Solar Drafting Services Portugal: UPAC & DGEG

Last updated: November 2026

Portugal’s installed solar capacity was 6.81 GW in 2025 and is forecast to reach 20.65 GW by 2031, according to Mordor Intelligence’s Portugal solar market report (page dated July 2026). Every one of those systems needed drawings before it could be registered and connected.

For Portuguese solar professionals, the question is not whether to produce technical documentation. It is whether to hire a drafting service, buy PV design software, or combine both. This guide lays out what drafting services deliver, which Portuguese rules shape the drawings, what drives cost, and how to decide. SurgePV publishes this post and sells solar design software, and the author’s company, Heaven Green Energy, is an EPC.

What Are Solar Drafting Services in Portugal?

Solar drafting services in Portugal are technical providers, usually an electrical engineer, technical drafter or CAD designer, who produce the drawings and documents needed to permit, finance and connect a photovoltaic system to the Portuguese grid.

These services sit between the sales conversation and the installation. Once a customer agrees to a project, the EPC or installer needs a plan set that shows the system is safe, compliant and viable. That plan set is what drafting services produce.

Who Provides Solar Drafting in Portugal

Providers fall into four broad groups:

1. Independent technical studios. Small firms that serve several EPCs on a per-project basis.
2. EPC in-house design teams. Larger EPCs employ their own drafters for everything from rooftops to ground mounts.
3. Freelance drafters. Individuals found through engineering marketplaces or general freelance platforms. Quality control is the buyer’s job.
4. Software-enabled design services. Providers that combine automated layout tools with human review for complex projects.

What Makes Portuguese Solar Drafting Different

Three factors separate Portuguese work from generic CAD:

UPAC rules shape the paperwork. Self-consumption systems follow the UPAC regime under Decree-Law 162/2019. The documentation must show capacity, connection type, self-consumption assumptions and surplus arrangements. A drafter who has only worked in another country’s regime will miss details the regulator expects.

RTIEBT governs low-voltage electrical design. RTIEBT is the Portuguese technical regulation for low-voltage electrical installations. Single-line diagrams, protection and cable sizing must follow it, and the distributor can return non-compliant drawings.

VAT changed the economics. Portugal’s reduced 6% VAT rate for residential solar equipment was scheduled to expire in mid-2025 and return to the standard 23%, per The Portugal News. Parliament later considered a bill to remove the sunset date, so check the rate in force before you build a customer proposal.

Why Does Solar Drafting Matter in Portugal’s 2026 Market?

Drafting matters because paperwork, not installation, is often the slowest step. Faster, cleaner documentation moves a project through registration and grid connection sooner.

Mordor Intelligence reports Portuguese installed solar capacity of 6.81 GW in 2025 and 8.19 GW in 2026, with a forecast of 20.65 GW in 2031, a 20.31% compound annual growth rate for 2026 to 2031. It lists residential as the fastest-growing segment at a 24.30% CAGR, and utility-scale at 84.50% of installed capacity in 2025.

The Bottleneck Is Often Paperwork

An installer can often fit a residential rooftop into a day or two. Registration with the regulator, grid-operator review and any municipal permit sit on the critical path, so a drawing returned for revision delays everything downstream. Ask providers for written lead times and revision policies instead of assuming a standard turnaround.

Commercial and Industrial Projects Add Deliverables

Commercial and industrial (C&I) projects are more complex than residential ones. They often involve:

• Multiple roof planes with different tilts and orientations
• Structural calculations for buildings with non-standard load capacity
• Connection studies for larger systems
• Battery storage integration for peak shaving and self-consumption
• Yield reports for financing

Each item adds to the drafting scope. A simple layout is no longer enough, so C&I teams need a drafting partner who can produce a full engineering package, or a platform that combines drawings with financial modeling and customer-ready solar proposals.

Utility-Scale Projects Need Specialists

Projects above 1 MW typically need civil and geotechnical drawings, substation design, environmental documentation, yield simulations and grid-connection studies. No single software platform covers all of it. Utility-scale teams usually combine software for early layout and yield work with specialist engineering firms for civil and electrical design. For commercial solar projects at the smaller end of this range, software can cover design and financial modeling while engineers handle structural and medium-voltage work.

Which Portuguese Regulations Shape Solar Drafting?

Four regimes shape most Portuguese solar drawings: the UPAC self-consumption rules, RTIEBT, the distributor’s connection rules and municipal or environmental requirements. Rules change, so check each against the regulator’s current text before you submit.

UPAC: The Self-Consumption Framework

Decree-Law 162/2019 created the UPAC framework, partly transposing EU Directive 2018/2001. Later decree-laws amended it. The control regime depends on installed capacity. Consumer guidance such as Goldenergy’s self-consumption registration guide summarizes it as follows.

This table is a consumer-guide summary, not legal text. The exemption thresholds for very small systems have differed between sources and decree versions, so check the current rules on the DGEG website before you choose a procedure.

RTIEBT: Electrical Installation Rules

RTIEBT sets the technical rules for low-voltage installations in Portugal. For solar drafters the practical impact is:

• Protection devices must be correctly sized and coordinated
• SLDs must show the main switch, breakers, surge protection and inverter connections
• Cable sizing must account for voltage drop and current-carrying capacity
• Earthing and bonding must be documented

Read the current regulation text, since this post is not a substitute for it.

DGEG and E-REDES

DGEG (Direção-Geral de Energia e Geologia) is the national energy authority that runs the self-consumption registration process. E-REDES is the main electricity distribution operator and handles grid-connection questions for systems on its network. For larger projects connected to the transmission network, REN coordinates. Confirm with the operator which documents it wants for your project type.

Municipal and Environmental Rules

Building permits fall under municipal jurisdiction, and larger ground-mounted projects can trigger construction licensing and environmental assessment. Thresholds and timelines vary by location and project size. Ask the municipality and the environmental authority early, and put their requirements in the drafting brief.

What Do Solar Drafting Services Deliver in Portugal?

Deliverables scale with project size and complexity. The three tiers below describe typical scope, not fixed prices.

Tier 1: Basic Residential Package

This tier suits most small residential systems and is the segment where repeatable, fast documentation matters most.

Tier 2: Commercial and Industrial Package

Many C&I projects fall in the range where registration rather than simple communication applies, so the package must be more complete than a residential plan set.

Tier 3: Utility-Scale Engineering Package

Engineering firms usually handle this tier rather than standalone drafting services.

What Drives Solar Drafting Costs in Portugal?

Costs depend on scope, complexity, turnaround and provider location. Published price lists are rare, so obtain written quotes for the same scope from at least two providers.

Compare total cost rather than hourly rate. A cheap draft that needs three revisions can cost more than a pricier one approved first time.

Manual Drafting or Solar Design Software?

The choice is not binary. Most EPCs use both.

When Manual Drafting Wins

• Utility-scale projects need civil, geotechnical and medium-voltage engineering that software does not fully automate.
• Custom structural work on older buildings with non-standard roofs needs engineer review.
• First-of-a-kind projects, such as floating solar or agrivoltaic pilots, need bespoke documentation.
• Lender or authority requirements may specify drawings signed by a registered engineer.

When Software Wins

• Small residential projects are repeatable, so software can produce layout and yield output quickly.
• Commercial rooftops benefit from automated shading analysis and financial modeling.
• High-volume installers need consistent output without a large drafting team.

SurgePV’s published scope covers 3D roof modeling, solar array layout, shading analysis, energy-yield and financial modeling, electrical workflow support, bill-of-materials output and proposal generation. SurgePV does not publish Portugal-specific outputs such as RTIEBT-formatted diagrams or UPAC submission forms, so ask for a demonstration with your own project before assuming a tool produces the documents Portuguese authorities expect. Outputs support design and documentation workflows but do not replace approval by the responsible engineer, authority or utility.

The Hybrid Model

A practical split is software for repeatable residential and small commercial work, and drafting studios or engineering firms for complex projects. This keeps per-project effort low while leaving room for larger or unusual work. Set the split from your own project mix, not from a generic percentage.

How Do You Choose a Solar Drafting Service in Portugal?

Choose on regulatory knowledge, sample quality, turnaround and total cost.

Verify Regulatory Knowledge

Ask specific questions:

• Can you produce single-line diagrams that follow RTIEBT?
• Do you know the registration route for my system size?
• Have you worked with E-REDES connection documentation?
• Can you model the Portuguese tariff options my customer is on?

A provider who knows only generic solar CAD will create delays at registration.

Check Deliverable Quality

Request a sample plan set. Look for:

• A clear panel layout with dimensions and orientation
• A complete single-line diagram with all protection devices
• An equipment schedule with manufacturer part numbers
• Wire sizing calculations
• Structural notes for rooftop systems

Evaluate Turnaround and Communication

Ask what the standard turnaround is for your project type, whether expedited delivery exists, how revisions are handled, and what working hours and languages the provider covers.

Compare Total Cost, Not Hourly Rate

Factor in revision cycles, registration delays and the time your team spends managing the provider.

Key Portuguese Solar Market Data

Source: Mordor Intelligence, Portugal Solar Energy Market, page dated July 2026. These are one research firm’s estimates, not official statistics.

Which Software Tools Do Portuguese Drafters Use?

Portuguese drafters and EPCs use a mix of general CAD, specialist yield simulation and all-in-one design platforms.

The trend is toward fewer tools and fewer file handoffs, because every handoff is a chance for the layout, the single-line diagram and the proposal to drift apart. See PVsyst for one example of a dedicated yield-simulation tool.

What Are the Most Common Drafting Mistakes in Portugal?

Most delays trace back to a short list of mistakes.

Wrong UPAC Category

A system designed to sit under one capacity threshold may fall into a heavier registration route once inverter capacity or the connection arrangement is counted. Verify the exact category before submitting.

Ignoring Tariff Structure

Portuguese customers can be on simple, two-period or three-period tariffs. A design that ignores time-of-use rates produces inaccurate savings figures.

Undersized Conduit or Cable

RTIEBT sets requirements for voltage drop and current-carrying capacity. Undersized cables are a common reason for returned documents.

Missing Export Limitation

Some grid operators or municipalities require export limitation. The single-line diagram must show the control device and its settings.

Outdated VAT or Incentive Assumptions

Proposals that still assume the old 6% VAT rate create pricing disputes. Check the rate and any incentive eligibility rules before you quote.

Conclusion: Build the Right Drafting Stack for Portugal

The bottleneck in Portuguese solar is often the design, documentation and registration work that must happen before panels go on the roof. A hybrid stack suits most installers and EPCs:

• Use solar design software for repeatable residential and small commercial projects.
• Use drafting services or engineering firms for utility-scale, custom structural or medium-voltage work.
• Check that every provider knows UPAC, RTIEBT, DGEG and E-REDES requirements.

To see how SurgePV handles layout, shading and proposals on a Portuguese project of your own, book a demo. For the incentive side, read the guide to solar incentives in Portugal.

Frequently Asked Questions

What are solar drafting services in Portugal?

Solar drafting services in Portugal are technical providers that create electrical drawings, single-line diagrams (SLDs), layout plans and registration documentation for photovoltaic installations. They are typically staffed by electrical engineers or technical drafters who know RTIEBT rules, UPAC registration and E-REDES connection practice.

How much do solar drafting services cost in Portugal?

No single published price list exists, so get written quotes. Cost depends on project size, deliverables such as structural calculations or yield reports, turnaround and revision rounds. A cheap draft that needs several revisions can cost more than a pricier one approved first time.

What is UPAC and why does it matter for solar drafting?

UPAC (Unidade de Produção para Autoconsumo) is Portugal’s self-consumption production unit regime, set up by Decree-Law 162/2019. Registration steps depend on installed capacity, so the drawings must state capacity, connection type and surplus arrangements accurately. Check the current DGEG rules for your system size.

Can solar design software replace manual drafting services in Portugal?

For repeatable residential and small commercial plans, design software can replace much of the manual work. Utility-scale projects, custom civil work and medium-voltage studies still need engineers. Check whether a tool produces the specific Portuguese documents you must submit before relying on it.

What deliverables should I expect from a Portuguese solar drafting service?

Expect a site or roof layout plan, a single-line diagram, a stringing configuration, an equipment schedule and support for the registration submission. Larger projects add structural calculations, protection studies, cable sizing and a yield report. Agree the list in writing before work starts.

How long does solar drafting take in Portugal?

Turnaround depends on project size and complexity, so ask each provider for a written lead time. A simple residential plan set is quicker than a commercial package with structural calculations. Revisions requested by the grid operator or registration portal add time.

What is the difference between solar drafting and solar design software?

Solar drafting services produce drawings for a per-project fee, while design software automates layout, shading, electrical design and financial modeling through a subscription. SurgePV publishes its scope as 3D roof modeling, array layout, shading analysis, energy-yield and financial modeling, electrical workflow support, bill of materials and proposals.