent lamp produces about 1750 lumens.
The distribution of light on a horizontal surface is called its illumination. Illumination is measured in footcandles. One footcandle of illumination is a lumen of light distributed over a 1-sq.-ft. area. Ideal illumination is the minimum number of footcandles necessary to allow a task to be performed comfortably and proficiently without eyestrain. According to the Illuminating Engineering Society, 30 to 50 footcandles is adequate for home and office work, while more difficult tasks require 200 to 500 footcandles.
The ratio of light output from a lamp to the power it consumes is called its efficacy, and is measured in lumens per watt (LPW).
Light color and color rendering
Lamps are assigned a color temperature according to the Kelvin temperature scale, based on their "coolness" (blue-green) or "warmness" (red). Cool light is preferred for visual and manual tasks because it produces higher contrast than warm light. Warm light is preferred for living spaces.
Artificial light sources vary widely in their color-rendering indexes (CRI). The CRI is a measure of a light source's ability to render colors the same as sunlight does. For example, incandescent lamps are rated at a CRI of 100, nearly equal to sunlight, while some high-pressure sodium lamps have a CRI of 22, which means they render colors poorly.
Types of lighting
Of the four basic types of lighting - incandescent, fluorescent, high-intensity discharge (HID) and low-pressure sodium - fluorescent and HID are considered best for industrial uses. Fluorescent lighting is used primarily in commercial indoor lighting systems, while HID is used for both indoor and outdoor applications. Incandescent bulbs are used mostly in residential applications, and low-pressure sodium lighting is used where color rendering is not important, such as highway and security lighting.
The characteristics of these four lighting types vary widely:
Incandescent lamps are the least expensive to buy but the most expensive to operate. Incandescent light is produced by a tiny coil of tungsten wire that glows when heated by an electrical current. These lamps have the shortest lives of the common lighting types, and are relatively inefficient. Common types of incandescent lights include standard, tungsten halogen and reflector lamps.
Fluorescent light is produced by an electric current conducted through a tube containing mercury and inert gases. Fluorescent lighting is used mainly indoors, both for ambient and task lighting, and is up to four times as efficient as incandescent lighting. Fluorescent lamps last about 10 times longer than incandescents. To gain the most efficiency, fluorescents should be installed where they will be on for several hours at a time. Energy savings can be increased for fluorescent lighting by relamping, replacing ballasts and replacing fixtures with more efficient models.
High-intensity discharge (HID) lamps provide high efficacy and long life, but generate more heat than other lamps. They are commonly used for outdoor lighting and in large indoor areas. HID lamps use an electric arc to produce intense light. The most common types of HID lamps are mercury-vapor, metal-halide and high-pressure sodium.
Low-pressure sodium lamps work similarly to fluorescent lamps. They have the longest service life and maintain light output better than any other lamp type. This type of lighting is generally used where color is not important, however, because it renders all colors in tones of yellow or gray.
Source: U.S. Department of Energy