How to Choose a Solar Provider for Your Company: The Industrial Buyer's Checklist

A business solar project has four layers, and a provider can be strong in one and weak in another: the design, the construction, the certification that what was built meets the regulation, and the connection procedure with the grid operator. Each has its own rules, and each produces documents with a signature and a responsible person.

The framework is the Technical Regulation for Electrical Installations (RETIE). Its current text is that of the four books and annexes issued with Resolución 40284 of 23 June 2026 of the Ministry of Mines and Energy, published in the Diario Oficial on 1 July 2026, which amended the regulation contained in Resolución 40117 de 2024, itself already adjusted by Resolución 40304 de 2025. The transition period with the 2013 RETIE ended on 31 December 2025: works started on or after 1 January 2026 can no longer be inspected under the old rule.

That gives a first simple test. An offer that cites only Resolución 90708 de 2013 as its framework, or does not mention RETIE at all, comes from a template nobody has updated. It does not disqualify the provider on its own, but it shows how much attention is paid to the part of the project you cannot see.

RETIE requires the design, construction, operation and maintenance of an electrical installation to be directed, supervised and carried out by technically and legally competent persons (article 3.2.1). For design it names electrical, electromechanical and distribution-network engineers, with the competence granted by their licence under Ley 51 de 1986 and Ley 842 de 2003. Electrical technicians may build only the installations expressly included in their licence, which is issued by CONTE.

There is one threshold a company almost always exceeds: generation with non-conventional sources of 10 kVA or more must have a design before it is built (article 3.3.1), and that design carries the name, licence number and signature of its author, who thereby takes responsibility for its effects (article 3.2.3). Non-electrician staff may carry out activities with no direct electrical risk, such as civil works or cable laying, but under the supervision of a person competent in electrical engineering.

The consequence of skipping this is not theoretical. If the person directing or carrying out the installation has no licence, or holds one without the competence the work requires, the regulation orders the grid operator not to put the installation into service and to report the case to the Superintendence of Industry and Commerce and to the professional council.

Checking takes a few minutes. Ley 842 de 2003 allows any contracting party to ask Copnia for an engineer's certificate of good standing; for electrical, mechanical and related engineering, the Consejo Profesional de Ingenierías Eléctrica, Mecánica y Profesiones Afines, which licenses them under Ley 51 de 1986, offers a licence look-up on its website and the download of a certificate of good standing and disciplinary record, and CONTE publishes the register of licensed technicians, their validity and those sanctioned. Ask in writing for the name and licence number of whoever will sign the design and whoever will direct the works, and look them up. The regulation also requires those who issue declarations of compliance to be registered in the Superintendence of Industry and Commerce's registry of producers, importers and service providers: ask for proof.

On completion, the builder must show that the installation meets the regulation through the declaration of compliance, signed by the competent person responsible for directing the works or building them directly. The official form is a declaration under oath, with ID and licence number, in which the signatory states that the installation complies with RETIE and that the product certificates were checked against the equipment installed. There is an equivalent declaration by the designer.

When the installation requires full certification, those two declarations must be validated by an inspection report issued by a body accredited by Colombia's National Accreditation Body (ONAC) under ISO/IEC 17020, with the independence criteria of Type A bodies. Full certification is required, among others, for small-scale self-generation and non-conventional-source installations of 10 kVA or more that connect to the grid to export surplus, for self-generation of 10 kVA or more that does not connect to the grid, for industrial installations of 20 kVA or more and for commercial ones above 15 kVA (section 4.3.2.1 of Book 4). A grid-connected plant that exports no surplus usually falls under the last two, or counts as an extension. Extensions also require full certification: in small-scale self-generation, when they exceed 30% of installed capacity or when equipment is installed to export surplus.

Two practical consequences. First: the regulation requires the inspection body to meet the independence criteria of Type A bodies under ISO/IEC 17020, which in practice rules out inspection by the installer itself or by a company linked to it; its accreditation can be checked in ONAC's Official Directory of Accredited Bodies, which can be searched by company name and shows suspended, withdrawn and expired accreditations. Second: the regulation says that until the certification exists the installation may not be used by end users, so the inspection report is part of the schedule and of the price. Ask who hires the inspector, who pays, and what happens if the first report comes back with non-conformities.

The regulation also sets what the builder must hand over: the signed as-built drawings, an operation and maintenance manual, also signed, and verifiable evidence of the products installed, attached to the declaration. If the offer does not mention these deliverables, make them a condition of the final payment.

The builder is obliged to use products that meet the regulation and hold a product certificate. RETIE's table of covered products includes photovoltaic panels of 100 W or more, inverters, batteries, charge regulators, cables and conductors (with specific tests for cable used in renewable energy), connectors, surge protection devices and fuses, among others. For panels the regulation takes as reference standards such as IEC 61215 and IEC 61730, and for inverters IEC 62109-1, IEC 62109-2 and IEC 62116.

For each item, ask for the brand, the exact model, the certificate number and its validity, and check that the model quoted is the one certified. Certification bodies must register certificates in the SICERCO system, run by the Superintendence of Industry and Commerce. The mounting structure is treated differently: the regulation handles it as an installation requirement, which must take into account the weight and dimensions of the panel and not damage the building, and it requires the design to define access and walkways for assembly, inspection and maintenance, which the inspector checks physically. That is why the offer should include the structural report and the maintenance walkways.

It also helps to know what is not proof. Many proposals present their panels as “Tier 1”. That classification is produced by BloombergNEF, and its own methodology, in the version of 4 September 2026, says it measures a manufacturer's acceptance by banks: “Tier 1” makers are those that have supplied own-brand, own-manufacture products to six different projects financed non-recourse by six different commercial banks in the past two years. The document expressly recommends that buyers and banks do not use the list as a measure of quality, warns that it does not take product quality information into account and that there are documented examples of quality issues and bankruptcy among manufacturers on the list. It adds that only the list for the most recent quarter is valid, that only its clients can access it, and that a manufacturer's press release is not evidence of being on it.

There are three checks on the company that any buyer can make. The first is the Registro Único Empresarial y Social (RUES), where the chambers of commerce give free access to data such as the company name, tax ID (NIT), dates of registration and renewal, registration status, economic activity and the legal representatives with any limits on their power to contract. That last point matters: confirm that whoever signs the contract can bind the company for that amount.

The second is experience. Resolución CREG 174 de 2021, in the current text of its article 14, lists among the documents of the connection application a certificate of training or experience: the company in charge of the installation, or the installer, must certify at least one year of specific experience with the technology to be installed, or attach a certificate of staff training. It is the minimum for filing, not a measure of capability. Ask as well for three projects comparable to yours in size and roof type, with a contact you can call and, if possible, a visit.

The third is the Registro Único de Proponentes (RUP, the bidders' registry). Only those who want to contract with state entities register, so not having it says nothing bad about a private provider. If the provider has it, ask for the certificate: it is a good sign, because the chambers of commerce verify and certify in it contract experience and financial-capacity indicators such as liquidity, indebtedness and interest coverage.

Finally, ask who does each part. It is common for the provider that sells not to be the one that builds. Subcontracting is not a problem; not knowing to whom is: the licences, experience and certifications that count are those of whoever will actually be on your roof.

Connection is governed by Resolución CREG 174 de 2021, amended in 2025 and 2026. It regulates small-scale self-generation (AGPE), which goes up to 1 MW under Resolución UPME 281 de 2015, and the connection aspects of large-scale self-generators with a declared maximum power below 5 MW. When connection is through inverters, capacity is the sum of their nominal capacities on the alternating-current side.

Size changes the procedure. AGPE above 100 kW that export surplus, and large-scale self-generators with a declared maximum power below 5 MW, must submit a simplified connection study; it does not apply to those that export no surplus; nor to exporting AGPE of up to 100 kW, unless the voltage level 1 circuit fails the availability limits, in which case it is required as well. The study may be prepared by the applicant or by the grid operator, there are five months to produce it and the operator has twenty working days to review it. Protections and tests follow the agreements of the National Operation Council (CNO), which are updated often: as of October 2026 the ones in force are Acuerdo 2233 (protections) and Acuerdo 2229 (tests), both of 1 September 2026.

Three points of the rule protect the buyer. The application is made in the operator's online system and is free of charge. The operator may not ask for documents other than those the resolution lists. And approval expires: for an AGPE it lasts six months, extendable by three, and if the project does not enter operation with at least 90% of the assigned capacity, the operator releases the unused capacity. A provider that files early and builds late can leave the company without a connection point.

At low voltage there is one more limit. At voltage level 1, the combined power of all AGPE and distributed generators exporting on the same circuit must not exceed 50% of the capacity of the transformer feeding it; if it does, connection requires a simplified study and the applicant pays for the grid reinforcement works. The limit does not apply to those that export no surplus. A serious provider checks this before sizing, not after selling.

Responsibility for supplying the information lies with the user, even if the provider handles it. The offer should say who files, who answers the operator's observations, who pays for the connection study and the meter, and what happens to price and schedule if the operator asks for changes.

A rooftop plant is work at height. Resolución 4272 de 2021 of the Ministry of Labour defines it as any activity with a risk of falling more than 2.0 metres, and it applies to all contracting employers, contractors, apprentices and workers in every economic activity that involves work at height (article 2). It requires every exposed worker to hold a certificate of training or of occupational competence, every job to be covered by a permit to work, and a work-at-height coordinator to be in place.

The same resolution places on the employer the duty to verify that its contractors comply with it, including their occupational health and safety management system, and says the employer will be jointly and severally liable for accidents caused by its contractors' failure to implement those measures (article 61(k)). That article speaks only of the employer, although others mention the contracting party, and how far it reaches a company that merely contracts the works is debatable; the prudent course is to act as if it applied. Decreto 1072 de 2015 adds general duties: to include health and safety in the evaluation and selection of suppliers and contractors, to verify before the start and periodically their enrolment in the occupational risk system, and to inform the contractor of the hazards of the work area.

There is a labour risk as well. Article 34 of the Código Sustantivo del Trabajo (Labour Code), as worded by Ley 2466 de 2025, makes whoever contracts the works jointly and severally liable for the wages, benefits and compensation of the contractor's workers, unless the work is unrelated to the normal activities of its business, and allows the parties to agree the appropriate guarantees. Whether installing a solar plant is unrelated to a company's business is a case-by-case discussion, not a certainty.

In practice: ask for the work-at-height certificates of the staff who will come on site, the coordinator's name, proof of enrolment with the occupational risk insurer (ARL) and the result of the self-assessment against the minimum standards of the health and safety system. And ask how safe access for future maintenance will be provided, which RETIE requires the design to define.

Almost every offer carries an annual production figure. What sets a serious provider apart is saying where it comes from. A simulation gives a central value, the P50: the production that has a 50% probability of being exceeded in a year. The P90 is the value exceeded with 90% probability, and it is lower. The US National Renewable Energy Laboratory (NREL) explains that these exceedance probabilities are used to quantify the risk introduced by year-to-year variation in the solar resource.

There is a nuance worth knowing. The documentation of PVsyst, one of the most widely used simulation programs, warns that the P50–P90 calculation requires additional parameters that the simulation does not provide and that the user must specify, that is, assume. It follows that two providers can deliver a different P90 for the same design. Ask for the full simulation report, not just the figure: the source of the irradiation data, the assumed losses, the annual degradation and the uncertainties used.

A production guarantee is only useful if it can be measured. IEC 61724-1 deals with monitoring the performance of photovoltaic systems and defines classes of monitoring systems; IEC 62446-1 defines the documentation handed to the customer after installing a grid-connected system, and the commissioning tests and inspection criteria. Neither is mandatory under RETIE, but asking for handover and monitoring to follow them gives a written criterion. The contract should say which meter is used to verify production, how it is corrected for the year's actual irradiation, what is excluded and what the compensation is if the figure is not reached.

The Consumer Statute, Ley 1480 de 2011, treats as a consumer the natural or legal person who acquires a product as final recipient to meet a need of their own, private, family or domestic, and a business need when it is not intrinsically tied to their economic activity. The Superintendence of Industry and Commerce explained in a 2012 opinion that it is not possible to determine in advance whether a purchase creates a consumer relationship, and that the latter scenario is assessed case by case.

For a company installing a plant to supply its own operation, the prudent conclusion is not to take that protection for granted. What is not in the contract may not exist anywhere. Separate in writing four warranties that tend to be presented as one: the panel manufacturer's product warranty, the panels' performance warranty, the inverter warranty and the installation warranty, which is the provider's. For each, ask who is responsible in Colombia, who pays the labour and transport of a replacement, and within what time.

Insurance covers what a warranty cannot: the provider ceasing to exist or failing to perform. Between private parties it is freely agreed, but the catalogue in Decreto 1082 de 2015, which binds state entities, is a useful reference for naming the covers: proper handling of the advance payment, contract performance, payment of wages and benefits, stability and quality of the works, quality and correct functioning of the goods, and third-party liability, which under that regime must also cover authorised subcontractors, unless they show insurance of their own. The wages cover is the direct answer to joint labour liability, and the stability cover to deterioration of the works delivered; damage to the existing roof is best agreed separately.

If the project is going to claim the tax incentives, one point concerns the provider: Resolución UPME 135 de 2025 requires the product conformity certificates submitted to be valid when the application is filed. Ask the provider for the certificates and datasheets in time for that procedure.

These are the documents and answers to have from each provider before comparing prices. Almost all of them already exist if the provider works by the book.

None of these signs proves bad faith, but each one shows that the provider has not dealt with a part of the project that will have to be dealt with sooner or later.