Demand Response (DR) is a process for trimming electrical load, also referred to as load shedding, to reduce peak loads on a portion of the grid.
Load shedding has been used by utilities for many years, usually in cooperation with industrial or large commercial customers. When loads approached peaks, the utility would request those who were participating in the program to turn off non-critical electrical systems, such as a portion of the lighting in stores.
Today the practice has evolved and now involves software systems that automatically cut-off non critical circuits at locations where customers are participating in the program.
Sophisticated software programs are being adopted by utilities to manage their distribution systems, which includes DR as well as the control of circuit breakers and other devices on their system. These programs can maintain voltage levels and shift loads, and provide for more efficient use of the distribution network.
Similar software is being used to manage transmission systems.
These advances have become part of what is referred to as the “smart grid”.
Now, there are those who want to take this practice to the next level by using smart meters.
Smart meters can be designed to control circuits inside people’s homes. Theoretically, they could shut off refrigerators, air conditioners and other appliances that use large amounts of electricity, for short periods of time. Since thousands of homes would be involved, it could shave the peak load.
Smart meters could also be designed to control the thermostats in homes and in offices. The utility could reset thermostats so as to limit the amount of cooling or heating.
Smart meters can also be designed to record and transmit electronically the amount of electricity consumed by users.
The objective of these programs is to manage the entire grid more efficiently.
Utilities, and indirectly their customers, can benefit from better utilization of the grid, but there are some negative factors that should be considered when utilities begin to use smart meters.
By shedding load during periods of peak usage, DR can postpone the need for new power plants. Load shedding can also prevent blackouts if there is an unexpected emergency, such as failure of a power plant or unusual summer peak load. It can keep the utility from having to fire up gas turbine peaking units to meet temporary loads and thereby save money.
By transmitting meter readings directly to the utility’s office, smart meters eliminate the need for meter readers. This results in large savings for the utility.
Smart meters can also allow time-of-use pricing, which could provide savings for customers. This could become important if PHEVs or BEVs achieve widespread adoption by promoting the recharging of vehicles during off-peak hours.
Smart meters can also provide homeowners with information about their usage of electricity.
On the other hand, it’s doubtful that homeowners will shift much of their usage of electricity from during the day to off-peak periods at night. For example, doing the laundry at midnight may not be widely adopted.
Home owners and regulators should be leery of allowing utilities to shut off refrigerators and air conditioning units for short periods of time. It’s theoretically possible to shut off refrigerators in a group of homes for a few minutes, and then rotate the shut-offs to another group of homes, and then to another group etc., until the overload crisis has passed. If properly programmed, such a practice wouldn’t allow temperatures in refrigerators or freezers to rise by very much.
While this has been tried in a few locations, more study is needed before homeowners should feel comfortable with this practice.
Homeowners should never allow utilities to control their thermostats, since they will lose control over how cool or warm they keep their homes. State regulators, as nearly happened in California, could require utilities to set thermostats at temperatures not acceptable to homeowners – too hot in the summer and too cold in the winter.
Regulators should require utilities to obtain permission from homeowners before they are allowed to control homeowner’s equipment.
Some utilities are asking that homeowners absorb at least part of the cost of installing smart meters. Utilities are the main beneficiaries of smart meters through the lower cost of meter reading, avoiding theft of electricity and lower investment in power generation equipment. So why should homeowners be required to pay for this investment?
Commonwealth Edison in Illinois, for example, received approval from the Public Utilities Commission to charge ComEd’s customers for the smart meter program, but the appellate court has, at least temporarily, disapproved the increase.
Using smart meters for DR has advantages, but homeowners should always have the right to prevent utilities from controlling their use of electricity.
There is considerable hype surrounding smart meters and the smart grid, and we all need to understand what is being said and whether the claimed benefits are real or ginned-up to sell the smart grid.
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