Biogas and renewable natural gas (RNG) projects are unique in energy infrastructure. They blend complex mechanical systems with biological processes that are sensitive to variables like feedstock composition and availability, process temperature, equipment performance and reliability, and operator skill. Given the importance of gas output to a project’s economics, fluctuations in these variables can quickly erode a project’s financial viability.

In this complex landscape, well-structured contractual guarantees are vital for managing risk, ensuring performance, and maintaining project viability. Contractual guarantees—particularly performance guarantees, uptime guarantees, and full wrap guarantees—play a pivotal role in allocating technical and financial risk, but they are frequently misunderstood.

1. Performance Guarantees

A) What are Performance Guarantees?

Performance guarantees are commitments that the project or specific equipment will achieve certain measurable output or quality metrics. Performance guarantees answer the question: Does the system or equipment perform at the level required to support the project’s economics? In the biogas context, performance guarantees commonly relate to RNG production volumes (measured in standard cubic feet per minute or millions of British thermal units), methane concentrations by RNG volume, and natural gas pipeline specifications.

B) Who Provides Performance Guarantees?

It is common to see either (i) a technology or equipment supplier (equipment-level performance) and/or (ii) an engineering, procurement, and construction (EPC) contractor (project-level performance) offer performance guarantees. For example, an anaerobic digester equipment supplier may guarantee that its system will produce a certain volume and quality of RNG, but only from the equipment it provides and only if the feedstock meets defined criteria. This type of narrow performance guarantee only covers the specific equipment at issue, rather than the entire facility or integration with other equipment.

Alternatively, an EPC contractor may guarantee overall RNG output (meaning the entire system functions together to produce pipeline-quality gas). In this broader guarantee, the EPC contractor assumes the risk that all components, regardless of manufacturer, work together as a functioning facility.

C) Co-Existence of Performance Guarantees

Both types of performance guarantees can co-exist simultaneously. The equipment supplier and the EPC contractor may each have separate agreements directly with the project owner or developer, but no contractual relationship with each other. In that situation, if the project fails to achieve its guaranteed RNG output under the agreed feedstock conditions because of an equipment failure, the owner or developer typically must look to the equipment supplier for remedies, which may include liquidated damages.

The EPC contractor, however, often cannot be held responsible for the equipment supplier’s failure to meet its own equipment-level guarantees, even if the EPC contractor separately provided a performance guarantee for the integration and overall output of the facility, because the EPC contractor’s performance guarantee is often contingent upon each major component performing as warranted by its supplier. If the facility underperforms solely due to an equipment deficiency, the EPC contractor’s guarantee often does not “backstop” the supplier’s failure. Instead, the owner/developer would pursue remedies against the equipment supplier under that separate contract. The EPC contractor’s obligation is generally limited to ensuring that, assuming all major components perform as specified, the facility as a whole will meet the final output and quality metrics at the point of integration.

In practice, this means that owners and developers often bear the integration risk between two separate contractual chains. If the root cause of underperformance is unclear or disputed between the supplier and the EPC contractor, the owner/developer may find itself caught in the middle. This underscores the importance of clear contract drafting, robust performance testing protocols, and, where feasible, careful consideration of whether a single point of accountability (such as a full wrap guarantee) is preferable for project risk management.

2. Full Wrap Guarantee

A) What is a Full Wrap Guarantee?

A full wrap guarantee (sometimes called an EPC wrap) is not about a specific performance metric. Rather, it is a risk allocation structure. The EPC contractor assumes end-to-end responsibility for delivering a fully functional project that meets all contractual requirements. This structure is designed to absorb and manage risks associated with subcontractors, equipment suppliers, and the integration of all project components. The full wrap guarantee answers the question: If something goes wrong, who do I call? The answer is simple: the EPC contractor.

The principal advantage of a full wrap guarantee is the creation of a single point of accountability for the project owner. If any issue arises, whether related to design, construction, equipment failure, or integration, the owner is not required to pursue and allocate fault between multiple parties. Instead, the EPC contractor is solely responsible for remedying the issue. Contractually, this occurs via the EPC agreement between the owner and EPC contractor. The EPC contractor then separately enters into agreements with all subcontractors and suppliers. In some cases, owners may procure certain critical equipment directly. The full wrap can still be preserved if the EPC contractor formally accepts assignment of those equipment supply agreements and assumes responsibility for their integration and performance. This approach ensures that the single point of accountability is maintained, even with mixed procurement strategies.

B) Compatibility of Full Wrap and Performance Guarantees

A full wrap guarantee often incorporates the obligations found in performance guarantees. The EPC contractor is responsible for ensuring that all subcontractors and equipment suppliers fulfill their respective obligations, and the EPC contractor ultimately guarantees the performance of the specific equipment and the integrated facility. As such, both guarantee structures can coexist, with the full wrap providing an additional layer of risk protection for the project owner. The owner’s remedies can include performance liquidated damages against the EPC contractor, while the EPC contractor will want to ensure commensurate remedies in its subcontracts with the applicable suppliers.

C) Scope and Limitations of Full Wrap Guarantees

While a full wrap guarantee provides comprehensive risk allocation and a single point of accountability, it is important to recognize its boundaries. The effectiveness of a full wrap depends on the EPC contractor’s financial strength, technical expertise, and ability to manage its subcontractors and suppliers. Owners and lenders should conduct due diligence on the EPC contractor’s track record and capacity to deliver on large, integrated projects. Additionally, the scope of the full wrap is defined by the underlying contract and its exclusions, limitations of liability, and carve-outs (such as for force majeure events or owner-supplied feedstock); therefore, this should be carefully reviewed to ensure there are no gaps in risk coverage.

D) Bankability and Lender Perspective

Full wrap guarantees are highly favored by lenders and tax equity investors because they reduce project completion risk and eliminate the potential for “finger-pointing” among multiple contractors if something goes wrong. This single-point responsibility is preferred for project financing, as it streamlines enforcement of remedies and provides greater certainty that the facility will be delivered on time and to specification. It is worth noting, though, that obtaining a full wrap guarantee may increase project costs, as the EPC contractor will price in the risk of having to remedy issues outside its direct control. However, the additional upfront cost is often outweighed by the reduction in risk and increased bankability for the project.

3. Uptime Guarantees

Uptime guarantees focus on availability, not output. They ensure that the system or equipment operates for a minimum percentage of total hours in a defined period. In other words, uptime guarantees answer a different but equally critical question: Is the system, or a key component, available and running when it’s supposed to be?

A) What Does an Uptime Guarantee Cover?

Uptime guarantees specify that a facility, subsystem, or piece of equipment must be available for operation for a minimum percentage of total hours during a defined period (typically, a rolling 12 months). For example, a contract might require that a gas upgrading system achieve 92% uptime over a rolling 12-month period.

B) Facility-Level vs. Equipment-Level Uptime

It is important to recognize that uptime guarantees can apply at different levels of an RNG project:

• Facility-Level Uptime: Here, the guarantee covers the operational availability of the entire plant. If any critical component is down and prevents the facility from producing gas, that downtime counts against the uptime metric. This approach is most common when a single party, such as an operations and maintenance (O&M) contractor, operates the whole facility and is responsible for overall performance.
• Equipment-Level Uptime: In some cases, the guarantee is limited to a specific piece of equipment or subsystem, such as a digester or gas upgrading unit. This is typical in long-term service agreements with equipment suppliers or original equipment manufacturers, who do not control the entire plant but are responsible for the reliability of their own equipment. Here, only downtime related to that specific equipment counts against the uptime metric.

C) Where Are Uptime Guarantees Found?

Uptime guarantees are most commonly found in O&M agreements (in which an O&M provider is responsible for keeping the facility or certain equipment running) and long-term service agreements (in which equipment manufacturers or technology providers guarantee the reliability of their supplied systems).

It is uncommon to see uptime guarantees in EPC agreements, as EPC agreements are generally focused on delivering a completed and functioning facility that meets specified performance guarantees. Once the plant is handed over and achieves commercial operation, ongoing uptime is considered an operational risk, not a construction risk.

However, there are exceptions:

• Commissioning and Initial Operations: If the EPC contractor is responsible for commissioning and initial operations, the owner/developer may require an uptime guarantee during the performance testing or ramp-up phase to ensure the plant operates continuously long enough to demonstrate that performance standards are met.
• Performance Testing Period: In this scenario, the uptime guarantee is limited to the period necessary to complete the required performance test, not to long-term operations.

D) Remedies and Exclusions

If the uptime guarantee is not met, typical remedies include liquidated damages (often calculated based on the number of hours or days below the guaranteed uptime threshold) and corrective action plans (if uptime falls significantly short). It’s also important to specify exclusions, which may include downtime caused by force majeure events, scheduled maintenance, or owner-caused interruptions. These should not count against the uptime calculation.

4. Closing Summary

Biogas and RNG projects present a unique intersection of biological, mechanical, and contractual complexity. The thoughtful structuring of these types of guarantees is essential to managing risk, protecting project economics, and satisfying the expectations of owners, investors, and lenders alike. Each type of guarantee serves a distinct purpose: from ensuring that key metrics are met, to providing a single point of accountability, to safeguarding ongoing operational reliability.

Ultimately, the success of a biogas or RNG project depends not only on technical execution but also on the clarity and enforceability of its underlying agreements. Careful consideration of how these guarantees interact, and the remedies available if they are not met, can make the difference between a project that delivers on its promise and one that falls short. For those interested, a deeper dive into the remedies available under these guarantees (performance guarantees in particular), including the use of performance liquidated damages, is available here.