What is the peak load?

What are Base Load and Peak Load?

Load, in electrical engineering, is the amount of current being drawn by all the components (appliances, motors, machines, etc.).Load is further categorised as base load and peak load depending upon the nature of the electrical components connected. As you may be familiar, all electrical appliances at your home do not run at all times.

• A toaster or microwave oven may be used for a few minutes,
• A television or computer may be used for a few hours
• Lighting in the house is only required during the evening and so on.

There are several appliances which keep running at all the times, no matter what. The refrigerator, for example, has to be plugged in at all the times. Another such example are the heating, ventilation and cooling systems in the house (HVAC system).

, in electrical engineering, is the amount of current being drawn by all the components (appliances, motors, machines, etc.).Load is further categorised as base load and peak load depending upon the nature of the electrical components connected. As you may be familiar, all electrical appliances at your home do not run at all times.There are several appliances which keep running at all the times, no matter what. The refrigerator, for example, has to be plugged in at all the times. Another such example are the heating, ventilation and cooling systems in the house ().

Peak Load and Base Load defined

Base load is the minimum level of electricity demand required over a period of 24 hours. It is needed to provide power to components that keep running at all times (also referred as continuous load).Peak load is the time of high demand. These peaking demands are often for only shorter durations. In mathematical terms, peak demand could be understood as the difference between the base demand and the highest demand.Now going back to the examples of household loads: microwave oven, toaster and television are examples of peak demand, whereas refrigerator and HVAC systems are examples of base demand.

A broader perspective of understanding these concepts

Now on a broader perspective, it could be assumed that the electrical grid is a big household. Under normal circumstances, the power required by the electrical grid is fairly constant during various period of the day.This constant power, which is required at all times, is called the base loading. But during a special event, like the final match of World Cup, the demand will be more, as a lot of people will watch TV. This short, high demand period is considered to be a peak loading.Base Load and Peak Load

Base Load and Peak Load power plants

Power plants are also categorised as base load and peak load power plants.

Base Load Power plants

Plants that are running continuously over extended periods of time are said to be base load power plant.The power from these plants is used to cater the base demand of the grid. A power plant may run as a base load power plant due to various factors (long starting time requirement, fuel requirements, etc.).Examples of base load power plants are:

1. Nuclear power plant
2. Coal power plant
3. Hydroelectric plant
4. Geothermal plant
5. Biogas plant
6. Biomass plant
7. Solar thermal with storage
8. Ocean thermal energy conversion

Peak Load Power plants

To cater the demand peaks, peak load power plants are used. They are started up whenever there is a spike in demand and stopped when the demand recedes.Examples of gas load power plants are:

1. Gas plant
2. Solar power plants
3. Wind turbines
4. Diesel generators

is the minimum level of electricity demand required over a period of 24 hours. It is needed to provide power to components that keep running at all times (also referred as).is the time of high demand. These peaking demands are often for only shorter durations. In mathematical terms, peak demand could be understood as the difference between the base demand and the highest demand.Now going back to the examples of: microwave oven, toaster and television are examples of peak demand, whereas refrigerator and HVAC systems are examples of base demand.Now on a broader perspective, it could be assumed that the electrical grid is a big household. Under normal circumstances, the power required by the electrical grid is fairly constant during various period of the day.This, which is required at all times, is called the base loading. But during a special event, like the final match of World Cup, the demand will be more, as a lot of people will watch TV. This short, high demand period is considered to be a peak loading.Base Load and Peak LoadPower plants are also categorised as base load and peak load power plants.Plants that are running continuously over extended periods of time are said to be base load power plant.The power from these plants is used to cater the base demand of the grid. A power plant may run as a base load power plant due to various factors (long starting time requirement, fuel requirements, etc.).Examples of base load power plants are:To cater the demand peaks, peak load power plants are used. They are started up whenever there is a spike in demand and stopped when the demand recedes.Examples of gas load power plants are:

Highest power demand on a grid in a specified period

Loch Mhor is used to generate hydro-electric energy at peak demand or in an emergency

Peak demand on an electrical grid is the highest electrical power 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.[1] Peak demand, peak load or on-peak are terms used in energy demand management describing a period in which electrical power 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 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.[2]

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.[3] The renewable energy transition will include considerations for peak demand.[4]

Economic growth of the state is inversely associated with peak load.[5]

Demand Tariff

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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.[6]

Time of Peak Demand

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Peak Demand depends on the demography, the economy, the weather, the climate, the season, the day of the week and other factors. In industrialised regions of China or Germany, the peak demands mostly occur in day time. 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.[7]

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 rates. 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

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Typical daily consumption of electrical power in Germany

Peak demand may exceed the maximum supply levels that the electrical power industry can generate, resulting in power outages and load shedding. This often occurs during heat waves when use of air conditioners and powered fans raises the rate of energy consumption significantly. During a shortage authorities may request the public to curtail their energy use and shift it to a non-peak period.

Power stations

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Power stations specifically constructed for providing power to electrical grids for peak demand are called peaking power plants or 'peakers'. In general, Natural gas fueled power stations can be fired up rapidly and are therefore often utilized at peak demand times. Combined cycle power plants can frequently provide power for peak demand, as well as run efficiently for baseload power.[citation needed]

Hydroelectric power and pumped storage type dams such as Carters Dam in the U.S. state of Georgia help to meet peak demand as well.

The chances that a wind farm 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.[8]

Solar power's peak output often naturally coincides with daytime peaks of usage due to air conditioning.

See also

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References

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