How to Manage a 75 MW PV EPC Contract on NEC3 and Align Back to Back Supplier Agreements
A 75 MW PV plant at Lethabo Power Station is not a normal procurement exercise. At a project value of about R1.3 billion, small contract failures can become large commercial exposures very quickly. A late transformer, an unclear design interface, a missed compensation event notice, or a weak supplier programme can affect cash flow, energisation, grid compliance, and the relationship with Eskom.
NEC3 can work very well on a project of this nature, but only if it is actively managed. The contract is not designed to sit in a file until there is a dispute. It requires early warnings, current programmes, clear instructions, priced change, and disciplined communication.
For an EPC contractor employed by Eskom, the bigger challenge is that the main NEC3 contract must be managed together with the supply chain. The suppliers of high-value primary equipment, design, and engineering must carry obligations that support the EPC’s obligations to Eskom. If those agreements are not properly aligned, the EPC can end up holding the risk in the middle.
This article is written from a senior procurement and commercial management perspective. It is informational only and should not replace project-specific legal, technical, or commercial advice.
Treat NEC3 as a management system, not only a contract
The strength of NEC3 is that it creates a live management process. The weakness is that the process punishes poor administration. On a large PV EPC project, procurement, construction, engineering, planning, quality, and commercial teams must run NEC3 as one system.
The main contract with Eskom should be broken down into a practical control framework. At minimum, the EPC team should have:
A contract data summary that sets out the option, key dates, delay damages, payment terms, notice periods, and key Z clauses.
A responsibility matrix showing who issues, receives, drafts, approves, and prices each NEC3 communication.
A live risk register aligned to the Early Warning Register.
A compensation event tracker with dates, quotations, replies, assumptions, and implemented amounts.
A current Accepted Programme and a clear process for revisions.
A supply chain obligations matrix showing how Eskom obligations flow down to suppliers.
The project team should also be careful with language. NEC3 is built around defined terms. If the contract requires a communication to be in a specific form, through a specific system, or to a specific person, informal emails and site discussions may not be enough.
For procurement leaders, the key question is simple:
If Eskom issues an instruction or rejects a deliverable today, can the EPC recover the cost, time, and technical consequence from the responsible supplier without a gap?
If the answer is unclear, the back-to-back structure needs attention.
Start with the main EPC contract obligations
Before negotiating supplier agreements, the EPC must understand its own risk under the Eskom NEC3 contract. The team should not start with supplier templates. It should start with the main contract obligations and build the supply chain from there.
The main areas to map are:
Main EPC obligation | Why it matters for suppliers |
Completion and sectional completion dates | Supplier delivery dates must support access, installation, testing, and energisation milestones. |
Accepted Programme requirements | Supplier programmes must match the level of detail needed for NEC3 programme updates. |
Works Information | Technical specifications must flow down without weakening Eskom’s requirements. |
Defects obligations | Supplier warranties and defect correction periods must cover the EPC’s exposure. |
Compensation event procedure | Supplier notice and quotation periods must be shorter than the EPC’s periods under the main contract. |
Testing and commissioning | Suppliers must support factory tests, site tests, grid compliance, and performance evidence. |
Design responsibility | Design packages must align, especially between civil, electrical, SCADA, grid, and equipment interfaces. |
Documentation and records | As-built drawings, manuals, certificates, and quality packs must be delivered in time for takeover. |
This mapping should be done before purchase orders are placed. Once a supplier has commercial leverage because production slots are reserved or design has started, it becomes harder to correct weak contract terms.
On a 75 MW PV plant, high-risk packages usually include PV modules, inverters, transformers, switchgear, trackers or mounting structures, SCADA, protection systems, grid connection equipment, and design services. Each package needs its own risk profile. A module supply contract is not the same as an engineering design subcontract, and a transformer package is not the same as a cable supply agreement.
Build a proper back-to-back NEC3 structure
Back-to-back contracting does not mean copying the Eskom contract and pasting it into every supplier agreement. That approach often creates confusion. A supplier cannot take responsibility for obligations outside its scope. A better approach is to pass down the obligations that relate directly to the supplier’s work, while keeping the EPC’s coordination role clear.
For high-value equipment and engineering packages, the EPC should consider using NEC3 forms down the chain where appropriate, such as NEC3 Supply Contract, Supply Short Contract, Engineering and Construction Subcontract, or Professional Services Contract. The form should fit the scope and risk. A complex inverter and SCADA integration package may need a different approach from a simple material supply package.
The back-to-back agreement should deal clearly with the following.
Notice periods must protect the EPC
If the EPC has to notify Eskom of an early warning or compensation event within a defined period, the supplier must notify the EPC earlier. Internal review time is needed.
For example, if the main contract requires prompt notification, the supplier agreement should require notice as soon as the supplier becomes aware of the matter, with enough detail for the EPC to assess the impact. The supplier should not wait until delay is certain. Under NEC3, early warning is about matters that could affect cost, time, or performance.
A practical rule is to set supplier notice periods shorter than the EPC’s notice periods, with clear consequences for late notice where legally and commercially appropriate.
Programme obligations must be more than delivery dates
A supplier programme should not only show “manufacture” and “delivery”. It should show design submissions, approvals, procurement of long-lead components, factory acceptance testing, shipping, customs, delivery to site, installation support, commissioning support, defect correction, and documentation.
The EPC should require suppliers to submit programme updates in a format that can feed into the main Accepted Programme. This is critical where Eskom assesses delay or compensation events against programme logic.
A supplier delay is not only a procurement problem. It may affect civil access, electrical installation, commissioning sequence, grid connection, and completion.
Technical flow-down must be exact
The supplier must comply with the relevant parts of the Works Information, specifications, standards, grid requirements, site rules, quality requirements, and HSE obligations. These should be attached clearly to the supplier contract.
Avoid vague wording such as “supplier to comply with all main contract requirements”. That may be too broad to enforce and too unclear to manage. Instead, identify the documents and clauses that apply to the package.
For engineered equipment, the contract should also state design review requirements, approval hold points, document numbering, language, software formats, and responsibility for design errors.
Liability must match the risk profile
Back-to-back does not always mean identical liability caps. Some suppliers may refuse unlimited exposure, especially for imported primary equipment. The EPC must decide where it can accept a gap and where it cannot.
For critical equipment, consider:
Delay damages or liquidated damages linked to late delivery or late commissioning support.
Performance guarantees where output, availability, losses, or efficiency are part of the package.
Defect correction obligations that continue long enough to protect the EPC under the main contract.
Insurance requirements for transit, storage, installation support, and professional services.
Parent company guarantees, advance payment guarantees, or performance security where justified.
The commercial aim is not to push every risk down at any cost. The aim is to place risk with the party best able to manage it, while protecting the EPC from unmanaged exposure.
Use early warnings as a commercial tool
Early warnings are often treated as bad news. On NEC3 projects, they are a management tool. A strong EPC team encourages early warnings from internal functions and suppliers because they create a record of risk management.
For the Lethabo PV project, early warnings might include:
Delayed design approvals affecting procurement release.
Late factory acceptance testing slots for transformers or inverters.
Port, transport, or abnormal load risks.
Interface issues between inverter controls and SCADA.
Cable route clashes or geotechnical conditions.
Grid compliance test concerns.
Delayed permits, access constraints, or outage windows.
Each early warning should lead to a practical risk reduction discussion. The outcome should be recorded. Who owns the action? What date is required? What is the likely cost or time effect? Does the matter create a compensation event under the main contract? Does it create a claim against a supplier?
The Early Warning Register should also connect to procurement expediting. If the supplier indicates a production or shipping issue, that should not sit only with the buyer. It should move into the NEC3 risk process, because it may affect the Accepted Programme and the EPC’s position with Eskom.
Manage compensation events with discipline
Compensation events are where many NEC3 projects lose money. The process is strict, and records matter. On a R1.3 billion EPC project, every potential change should be assessed quickly.
A good process includes five controls.
Identify the event
The team should decide whether the matter is an Eskom instruction, a change to Works Information, a site condition issue, a delay by Eskom, a design change, or another event listed in the contract. Do not call everything a compensation event without analysis.
Notify on time
The EPC must protect its rights under the main contract. Supplier contracts must force early notification so the EPC is not left out of time.
Price with evidence
Quotation files should include supplier quotes, labour and plant records, programme impact, design hours, material price changes, and assumptions. Where a supplier caused the issue, the EPC should preserve recovery rights.
Assess time properly
Time impact should be assessed against the Accepted Programme. A late item only creates completion delay if it affects the critical path or a contractual key date. The planning team must be involved from the start.
Close the loop
Once a compensation event is implemented, update the budget, programme, procurement plan, and supplier recovery tracker. Do not leave implemented changes sitting outside the financial forecast.
For senior procurement, the key is to link each main contract compensation event to supplier responsibility. Some events will be employer risk. Some will be EPC risk. Some will be supplier risk. The contract team needs a clear view of who pays.
Control design and engineering interfaces
PV projects appear modular, but the design interfaces can be complex. The EPC may procure modules from one supplier, inverters from another, transformers from another, SCADA from another, and engineering design from one or more consultants. The risk sits in the gaps between them.
The EPC should establish a design responsibility matrix early. It should show who is responsible for each design output, who reviews it, who approves it, and who carries the risk if it is wrong.
Key interfaces include:
Module string sizing and inverter compatibility.
DC cabling, combiner boxes, and protection philosophy.
Inverter output and transformer sizing.
Earthing and lightning protection.
SCADA, data acquisition, and plant control.
Grid code compliance and protection studies.
Civil foundations for mounting structures and equipment.
Drainage, roads, and access for heavy equipment.
Fire safety, security, and operations access.
Supplier contracts should state that approval or review by the EPC, Eskom, or another party does not relieve the supplier of its design responsibility, unless the main contract says otherwise and the EPC has accepted that risk.
Design deliverables also need dates. Late drawings can delay manufacture, installation, and commissioning. A design subcontract without proper programme obligations can create serious downstream delay.
Protect cash flow through payment alignment
Large EPC projects can suffer when the main contract payment mechanism and supplier payment terms do not match. The EPC may have to pay suppliers before it receives payment from Eskom, especially for imported equipment with advance payments, production milestones, or shipping milestones.
Procurement should model cash flow by package before award. The model should compare supplier payment milestones to the EPC’s payment milestones under the main NEC3 contract.
Where possible, supplier payments should be linked to objective deliverables:
Approved drawings.
Factory acceptance test completion.
Delivery to site.
Complete quality documentation.
Installation supervision completed.
Commissioning support completed.
Defects resolved.
For expensive equipment, advance payments may be unavoidable. In those cases, security is important. The EPC should consider advance payment guarantees, vesting certificates, proof of insurance, inspection rights, and clear title transfer provisions.
Payment alignment should also address deductions, set-off rights, defects, rejected goods, and missing documents. A supplier that delivers equipment without the required test certificates, manuals, or compliance documents has not fully delivered the value needed by the EPC.
Make quality documentation a contractual deliverable
On utility-scale PV projects, quality records are not paperwork after the fact. They are part of completion. Missing factory test records, calibration certificates, material certificates, inspection reports, as-built drawings, and operations manuals can delay takeover and payment.
Supplier agreements should define the required quality documentation in detail. The contract should also allow the EPC to withhold payment or reject delivery if key documents are missing.
For imported primary equipment, inspect before shipment where the risk justifies it. Factory acceptance tests should be witnessed or reviewed according to the inspection and test plan. Non-conformances must be logged, closed, and linked to delivery release.
A strong quality process protects the EPC in three ways. It reduces defects, supports payment applications, and creates evidence if a dispute arises.
Keep governance tight from award to completion
The contract management system should be simple enough to use weekly and strong enough to defend in a dispute. For a project of this value, governance should not rely on individual memory.
A practical rhythm could include:
Weekly NEC3 commercial review covering notices, early warnings, compensation events, and instructions.
Weekly procurement expediting review for long-lead and critical packages.
Fortnightly programme review linking supplier updates to the Accepted Programme.
Monthly executive risk review covering Eskom issues, supplier claims, cash flow, and major exposures.
Formal correspondence audits to check that communications comply with the contract.
The EPC should also maintain a clear separation between negotiation and entitlement. Good relationships matter, but they do not replace notices, records, and contract compliance.
What good contract management looks like
A well-managed NEC3 EPC contract is visible. The team knows the current programme. The risk register is alive. Supplier delays are reported early. Compensation events are priced with evidence. Design interfaces are owned. Quality records arrive before they are needed. Payment claims are supported. Eskom receives clear, timely communication.
The best time to create this system is before supplier award. The second-best time is now.
For a 75 MW PV plant at Lethabo Power Station, the EPC sits at the centre of a high-value chain of obligations. Eskom will look to the EPC for delivery. The EPC must then make sure that its suppliers, designers, and engineers are contractually and practically aligned to that same delivery promise.
NEC3 gives the tools to manage that promise. Procurement’s role is to make sure those tools run all the way through the supply chain, without gaps where the biggest risks sit.
Best Regards,
Lukas.
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