Peak demand on an

electrical grid An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...

is simply the highest

electrical power Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billion ...

demand that has occurred over a specified time period (Gönen 2008). Peak demand is typically characterized as annual, daily or seasonal and has the unit of power. Peak demand, peak load or on-peak are terms used in

energy demand management Energy demand management, also known as demand-side management (DSM) or demand-side response (DSR), is the modification of consumer demand for energy through various methods such as financial incentives and behavioral change through education. Us ...

describing a period in which

is expected to be provided for a sustained period at a significantly higher than average supply level. Peak demand fluctuations may occur on daily, monthly, seasonal and yearly cycles. For an

electric utility An electric utility is a company in the electric power industry (often a public utility) that engages in electricity generation and distribution of electricity for sale generally in a regulated market. The electrical utility industry is a majo ...

company, the actual point of peak demand is a single half-hour or hourly period which represents the highest point of customer consumption of electricity. At this time there is a combination of office, domestic demand and at some times of the year, the fall of darkness. Some utilities will charge customers based on their individual peak demand. The highest demand during each month or even a single 15 to 30 minute period of highest use in the previous year may be used to calculate charges. The

renewable energy transition The energy transition is the process of downshifting fossil fuels and re-developing whole systems to operate on low carbon energy sources. More generally, an energy transition is a significant structural change in an energy system regarding ...

will include considerations for peak demand. Economic growth of the state is inversely associated with peak load.

Demand Tariff

Electricity network is built to deal with the highest possible peak demand otherwise blackout may happen. In Australia, demand tariff has three components: peak demand charge, energy charge and daily connection charge. For example, for large customers (commercial, industrial or mixed of commercial/residential), the peak demand charge is based on the highest 30 minutes electricity consumption in a month; the energy charge is based on a month electricity consumption. This type of demand tariff is gradually introduced to residential households and will be rolled out by 2020 in Queensland Australia. How to manage electricity bills under demand tariff can be challenging. The key solutions involve improving building efficiency and managing the operational settings of large power appliances.

When is the peak electricity demand?

It depends on the demography, the economy, the weather, the climate, the season, the day of the week and other factors. For example, in industrialised regions of China or Germany, the peak demands mostly occur in day time, while solar photovoltaic system can help reduce it. However, in more service based economy such as Australia, the daily peak demands often occur in the late afternoon to early evening time (e.g. 4pm to 8pm). Residential and commercial electricity demand contributes a lot to this type of network peak demand.

Off-peak

Peak demand is considered to be the opposite to off-peak hours when power demand is usually low. There are off-peak

time-of-use Dynamic pricing, also referred to as surge pricing, demand pricing, or time-based pricing, is a pricing strategy in which businesses set flexible prices for products or services based on current market demands. Businesses are able to change prices ...

rates Rate or rates may refer to: Finance * Rates (tax), a type of taxation system in the United Kingdom used to fund local government * Exchange rate, rate at which one currency will be exchanged for another Mathematics and science * Rate (mathema ...

. Sometimes, there are 3 time-of-use zones: peak, shoulder and offpeak. Shoulder is often the time between peak and offpeak in weekdays. Weekends are often just peak and offpeak in terms of managing electricity loads for the network.

Response

Peak demand may exceed the maximum supply levels that the

electrical power industry Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

can generate, resulting in

power outage A power outage (also called a powercut, a power out, a power failure, a power blackout, a power loss, or a blackout) is the loss of the electrical power network supply to an end user. There are many causes of power failures in an electricity ...

s and load shedding. This often occurs during

heat wave A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the ...

s when use of air conditioners and powered fans raises the rate of

energy consumption Energy consumption is the amount of energy used. Biology In the body, energy consumption is part of energy homeostasis. It derived from food energy. Energy consumption in the body is a product of the basal metabolic rate and the physical activit ...

significantly. During a shortage authorities may request the public to curtail their energy use and shift it to a non-peak period.

Power stations

Power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. Many ...

s specifically constructed for providing power to

s for peak demand are called

peaking power plant Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the powe ...

s or 'peakers'. In general,

Natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbon d ...

fueled power stations can be fired up rapidly and are therefore often utilized at peak demand times.

Combined cycle power plant A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...

s can frequently provide power for peak demand, as well as run efficiently for baseload power.

Hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

and

pumped storage Pumping may refer to: * The operation of a pump, for moving a liquid from one location to another **The use of a breast pump for extraction of milk * Pumping (audio), a creative misuse of dynamic range compression * Pumping (computer systems), ...

type dams such as

Carters Dam Carters Dam is an earthen embankment dam located south of Chatsworth in Murray County and west of Ellijay in northwestern Georgia, United States, that creates Carters Lake. Description The dam is tall and is situated above the mouth of ...

in the U.S. state of Georgia help to meet peak demand as well. The chances that a

wind farm A wind farm or wind park, also called a wind power station or wind power plant, is a group of wind turbines in the same location used to produce electricity. Wind farms vary in size from a small number of turbines to several hundred wind turb ...

will be unable to meet peak demand are greater than for a fossil-fueled power station, due to the ability to store liquid fuels for use during peak demand. Solar power's peak output often naturally coincides with daytime peaks of usage due to air conditioning.

References