Published: 27 Jan, 2025

Power Systems Studies: What Bankable Feasibility Actually Requires

Lenders do not fund optimism. They fund a document set that a third party engineer can interrogate and sign off. Power Systems Studies are the technical core of that document set, and the difference between a project that reaches financial close and one that circles for two years is usually not the resource, the offtake, or the sponsor. It is whether the engineering was done properly and early.

This guide sets out what Power Systems Studies actually cover, what separates a conceptual feasibility study from a bankable one, and which standards govern the work. USP&E Global has delivered more than 150 projects across 35+ countries with 350+ engineers and technicians, under ISO 9001:2015 and ISO 45001:2018 certification and with zero lawsuits in 25 years of operation. Your project is the one that has to reach close and then perform. Our role is to make sure the analysis underneath it holds up to scrutiny from a lender’s independent engineer.

One definition first. EPC means engineering, procurement and construction. The engineering comes first for a reason that is structural rather than procedural: procurement cannot be priced, and construction cannot be scheduled, until the studies have established what the plant actually needs.

What Power Systems Studies Cover

Power Systems Studies are a defined family of electrical network analyses, each answering a specific question and each protecting against a specific failure. They are performed in modelling software such as ETAP, and the software is a tool rather than a methodology. The value lies in the input data and the engineering judgement applied to the output.

Study	Question It Answers	What It Protects Against
Load flow	Will voltage and power flow stay within limits at every bus under every operating case?	Undervoltage, overloaded feeders, unstable operation at part load
Short circuit	What fault current will flow at each point in the network?	Switchgear and breakers rated below the fault duty they will actually see
Protective device coordination	Will the nearest device trip first and leave the rest of the plant running?	A single fault taking out the whole station
Arc flash	What incident energy is a technician exposed to at each panel?	Serious injury, and non compliant labelling and personal protective equipment
Motor starting	Will the largest motor start without collapsing bus voltage?	Failed starts, nuisance trips, commissioning delay
Harmonic analysis	What distortion do variable speed drives and rectifiers inject?	Transformer and cable overheating, protection misoperation
Transient stability	Does the plant survive a fault, a load rejection, or loss of a unit?	Cascading trips and blackstart events
Grid interconnection	Does the plant comply with the utility’s connection code?	Refusal of connection after equipment is bought

The short circuit study deserves particular emphasis in secondary equipment markets. Switchgear is routinely specified against the fault duty of the site it came from, not the site it is going to. If the new site has a stiffer source or more parallel generation, that switchgear is now under rated, and the failure mode is violent.

Conceptual Versus Bankable: Two Different Products

These terms are used interchangeably in the market and they should not be. They support different decisions, carry different confidence intervals, and cost very different amounts.

Dimension	Conceptual Feasibility Study	Bankable Feasibility Study
Decision it supports	Is this project worth pursuing?	Will a lender or investment committee commit capital?
Typical duration	30 to 60 days	60 to 120 days
Site work	High level survey, initial data collection	Full site visit, geotechnical investigation, measured data
Cost estimate class	Order of magnitude	Defined, suitable for a financing case
Options assessed	Two or three configurations compared	Selected configuration engineered in depth
Independent engineer review	Not usually survivable	Written to survive it

A conceptual study will typically cover site selection and a high level geotechnical survey, prime mover specification and performance analysis, cooling system specification, electrical system design covering cabling, switchgear and transformers, a grid connection and synchronisation overview, and CapEx and OpEx estimation with fuel supply chain and cost modelling. Deliverables run to a feasibility report, preliminary high level engineering designs, a risk and mitigation plan, and a stakeholder engagement summary.

A bankable study covers the same ground at a materially higher standard of evidence. The site survey becomes an on site geotechnical investigation with laboratory results rather than a desktop assessment. Fuel specification comes from third party laboratory analysis rather than an assumption. Grid connection moves from overview to a formal interconnection study against the utility’s actual code. The cost estimate carries a defined accuracy class that a financier will accept.

Detailed design engineering, which follows feasibility rather than forming part of it, is normally priced as a percentage of total project cost, typically in the range of four to seven percent. Feasibility study cost scales with the size and complexity of the plant and with the degree of certainty required in the output, which is why an order of magnitude study and a bankable study on the same site can differ by an order of magnitude in fee.

The Standards That Govern Power Systems Studies

The source of authority here has changed, and a good deal of published material has not caught up. The IEEE Color Books, including IEEE Std 399 (the Brown Book) for power systems analysis and IEEE Std 141 (the Red Book) for industrial power distribution, have been withdrawn from active status. Beginning in 2012, IEEE transitioned the Color Book content into the IEEE Std 3000 series, and that consolidation is now substantially complete.

The underlying methodology in the Color Books remains technically sound, which is why they continue to circulate. But specifying a study against a withdrawn standard is a defensible criticism for a lender’s independent engineer to raise, and it is avoidable.

Standard	Scope	Status
IEEE Std 3000 series	Industrial and commercial power system analysis and design	Current, successor to the Color Books
IEEE Std 1584	Arc flash hazard calculation	Current
IEEE Std 519	Harmonic control in electric power systems	Current
NFPA 70E	Electrical safety in the workplace	Current
ANSI C37 series	Switchgear and circuit breaker ratings	Current
IEEE Std 399 (Brown Book)	Power systems analysis	Withdrawn, superseded by the 3000 series
IEEE Std 141 (Red Book)	Industrial power distribution	Withdrawn, superseded by the 3000 series

Two practical notes. Arc flash work should be specified against IEEE 1584 and NFPA 70E together, because one gives the calculation method and the other gives the workplace safety framework. And in most non United States jurisdictions the binding requirement is the local grid code and national wiring regulations, with IEEE and ANSI documents serving as recommended practice rather than law. Confirm which applies before writing the scope.

What the Study Needs From You

Studies stall on missing input data far more often than on analysis. Assembling the following before kickoff removes most of the delay.

Input	Why It Is Needed	Acceptable Source
Site coordinates and elevation	Sets derate factors for every prime mover	Survey or GPS fix, not a town name
Design maximum ambient temperature	Sets derate and cooling duty	Meteorological record, not annual average
Fuel composition analysis	Determines engine or turbine suitability and treatment	Third party laboratory report
Load list with largest motor rating	Drives sizing, motor starting and protection studies	Client process engineering
Grid code and point of connection data	Governs interconnection compliance and fault level	Utility, in writing
Existing plant nameplates and drawings	Establishes ratings of anything being retained	Site survey and as built records
Required frequency and voltage	Fixes the equipment market you can buy from	National standard confirmed by site measurement

Why Frontier Projects Need More Analysis, Not Less

There is a persistent assumption that engineering rigour is a luxury for well resourced markets and that frontier projects should move faster with less. The opposite is true, for three reasons.

Source impedance is often unknown. In markets with limited utility record keeping, the fault level at the point of connection may not be documented. It has to be established by study and measurement rather than looked up, and everything downstream depends on it.

Equipment is frequently secondary. Used and surplus plant carries the ratings of a previous installation. Establishing whether it suits the new network is a study, not an assumption.

The consequence of failure is larger. A protection miscoordination at a mine in the Sahel does not mean an inconvenient outage. It means a stopped process plant with no alternative supply and a multi day recovery. Grid unreliability across much of Sub Saharan Africa is well documented by the International Energy Agency and in the access and reliability data published by the World Bank, and it is precisely why captive plant on these sites has to be engineered to carry the whole load rather than to supplement a dependable grid.

Development finance institutions active in these markets, including the International Finance Corporation and the African Development Bank, apply technical due diligence standards that assume this work has been done to an internationally recognised level.

What Skipping the Studies Costs

USP&E’s experience across more than 150 delivered projects is consistent on this point. Where proper engineering is not performed up front, installed project cost typically increases by around 20 percent, and plant delivery is typically extended by at least 6 to 12 months. That is our own observed pattern across our project portfolio rather than an independent finding, and it is offered as such.

The mechanism is not mysterious. Equipment is bought before the load list is settled, so it is either wrong or has to be supplemented. Balance of plant is discovered rather than specified, so it arrives late and at spot pricing. Switchgear turns out to be under rated for the fault duty and has to be replaced after delivery. Each of these is a schedule event as well as a cost event, and schedule events compound.

There is a related commercial reality worth stating plainly. A lump sum turnkey price cannot be produced without either a complete set of detailed engineering plans showing every component, or a paid conceptual feasibility and engineering design study to generate them. Any contractor offering a firm lump sum price on a greenfield site without one of those two inputs is pricing a guess, and the variation claims will follow.

Our power plant engineering team performs this work as owners engineer and as EPC contractor, and our EPC and EPCM project delivery carries the design through to commissioning. Where a study concludes that an existing asset is worth rehabilitating rather than replacing, our power generation asset refurbishment practice scopes that honestly.

Frequently Asked Questions

What is the difference between a feasibility study and a bankable feasibility study?

A conceptual feasibility study answers whether a project is worth pursuing and typically takes 30 to 60 days, working from a high level site survey and desktop analysis. A bankable feasibility study is written to survive review by a lender’s independent engineer and typically takes 60 to 120 days, with an on site geotechnical investigation, third party fuel analysis, a formal grid interconnection study, and a cost estimate carrying a defined accuracy class. They support different decisions and are not substitutes.

What software is used for power systems studies?

ETAP is the most widely used package for industrial and generation network analysis, alongside comparable tools such as DIgSILENT PowerFactory and SKM PowerTools. The software performs load flow, short circuit, protective device coordination, arc flash, motor starting, harmonic and transient stability analysis. It is worth being clear that the software is a calculation engine. Output quality depends on the accuracy of the network model, the equipment data entered, and the engineering judgement applied to the results.

Which IEEE standard covers power system analysis?

The current source is the IEEE Std 3000 series, which superseded the IEEE Color Books. IEEE Std 399, the Brown Book, was the historical reference for power systems analysis and has been withdrawn from active status, as has IEEE Std 141, the Red Book, for industrial power distribution. Arc flash work is governed by IEEE Std 1584 alongside NFPA 70E, harmonic limits by IEEE Std 519, and equipment interrupting ratings by the ANSI C37 series.

Why is a short circuit study necessary if the equipment is already rated?

Because the rating reflects the network the equipment was originally specified for, not the one it is going into. Fault current at any point depends on source impedance, transformer impedance, cable lengths, and how much generation is running in parallel. Move a switchboard to a site with a stiffer source or add a second generator and the available fault current rises. Equipment that was correctly rated becomes under rated, and the failure mode is an uncontained arc rather than a nuisance trip.

Can a lump sum turnkey price be given without engineering?

Not credibly. A firm lump sum price requires either a complete detailed engineering package showing every component and drawing, or a paid conceptual feasibility and design study to produce one. Prime mover cost is typically only a fraction of installed cost, with shipping, balance of plant, installation and spares frequently amounting to one to two times the cost of the engine or turbine itself. A lump sum quoted without that work is an estimate wearing a firm price, and it will be corrected through variations.

How long does a grid interconnection study take?

It depends far more on the utility than on the engineering. The analysis itself is a matter of weeks once the network data is available. Obtaining that data, and then obtaining the utility’s review and approval, is frequently the longest single item on a project’s critical path in markets with limited utility capacity. This is why interconnection should be opened at feasibility stage rather than treated as a construction phase activity.

Does USP&E perform power systems studies as an owners engineer?

Yes. USP&E Global works both as owners engineer, representing the project against a third party contractor, and as EPC contractor delivering the plant. The studies are the same in either role. Where we act as owners engineer, the deliverable is an independent technical position the sponsor can take to lenders. Our work spans feasibility, detailed design, procurement support, construction, commissioning, and long term operations and maintenance.

Summary

Power Systems Studies are a defined family of analyses, each answering a specific question and protecting against a specific failure mode.
A conceptual feasibility study runs 30 to 60 days and answers whether a project is worth pursuing. A bankable study runs 60 to 120 days and is written to survive a lender’s independent engineer.
Detailed design engineering typically costs four to seven percent of total project cost and follows feasibility rather than forming part of it.
The IEEE Color Books, including the Brown Book and Red Book, are withdrawn. The current reference is the IEEE Std 3000 series, with IEEE 1584, IEEE 519, NFPA 70E and ANSI C37 covering their specific domains.
Secondary equipment carries the fault ratings of its previous installation, which makes a short circuit study essential rather than optional.
On USP&E’s own project experience, skipping front end engineering typically adds around 20 percent to installed cost and 6 to 12 months to delivery.
A firm lump sum turnkey price cannot be produced without either complete detailed engineering or a paid study to generate it.

Power Systems Studies are not a procedural hurdle before the real work starts. They are the work that determines whether everything after them is buildable, financeable, and safe.

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