Efficient Standards

iStock/ Schlol

We first started to realize how dependent we were on fossil fuels and imports from other countries when the 1973 oil crisis struck. One barrel of oil contained 42 gallons and cost $3. The crisis increased the price 400% to about $12 per barrel. Shortages led to long lines at gas stations and caused a sharp reduction in driving. It also led to price increases in products made from fossil fuels, such as plastics, asphalt, solvents, etc. Other product costs rose due to the steep increase in transportation costs. The mileage ratings of cars weren’t a concern at the time. I had just bought a brand-new car, and it had terrible mileage efficiency of approximately 10 miles per gallon.

Today, a barrel of oil costs more than $60. There is some dispute as to the highest price ever paid, but figures range between $136 and $146, depending on where the oil came from. Oil prices affect the price of other fossil fuels, such as natural gas and coal, because the increase in the cost of one fuel drives consumers toward other, lower-priced fuel sources. The volatility of the energy markets has required the electrical industry to do what it can to reduce energy consumption while allowing us to live normal lives.

Fuel prices have had a major impact on the electrical industry. Electrical distribution and utilization equipment have been required to become more efficient. A recent U.N. publication, “Accelerating the Global Adoption of Energy-Efficient Transformers,” notes, “Well over half of the world’s electricity is consumed by just four products: electric motor systems, lighting, room air conditioners and residential refrigerators. These products, and the transformers that help get power to them, often waste significant amounts of electricity due to poor designs and improper use.”

The Department of Energy has mandated improvements in the energy efficiency of transformers for several years. There are a number of steps that manufacturers take to reduce transformer losses, including using cores with lower hysteresis and eddy current losses. Thinner laminations for iron cores are one way to reduce these losses. Obviously, the use of coil material for a larger cross section will also reduce losses. Keeping transformers cool reduces heat loss. A more efficient transformer also means that there is more available fault current. So, the reduction in energy losses can have a negative effect on safety.

When transformers installed in a facility are replaced, the increased available fault current will require analysis of existing systems to ensure the current will not exceed the equipment ratings. A plant engineering staff or an electrical contractor doing the work is at least aware that the replacement is taking place and can plan accordingly.

A big concern for commercial and industrial facilities is the installation of more efficient utility transformers without the knowledge of the customers. Such grid upgrades can have serious consequences for the electrical installation and anyone who works on it, if the available fault current now exceeds existing withstand ratings. If new commercial construction is underway in the neighborhood, it is likely that some upgrades to the utility infrastructure are also coming. However, the utility may also upgrade older equipment to comply with DOE directives.

More efficient motors can also increase the available fault current because they contribute additional current. So, they too require an analysis of available current and its impact on existing equipment.

Since the adoption of the Energy Policy and Conservation Act of 1975, the DOE has developed energy-conservation standards for appliances and lighting. Some programs, such as Energy Star, are voluntary. It is jointly administered by DOE and the Environmental Protection Agency. The energy-efficiency standards have not remained static because they have required improvements in efficient new products over time.

While DOE has been responsible for efficiency standards, the Federal Trade Commission is responsible for the Energy Guide labeling requirements for energy efficiency. These labels indicate an approximate annual cost to operate along with an estimate of annual power consumed. The guide also indicates how the estimated annual cost to operate compares with similar equipment. Since all similar equipment is required to have the label, it is easy to compare the costs of equipment from the same or different vendors.

Much of today’s utilization equipment is also more efficient due to DOE requirements. The Environmental and Energy Study Institute notes that DOE energy-efficiency standards for consumer products include “Furnaces, central air conditioners and heat pumps, refrigerators and freezers, dishwashers, microwave ovens, televisions, battery chargers, and ceiling fans.” The standards for commercial products include “Commercial package air conditioners and heat pumps, water heating equipment, refrigerated beverage vending machines, walk-in freezers, and electric motors.” However, there are still products that don’t yet have energy-efficiency standards, such as personal computers.

Efficiency effects Code changes

LED lighting is another energy-efficient success story. LED lights use 75% less energy than equivalent incandescent light bulbs. There are also claims of longer life than their incandescent counterparts. LED lighting has been recognized in Article 410 since the 2011 NEC .

The lighting loads in Table 220.12, General Lighting Loads by Occupancy, have been in the NEC with few changes for many years. The loads require a calculation that is expressed in volt-amperes per square foot. The required load is based on the occupancy. The table has served the industry well. However, the Code had never taken advantage of the decrease in energy consumption that was a reality due to newer-technology lighting systems. The 2014 NEC provided the first relief. It recognized the lighting loads from model energy codes and allowed them to be used. However, a power-usage monitoring system had to be installed to monitor the lighting load. The system would sound an alarm if the energy code values were exceeded.

An NEC Correlating Committee task group was formed to look at the way loads are calculated. This large task will take more than one cycle to complete. The first thing the task group did was review the lighting loads in 220.12 and studied the loads in Article 220. The information in the Code was compared with information available from ASHRAE, and a new Table 220.12 was developed for the 2020 Code . This was just a first step.

A Fire Protection Research Foundation project has been started to develop more data for the next cycle. A major focus will be cord-and-plug-connected loads. This new project has widespread support, with key sponsors including healthcare facilities’ engineering organizations and a group of facilities engineers from colleges and universities. The premise is that not taking advantage of the fact that newer equipment consumes less energy can lead to overdesigned installations. More public inputs are anticipated for the 2023 NEC because these Code users believe that they will save on energy costs and save money on the cost of new equipment installations. However, changes to requirements need to anticipate future growth. What is the next new thing to come along that every workstation will have to have? Will the building infrastructure support it? The office building that I worked in for the last 33 years of my career was built in 1981. Personal computers did not exist at the time. There was a mainframe computer with the usual air conditioning infrastructure. Yet, many years later, there were hundreds of computers, monitors and devices of various kinds plugged in all over the building. There were some upgrades over the years, but nothing dramatic until 2014. How many buildings have been able to cope with unanticipated expansion with little impact on the electrical system? If systems are designed with no flexibility, will the installation be safe? These are important considerations as new requirements are developed.

For the building owner, the investment in energy-efficient upgrades can result in long-term savings. It also often results in energy rebates and other tax incentives. Those savings become particularly dramatic if the fuel costs increase, but that is unpredictable. At best, we know that the costs will fluctuate. Building owners who do energy-efficient upgrades can often take advantage of the positive public affairs aspect that shows their neighbors that they are a good member of the community.

Achieving energy efficiency for a new building is an ongoing process. I saw one study that indicated that energy-efficient buildings become inefficient over time. Certainly, new equipment comes into the marketplace that is more efficient. However, equipment must also be maintained in order to keep it operating at its peak efficiency.

About the Author

Mark Earley

Mark Earley, P.E., is the chief electrical engineer. Retired from the National Fire Protection Association, he was secretary of the National Electrical Code Committee for 30 years.

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.