In today’s new era of ever-more expensive fossil fuels, assessing every dimension of energy illuminates inefficiencies where cost savings can be identified.
by Jerry Carter, SSOE Group
While today’s new manufacturing plant designs feature state-of-the-art energy efficiency, virtually all factories more than a few years old consume more energy than their operations demand.
Recent energy-efficient factory designs seek energy efficiency in response to costs for electricity, natural gas, propane and other fossil fuel-based energy sources.
By comparison, factories designed and built when energy was less expensive focused on productivity to the exclusion of energy efficiency.
As a result, older factories need power and energy efficiency assessments. To be sure, newer factories that appear efficient probably need assessments, as well. Power and energy efficiency assessments evaluate factory operations and processes to identify and eliminate inefficiencies that might be raising the cost of lighting, heating and air conditioning. More significant, successful audits pinpoint systems that waste energy and recommend ways to use it.
Why Commission an Assessment?
Plant managers know their facilities. They can tell when utility consumption is suspiciously inconsistent and when it increases without good reason. Of a plant’s two manufacturing lines, for instance, one might gradually begin to devour more power than the others. Noticing that, a plant manager can ask a skilled energy auditor to investigate the cause and suggest solutions.
In these days of high utility costs, it isn’t unusual for corporate officials to order operating divisions to cut energy costs or consumption by a certain percentage.
In that case, an auditor would deal with known power issues while searching out unknown inefficiencies. Then again, a plant manager simply might want an extra pair of eyes to evaluate how the plant uses energy.
Utility company executives of generating plants operating close to capacity are always seeking ideas that can reduce overall demand because they want to avoid the capital spending necessary to construct more generating stations. Recommending an assessment for existing customers is one way to help.
Another consideration important to utilities involves renewable portfolio standards (RPSs). Twenty-eight states have passed RPS legislation requiring utilities to generate from renewable resources a percentage of the power they sell. RPS percentages vary by state from 4 to 30 percent.
Sometimes manufacturing plants use renewable power to supplement their electricity or natural gas use. Available sources of renewable power include solar, wind and landfill-generated methane gas. When manufacturers choose renewables, local utilities sometimes are able to count that power toward their RPS goals.
What to Expect From an Assessment
A power and energy assessment is an organized energy audit performed by at least one engineer familiar with different manufacturing plants, their energy needs and inefficiencies. The engineering team first meets with the plant manager to discuss goals:
- Is there a particular energy problem to look for?
- Have company officials mandated some level of energy savings?
Answers to these questions determine the scope of the assessment. Initial discussions also consider return on investment. If additional equipment must be installed to cure inefficiencies, how long will it take the energy-saving solutions to pay for the improvement? The auditor studies basic utility information, including drawings of the electrical system.
The assessment itself might last a day, week or month depending upon the facility’s size and goals. An SSOE auditor examines the plant with engineers from various disciplines, and they gather data, take photos, request documentation about processes and energy use, talk to workers on the line, look behind the scenes and generally brainstorm.
Experienced auditors can look at a furnace and recognize the brand, its age and even its burner technology. They know that a 20-year-old furnace uses burner technology that is dramatically inefficient compared with today’s technologies.
Experienced auditors easily can tell when equipment has not undergone adequate maintenance or has been operated beyond a manufacturer’s guidelines.
Given today’s advances in energy-efficient fluorescent lighting, an auditing team almost always expects to recommend updating older, inefficient incandescent lighting systems with fluorescent systems. These are easy fixes. It is relatively inexpensive to replace incandescent light fixtures with ballasts and fixtures tailored to high-performance fluorescent lamps four to six times more efficient than incandescent bulbs.
Most lighting schemes offer opportunities for savings. Dimmers, for instance, can enable adjustments of artificial light to supplement existing natural light in a space. Motion sensors can turn lights off when no one is in a given area.
Turning up the Heat
Auditors also look for wasted heat and ways to use it. During a recent project, an auditor noticed that a food-processing plant used a simple boiler to make steam, but then vented the exhaust heat through the roof.
The assessment report recommended installing a heat exchanger above the boiler to transfer the heat from the exhaust to preheat boiler feedwater and incoming water for additional processes and cleaning. This eliminated a large portion of the fuel needed to provide this heat. The capital outlay for the heat exchanger system was about $250,000 with an expected annual savings of $1 million.
In a cereal-processing plant, auditors noticed the plant had been selling waste product from the cereal line–mostly raw and cooked grain and shredded wheat excesses from the process–as animal feed.
The return was not worth the cost of the raw cereal product. The assessment recommended installing equipment to collect the waste and burn it as fuel to generate steam for processing. If installed, the equipment would be paid off within one year and save more than $1 million annually.
Decaying materials in landfills produce methane gas, which landfills must get rid of, usually by burning it off in flairs. Manufacturing plants, however, can and do put that gas to use. According to the U.S Environmental Protection Agency (EPA), some 480 landfill gas-to-energy projects were in operation at the end of 2008.
The EPA estimates that about 520 additional landfills present attractive opportunities for gas-to-energy projects. Such projects work this way: A pipeline is constructed from a landfill to a manufacturing facility. At the plant, the methane is cleaned and used like natural gas to power turbines that generate electricity and boilers that provide heat and hot water.
At such plants, a landfill gas-to-energy system can save manufacturers more than $5 million annually in energy costs.
An auditor can discover inefficiencies caused by errors, as well. At one manufacturing plant, an auditor noticed that the plant was paying for steam from a neighboring factory. A meter at the supplier’s end provided data that calculated the bill. No one had checked the meter for years. The auditor discovered a calibration error that caused a 30 percent billing error favoring the supplier company. As a result, the manufacturer received a large credit and reduced operating costs going forward.
These examples illustrate some energy savings that power and energy efficiency assessments have produced. Many more examples of easy-to-find, easy-to-correct inefficiencies exist, as well as problems that require detective work.
In today’s era of ever-more expensive fossil fuels, carrying out a power play means exercising less rather than more power.
Jerry Carter, LEED AP BD+C, serves as the sustainability and renewable energy business leader and senior associate at SSOE Group, an international engineering, procurement and construction management firm. Carter has 25 years of experience in mechanical engineering, sales, marketing and management of energy project financing, automotive industry supplier relationships and demand side energy programs. Reach him at 419-255-3830 or jcarter@SSOE.com.