Closed Circuits for Distributed Generation

Before making the request for technical feasibility, it must be verified if the service is within the following circuits that, according to the #44 article of the Regulation, already exceeded the 15% of the maximum capacity of systems connected to a circuit:

- 2706 Lindora - Brazil

- 1406 Brazil - Ciudad Colón

- 1405 Brazil - Forum

- 1404 Brazil - Reform

- 2703 Lindora - Guacima

2019 Belén - Asunción

- 1504 Box - Electriona II

- 1804 Electriona - Potrerillos

- 1805 Electriona - Scott

- 304 Colima - Guadalupe 1

- 2604 San Miguel - Socorro neighborhood

- 902 Uruca - Virilla

- 505 Guadalupe - San Vicente

How to know which circuit gives me the electric service?

Download the following image: click here.

What is distributed generation?

It is the generation of electrical energy made from renewable sources (solar, wind, biomass, micro-hydro, etc.) within the property of the client, in order to satisfy the energy needs of the subscriber-user in the generation site and the possibility of injecting surplus energy into the distribution network for later use at the same point of interconnection within an annual period, that is, there is an exchange of electricity with the distribution company (netting) to be liquidated annually and up to 49% of the total energy produced that can be injected into the network.

Researchers of the EPER-Lab of the School of Electrical Engineering of the UCR explain in the following video, how the distributed generation model works in Costa Rica and offer advice for clients who wish to install solar panels in their homes.

UCR, School of Electrical Engineering - EPERLab. Office of Disclosure and Information. Production and script: Katzy O'neal Coto. Graphic design: Ana María Sibaja Quirós David Varela Rojas. Animation: Ricardo Prado Calderón.

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Reference Information Documents

Document Link download
Guide for the Distributed Generation process before CNFL. Click Document in pdf formathere
AR-NT-POASEN "Planning, Operation and Access to the National Electric System Click Document in pdf formathere
AR-NT-SUCOM "Supervision of the commercialization of electricity supply in low and medium voltage" Click Document in pdf formathere
AR-NT-SUINAC “Supervision of the installation and equipment of electrical connections” Click Document in pdf formathere
MINAE - Distributed Generation Regulation for Self-consumption with Renewable Sources Contracting Model Simple Net Measurement Click Document in pdf formathere
ARESEP - Application for the first time of the methodology for the tariff of access to the distribution networks by the producer-consumer Click Document in pdf formathere

Interconnection Service Contract Scheme Model Generation Hiring Simple Net Measurement

Note: This document is a base contract, it can be varied according to the service requirements.

Click Document in pdf formathere
Guide for the processing of distributed generation systems, for self-consumption, with renewable sources in the Federated College of Engineers and Architects of Costa Rica (CFIA). Click Document in pdf formathere

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Please note: Click on the question to see the answer.

1 What is distributed generation for self-consumption?

Alternative so that the subscribers generate electricity through renewable sources with the purpose of satisfying their needs, working in parallel with the electrical distribution network, under the concept of deposit and return of energy.

2 What is self-consumption?

It is the use of the energy generated by the producer-consumer to exclusively supply their own consumption, in the same place where it is produced.

3 What is the parallel operation?

It is when a distributed generation system and the electric distribution network operate simultaneously, there being the possibility of exchanging electricity between them, while they remain interconnected.

4 What is the Distributed Generation Community?

It is the group of clients interested in Energy Efficiency, who wish to incorporate renewable energy generation systems interacting with the power grid of the distribution company.

Conditions for a client to process the distributed generation request:

- Be an active client with the definitive electric service and have at least six consecutive monthly billings registered.

- Submit the respective request, with the calculation memory of the Distributed Generation system to be installed by a collegiate engineer.

- Complement its consumption, with energy from the distribution network.

- Cover the respective costs that arise from the studies and other services that the distribution company must provide.

- Assume the tariff costs applicable to the regulated activity, associated to the distributed generation for self-consumption once interconnected. (Access fee).

- Conditioning the electrical installation of the respective building, according to the regulations established by the Federated Association of Engineers and Architects (CFIA), the Public Services Regulatory Authority (ARESEP) and technical requirements established by the ICE Group.

- Install measurement systems in the property boundary; or in case you need to install one of the systems in another place, you must implement a remote reading system for the entire measurement system.

- Adhere to what is indicated in Decree #39220 of the Ministry of Environment and Energy (MINAE) in all its aspects.

5 What is the power availability study in the circuit?

The study of power availability determines, through the review and analysis of different aspects and technical variables, the possibilities of interconnection of the Distributed Generation System of Autoconsumo to the distribution network for the maximum capacity of power requested by the clients. It allows to check if the circuit to which the generator is intended to connect has enough capacity to absorb the energy generated through its different elements. For solar systems, the power to be installed must be calculated, according to the historical consumption of at least six months.

When there is more than one application for the same feeder, these will be processed and evaluated according to the chronological order of entry.

When feasibility is requested, the investor information, brand, model, certification that complies with UL 1741 must be indicated, as well as the number of panels and estimated annual generation energy. All these characteristics can not be changed during the previous process or during the installation of the system without the authorization of the distribution company.

If any variation is made in the technical characteristics prior to the completion of said study or during the installation of the system, before the inspection of the system to be carried out by CNFL and without its authorization, they leave the study without effect, so process a new one, paying the corresponding processing and / or inspection costs, as the case may be.

Once the power availability study is completed, it will have a validity of 3 months, extendable by 3 additional months maximum.

6 Where to request the power availability study in the circuit?

You can do it through our Branches, or through our Virtual Agency.

The electric service must be definitive and have at least six consecutive monthly billings registered, it must be in the name of the direct interested in the installation of the photovoltaic system, who will be responsible for signing the Interconnection Contract

7 What should be presented for the power availability request in the circuit?

The client must submit the power availability request in the circuit to carry out the interconnection study or availability of the distribution circuit.

You can fill out this form online, through the Virtual Agency, or you can download it on the website (F-102)and present it directly in the Branch, with the documents indicated below:

a- Calculation memory, containing at least:

General description of the project, source of energy to be used and particular considerations, for example: historical records of solar radiation, water flows, volumes and type of solid waste, average wind speed or power, etc., (Historical data must be taken of competent entities), calculation of the power to install, average power generation monthly and annually, expected savings. For solar systems, the power to be installed must be calculated, according to the historical consumption of at least six months.

b- Payment for the power availability request in the circuit

Power availability request in the circuit

- Services under 50 kVA: ₡ 35.000 (Thirty-five thousand colones)

- Services of 50 kVA to 150 kVA: ₡ 70.000 (Seventy thousand colones)

- Services greater than 150 kVA: ₡ 100.000 (One hundred thousand colones)

c- Administrative documents:

Copy of physical or legal identity card as applicable, current legal status, special power in case the proceedings are carried out by a third party.

d- Specification of the equipment according to the following format:


e- Certificate of compliance with the UL1741 standard, of the investor (s) to be used.

f- Present protection system of the equipment to be installed and its calculation memory.

g- For hydroelectric projects, it is required to provide the hydraulic power concession and the environmental feasibility study in compliance with article 6, of Regulation # 39220.

h- All information presented is the responsibility of the client and the engineer in charge of the work, which the utility will use to verify the eventual interconnection of the project. Any data that is varied or that leads to error, may be cause for the rejection of the interconnection.

i- The electric company will carry out the corresponding study and issue the response to the client

j- In case there is no availability in the circuit, the project will be rejected.

k- If there is availability in the circuit, the interested party will have three months counted from the date of notification, to specify or implement the distributed generation project and request the interconnection.

l- If, to interconnect the DG project, the adequacy of the network is required, the interested party must cover the costs indicated by the electric company.

The interested party may request, for a single time, an extension of the project process for up to three additional months. You must submit a written note, with 10 business days in advance of expiration, stating the reasons and the new date of entry of operation. The electric company must respond if it grants the requested extension.

8 What is the revision of the distributed generation system for self-consumption?

The distribution company will review the distributed generation system to verify that it complies with the technical standards for the operation in parallel with the electrical distribution system.

a- Prior to the respective inspection, the interested party must pay the amount established for the inspection, as indicated in the following table:

Request for inspection and reinspection

- Services under 50 kVA: ₡ 30.000 (Thirty thousand colones)

- Services of 50 kVA to 150 kVA: ₡ 60.000 (Sixty thousand colones)

- Services greater than 150 kVA: ₡ 100.000 (One hundred thousand colones)

b- The measurement equipment necessary for the data registration will be paid by the interested party.

c- Once the documents with the respective technical information have been verified and the project has been inspected, if there are no technical problems or changes in the capacity of the project, the interconnection contract will be signed. If there are changes in the specifications or models of the equipment or increase the capacity of the project, according to what was previously reported, the request will be rejected and the client must make a new request for interconnection.

Once the above is fulfilled, the Interconnection Contract between the Producer-Consumer and CNFL will be signed.

9 What is the Contract interconnection service distributed generation scheme contracting model net simple measurement?

This contract is an accessory to the Electric Supply Contract that exists between the distribution company (CNFL SA) and the Client (PRODUCER - CONSUMER), establishing a series of obligations and conditions for the commissioning of distributed generation systems for self-consumption with the electricity distribution network, as established in the decree 39220-MINAE "Distributed generation regulation for self-consumption with renewable sources simple net metering model".

The client must present, once CNFL notifies the approval for the contract subscription:

- Seal of the CFIA and copy of plans (in PDF) approved of the Distributed Generation project

- Current legal status for legal and physical persons identity card

- Cancel the costs associated with the process of interconnection of the distributed generation system of self-consumption (contemplates the different stages of the process, inspections, studies)

- Cancel the costs of the meters, according to the type of measurement system to be installed.

10 Can any customer connect their distributed generation system for self-consumption?

Accessing the distributed generation scheme for self-consumption through the simple netting scheme can be done by any customer in the country with their distribution company. The conditions are that energy must be generated with renewable sources, that generation and consumption must occur in the same place and the Contract must have been signed with the distributing company.

11 What are the permits that have to be taken to develop a solar power plant in Costa Rica?

For a self-consumption solar power plant, environmental permits must be available if it is greater than 500 kWp of installed capacity, in addition to the permits for the construction of any work in our country. To interconnect a self-consumption system to the distribution network, the Interconnection Contract must be signed, complying with its requirements.

12 Is there any kind of application or proposal that must be presented to MINAE or ICE to develop a solar energy sales project in Costa Rica?

Every energy sale project produced by a private company is considered a public service and is governed by the 7200 Law. The project must win the ICE eligibility process to be able to sell the energy produced to ICE. Currently ARESEP sets the minimum and maximum rates for this type of generation. To win the process you must submit an energy offer between those two costs.

According to this Law, the maximum capacity of a private generation plant is 20 MW of installed power and is independent of the generated power.

The ICE pays the amount offered by the interested party in the eligibility process with which the Energy Sales Contract is signed.

The generation schemes through the 7200 law are for sale of energy and can be located in any area of ​​the country, but energy can only be acquired by ICE and its companies (CNFL). A toll rate is currently being defined for cases where the producer connects to the distribution network of a company other than the one that sells the energy. In this type of connection scheme, it is likely that energy should also pay transmission tolls.

13 What is simple net measurement?

This method allows energy not consumed monthly to be deposited in the distribution network, to be used during an annual cycle, in the form of deferred consumption.

14 What is the difference between simple netting and complete netting?

Simple netting only proceeds for self-consumption without the sale of surplus at the end of the year, so it is not considered a public service, the interconnection scheme is relatively simple. In the complete netting, there is a surplus sale at the end of the year and it is considered a public service for which it requires the concession of energy sales, a scheme that has a complex process and is governed by the 7200 law, it must be started by participating in the processes of ICE eligibility, earn it and sign the sales contract with ICE.

15 What are the conditions so that it can not be neat?

If after installing the measurement equipment, any modification was made to the property (fences, walls or other infrastructure), CNFL will grant 20 business days, in order to execute on behalf of the PRODUCER-CONSUMER, the relevant changes for the Relocation of the measuring equipment. The energy injected into the network during this period will not be recognized.

If for reasons attributable to the producer-consumer it is not possible to take the reading of the generation meter, then the netting of that month will not be possible.

16 What is the storage and withdrawal of energy?

Rule of 49% and 51% according to Art. 34 of the Regulation of Distributed Generation for Self-consumption.

The generation of self-consumption consists in the fact that the customer must consume at least 51% of the energy that he generates annually as a minimum, with which he will be able to inject only up to 49% of the generated energy as a maximum; Any additional energy generated in the annual period will be donated by the customer to the distribution company. Settlement of the system will be done by calendar year (December 31).

The formula would be the following:

(Energy that is injected into the network) ≤ 49% * (total generation of the installed system).

And CNFL's internal calculation for billing would be:

Extraction of the generated by the photovoltaic system and saved in the network (kWh) * Access rate) + Additional electricity purchased from the distribution company (kWh at the current rate) = Monthly energy billing.

- If the energy purchased from the distribution company is ≤ 30 kWh, the minimum rate is paid.

- On this total the public lighting and the Fire Tribute are calculated.

- On the energy purchased from the distribution company, the sales tax is paid.

In all invoices, the charge for Public Lighting, Fire Tribute, both on the total extracted and the Sales Tax when there is energy sold by the distribution company must be considered.

17 If it is 49% of the generated what I can inject and recover, then?

If it is 49% of the generated what I can inject and recover, then I can oversize and generate more than what is required in my own consumption to the point that my rate is almost zero? Does everything extra of what I consumed remain with the company and does not recover?

It does not make sense to oversize if there is no retribution on the generated excess, it would be taking the client to unnecessary expenses in the additional capacity of the system that becomes unnecessary.

18 What is the access fee?

It is defined by the Public Services Regulatory Authority, ARESEP, corresponds to the payment received by the distribution company to receive on deposit the energy for its subsequent use in time by the producer-consumer. The energy deposited can be used in the same month or in subsequent months of the 12 months period, after which the remainder is lost and the energy accounting starts again at zero.

19 How does the access fee for TRH services apply?

Since there are three hourly measurements of injected and three energy extracted monthly, the netting is done in each time slot and the access fee is charged for each unit (kWh) previously deposited regardless of the time slot in which it was extracted. After the 12 months of netting, the energy in each time slot is liquidated to start a new period of netting and accounting of the generated energy. The maximum 49% of energy generated and injected into the distribution network is considered in relation to the sum of the injections for each time slot.

20 What requirements must be met to return to the monomic tariff?

In Costa Rica's tariff system, in general, the General and the Social Character rates are monomic rates, only energy consumption is paid. However, if the customer, in the last year, exceeds the consumption of 3000 kWh in six months, the meter is changed and the tariff becomes binomial, that is, it is paid for consumption and power. What requirements must be met to return to the monomic tariff? If the energy consumption of the 3000 kWh is lowered, during a period established by the distribution company, energy charge is no longer paid?

It is not necessary to go back to the monomic rate because in reality the Rate behaves as such if the customer does not exceed 3000 kWh, in which case he only pays the amount of energy, but if that limit is exceeded in a month, it automatically He takes charge of Power (Demand).

When you are a producer-consumer, the volume of energy that establishes whether power is charged or not, will be determined by the total extracted from the distribution network, this is what was previously deposited plus the sale of energy from the distribution company. Only the energy that is produced and consumed directly in the producer-consumer facilities is not counted for the limit of the 3000 kWh.

21. If the distributed generation system is not interconnected to the distribution network, will it be subject to this regulation?

If in a month of service, which is classified in the CNFL binomial block general rate, it does not have accumulated surpluses of previous months, it withdraws 3001 kWh from the CNFL network and injects 1500kWh (result of generation with solar panels less momentary consumption ), has a net consumption of 1501 kWh, will that month be charged a charge on demand?

The maximum demand present in the month will be invoiced, in addition to the energy charge for the 1501 kWh sold, the charge for access by 1500 kWh deposited and extracted and the charges for public lighting and Fire Tribute on the total extracted from the network ( sale + deposit). The sales tax will only be applied for the 1501 kWh effectively sold by CNFL.

When one is a producer-consumer, the volume of energy that it establishes (if power is charged or not), will be determined by the total extracted from the distribution network, this is the previously deposited plus the sale of energy of the distribution company.

Only the energy that is produced and consumed directly in the facilities of the producer-consumer is not counted for the limit of the 3000 kWh.

The issue of billing the maximum demand in binomial rates, is regulated according to what is established in article #134 of the Supervision of Marketing standard of ARESEP (SUCOM).

22 If I have a residential hourly rate, can I install a generation system for self-consumption?

It is convenient that in the analysis for the installation of a generation system for self-consumption, the client that counts today with the hourly residential rate (T-RH) establishes if said rate continues to be favorable according to their consumption patterns and expected generation.

23 If the distributed generation system is not interconnected to the distribution network, will it be subject to this regulation?

A distributed generation system that operates in isolation, is not regulated by the provisions of the regulations, however must register with MINAE.

However, it is the responsibility of the non-interconnected producer-consumer:

a) Ensure that the electrical installation of your property complies with current legislation and technical standards required for this purpose.

b) Use devices for energy storage that comply with the corresponding technical regulation.

c) Have the appropriate conditions for the installation of storage devices (batteries).

d) Operate securely the generation system that installs.

e) Install the necessary systems to prevent your system from coming into contact with the electrical distribution network.

f) Make a correct final disposal of waste devices for the storage of energy according to current legislation.

24 What is an investor?

It is the device that the solar panels have to convert the direct current generated by the panel into alternating current so that it enters the distribution network.

25 Can a meter be installed per inverter?

No, you must totalize the entire generation in a single meter.

26 Why two meters?

The client must have a measurement system in order to measure the production of electrical energy and verify compliance with 49% of the annual energy produced as a maximum to inject into the network.

- The interconnection measurement system, It will be located at the point of coupling with the distribution network of the electric company and will be four quadrants, allowing to measure both the energy delivered and the energy extracted from the distribution system.

- The generation measurement system it can be supplied by the electric company and will form part of the interconnection costs.

Outline installation model

Image that shows the technical diagram for the installation of measurement equipment: Panels, breaker box, meters, among other elements.

27 What procedure should the client do if he has the generation and distribution meters?

In case the interested party contributes his own system of measurement, he / she must comply with the AR-NT-SUMEL standard and have a calibration certificate issued by an Accredited and current Laboratory, a document that must be endorsed by the Systems Laboratory of Measurement of Electric Power of the CNFL. In these cases, the measuring equipment must be delivered by the manufacturer or supplier of the meter to the Measurement Systems Laboratory Area of ​​the CNFL, located in Uruca, next to Capris.

The meter must be certified by a laboratory that complies with:

a) Be a National Institute of Metrology (INM), whose requested service is covered by the agreement of the CIPM (CIPM-MRA) Mutual Recognition Agreement of the International Committee of Weights and Measures and is published in the respective capacity of measurement and calibration ( CMC) of the INM before the BIPM International Bureau of Weights and Measures. The services covered by the CIPM-MRA agreement and the CMCs duly published can be verified in appendix C of BIPM KCDB (see link).

Note 1: The INM can indicate that their calibration services are covered by the agreement of the CIMPM-MRA, by using the logo of said agreement, however since the use of this logo is not obligatory, it should be consulted in appendix C of the BIPM KCDB to verify the compliance of the calibration service provider with the previous requirement.

Note 2: The NMIs of the member states that participate in the metro convention can obtain traceability directly from the measures carried out by the BIPM. The KCDB provides an automatic link to the relevant BIPM calibration services (including scope and uncertainty). Individual calibration certificates issued by the BIPM are also listed.

b) Costa Rican Metrology Laboratory LACOMET for calibration services.

c) Laboratories designated by LACOMET, whose required calibration service is published in their respective CMC before the BIPM. See appendix C of the BIPM-KCDB (see link).

d) Calibration laboratories accredited by ECA, which has within its scope of accreditation, the capacity of measurement and specific calibration for the magnitude and scope of measurement, including uncertainty, in that it requires traceability.

e) Calibration laboratories accredited by accreditation bodies homologous signatories of the Multilateral Recognition Agreement for calibration laboratories with:

• Inter-American Accreditation Cooperation (IAAC): check link.

• International Laboratory Accreditation Cooperation (ILAC): check link.

• Asia Pacific Laboratory Accreditation Cooperation (APLAC): check link.

• European Accreditation (EA): check link.

That it has incorporated within its scope of accreditation the capacity of measurement and calibration specific for the magnitude and scope of measurement, including uncertainty, which requires traceability.

28 Is there a cost to approve and calibrate the equipment? If there is, what is the cost?

CNFL does not approve suppliers or brands, what the Electricity Measurement Systems Laboratory does is calibration and has a cost of ₡ 80.000 (eighty thousand colones) per unit.

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