By AGILE Consulting Engineers, Solar PV and Battery Energy Storage Systems (BESS) specialists.
Most rejected renewable energy grant applications don’t fail because the project idea is bad. They fail because the applicant hasn’t done the engineering homework to prove the idea will actually work at the scale, cost and performance level claimed. A feasibility study is that homework, and grant assessors read it first to decide whether the rest of the application is worth their time.
Table of Contents
- What a Feasibility Study Actually Covers
- Technical Design Basis and Site Assessment
- Energy Yield and Performance Modelling
- Cost Estimation and Financial Modelling
- Risk Assessment and the Assumptions Register
- Why Grant Assessors Expect This Level of Rigour
- How This Maps to Real Feasibility Study Funding
- What to do next
- FAQ
What a Feasibility Study Actually Covers
A technical and financial feasibility study for a solar PV or Battery Energy Storage System (BESS) project is not a marketing document or a rough back-of-envelope estimate. It is an engineering-led assessment that establishes whether a proposed project is technically achievable, financially viable and ready to move to the next stage of development. For a business seeking grant funding through the Australian Renewable Energy Agency (ARENA) or a state equivalent, the feasibility study is usually the single document that carries the most weight in the assessment process, because it is where the applicant’s claims about performance, cost and risk are tested against engineering reality rather than assumption.
A properly scoped study typically covers four core areas: the technical design basis, energy yield or performance modelling, cost estimation, and risk assessment. Each of these needs to be developed to a level of detail proportionate to the size and complexity of the project, and each needs to be defensible if a grant assessor, a co-funder or an independent technical reviewer asks to see the working behind the numbers.
Technical Design Basis and Site Assessment
The technical design basis sets out the fundamentals of the proposed system: site conditions, available area or roof structure, grid connection point and capacity, equipment selection at a concept level, and how the system will integrate with existing electrical infrastructure. For a commercial or industrial solar and battery project, this usually means a site assessment covering shading, structural loading, switchboard capacity, and proximity to the network connection point, along with an initial single line diagram showing how generation, storage and existing loads will interact.
This section matters to a grant assessor because it demonstrates the project has moved past the concept stage. A study that names a system size without explaining how that size was derived from site constraints, load profile and network capacity reads as unsubstantiated, and assessors are trained to notice the difference between a design basis grounded in site data and one that has simply been assumed.
Energy Yield and Performance Modelling
Energy yield modelling estimates how much electricity a solar array will generate across a typical year, factoring in irradiance data for the specific location, tilt and orientation, shading losses, temperature derating, inverter efficiency and system losses. For battery storage, performance modelling covers expected cycling behaviour, depth of discharge, round-trip efficiency and degradation over the asset’s operating life, which for a BESS is usually modelled across a ten to fifteen year horizon depending on the chemistry and warranty terms.
This modelling underpins almost every other number in the application, including the emissions abatement claimed, the payback period, and the revenue or cost savings the business expects to realise. Grant programs that assess value for money, which is most of them, need this modelling to be traceable to recognised methodologies and, wherever possible, to independently sourced weather and network data rather than generic assumptions pulled from a supplier brochure.
Cost Estimation and Financial Modelling
Cost estimation needs to move well beyond a single supplier quote. A credible feasibility study typically presents capital cost estimates with a defined accuracy range (for example, plus or minus fifteen to twenty five per cent at a pre-feasibility level, tightening as the design matures), broken down across major cost categories such as equipment, balance of system, installation, grid connection works and project development costs. Operating costs, maintenance schedules and any augmentation costs for battery capacity over time also need to be captured, since these affect the whole-of-life economics that a grant assessor will use to judge whether the project is genuinely viable without ongoing subsidy.
The financial model then needs to translate this cost base into project economics, typically expressed as simple payback, net present value or internal rate of return, alongside a clear statement of how much of the total project cost the applicant is asking the grant program to fund versus what the business or other financiers are contributing.
Risk Assessment and the Assumptions Register
Every feasibility study rests on assumptions, about equipment pricing, connection timeframes, construction duration and future energy prices among others. A rigorous study documents these assumptions explicitly, rather than burying them, and pairs them with a structured risk assessment covering technical risk (equipment performance, integration complexity), commercial risk (cost escalation, offtake or usage assumptions), and delivery risk (approvals, grid connection timing, contractor availability).
Assessors are not looking for a project with no risks; that is not realistic for any infrastructure project. They are looking for evidence that the applicant has identified the risks that matter and has a credible plan to manage them. A study that presents a project as risk-free is, paradoxically, one of the faster ways to lose credibility with an experienced reviewer.
Why Grant Assessors Expect This Level of Rigour
Government funding bodies are ultimately accountable for how public money is allocated, and most renewable energy grant programs are assessed against value-for-money principles that require evidence, not intent. ARENA’s own assessment approach, for example, includes testing for additionality, essentially whether a project would go ahead anyway without grant support, alongside commercial readiness and the strength of supporting technical and financial evidence. A feasibility study is the vehicle through which an applicant demonstrates all three: that the project is real, that it needs support to proceed, and that it has a credible pathway to delivery.
This is also why funding programs at the more established end, including several delivered through ARENA, explicitly fund feasibility and engineering studies as a distinct category, separate from construction or deployment funding. It reflects a widely held view among program administrators that under-scoped feasibility work is one of the more common reasons projects stall or fail once funded, and that better information at the front end reduces risk for everyone in the funding chain.
How This Maps to Real Feasibility Study Funding
As of August 2026, ARENA’s Industrial Energy Transformation Studies (IETS) Program illustrates how directly feasibility work and grant funding are linked. The program has provided a total of $43 million to help large energy users in sectors such as manufacturing, mining, agriculture and data centres undertake feasibility and engineering studies into energy efficiency and renewable energy opportunities. Within that program, feasibility studies have been funded in the $100,000 to $500,000 range from a dedicated pool, while more detailed engineering studies have attracted funding between $250,000 and $5 million, reflecting the greater design and cost-estimation depth those later-stage studies require. The structure of that program is a useful reference point for the kind of technical detail assessors expect, even for businesses applying through other grant channels.
Guidelines, funding pools and eligibility criteria for programs like this change over time and between rounds, so any business considering an application should confirm current details directly with ARENA or the relevant state body, or with a qualified technical or financial advisor, before relying on the figures above.
What to do next
A feasibility study that is scoped and delivered to grant-assessment standard from the outset tends to move faster through review than one that is retrofitted after a program officer asks for missing detail. This is the point where an early technical feasibility review can strengthen an application significantly, particularly around energy yield modelling, cost estimation accuracy and risk documentation. AGILE Consulting Engineers has worked with project teams on the technical basis for renewable energy funding applications, and can help scope a feasibility study that holds up to assessor scrutiny before it is submitted.
FAQ
How long does a feasibility study for a commercial solar or BESS project usually take?
It depends on project complexity and site access, but a pre-feasibility study for a mid-size commercial project can often be completed in four to eight weeks, while a more detailed feasibility or engineering study supporting a formal funding application can take longer, particularly if it requires site surveys, network capacity checks or detailed yield modelling.
Do I need a feasibility study for every grant application?
Most programs assessing projects above a small threshold expect some form of technical and financial justification, and the required depth generally scales with the size of the grant requested and the maturity of the technology involved; smaller, more established technology applications may need less than a large or novel project.
What is the difference between a feasibility study and an engineering study?
A feasibility study typically establishes whether a project is technically and financially viable at a concept level, while an engineering study goes further into detailed design, tighter cost estimates and construction-ready specifications, which is why programs such as ARENA’s Industrial Energy Transformation Studies Program fund them at different scales.
Can a feasibility study be funded by a grant itself?
In some cases yes. Programs such as ARENA’s Industrial Energy Transformation Studies Program specifically fund feasibility and engineering studies rather than construction, though eligibility, sector coverage and funding availability vary by program and should be confirmed directly with the relevant body.
What makes a feasibility study weak in the eyes of a grant assessor?
Common weaknesses include system sizing that isn’t tied to site data, yield or performance figures without a stated methodology, cost estimates based on a single unverified quote, and risk sections that gloss over genuine project risks rather than addressing them.
Should the feasibility study be done before or after choosing an equipment supplier?
Generally before, or at least in parallel with a competitive process. A study built around a single supplier’s figures without independent verification can weaken an application’s credibility, since assessors often look for evidence that costs and performance claims aren’t simply vendor-supplied.
