What is the effect of leaving the computer running all the time on electricity consumption?

 

The use of desktop and laptop computers has become indispensable for some commercial and office businesses and even some home uses, and with the escalation of the global energy crises, some companies and institutions have resorted to adopting policies to rationalize energy consumption. Desktop computers need to be permanently connected to a huge source of electrical energy, whose efficiency is commensurate with the high performance of this type of device and its operating power, which makes it greatly affects the rate of electrical energy consumption in kilowatt-hours. Even if it is left in Sleep mode, it will consume energy.

 

The solution to reducing energy consumption rates in some cases may be to use laptops that rely on energy stored in batteries instead of desktop computers that remain connected to electricity all the time, but what about the efficiency and effectiveness of this method in reducing electricity consumption? What kind of device will consume less energy? Does keeping a computer or laptop plugged in all the time while keeping it in hibernation, standby, or even completely turned off affect its electricity consumption? This is what we will discuss in the following lines in some detail.

 

How are electrical energy consumption rates measured?

 

The consumption rates of various devices for electrical energy are measured in watt-hours, which refers to the average electrical power that the device draws from the electricity supply around the clock. The use of the average value of the electrical power drawn is necessary when comparing in terms of consumption between different computers, which do not use fixed levels of energy, for example; A computer, while performing various data processing operations to complete a specific task, uses more electrical energy than the same computer uses while it is in Hibernate mode.

 

The rates of electrical energy consumed by a computer, laptop, or any other device can be measured using one of the electric capacity meters in watts such as the Kill-A-Watt device, which is a device that is connected to one end of the wall, and the computer is connected after it is completely turned off to the other end, then press the purple KWh button to turn on the meter and turn on the computer or laptop again for the device to start measuring the exact amount of energy consumed by the device.

 

The meter simply consists of a power transformer that reduces the voltage and current drawn from the electricity source to small values that the metering circuit can handle. The electrical power drawn in watts is equal to multiplying the value of the voltage in volts by the value of the current drawn in amperes and the power factor, and then calculates the value of the measured capacity per hour, which is proportional to the electric power that the computer or laptop draws from the electricity source per hour. The device can then calculate the average watt-hour energy consumption of the computer over the course of the day.

 

Which is better in terms of energy consumption and efficiency

 

Laptop manufacturers are aware of the importance of the advantage of being able to use these devices without connecting them to the electrical outlet for some time, and that the greater the capacity of the battery to operate the device for as long as possible before it needs to be recharged with electricity, the more this will help in the popularity of the product and the more users will want to buy it. In order to increase the operating time of the device using the rechargeable battery, laptop designers usually resort to one of two methods:

 

● Larger capacity rechargeable battery design, which makes it bigger and heavier.

● Make laptops use less energy and have higher efficiency.

 

Laptops generally consume energy at much lower rates, sometimes up to 80% less than the energy consumption rates of desktop computers. Even high-performance laptops may consume a maximum of only about 60 watts of power, while commonly used desktop computers consume a maximum of about 175 watts while performing similar tasks and processing operations.

 

The main reason behind this difference in electricity consumption rates is that the power supply units in desktop computers consume more than 300 watt-hours when working at their maximum potential, which exceeds even the main requirements of the operating system, while computers contain is carried on smaller power supply units with an electrical power ranging from 30-90 watts, and its energy efficiency can reach 20% when operated by connecting the charger to electricity in addition to battery power.

 

Power supply units or power supplies contain step-down transformers and signal regulators whose main role is to convert the electricity coming from the power socket with a large AC voltage of about 220 volts into a low-value direct voltage commensurate with the power needs of the computer, usually, the value of this voltage is 12 volts. Laptops also contain a central processor, graphics, and components that operate at a significantly slower performance compared to the performance of similar parts found in desktop computers, so laptops take longer to perform various data processing operations, and in return they use less energy, meaning they are more energy efficient.

 

Note that we referred more than once in the previous paragraphs to the concept of energy efficiency and talked about it as a concept separate from the rate of energy consumption, and you may have wondered what the difference is between energy consumption and energy efficiency.

 

In order to understand this difference accurately, let us agree that the passage of electricity in any connector or electronic circuit is always accompanied by the emission of heat that we feel when touching wires and electronic parts and we find them hot. This heat is nothing but energy that is not created out of anywhere, but its source is the power socket or the battery, and it is lost in heating the wires and electronic parts without the device actually benefiting from it. Rather, some parts are usually added to the device to get rid of this heat using fans or cooling methods. That is, the energy that the computer draws, the microchips and its internal components use part of it to transfer information, process data, and operate other components of the device, and part of it turns into unwanted heat.

 

In this case, we use the concept of energy efficiency to refer to the percentage of effective energy used in operating the components of the device and transmitting information from the total energy that the device draws from the electricity source or battery.

 

The heat produced by each type of electronic device differs, according to the amount of total energy it draws, and the type of operations carried out by the components of the device. Mobile phones, for example, when operating in standby mode, consume only a few milliwatts in the form of heat, meaning that the efficiency of their energy use is high and maintained It depends on the life of the battery.

 

Laptops also lose less energy as heat from the total energy drawn from the battery than desktop computers. Fans in computers, whether desktop or laptop, sense the temperature of the microprocessor, so they run slowly at lower temperatures during light use of the device, and operate more quickly at higher temperatures during more complex computing operations, which reduces fan noise and saves energy.

 

Does an always plugged-in computer mean that power is still being used?

 

The energy consumed varies according to the type of device, as well as the energy consumed by each part of the computer itself. There are components that consume more electricity than others, and the largest part of the energy consumed is always the share of the screen and the processor. Energy consumption also varies according to the user's activity on the device and the type of operations performed by the device. For example, a single device while playing a 3D video game or while mining digital currencies do not consume the same amount of energy as writing a Word text.

 

Here it is worth noting that a study conducted by the Energy Saving Trust found that computers and peripherals account for about 8 percent of the total electricity consumption in the home, given that the study was conducted based on the average consumption of devices in the United Kingdom, with another 25 percent used by electronic devices another consumer. The study also shows that desktop computers consume much more energy than laptops – nearly six times as much – because laptop manufacturers are testing battery life and optimizing energy consumption in a way that desktops can't.

 

Laptops consume almost no electricity while they are in sleep mode or when turned off completely because this reduces battery life unnecessarily. On the contrary; When a desktop computer is in sleep mode, it consumes the minimum amount of power needed to run programs in the background.

 

In sleep mode, the computer consumes a small amount of energy, which is sufficient to restore its original state upon reuse, as the computer in this mode keeps the contents of the RAM on the hard disk drive and then turns off the device, and when the user restarts the device, it will re-transfer the previous contents and restore it to RAM from the hard disk.

 

Even if the device is completely turned off and kept connected to the mains, the computer consumes about 1 watt of energy. This energy is consumed in operating some parts such as the LED lights in some components such as the Ethernet cable entrance, lighting the mouse, keyboard operation, and USB ports in preparation for any user input before starting operation.

 

How to reduce the consumption of computers and laptops for electricity

 

Most computers come with energy-saving features that reduce their energy consumption when the computer or laptop is in sleep mode, or in the case of light usage and basic tasks such as browsing the web. Such features can be controlled and chosen to be activated or deactivated by controlling the settings options The operating system of the device and is also possible to set up a schedule to turn off the device after a specific period if the user does not turn it off himself.

 

As we mentioned before, the bulk of the power drawn by the components of computers and laptops is usually consumed by the device screen, and therefore turning off the screen at times when the user is not active on the device may save about 50 watts of the total energy consumed by the device. Lowering the brightness of the screen also helps reduce the energy it consumes, so the higher the brightness of the screen, the more energy it consumes.

 

Placing a computer or laptop in hibernate mode consumes a very small amount of energy, and this feature can be used to save energy consumption if you want to stop using the device for some time, for an hour or two, for example, and then return to resume use again without restarting the device.

 

Putting your computer or laptop into flight mode turns off Wi-Fi and turns off Bluetooth when needed, which in turn helps reduce the device's power consumption.

 

It is always recommended to close unnecessary programs and applications, as well as tabs that you do not need in the browser while the computer or laptop is running. Programs, applications, and pages that run unnecessarily in the background increase the computer’s consumption of energy that the CPU and RAM use to keep these programs and applications running. But also avoid repeatedly closing and reopening applications and programs that you are already using, as this in turn consume some energy.

 

You can also use a power-saving browser like Microsoft Edge and Opera, which offer some power-saving features like putting some tabs into hibernation when you want to stop using them for a while.

 

Finally, make sure to unplug your computer from the power outlet if it is turned off, and plug it back in only when you need to turn it on. This will save you some energy.

 

Abstract | Desktop computers consume between 170-175 watt-hours during operation, while laptops consume up to 60 watt-hours during operation, i.e. they consume much less electrical energy than desktop computers during operation, and they use this consumed energy more efficiently, and the difference is due to Consumption rates are due to the small size of the power supply used in laptops compared to those used in desktop computers, in addition to the fact that laptops contain a slow performance CPU and graphical processing unit compared to desktop computers.

 

The graphics card and processor in computers generally consume most of the electrical power that the device draws from the source. In the case of using the device in complex processing operations, it consumes energy at higher levels than it consumes when using it lightly, such as browsing the web, which in turn consumes more energy than when it is running in standby mode when the device does not perform any processing operations and when it is not The user is active on the device.

 

Unlike a laptop that consumes no electricity while operating in hibernation mode or when turned off completely, a desktop computer draws the least amount of power possible when it is in hibernation mode, and the device continues to draw a small amount of electrical power from the source even when it is turned off completely as long as it remains connected to the electrical current, so it is preferable to separate the device from the power socket after turning it off to reduce electricity consumption and not to reconnect it except when needed for use.