Going green can have two meanings: one from an environmental point of view, and the other relating to money — “green dollars.” Even though money is largely digital now, the metaphor remains. Automation and power monitoring can help achieve both goals. The financial motivation is rooted in accounting and self-preservation, while the environmental motivation is rooted in social responsibility and mass preservation.
Regardless of the motivation, both versions of “green” can be achieved through the combined use of power (energy) monitoring and productive, efficient use of that power. Using sensing devices and logical control devices in harmony with human activities is the starting point of this beneficial pursuit. The sensing components include voltage, amperage, and power factor sensors. Logical control devices include PCs, PACs, PLCs, and other controllers or direct relay devices.
Power quality is as important as total power usage. Eliminating damage caused by poor electrical quality helps prevent the costly repair of expensive motors, electronics, computers, UPS systems, and other equipment. Improving power quality also enhances safety in fire, disaster, and security systems.
To understand where power is used and how to improve efficiency, a logical approach is required. This includes determining where energy is consumed, how profitably it’s being used, and where waste or poor-quality power causes damage.
A major source of wasted power comes from non-productive energy consumption, such as lighting and heating/cooling in unoccupied spaces. Building automation is key to solving this.
Occupancy and vacancy sensors help reduce wasted watts by turning off lighting, HVAC, and equipment when spaces are empty. Hotels save money by shutting off unused rooms. Office buildings reduce lighting and HVAC loads after hours and on weekends. Schools reduce wasted power in empty classrooms and lobbies. Many of these sensing systems are inexpensive on/off control circuits and are now required in some states.
A more sophisticated approach includes ambient light sensing to adjust lighting through dimming or by switching pre-planned lighting circuits. Automatic shades can block unwanted solar heat, reducing air-conditioning loads. However, this requires balancing natural light with heat reduction — a challenge solved through algorithmic control.
Elevator operation can also be integrated into building automation. When elevator doors open, HVAC loads can be temporarily shed to reduce peak demand. Elevators may also shut down during non-use hours. Integration with fire alarms enables evacuation messaging and system responses.
To know where energy is used and whether power quality is good, power monitoring devices are essential.
Monitoring begins with CTs (current transformers), which measure current and voltage. The secondary coil transmits reduced current to a monitoring device, which assigns values and performs calculations.
In a three-phase system, voltage and current are measured on each phase and compared to each other and the neutral line. Imbalances cause power factor issues and loss of effective power. Significant discussion is required to fully explore power factor and phase imbalance, but they are critical aspects of power quality.
Data loggers, combined with power monitors, enable long-term analysis. They provide historical data to identify patterns and support corrective actions. SCADA systems enhance this by integrating process monitoring, security, safety, and DCS-level control.
Many facilities benefit from energy monitoring and automation, including offices, schools, hospitals, hotels, museums, and retail environments. Major energy consumers include:
Lighting
Heating and air conditioning
Computers and office equipment
Occupancy sensors trigger partial or complete shutdowns depending on need. PLCs and PACs can use scheduling for different times of day, days of the week, or seasonal patterns. Hot water heaters can also be timed accordingly.
Hotels reduce HVAC use in empty rooms. Offices shut down equipment at night. Educational facilities reduce loads during off-hours or holidays.
A significant component of electrical cost is not how much electricity is used, but when it is used. Utilities charge higher prices during peak demand periods due to production limits, environmental regulations, and grid capacity.
Shifting usage to off-peak hours yields major savings. Strategies include:
Running HVAC earlier so peak loads are reduced
Staggering motor and equipment startups
Avoiding simultaneous activation of large loads (air handlers, elevators, lighting)
Using VFDs (variable frequency drives) or soft starters to lower peak inrush currents
Voltage quality must be monitored to avoid equipment damage. Phase imbalances, frequency variations, excessive voltage (10% above normal), harmonic distortion, and startup/shutdown spikes can all cause costly failures.
With proper monitoring, power conditioning can be added to prevent damage and extend equipment life.
Industrial environments require more rigorous monitoring due to higher consumption and expensive equipment. Motors, VFDs, and heavy fabrication processes require careful control to avoid peak demand penalties and prevent damage from unstable conditions.
Quick reaction to abnormal events is critical in industrial settings.
Hospitals require fast response to power loss for patient safety, relying on UPS systems and generators that must activate immediately after power drops.
Banks, retail stores, and facilities with sensitive computers or alarm systems must detect voltage issues to ensure equipment runs long enough to shut down safely.
Emergency lighting and alarm systems depend on reliable power quality monitoring.
Constant monitoring with SCADA enables historical logs that help identify recurring problems. With proper data acquisition, root causes of irregularities can be tracked and eliminated.
Utility company data, combined with SCADA logs, helps pinpoint the origin of power quality issues.
The rise of alternative energy — solar, fuel cells, backup generators — adds new requirements for power monitoring.
If alternative sources cannot meet demand, systems must automatically switch to the main grid. If neither source is available, an ATS (Automatic Transfer Switch) must activate backup generators. Monitoring ensures systems switch back to grid power when stable.
