The Nature of Voltage

Voltage is what makes electricity work. Too much voltage and it damages equipment and/or costs you more to operate. Too little and equipment does not work as well. Voltage is a variable which can and should be controlled for maximum benefit. Gretchen Bakke, in The Grid, defines voltage, poetically but insightfully, as "desire." Electrical potential is created when atoms are separated into positively-charged and negatively-charged particles, which are forced to do work in order to reunite.  These lonely charged particles are in one sense indentured servants, eager to work their way home to each other. The urgency of their desire to get there is expressed in units called volts: the greater the desire, the higher the voltage. To abuse this metaphor further, the higher the voltage, the faster you can convert electrical energy into work--toasting the toast, moving the train, powering the servers. Every use of electricity is designed to work best at a specific voltage. If electrical equipment receives voltage that is higher or lower than its optimal voltage, it can waste energy in the form of heat, function improperly, or be damaged, leading to either rapid destruction or a gradual shortening of useful life.

Voltage and Power Quality

Electrical power needs to be constrained to a very specific form to do useful work. Lightning bolts, for example, are not a very useful form. The primary parameters that describe electrical power are voltage and resistance. High quality power does not have jittery voltage, voltage transients, overvoltage, or undervoltage. If it is three-phase power, the voltage of the three phases is ideally the same, not out of balance. For more about power quality, read our power quality explainer, Demystifying Power Quality.

Energy Conservation through Dynamic Voltage Management (a.k.a. CVR, VO)

According to the US Department of Energy, up to 67% of energy used to create electricity is wasted by the time the consumer uses the electricity, due to inefficiencies in generation, transmission, and distribution. Conservation Voltage Regulation (CVR) or Voltage Optimization (VO)  is a technique for improving the efficiency of the electrical grid by optimizing voltage on the feeder lines that run from substations to homes and businesses. Utilities have been experimenting with CVR for over 30 years. Although it was partially implemented in California beginning in 1977, CVR has not been widely adopted due to high costs and technical limitations. In the past, broad implementation of CVR would require extensive additions to the utility infrastructure, adding many substations and shortening feeder lines. Pacific Volt's technology helps CVR to be implemented effectively and economically in two ways. Either by direct optimization of the voltage supplied to a house or business, or more broadly, used by a utility to extend the limits of feeder line voltage reduction by selectively raising the voltage to a small percentage of customers that fall too low.

In the US, regulations require that voltage be made available to consumers at 120V +/- 5% – which yields a range of 126V to 114V (European Standards: 230V +10%/-6%). On any feeder line, especially those over three miles long, voltage on the line gradually decreases as the cumulative load (number of customers) on the line increases. This is called “line drop.” Because of line drop, power must be transmitted from the substation to the feeder line at a high enough voltage that the last house on the end of the line gets at least 114V. Consequently, power is often transmitted from the substation at the legal maximum, 126V. US homes receive an average of 122.5V, with approximately 90% of homes and businesses receiving more voltage than they need. 

CVR lowers the voltage at which electrical power is delivered and yields on average, ~ 0.7% energy savings for each 1% in voltage reduction down to 114V. With Pacific Volt's CVR technology, it is now far less expensive to save energy at the point of consumption than it is to increase the capacity of the grid, build more substations, or create additional generation from power plants.

Electrical equipment, including air conditioning, refrigeration, appliances and lighting is designed to operate most efficiently at 114V. If power is delivered at a voltage higher than 114V, energy is wasted. Higher than necessary voltage also shortens the useful life of many types of equipment, since the excess energy is dissipated as heat. If the incoming voltage is too low (also damaging) our regulators raise it to 114V. All adjustments are made in less than one cycle - 1/60th of a second.

Delivering voltages at the optimal levels reduces consumption, improves service quality and extends the life of equipment. Utilities and consumers save energy and lower operating costs. By reducing the need to generate additional energy at power plants, CVR also helps to lower greenhouse gas emissions.

With the same behavior or usage levels, an electrical bill can be significantly higher (up to 15%) for a business or home if they receive voltage higher than 114V due to being close to a substation. They are paying for extra energy that does nothing for them except generate waste heat.