Load refers to the amount of power in the electrical grid. The load must be balanced so that supply continuously meets demand levels which are subject to variations and changes that impact the grid. Thus, load is separated into base load, and peak load.
What is base and peak load?
Electrical power demand fluctuates and falls on a daily basis, depending on external factors such as weather, time, seasons, events and so on. We tend to use less energy at 1:30am than we do at 6pm for example. Our demand increases when we turn on lights, boil the kettle or turn on the heating, and decreases when we turn off lights and air conditioning. It is important that the supply of energy can meet these changing demands, which is why a power plants output is defined as either base load, or peak load. The difference between the two “isn’t in the power itself, but rather in the economics and engineering limitations of the power plant”.
Base load, also called continuous load, is relatively stable and refers to the minimum amount of electrical demand over a 24-hour period. Effectively, the constant power required by a home or business over 24 hours is the base load. This includes appliances that require a constant source of power, such as IT systems, alarm systems, machinery and security lights, which are not turned on and off. Base load is simply the level that demand typically does not fall below, or the basic amount of energy that is always required.
Peak load is typically a shorter period of time with high demand. It is far less predictable than base load, as it can spike when, for example, heating or air conditioners are turned on. Due to high demand, peak electricity is more expensive. Demand tends to be highest in the early evening but can vary depending on televised events, seasons, and weather. For example, commercial breaks in big sporting events will see peak demand, as will cold weather periods when more people use heating.
Who is the base load and peak load suppliers?
A power plant who is responsible for base load power, needs to be able to run continuously and consistently, without being shut down. Typically, they are large coal-fired and nuclear power plants, however can also be powered by hydro-electric and geothermal sources. Whilst these plants take a long time to start up, this is hardly ever an issue as they are so rarely taken offline. Fuel costs per kilowatt generated tends to be low, meaning that end-users pay less for energy provided during these periods. Examples of base load plants are:
1. Coal
2. Nuclear
3. Hydroelectric
4. Geothermal
5. Biogas plant
6. Biomass plant
7. Solar thermal with storage
8. Ocean thermal energy conversion
Peak load power is supplied by plants using natural gas, diesel oil, or jet fuel (the latter two being significantly more costly than the first). Gas prices are currently low due to high supply levels through fracking, but despite this, peak prices remain a lot higher than base load prices. Renewable forms of energy such as hydro, solar, and wind can also be used in times of peak demand, particularly as they become more reliable and more widely used. It is important that peak load is managed by more responsive, smaller plants whose output can be quickly increased, decreased, or turned on and off. Peak prices are more expensive as the demand is higher and shorter, so it is less crucial to keep prices down. Although renewable energy sources are cheaper, due to high levels of demand causes the prices to soar. A list of the most popular peak load power plants, which work in combination with base load power plants, are:
1. Gas
2. Solar
3. Wind turbines
4. Diesel generators[JX1]
Understanding your energy bills…
Primary charges on your bill will be split into consumption, and demand. Consumption charges are for the energy you use over the course of the month, while demand is for the highest amount of power used at a given time. Consumption is charged at different rates: on-peak, mid-peak and off-peak. On-peak charges are times with the highest demand, and therefore the cost of energy at this time is highest.
How can you save on your energy bills?
Staying informed about peak load and base load times is important so you know when you are paying more money for your electricity. Avoiding using excessive electricity during peak times, reducing consumption or scheduling machinery to run at off-peak periods can reduce energy bill and save money. For those who have access to technology such as energy storage, homes and businesses can use stored energy, accumulated during base load times, and use it during peak load times, thus shaving money off their energy bills. Combining this with renewable energy sources such as solar photovoltaic systems (Solar PV) can simultaneously reduce your carbon footprint too. These technologies enable organisations to reduce peak load demand, overall energy costs, strain on the grid and their impact on the environment.
Businesses can also reduce peak load by starting their buildings up earlier, and staggering equipment start up times, as it can be less expensive to use the same amount of energy over a longer period of time.
Knowing about the difference between peak and base load demand is vital in saving money and increasing operational and economic efficiency.
