According to projections by EPE (Energy Research Company), the energy consumption is expected to grow by 3,4% per year until 2034, reaching 870 TWh (terawatt-hours).
In October 2024 alone, for example, Brazil consumed 2,1% more electricity compared to the same month last year, according to data from CCEE (Electric Energy Trading Chamber).
The heat and the booming economy in many sectors influenced the increase, which was concentrated in the South, Southeast, North, and part of the Northeast. There is no doubt: the trend is for the population to consume more and more energy, mainly due to climate change and daily needs in their homes and workplaces.
Given this scenario, it's essential to know how to calculate energy consumption, because it's possible to identify areas where energy is being wasted and how to change that. The greater the energy waste, the higher the price you and the environment pay for it.
By using energy correctly, you save on your electricity bill and also help the country preserve ecological reserves and, consequently, life on the planet. But do you know how much energy each appliance consumes? Do you want to reach the end of the month without facing a frightening bill?
This content will show you how to calculate energy consumption in kWh, how consumption is charged and will give you tips to save on your electricity bill. Check it out!
How to calculate energy consumption in kWh per month?
Knowing how to calculate energy consumption in kWh (kilowatt-hours) is essential in energy management, especially when it comes to solar energy projects in homes and businesses.
If you want to understand all about solar energyThis is one of the first steps towards making more informed and efficient decisions. This calculation is done by multiplying the power of the equipment (in kW) by the usage time (in hours), providing an accurate measure of the energy consumed.
For example, a 3 kW appliance used for 4 hours would consume 12 kWh (3 kW x 4 hours = 12 kWh). However, depending on the size of the property and the number of appliances installed, looking for technical data labels, analyzing the power of each one and interpreting them can be laborious.
Check out the step-by-step guide below, prepared by the engineering team at Canal Solar, with two methods for calculating energy consumption in kWh – with the help of reference tables from Eletrobras/UNESP and CEMIG:
- List all electrical equipment at the location under analysis, which could be your home or business, for example;
- Once you have the list of equipment, consult the Eletrobras reference tables. Where it indicates, for each existing electrical appliance, in the “average monthly consumption” column. Note down the values and proceed to the next step;
- Add up the monthly consumption of each piece of equipment and analyze the final result, which is the consumption of the analyzed location in average kWh per month.
Another way to calculate, if you have more time to analyze your bill, is to check your consumption characteristics more accurately. To do this, you need to check the number of people and the time the equipment is used:
- In the reference table, write down the power in the “average power of devices” column and estimate the number of hours each device will be on per day;
- Multiply the equipment's power by the time it will be on per day, resulting in the daily consumption of each equipment in kWh/day;
- Multiply the daily consumption of each device by the number of days they will be used per month, resulting in the monthly consumption of each device in kWh/month;
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How to understand the energy consumption charged on the electricity bill?
Now that we understand how to calculate energy consumption, let's identify how consumption is charged. We will identify the most important points, from meter reading to the operation of tariff flags, in addition to calculating the cost per kWh in reais (Brazilian currency) on the electricity bill.
How does the electricity meter work?
The first step to knowing how to calculate energy consumption is to read the electricity meter – usually installed in the distribution panel, on walls (in the case of houses) or other places that make it easy to see.
Meters are fundamental devices in industrial, commercial and residential electrical installations, as they measure the amount of energy consumed from the distribution network.
There are two types: electromechanical and electronic. In the first model, the device has a metal disc that moves every time an electric current passes through the coils, generating a magnetic field. In other words, the higher the speed of the disc, the stronger the magnetic field identified and, consequently, the more energy is being consumed.
The analog model was popularized as the "electricity meter" and is still widely used in residential and commercial building installations. In contrast, the electronic meter is considered more efficient than the first model because it provides accurate consumption information. Another advantage of the device is that it can be monitored remotely (via modem and internet).
In general, electromechanical energy meters work using electromagnetic induction, triggered when electricity is being used in the installation and circuits. This field moves the gears of the device, causing the pointers to move, thus enabling the measurement of electricity usage.
In the case of electronic meters, the measurement is based on associated sensors and transducers (parameter signal converters). These devices record the amount of current and potential through input signals, which are multiplied to obtain the instantaneous power. Finally, this result is integrated to obtain the amount of energy consumed.
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How do electricity bill tariff flags work?
Another important point in the text on how to calculate energy consumption concerns the Tariff Flags, which is the system that signals to consumers the real costs of generating electricity. To this end, the colors of the Flags (green, yellow or red) indicate whether the energy will cost more or less depending on the electricity generation conditions.
The system, implemented in 2015, is a different way of presenting a cost that was already included in the energy bill, but which generally went unnoticed.
There is therefore no new cost, but a price signal that signals to the consumer the real cost of generation at the time they are consuming the energy, giving them the opportunity to adapt their consumption, if they so wish.
With Tariff Flags, the electricity bill becomes more transparent and the consumer has better information to use electricity more consciously.
What was it like before the Flags?
Any variations that occurred in energy generation costs, whether upwards or downwards, were passed on up to a year later, in the following tariff adjustment.
What does each color mean and how much does it cost?
- Green flag: favorable conditions for energy generation. The tariff does not suffer any increase;
- Yellow flag: less favorable generation conditions. The tariff increases by R$0,01885 for each kilowatt-hour consumed;
- Red flag – Level 1: more expensive generation conditions. The tariff increases by R$0,04463 for each kilowatt-hour consumed;
- Red flag – Level 2: even more costly generation conditions. The tariff increases by R$0,07877 for each kilowatt-hour consumed.
Who does it apply to?
All captive consumers of distributors are billed using the Tariff Flag System, with the exception of those located in isolated systems.
Read more: Clean energy: see what it is, sources and 6 examples
How do I calculate the kWh value in reais on my electricity bill?
To calculate the real value of energy consumption in kWh on your energy bill, follow these steps, listed by engineers at Canal Solar.
- Record the value of your monthly electricity consumption on your bill;
- Find the value of the electricity tariff (TE) and distribution tariff (TUSD) on your energy bill, including PIS/COFINS and ICMS taxes. This value is given in R$/kWh;
- The price to be paid is the multiplication of energy consumption by the sum of TE + TUSD;
- In the case of application of the tariff flag (yellow, red 1 or 2), the respective cost of the tariff of the flag applied in the billing period must be added;
- The public lighting fee (which may vary between different regions) and other fees applicable at the time of billing of the energy bill must be added to the total amount;
- Example: a residential customer with a total of 200 kWh in a month, considering a tariff (TE + TUSD) of R$0,80/kWh including taxes, will have a cost of 200 kWh x R$0,80/kWh = R$160,00. If the red tariff flag level 1 was in effect for the entire month and the tariff applied is R$0,04463/kWh, the value of 200 kWh x R$0,04463/kWh will be added. Finally, the value of any applicable additional fees, for example, for public lighting, must be added.
Check for any specific discounts or additions to your bill that may change the final amount. Your electricity bill should detail all of these amounts, making it easier for you to calculate and understand the total amount you will have to pay.
Also check out: Price of solar energy: how much does installation cost on average?
How to save on your home or business electricity bill? Check out the tips!
We discussed how to calculate energy consumption and now check out tips on how to save on your electricity bill at home or in your business.
- When equipment is not well maintained, it tends to consume more energy. Therefore, don't forget to keep it maintained;
- During storms, unplug electrical appliances and electronic devices to prevent them from being damaged by electrical discharges;
- Avoid connecting multiple devices to the same socket to avoid short circuits;
- Turn off the lights, air conditioning and TV when no one is in the room;
- Avoid “makeshift” solutions and always use the appropriate wires for each type of installation. Ideally, electrical work should always be carried out by a qualified professional;
- Use an energy-saving device on the outlets of refrigerators, freezers and washing machines to determine how much each one will consume to keep running.
Another way to save energy and reduce your electricity bill is to use alternative renewable energy, such as solar. Look for sustainable solutions, in addition to savings for the consumer, brings benefits to the environment, such as reduced impacts and decarbonization.
Why is solar energy a more sustainable solution?
Photovoltaic energy is a clean and renewable energy source, easy to install and maintain, in addition to being accessible to any energy consumer and having a long useful life of at least 25 years.
According to the DOE (United States Department of Energy), solar is the best source in the world in terms of sustainability, as it emits 98% less CO2 than energy from fossil fuels.
In Brazil, more than 47,8 million tons of carbon have been eliminated with the installation of solar plants since 2012, according to mapping by ABSOLAR (Brazilian Photovoltaic Solar Energy Association).
Do you want to install solar energy in your home or business? Find the best solar energy companies and reduce your monthly electricity bill!
Conclusion
We have highlighted throughout the text how to calculate energy consumption, and we know that by adopting energy saving strategies and considering the transition to solar energy, homes and businesses can not only reduce costs, but also align their operations with environmentally responsible practices.
To get an idea of the strength of solar, global investments in photovoltaic energy should surpass the $500 billion mark in 2024 – the same as R$2,6 trillion – according to a report published by the IEA (International Energy Agency).
Just as happened in 2023, the entity expects solar energy to attract more investment than all other energy sources this year, surpassing investments in fossil fuels such as coal, oil, and gas, and in clean energies such as wind, nuclear, and hydroelectric power. To keep up with these and other updates on the sector, it's worth keeping an eye on... news of Canal Solar.
