Project Execution Models: Choosing the Right Delivery Strategy

Choosing the right execution model is one of the most consequential decisions in the project lifecycle. It shapes how cost, schedule, quality and risk are distributed between owner and contractor. This reference summarises the principal project execution strategies, where each sits on the owner-control spectrum, the trade-offs each one carries, and the kinds of buildings and facilities each is best suited to.

Execution Models at a Glance

Model	Owner's Control	Primary Risk Holder	Best Suited For
EPC	Moderate to Low	Contractor	Well-defined process plants wanting single-point delivery
LSTK	Low	Contractor	Straightforward, fully scopeable facilities
EPCM + Implementation	High	Owner	Large, complex multi-package projects
Design-Build	Moderate	Contractor	Time-sensitive commercial and civic buildings
CMAR	High	Owner (GMP-capped)	Complex owner-led buildings needing cost certainty
BOT	Very Low → High	Contractor, then Owner	Revenue-generating infrastructure with financing needs
PPP	Low to Moderate	Shared	Public infrastructure with private participation
IPD	High	Shared	Collaborative, innovation-driven buildings

The Owner-Control Spectrum

Every execution model trades owner control against risk transfer and delivery speed. The spectrum below orders the models from lowest to highest owner influence:

Models on the left push execution risk onto the contractor in exchange for lower owner involvement and more predictable cost. Models on the right keep the owner in command but demand stronger in-house capability and greater exposure to cost and schedule risk.

1. EPC (Engineering, Procurement, and Construction)

Owner's Control: Moderate to Low. The owner delegates significant responsibilities to the EPC contractor, who oversees engineering, procurement and construction and delivers the project as a complete package. The owner's role is limited to high-level oversight and decision-making at key milestones.

EPC is the dominant delivery model for large, technically complex process facilities. The contractor is typically selected after a defined scope and is held to a lump-sum or target-price arrangement. Because the contractor owns design and execution, the owner's leverage narrows sharply after contract award — so front-end definition and contractor selection are disproportionately important to the final outcome.

Characteristics

• Contractor takes full responsibility for design, procurement and construction.
• Risk is largely transferred to the contractor.
• Limited owner involvement in daily decision-making.

Advantages

• Simplifies management for the owner.
• Fixed-price contracts are common, minimising cost uncertainty.

Challenges

• Less flexibility to influence design or execution once the contract is signed.
• Potential misalignment of priorities between owner and contractor.

Example Applications

• Oil & gas refineries and petrochemical complexes
• LNG liquefaction and regasification terminals
• Combined-cycle and thermal power stations
• Large-scale water and wastewater treatment plants
• Cement, steel and minerals processing plants

2. LSTK (Lump Sum Turnkey)

Owner's Control: Low. The contractor delivers the project ready for operation, transferring nearly all execution responsibilities. The owner's role is limited to defining upfront requirements and performing acceptance testing at completion.

LSTK is the most price-certain variant of EPC. The contractor warrants a fully commissioned facility for a single lump sum, accepting both scope and execution risk. It suits projects where the scope is fully defined up front and the owner values cost certainty over the ability to influence execution; poorly defined scopes tend to generate claims and change orders that erode the lump-sum benefit.

Characteristics

• Contractor manages the entire project, from design to commissioning.
• Minimal owner involvement during execution.
• Lump sum payment reduces cost risk for the owner.

Advantages

• Predictable project costs.
• Ideal for straightforward, well-defined projects.

Challenges

• Minimal ability to influence execution once started.
• High dependency on the contractor's expertise and execution quality.

Example Applications

• Standardised gas processing and compression plants
• Cogeneration and captive power plants
• Mid-size refineries and gas-to-liquids units
• Modular industrial facilities and packaged plants
• Desalination and utility plants with fixed output specifications

3. EPCM (Engineering, Procurement, and Construction Management) & Implementation Contractor

Owner's Control: High. The EPCM contractor provides project management services (engineering and procurement), while construction is managed by separate implementation contractors. The owner retains decision-making authority throughout.

EPCM keeps the owner as the central decision-maker. The EPCM consultant manages engineering and procurement on the owner's behalf, while separate construction or implementation contractors build discrete work packages. This multi-contract structure maximises flexibility and control but places coordination, interface and risk management firmly with the owner, who needs strong in-house capability to manage the package structure effectively.

Characteristics

• Owner retains authority over procurement, contracting and construction strategy.
• EPCM contractor acts as advisor and coordinator, not single-point executor.
• Multiple contracts managed by the owner with different suppliers and contractors.

Advantages

• Flexibility to make changes and align with evolving project needs.
• Greater influence on technical and commercial aspects.

Challenges

• Requires strong in-house expertise and resources.
• Owner assumes more risk for cost overruns and schedule delays.
• Higher complexity in managing multiple contracts and interfaces.

Example Applications

• Integrated offshore and onshore oil & gas field developments
• Mega-refinery and petrochemical complexes with multiple packages
• Energy transition, hydrogen and CCS projects
• Brownfield revamps and plant integration programmes
• Large multi-package infrastructure with evolving scope

4. Design-Build (DB)

Owner's Control: Moderate. A single contractor handles both design and construction under one contract, offering single-point responsibility with more owner involvement than EPC.

Design-Build collapses design and construction into a single contract, enabling construction to start before design is fully complete. The owner sets performance requirements and reviews key design milestones, but the contractor controls the means and methods. This suits buildings where schedule and single-point accountability outweigh fine design control.

Characteristics

• Design and construction combined into one contract.
• Owner provides performance requirements and approves design stages.

Advantages

• Faster delivery through overlap of design and construction phases.
• Simplified contract structure with fewer disputes.

Challenges

• Reduced ability to influence design decisions compared to EPCM.
• Contractors may optimise for cost rather than the owner's long-term needs.

Example Applications

• Commercial office buildings and corporate headquarters
• Hospitals and healthcare facilities with fast-track delivery
• Schools, universities and educational campuses
• Industrial and warehouse buildings
• Hotels, residential and mixed-use developments

5. Construction Management at Risk (CMAR)

Owner's Control: High. A Construction Manager (CM) oversees the project, providing input during design and managing construction under a Guaranteed Maximum Price (GMP).

CMAR brings the construction manager in during design as a consultant, then converts to a builder under a Guaranteed Maximum Price. Early constructability input and GMP cost certainty make it well suited to complex, owner-led buildings where both design quality and budget control matter.

Characteristics

• The CM acts as a partner to the owner, balancing risk and oversight.
• Separate contracts for design and construction.

Advantages

• Owner retains significant control over design and construction.
• Early CM involvement reduces risks and optimises constructability.

Challenges

• Requires active owner involvement.
• Risk of GMP exceeding initial estimates if poorly managed.

Example Applications

• Hospitals and medical centres
• University campuses and research buildings
• Civic, government and cultural buildings
• Complex renovations and retrofits of operating facilities
• Mixed-use developments with shared infrastructure

6. Build-Operate-Transfer (BOT)

Owner's Control: Very Low initially, High post-handover. The contractor finances, builds and operates the facility for a defined period before transferring it to the owner.

BOT structures private financing, construction and operation into a single concession that reverts to the owner after a defined period (often 20-30 years). The concessionaire recovers its investment through operations, tolls or offtake, making BOT attractive for projects that generate revenue and need upfront capital off the owner's balance sheet.

Characteristics

• Suitable for large-scale infrastructure or industrial projects.
• Contractor responsible for financing and operational performance.

Advantages

• Minimises upfront capital investment by the owner.
• Contractor bears performance and operational risks during the initial phase.

Challenges

• Limited owner input during design and construction.
• Long-term contracts can be complex and difficult to renegotiate.

Example Applications

• Independent power plants (IPPs) and cogeneration facilities
• Toll roads, bridges and transport infrastructure
• Desalination and water treatment concessions
• Ports, terminals and logistics hubs
• Waste-to-energy and district energy systems

7. Public-Private Partnership (PPP)

Owner's Control: Low to Moderate. A partnership between public and private entities, where the private partner finances, builds and operates the project for a concession period.

PPPs share risk between a public owner and a private partner across design, build, finance and operate over a long concession. Unlike BOT, PPP emphasises risk allocation and service outcomes rather than a single asset transfer. They are most common where public capital is constrained and private delivery can improve efficiency.

Characteristics

• Often used for infrastructure such as roads, bridges or utilities.
• Risk-sharing agreement between the public owner and private entity.

Advantages

• Reduces the public sector's financial burden.
• Encourages efficiency through private sector participation.

Challenges

• Owner's control is constrained by contractual agreements.
• Requires robust contract management to protect public interest.

Example Applications

• Roads, bridges and highway networks
• Hospitals and healthcare facilities
• Schools and public education buildings
• Transit systems, rail and metro lines
• Utility and water infrastructure

8. Integrated Project Delivery (IPD)

Owner's Control: High. IPD fosters collaboration among owner, designer and contractor through shared incentives and integrated processes.

IPD binds owner, designer and key contractors under a single multi-party agreement with shared risk and reward. It is built on transparency, early involvement and target value design. IPD works best where all parties are aligned culturally and the project rewards collaboration and innovation over lowest price.

Characteristics

• All parties sign a single contract and share risks and rewards.
• Promotes transparency and trust among stakeholders.

Advantages

• Encourages innovation and collaborative problem-solving.
• Highly flexible and aligned with the owner's goals.

Challenges

• Complex to implement; requires cultural alignment among parties.
• Demands a high degree of owner involvement and expertise.

Example Applications

• Healthcare facilities and hospitals
• Research laboratories and innovation centres
• Corporate campuses and headquarters
• Complex technical buildings with many interfaces
• Sustainability-led and net-zero buildings

Key Takeaways

• There is no universally "best" model — selection depends on project complexity, owner capability, schedule pressure and risk appetite.
• Fixed-price models (EPC, LSTK) simplify management but reduce the owner's ability to influence execution once signed.
• Management models (EPCM, CMAR) maximise owner control but require strong in-house resources.
• Collaborative models (IPD, PPP) share risk and reward but demand cultural alignment and robust contract management.
• Match the model to the project: well-defined process scopes favour LSTK/EPC; evolving, complex scopes favour EPCM; commercial and civic buildings favour Design-Build/CMAR; financing-led infrastructure favours BOT/PPP; collaborative, innovation-driven buildings favour IPD.