As the energy transition accelerates, renewable projects are moving from single technology deployments to hybridized systems that blend solar, wind, and battery energy storage (BESS). Thoughtful harmonization — of technology, contracts, governance, and financing — is now mission critical.
“BESS developments are helping developers on their integration journey by extending battery life to over 12 hours, which will be an operational gamechanger.”
Babak Eftekharnejad | Associate Director, Risk Engineering, Willis Natural Resources
The theory is simple: pairing intermittent solar and wind energy generation with energy storage stabilizes output, broadens grid services, and reduces reliance on peaking power plants.
In storing renewable energy, “BESS developments are helping developers on their integration journey by extending battery life to over 12 hours, which will be an operational gamechanger”, Babak Eftekharnejad, Associate Director, Risk Engineering, Willis Natural Resources. Longer duration storage creates readily dispatchable power, enabling developers to time shift generation and provide fast frequency response and other ancillary services that open up additional revenue streams.
But hybridization brings practical challenges — especially at the interfaces where systems meet.
Historically, renewable energy projects were delivered as standalone assets solar and wind farms or BESS sites with clear responsibilities and control systems. Hybrid projects change this model.
There is no one-size-fits-all approach due to the various project types that are emerging.
Firstly, new and upgrade projects face different integration challenges:
For greenfield sites, projects start with a blank sheet of paper that can be built to a specification that will best achieve the optimal hybridization of technologies. Greenfield projects are more challenging upfront, demanding a strong project team to make decisions early on to design grid connection points, substations, and potentially building the grid infrastructure if not readily available in the area.
For existing operational sites and upgrades, the process of integration is more complex. Projects receiving upgrades have existing grid connection points which will need to be assessed to establish whether the grid infrastructure can cope with the new demands. Retrofitting new technologies into existing infrastructure can create unexpected risk exposures that directly impact revenue stability.
Secondly, different stakeholders can shift project structures:
Together, these two factors create a matrix of project identities, each with distinct risk exposures that must be assessed and managed.
Four practical realities are potential risk exposures:
01
Hybrid projects are typically built in remote areas by different contractors, each expert in a specific domain. It’s rare to find one engineering, procurement and construction (EPC) or original equipment manufacturer (OEM) truly fluent across all technologies and their combined controls. The result is a skills gap at the interface, where responsibility can blur and issues can propagate undetected.
02
Accessing the required skills and experience is a major challenge for project sponsors. Engineers and technicians that have experience across multiple technologies are rare, and the explosion in demand for power from data centers and widespread electrification of industries has made this situation more acute.
03
Optimizing substation operations demands harmonized protection settings, coordinated dispatch logic, and clear rules for reactive power management. Misalignment can cascade into trips, warranty disputes, and lost revenue during high value periods.
04
Integrated plant-level architecture is powered to coordinate all grid-facing functions, including active and reactive power dispatch, protection logic, generation curtailment, and charging/discharging strategies. With a unified control hierarchy, companies can ensure consistent grid code compliance and mitigate the interface-driven risks that emerge in large multi-technology systems.
Large utilities, with portfolios spanning multiple technologies and grid interfaces, tend to be battletested. Medium-sized developers — often agile, innovative, and capital efficient — may lack exposure to multi-interface programs and may operate with a lean structure without a dedicated interface manager. This is where a specialist project manager becomes critical from planning, through construction, to operational phases.
Early-stage scoping and planning activities are bolstered by including a range of perspectives. Risk engineers can support project teams with data-driven insights alongside:
At the construction phase embedding a rigorous, portfolio‑wide lessons‑learned discipline from the earliest project stages is essential for safe, efficient, and repeatable delivery. While large utilities typically operate mature, structured feedback mechanisms that systematically capture and institutionalize operational insights, smaller developers have not yet established these processes and must adopt comparable frameworks to prevent the recurrence of failures across their hybrid portfolios.
Establishing an owner's engineering office and recruiting an established PMC early, is critical to clarify accountabilities and keep the project moving safely and efficiently. These teams will:
In moving from construction to operation, ensuring a robust risk management approach is an operational imperative. Traditional underwriting approaches risk by asset class,are not well suited to hybridized architectures where technology interdependence can amplify or dampen performance across the integrated system. A portfolio‑level risk perspective is essential. By applying advanced analytical tools and rigorous engineering evaluation, project owners can obtain a clearer understanding of these interdependencies and make optimized financial and operational decisions.
In parallel, independent risk engineers provide a complementary layer of technical assurance by systematically identifying latent hazards and quantifying their likelihood and impact. With these insights, risk controls can be prioritized with a smart, data-driven approach.
“Risk engineers are stitched into the fabric of strategic decision making because insurance and risk assessment remain with the asset for its full life. Making the right decisions early paves the way for a streamlines and successful projects that continues to deliver value throughout its lifetime.”
Alan McShane | Global Head of Risk Engineering, Willis Natural Resources
External risk engineers' perspectives help to ensure that lessons‑learned are translated into actionable engineering controls, updated operating envelopes, and improved interface resilience. By providing objective guidance from development through decommissioning, risk engineers ensure decisions are grounded in risk, not just short-term delivery pressures.
“Risk engineers are stitched into the fabric of strategic decision making because insurance and risk assessment remain with the asset for its full life. Making the right decisions early paves the way for a streamlines and successful projects that continues to deliver value throughout its lifetime”, Alan McShane, Global Head of Risk Engineering, Willis Natural Resources.
For developers without a large PMC or mature asset management function, risk engineers act as an independent intermediary to keep projects fit for purpose for 20–25 years.
01
Appoint a single, fully accountable focal point responsible for overseeing all interface risks across the hybrid project including grid interconnection, construction activities, control system integration, and commercial arrangements. This role ensures that interface issues are systematically tracked and resolved, and decision-making is consistent.
02
Decide exactly which controller is the authority in each operating mode (normal, contingency, islanding, grid events). Document set points, override rules, and safe states.
03
Plan for voltage support and reactive power obligations, and model how reactive flows affect battery performance and thermal limits to avoid unintended battery stress that erodes warranties. Other key preparation activities include spares strategies, access plans and inspection protocols.
04
Include battery augmentation/replacement, inverter repowering, and control upgrades as scheduled events in the financial model. Stress test revenue under curtailment, grid constraints, and market price volatility.
05
Run formalized reviews and annual portfolio audits led by risk engineers, and use these findings to update design standards, warranty negotiations, and dispatch policies.
For hybridization to become a widespread success, two key challenges must be addressed at project, sector, national and international levels.
The sector is already short on skilled electricians, particularly in geographies such as Australia and the U.K.. Filling the pipeline with multi‑domain engineering capability when deployment is accelerating, and specialisms are deepening, is a critical and time-sensitive challenge.
As projects grow larger and capital stacks more complex, investors will increasingly expect system assurance, not just component compliance. What’s missing is an overarching, project‑wide certification that validates compatibility across technologies.
Partnerships with certification bodies provide opportunities to codify interface best practices, while coalitions of developers pool knowledge from multi‑technology builds. Overlaying these collaboration initiatives with robust peer reviews by OEMs, grid operators, and independent experts can boost practicality and adoption.
The smart path for most sponsors will be staged integration—adding one technology to an existing asset or designing two-technology projects first, then layering in the third once controls and operations mature. With BESS now frequently reaching 12 hour durations, the operational value of hybrids becomes tangible: firming renewable output, shaving peaks, and providing grid services that unlock new revenue streams.
But scale demands discipline.
Hybridization done well is more than co‑location; it brings together engineering, digital control, finance, and risk management into one coherent operating model that withstands shocks and enabled commercial growth.
To find out how specialist risk engineering can keep your project on track by contacting our team.
