Contracted Power Simulator

This simulator supports electricity consumers choosing the contracted power for single-phase electrical installations up to 10,35 kVA.

The contracted power is chosen by the consumer and corresponds to the maximum power limiting the operation of electrical equipments used at the same time.

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Disclaimer

This simulator recommends a contracted power considering a simple proxy and therefore must be considered as an approximate value. ERSE shall not be liable for any damages arising from the use of this simulator.

FAQ

What contraced power should I hire?
What if I hire a low contracted power?
How much can I save by reducing my contracted power?

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More info

Chosing your contracted power
- What do I have to do to have electricity at home?
  First you need to choose an electricity supplier. Consult ERSE's energy price simulator to find the best market electricity supplier.
  In order to have a electricity contract (household consumer) you will have to choose your contracted power, which can range from 1.15 kVA to 41.4 kVA.
  Once you chose the contracted power echelon, the supplier requests, if necessary, a technician to go to your home and configure the contracted power echelon in your switchboard.
- When do I choose my contracted power echelon?
  
  IDuring the process of connection to the grid you only determine the required power for the house electrical installation. Usually this is made by the owner or the builder of your house.
  
  The contracted power echelon is chosen by the consumer after the contract with a electricity supplier. After, it is necessary to set the contracted power echelon at your house by a distribution network technician.
- How to choose the contracted power echelon I need?
  
  A higher contracted power echelon allows you to connect more electrical equipment at the same time, but also a more expensive electricity bill.
  
  This simulator allows you to choose the contracted power echelon depending on the equipment you use at the same time. Try this simulator to use different sets of equipment used at the same time and see how they influence the power.
- Can I choose any contracted power echelon?
  
  No.
  
  Small or medium-sized houses are usually limited to contracted powers between 1.15 kVA and 10.35 kVA (single-phase installations).
  
  Large houses are usually limited to power between 10.35 kVA and 41.4 kVA (three-phase installations). Check with your supplier or the technician responsible for the electrical installation, to know whether you have a single-phase or three-phase installation.
  
  Note that the contracted power can not exceed the required power of your house, which corresponds to the maximum power for which your house electrical installation was dimensioned.
  
  If you are the owner of the house, consult the Electrotechnical Sheet of your electrical installation to check your house required power.
- How to change your contracted power echelon?
  
  Contact your electricity supplier. If necessary, he will schedule a visit of a distribution network operator technician, who must have access to your house switchboard. The visit is scheduled for a period of time that can go up to 2 hours and 30 minutes and the visit will take about 10 minutes.
  
  For customers whose installation has already a smartmeter, integrated into the network operator network, the change in the contracted power echelon is done remotely, without your presence. Your supplier can inform whether you have a smartmeter able to do this.
- How often can I change my contracted power echelon?
  There is no limit.
- Can I change my contracted power echelon if I am a client with social tariff?
  
  Yes you can.
  
  But since the social tariff discount only applies to consumers with contracted powers up to 6.9 kVA (in addition to the other eligibility criteria), if a higher contracted power echelon is requested, you may lose the social tariff benefit.
- Are there costs changing the contracted power echelon?
  
  No.
  The change in the contracted power echelon is free of charge. However, if you are not present during the network operator technician's scheduled date and time interval, with you will have to pay a compensation.
  
  Switching to a higher contracted power echelon imply an increase in the value of your electricity bill.
- Changing my contracted power echelon affects my electricity contract?
  
  Changing the power echelon always affects the price of the fixed term of your invoice and can affect the price you pay for the consumed energy.
  
  It may happen that your current commercial offer has specific limits of contracted power echelon, and therefore it is not possible to change it beyond those limits without starting a new contract.
  
  Contact your supplier, in particular whether the change affects the end date of the contract or other contractual conditions.
- Should I increase the contracted power if after installing a smartmeter my switchboard starts powering off?
  
  If you have a smartmeter there is no reason to reduce the available power. However, some older power control devices allowed the user to have more power than the contracted power.
  
  However, the installation of a smartmeter eliminates this situation and makes a strict control of the power.
  Note that some customers with three-phase electrical facilities benefit from an available power range, because they have a three-phase power supply resulting from a network operator option. This margin allows the customer to have an available power higher to the contracted one, in 3 x 1.15 kVA.
  
  If you house electrical installation is a three-phase and there is already a power margin, it must be maintained.
General Questions
- What is contracted power?
  
  The contracted power is the maximum available capacity and is chosen by the consumer.
  Each contracted power echelon has a specific price. The contracted power is measured in VA (VoltAmpere).
  
  The higher contracted power, the greater number of electrical equipment that can be used at the same time. There are 13 contracted power echelons, ranging from 1.15 kVA to 41.4 kVA.
  
  The most frequent power echelons in Portugal are 3.45 kVA and 6.9 kVA.
- What contraced power should I hire?
  
  The value of contracted power must be sufficient to satisfy the aggregate power of the equipment used at the same time. The more electrical equipment you want to connect at the same time, the higher the contracted power must be.
  
  To choose which power you should hire, you have to take into account the electrical equipment you use at the same time. For example, consider a typical winter day at dinner time using at the same time an electric heating, an electric oven and a microwave.
  
  Use this simulator to try different equipment sets at the same time and see how they influence the contracted power you need.
- How much can I save by reducing my contracted power?
  
  If you have a contracted power less or equal than 6.9 kVA, you can save approximately € 22 per year for each reduction of contracted power echelon.
  
  To calculate your exact savings use the calculator prepared by ERSE (only available in Portuguese).
- What if I hire a low contracted power?
  When the aggregate electrical equipment power (used at the same time) is greater than your contracted power, the electrical switchboard in your house will shut off. In this case is you should:
  
  1 - Turn off the last equipment you have connected,
  2 - Reconnect the electrical panel of your house.
  
  If you really need to use the set of equipment that turned off your the switchboard, contact your supplier and hire a higher power echelon. Note that this change, while cost-free, will increase the value of your bill. Check the prices with your supplier or use ERSE price simulator.
- How is the contracted power billed?
  
  The contracted power is billed in euros per day (euros / day) and does not depend on the consumed energy. A higher contracted power implies a higher price.
  
  Its value depends mainly on the Network Access tariffs, approved annually by ERSE, and reflect the cost of using the electricity networks by all consumers.
  
  The electrical networks are built to withstand situations of maximum electric capacity, the greater the consumers contracted power is, the more investments will be needed in the electrical networks. This explains why a higher contracted power rating implies an increase in your electricity bill.
- How should I use this simulator?
  
  This simulator recommends a power echelon based on the sum of the individual power of each electrical equipment. The electrical equipment can be divided into two categories:
  
  1 - Equipment that easily reaches the manufacturer rated power. For example: lamps, electric kettles.
  2 - Equipment that only reaches the manufacturer rated power when used in its maximum program or with all the functionalities at the same time. For example: washing machines (at the maximum temperature), electric stoves (with all the heating areas connected at the same time).
  
  When you are editing your equipment remember to enter the power values according to the use you give to the equipment. There are power meters that you can place between the jack and plug of the equipment to help you measure the power input of your equipment.
  
  Remember: If your switchboard has never turned off since you have an electricity contract, then you can try lowering your contracted power by one echelon.
ERSE tips for choosing a suitable contracted power
- Efficient equipments allow lowering contracted power?
  
  Yes.
  Generally, higher class equipments have less energy consumption and also require less power. An example are LED lights that with less power have the same lighting quality.
  
  Efficient behavior also allows to reduce electric power.
  Also, eletric power can be decreased by turning off equipment when they are not needed, such as TVs or others.
  Some equipment can be used in sequence and not at the same time, such as washing machines and dryers.
  
  Long time running equipment can be used after more urgent tasks such as meal preparation, avoiding simultaneous use of equipment.
- Reducing the contracted power is enouth to lower the electricity bill?
  
  Reducing contracted power is a way to lower your electricity bill. Other ways are:
  
  - Search for the best commercial offers available in the market. Use ERSE's energy price simulator to find the best market offer;
  
  - Use appliances with higher energy class, which generally consume less energy and have equipment to control the power they need. A simple example are LED bulbs that have relatively low rated power for the same lighting quality;
  
  - Change your electricity consumption habits and adhere to time-of-use tariffs.
- Does the installation of photovoltaic solar panels allow me to lower the contracted power?
  No.
  Rooftop Solar panels usually have low power and do not reduce significantly the power requested from the grid. Moreover, without the presence of batteries there is also the mismatch between the power generation of the panel (during the day) and your peak consumption (usually at the end of the day).
- Does charging an electric vehicle at home implies increasing my contracted power?
  
  It depends.
  
  Slow charging of electric vehicles is possible with powers, normally between 2.3 kVA and 3.7 kVA.
  
  If you charge your car's batteries during peak hours, certainly you will need to increase your contracted power.
  
  If you charge during off-peak hours, for example during the night (after 23h), you may not need to raise your contracted power echelon.
- Does a smartmeter helps choosing the contracted power?
  Yes, since it collects detailed information about your consumption. If you have a smart meter installed and it is already integrated into a central smartmeter system of your network operator, then you can request access to your consumption history and adjust your contracted power to the maximum power you used.
- If the switchboard turns off, do I have to increase my contracted power ?
  When the power of your connected equipment is higher than your contracted power, the switchboard in your home will switch off. If this occurs once or twice a year, this does not mean that you must increase your contracted power. Just keep in mind that you should not connect too many devices at the same time. If your switchboard has never turned off, try lowering your contracted power.
- Should I use my appliances at its maximum power?
  
  No.
  
  Depending on the use you make of your appliances these may operate at different power values. Using some appliances not at its maxmimum power will allow you to use other aplliances at the same time.
  
  The electric power can be reduced by turning off equipment that is no longer needed, such as lamps, televisions or others.
- Should I include all my appliances in the simulation?
  
  It is crucial that you include the appliances with the greatest power (measured in Watt), such as a dishwasher or an electric kettle (kettles usually have more than 2 000 Watt).
  
  You should also test different scenarios where you use a different set of appliances at the same time.
Technical Questions
- What is the difference between kVA and kW?
  
  The power of electrical equipment is rated in Watt (W), but some equipment, such as electric motors, beyond active power, in Watt (W), also require Reactive Power, in reactive Volt-Ampere (VAr).
  
  The conjugate effect of these two powers its called "Apparent Power", measured in Volt-Ampere (VA). The relation between these two is given by a ratio called "Power Factor".
  
  Household customers meters mesure "Apparent Power" and, therefore, the contracted power is measured in kVA (1 kVA = 1 000 VA).
  In order to choose the contracted power, we can use directly the power indicated in the equipments (generally in Watt).
  
  The power factor is not measured for household customers and small businesses, and therefore, reactive energy is not billed separately. Only non-households customers explicitly pay reactive energy .
- What is a single-phase electrical installation?
  It is an installation with only an electric phase and a neutral. For security reasons it has a third conductor called "earth". In this type of installations all power is supplied by a single electric conductor (phase).
- What is a three-phase electrical installation?
  
  It is an installation consisting of three electrical phases and a neutral. For security reasons it has a fifth conductor called "earth". In this type of installations all power is supplied by three conductors (three phases). For example, a contracted power of 6.9 kVA, in a three-phase installation, corresponds to having a power of 2.3 kVA available in each of the three phases.
  
  In some networks operators it is already possible to have the contracted power available in a single-phase, even for three-phase installations and within certain limits.
  
  Contact your network operator to know more about this.
  
  In household, even being three-phase electrical installations, the equipment is usually single-phase.
- Can I switch between a single-phase and three-phase installation?
  
  Yes but...
  
  The choice between a single-phase or three-phase installation is made during the construction of the building, depending on the total power that is intended to be available in the installation.
  
  Before signing a supply contract there must be a declaration of conformity, signed by an Installing Entity of Electrical Installations or by an authorized person.
  
  To change the number of phases it is necessary to make changes in the house electrical installation. Again, after the changes you need to contact an Installing Entity of Electrical Installations or an authorized person.
  
  For more information consult the Directorate General of Energy and Geology.
- What is the difference between requested power and contracted power?
  
  The requested power corresponds to the value for which the connection from the house to the network was dimensioned and will impact on the connection cost.
  
  The contracted power is the maximum available power for the consumer to use. The contracted power cannot be higher than the requested power and increasing the requested power has additional costs.
- Can I increase the requested power?
  
  Yes but...
  
  If the house is yours, you will have to bear the cost of this change.
  
  If your house is part of a condominium, the change may imply an increase in the requested power of the entire condominium, therefore requiring the condominium owners' authorization and implying costs to the condominium.
  
  If the house is rented, increasing the requested power requires an authorization of the landlord and/or the condominium.