By AGILE Consulting Engineers, Solar PV and Battery Energy Storage Systems (BESS) specialists.
The cheapest detailed design quote is rarely the cheapest detailed design. A design package that misses a protection coordination issue, underspecifies a foundation, or produces documentation a Distribution Network Service Provider (DNSP) bounces back for clarification costs far more in rework and delay than the difference between two consultants’ fee proposals. Choosing a detailed design partner is a risk decision as much as a procurement one, and it deserves more scrutiny than most developers give it.
Table of Contents
- Relevant Technical Experience, Not Just Volume
- Independence From Equipment and EPC Interests
- Software and Tooling Capability
- Quality Assurance Processes
- Communication and Documentation Standards
- Track Record and References
- Engagement Model and Scalability
- Red Flags Worth Watching For
- What to Do Next
- FAQ
Relevant Technical Experience, Not Just Volume
A firm’s total project count matters far less than whether its experience matches your project’s specific technical demands. Solar-only design experience does not automatically transfer to BESS, where thermal management, fire safety, and battery-specific protection design introduce genuinely different engineering considerations. Grid-connected commercial project experience does not automatically transfer to a remote mine site hybrid system, where diesel integration, weak grid stability, and transport logistics dominate the design problem in ways a suburban rooftop project never encounters. When evaluating a potential partner, ask specifically about their experience with projects that share your scale, your technology mix, and your site conditions, rather than accepting a general renewable energy engineering credential as sufficient. Sector-specific experience helps a design team anticipate problems before they surface, which is worth considerably more than a long but generic project list.
Independence From Equipment and EPC Interests
Some engineering firms are commercially linked to, or owned by, an equipment manufacturer, an Engineering, Procurement, and Construction (EPC) contractor, or a developer, which can create a structural incentive to favour certain equipment, design approaches, or cost outcomes that are not necessarily the best technical fit for your project. An independent design partner, one whose commercial interest is in producing an accurate, defensible design rather than in selling you a particular vendor’s equipment or steering the project toward a related construction arm, is generally better positioned to give you an unvarnished technical assessment. This matters particularly at the detailed design stage, where equipment selection, protection philosophy, and layout decisions have long-term implications for performance and maintainability that outlast any single commercial relationship. It is a reasonable question to ask directly: does this firm have a financial relationship with a specific equipment vendor or contractor that could shape their recommendations, and if so, how is that managed?
Software and Tooling Capability
Detailed design for solar and BESS projects draws on a range of specialist software, from energy yield modelling and electrical protection studies through to structural analysis and geotechnical assessment tools. A design partner’s tooling capability is a reasonable proxy for the rigour of their process, not because software alone produces good engineering, but because industry-standard modelling and analysis tools generally reflect a firm that has invested in doing detailed calculations properly rather than relying on rules of thumb or simplified spreadsheets for complex problems. It is fair to ask a prospective partner what software they use for energy yield modelling, protection coordination studies, and structural analysis, and how their outputs are typically presented and verified. A firm that struggles to answer this in specific terms may not have the depth of process their marketing suggests.
Quality Assurance Processes
Detailed design documentation that has not been independently checked before issue is a real risk, both to project outcomes and to the design firm’s own professional liability. Ask a prospective partner how their internal review process works: who checks a design before it is issued, whether checking is done by someone other than the original author, and how revisions and design changes are tracked and version controlled through the project. Firms with a genuine quality assurance culture will generally have a clear, specific answer to this, describing a defined review gate structure rather than a vague assurance that “everything gets checked.” For projects seeking finance, ask specifically whether the firm’s documentation and processes are structured in a way that will satisfy a financier’s independent engineer or technical due diligence review, since design documentation that has to be substantially reworked at that stage is a common and avoidable source of delay.
Communication and Documentation Standards
The quality of a design firm’s day-to-day communication is a reasonably reliable predictor of how the engagement will actually run. A partner who responds promptly and specifically to technical questions during the proposal stage is more likely to do the same once a contract is signed and the project inevitably hits a decision point that needs input quickly. Documentation standards matter just as much: ask to see a sample of a previous design package, redacted of any confidential project detail if necessary, to assess whether drawings, calculations, and reports are clear, consistently formatted, and genuinely usable by a contractor pricing the work or a DNSP reviewing a connection application. Poorly organised or inconsistent documentation creates friction at every downstream stage of a project, from tendering through to commissioning, and it is far easier to assess this before engagement than to discover it partway through a project.
Track Record and References
Ask for references from projects genuinely comparable to yours in scale and technology, and ask those referees specific questions rather than accepting a general endorsement. Useful questions include whether the design package required significant rework once issued for construction, whether the firm met its stated program, how they handled unexpected site conditions or scope changes, and whether the referee would engage the same firm again for a similar project. A firm confident in its track record will generally be willing to facilitate a genuine reference conversation rather than only providing a curated case study.
Engagement Model and Scalability
Consider whether the firm’s scale and structure genuinely match your project’s needs. A very small practice may offer excellent personal attention but lack the depth across electrical, structural, and civil disciplines to coordinate a complex project without relying heavily on subcontracted specialists, which can introduce its own coordination risk. A very large firm may have all disciplines in-house but allocate a junior team to a project that does not carry enough fee value to warrant senior attention. Ask directly who will actually be doing the work on your project, not just who the firm’s senior representatives are during the sales process, and clarify how the team is structured across the disciplines your project needs.
Red Flags Worth Watching For
A few patterns are worth treating cautiously. A firm unwilling to provide references or discuss a previous project’s outcomes in specific terms. A proposal that quotes a single fixed timeline for detailed design without asking enough questions about your site and connection pathway to justify that figure. Vague answers about quality assurance or internal review processes. And a design fee that is dramatically lower than comparable proposals, which sometimes reflects genuine efficiency, but sometimes reflects a firm planning to cut corners on review, site investigation, or documentation depth to hit the price. None of these are disqualifying on their own, but they are worth probing further before committing.
What to Do Next
Choosing a detailed design partner is worth the same diligence you would apply to any decision that shapes a project’s technical foundation and financeability. If you are evaluating options for an upcoming solar or BESS project, AGILE’s solar and BESS system design service is a reasonable point of comparison, an independent, multidisciplinary engineering team working across electrical, structural, and civil design for solar and BESS projects across Australia and the Pacific.
FAQ
What is the most important factor when choosing a detailed design partner?
Relevant technical experience matching your specific project type, scale, and site conditions matters more than a firm’s overall project count or general renewable energy credentials.
Does it matter if a design firm is linked to an equipment vendor or EPC contractor?
It can. A commercial relationship of that kind may create an incentive to favour certain equipment or outcomes, so it is worth asking directly whether such relationships exist and how they are managed.
What should I ask about a firm’s quality assurance process?
Ask specifically who checks a design before it is issued, whether the checker is independent of the original author, and how the firm’s documentation would hold up to a financier’s independent engineer review.
How can I assess documentation quality before engaging a firm?
Ask to see a redacted sample of a previous design package and assess whether it is clear, consistently formatted, and genuinely usable by a contractor or network operator.
Is the cheapest detailed design quote usually the best value?
Not necessarily. A design that requires rework due to insufficient review, site investigation, or documentation depth usually costs more overall than paying a fair price for a rigorous process upfront.
Should I ask for references when choosing a design partner?
Yes, and it is worth asking those references specific questions about rework, program adherence, and how the firm handled unexpected issues, rather than accepting a general endorsement.
