Supply-Only vs Turnkey Solar Carports: Which Model Suits Your Project?
- Keith Lin
- Mar 24
- 5 min read
Updated: Apr 9
Last updated: 24 March 2026
If you are procuring a commercial solar carport in the UK, one of the first decisions you will face is whether to buy a supply-only frame kit or commission a full turnkey installation. Supply-only means you receive an EN 1090-1 certified structural frame kit with engineering documentation, and your own EPC contractor handles installation. Turnkey means a single company delivers everything — design, structure, panels, electrical, grid connection, and commissioning.
The Two Models Explained
Supply-Only (Frame Kit Model)
In the supply-only model, the frame kit manufacturer designs and fabricates the structural steel carport frame, then delivers it to your UK site on a DDP (Delivered Duty Paid) basis. The package typically includes: hot-dip galvanised structural steel frame (columns, rafters, purlins, bracing), full structural engineering calculations by a chartered engineer, general arrangement and fabrication drawings, EN 1090-1 Declaration of Performance (CE/UKCA marked), material certificates (EN 10204 Type 3.1), and an installation guide with torque specifications.
The buyer — typically an EPC contractor, commercial installer, or facilities management team — is then responsible for foundations, erection, PV panel installation, electrical works, and grid connection.
KLY Solar operates exclusively on this model.
Turnkey (Full-Service Model)
In the turnkey model, a single contractor manages the entire project from feasibility study through to grid connection and commissioning. The buyer receives a completed, operational solar carport with a single point of responsibility.
Turnkey providers in the UK market include Solspan UK, SolarSense UK, EvoEnergy, and RenEnergy UK, among others. Most turnkey providers manufacture or source their own frames, install their own panel and electrical systems, and manage the DNO application and grid connection.
Comparison Table
Cost per kWp: Supply-Only £600–£900 (frame only) vs Turnkey £900–£1,400+ (complete system)
Project control: Supply-Only — Full (you choose installer, panels, inverters) vs Turnkey — Limited (provider selects components)
Lead time (frame): Supply-Only 6–10 weeks vs Turnkey 12–20 weeks (full project)
Structural certification: Supply-Only — EN 1090-1 DoP with engineering pack vs Turnkey — Varies (ask for documentation)
Warranty (structure): Supply-Only 25 years (KLY Solar) vs Turnkey 10–25 years (varies)
Panel/inverter choice: Supply-Only — Your selection vs Turnkey — Provider's selection
Suitability: Supply-Only — EPCs, experienced installers, multi-site rollouts vs Turnkey — End-users wanting hands-off deliveryWhen Supply-Only Is the Better Choice
You Have an Existing EPC or Installer Relationship
If you already work with a trusted solar installer or EPC contractor, supply-only lets you keep that relationship. Your installer knows your site, your electrical infrastructure, and your operational requirements. Adding a new turnkey provider introduces a new relationship with new risks.
You Want to Control Component Selection
In a turnkey contract, the provider selects the PV panels, inverters, cabling, and mounting hardware. You may have preferences — a specific panel manufacturer for warranty reasons, a particular inverter brand for compatibility with your BMS, or a cable routing approach that suits your site layout. Supply-only gives you that control.
You Are Rolling Out Across Multiple Sites
For multi-site commercial portfolios (e.g., retail chains, logistics operators, fleet depots), supply-only is significantly more cost-effective. You standardise the frame design, procure in volume, and deploy your installation team across sites. Turnkey pricing per site does not typically offer the same economies of scale.
You Want Competitive Pricing on the Structure
Because supply-only manufacturers focus exclusively on the frame (not the full system), they can offer lower structural costs. KLY Solar's supply-only pricing for the frame kit is typically 30–40% less than the structural component cost embedded in a turnkey quote — because there is no markup from a turnkey margin on the steelwork.
Your Project Requires a Specific EPC Scope Split
Some large commercial projects have contractual requirements for scope separation — the structural frame as one package, the electrical installation as another. This is common in public sector procurement, corporate ESG programmes, and PPA-funded projects where the funder requires distinct responsibilities.
When Turnkey Is the Better Choice
You Have No Installation Capability
If you are an end-user (e.g., a facilities manager, property developer, or business owner) without access to an EPC contractor, turnkey is simpler. You sign one contract, deal with one company, and receive a working system.
You Want a Single Point of Responsibility
Turnkey provides contractual simplicity. If something goes wrong — structural, electrical, or performance-related — there is one party to hold accountable. In a supply-only model, responsibility is split between the frame supplier and the installer, which requires clear contractual boundaries.
You Need Help with Grid Connection and DNO
For smaller projects without dedicated energy procurement teams, the DNO application and grid connection process can be complex. Turnkey providers manage this as part of their standard scope.
Your Project Is a One-Off
For a single site with no intention to replicate, the convenience of turnkey may outweigh the cost premium. The project management overhead of coordinating a supply-only frame with a separate installer may not be justified for a one-off project.The Cost Difference
The cost gap between supply-only and turnkey is primarily driven by three factors: margin stacking (turnkey providers apply a project management margin on top of every component cost), component selection (turnkey providers select components for their standard system, which may not be the lowest-cost option), and overhead allocation (turnkey providers carry larger overheads recovered through project pricing).
For a typical 50-bay commercial solar carport (approximately 150 kWp):
Supply-Only Route: Structural frame kit £90,000–£135,000 + Foundations £20,000–£35,000 + PV panels + inverters £45,000–£60,000 + Electrical installation £15,000–£25,000 + Grid connection £5,000–£15,000 = Total £175,000–£270,000
Turnkey Route: Complete system Total £210,000–£350,000
These are indicative ranges. Actual costs depend on site conditions, panel specifications, grid connection requirements, and regional labour rates. The Annual Investment Allowance (AIA) of £1 million means the full capital cost qualifies for 100% first-year tax relief for most UK businesses.
Making the Decision
The right model depends on your capabilities, your project pipeline, and your commercial objectives:
Choose supply-only if you are an EPC, installer, or experienced project team seeking cost efficiency, component control, and scalability across multiple sites.
Choose turnkey if you are an end-user seeking simplicity, a single point of responsibility, and no installation capability of your own.
Neither model is inherently superior. The question is which one aligns with how you operate.
Looking for a supply-only solar carport frame kit? View our solar carport systems
About the Author
Keith Lin is the Director of KLY Solar (KLY Global Ltd), a UK supplier of solar carport structure kits for commercial project teams.
Sources cited in this article:
KLY GLOBAL LTD trading as KLY Solar | Company No. 14169672
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