Energy Conservation Definitions
Apparent Power is the product of the measurements of voltage and current in an electrical system. Voltage measurements (kV) and current measurements (Amps) are multiplied together to calculate the apparent power (kVA). 1kVA = 1kV x 1A.
Biomass fuels are an alternative to fossil fuels that can be a cost-effective and eco-friendly option for your facility. Primarily waste byproducts such as wood chips from a sawmill or black liquor from a paper mill, these fuels can be burned in a boiler for hot water, steam, or combined heat and power operations. Agricultural facilities such as feed mills and food processing facilities may have sources of animal waste that can be burned directly or digested to form methane gas.
Building Envelope is a term used to describe the boundaries of the internal environment of a building. This generally includes the roof, walls, and foundation, as well as the windows and doors.
Energy Content – Fuels are ultimately sold based on the amount of energy they contain. A typical unit of energy content is the Btu, or British Thermal Unit. The energy content of natural gas is sometimes represented in Therms (thm). One Therm is 100,000 Btu. 1 thm = 100,000 Btu.
Energy Intensity is the amount of energy used per unit of measure. For lighting systems, this is generally measured in kW/ft2. In manufacturing, this can be measured in kWh/unit (e.g. kWh/piece or kWh/lb). Energy savings goals are generally set as a reduction in energy intensity rather than a reduction in overall energy usage, since that measure does not account for variation in output. For instance, if your goal is to reduce energy usage by 10%, this can technically be achieved by reducing your production output to reduce energy used. Additionally, energy efficiency improvements can be hidden by increases in production levels if total energy usage is the only unit of measure. Energy intensity can account for these changes in production levels.
For example, a processing plant currently uses 10 kWh to produce 1 ton of product. They produce 10 tons of product each day, for a total of 100kWh. If this plant reduced energy intensity by 10%, they can produce 11.11 tons/day for the same 100kWh of energy usage. The overall energy usage does not change, but the intensity changes from 10kWh/ton to 9kWh/ton.
Energy usage is the application of power over time. For example, electrical energy usage is measured in units of kilowatt-hours (kWh), which is kilowatts (a measure of power) times hours (a measure of time). To reduce energy usage, you must either reduce the amount of power used, or reduce the duration that it is used, or both.
ESCO’s, or Energy Service COmpanies, are companies that negotiate performance contracts with their customers.
Horsepower - Most motors, and many other types of equipment, are rated in units of horsepower. One horsepower is equal to 746 watts (.746 kW).
Natural Gas Content - Natural gas is mostly methane, but does contain some other hydrocarbons and contaminates. Additionally, the density of natural gas does change with temperature. These factors contribute to the fluctuation of natural gas prices, since the value of the natural gas is ultimately tied to its energy content, not its volume. Pipeline quality natural gas is 950 - 1150 Btu/ft3.
Natural Gas Measures - Natural gas is sold most commonly in units of Ccf, or hundred cubic feet (1 Ccf = 100 ft3), a unit of volume that is easily measured. An average energy content of natural gas is generally cited as 1000 Btu/ft3. One Ccf of natural gas would therefore contain an average of 100,000 Btu, or 1 therm. 1 Ccf x 1000 Btu/ft3 x 100 ft3/Ccf = 100,000 Btu = 1 thm
Performance contracting is a method of acquiring equipment upgrades in a facility without spending the company’s capital on the equipment. In a performance contract, the ESCO will provide the energy efficiency equipment in exchange for a large portion of the energy savings that the equipment provides. The client company usually pays no costs up-front, and still receives part of the energy savings.
Power is work done per unit time. Power is measured in units of kW (kilowatt) or horsepower (hp). 1hp = .746 kW.
Power Factor is the ratio of real power (kW) versus apparent power (kVA). PF = kW/kVA. Electric utilities provide kVA, but the bill is calculated based on kW. All electric utilities in Arkansas will adjust electricity bills for low power factors. A system with a power factor of 0.85 will cause almost 18% more current to be supplied to the system than is required to produce the required amount of work. The extra current increases the losses in the system and serves no purpose other than to create the magnetic field required to operate the system. This magnetizing current should be supplied by capacitors instead of the distribution system.
Power factor can be corrected with the application of capacitors. Low power factor can cause high losses in electrical wiring, so power factor correction can save money on electric bills by avoiding power factor adjustments, improve efficiency by reducing losses, increase plant electrical capacity without adding additional wiring, and stabilize supply voltages. Modern power factor correction equipment can automatically adjust to changing load conditions in your facility and keep your plant power factor very near 100%.
Purchased Steam - Steam is heavily used in industrial processes. While steam is often generated on-site by means of a boiler, it is sometimes economical to purchase steam from a nearby facility with excess capacity. The cost of purchased steam can be compared to the cost of the fuel and overhead associated with generating the steam. The energy content of the purchased steam can be calculated based on the pressure, temperature, and quality of the steam that is received. The same concepts can be applied to chilled water.
Real Power or Actual Power or Active Power is the measurement of actual work done per unit time.
Sources of Energy - Industrial Energy Systems may be powered by electricity, fossil fuels, or other combustibles such as bio-waste. In some cases, purchased steam is considered as a source of energy, even though the technical source is the fuel that fired the boiler. The cost of the purchased steam, and the fact that it is used in lieu of operating a boiler on-site, justifies the classification.
Watt-hours - Electrical equipment uses energy in the units of watts over time, or watt-hours. A 100 watt light bulb operated for 1 hour uses 100 watt-hours. Electrical energy is sold in the unit of kilowatt-hours (kWh), which is 1000 watt-hours.