Lender's Due-Diligence Engineering (LDED) — A Checklist for India

Lender’s due-diligence engineering (LDED) is the technical evaluation process that a solar project’s financier — IREDA, PFC, SBI, REC, or a foreign DFI — conducts before agreeing to disburse project finance. Unlike an internal project report, LDED is designed from the lender’s point of view: every number, every assumption, and every engineering deliverable is stress-tested against what happens to the loan if the project underperforms. For the developer, understanding what the lender is actually looking for — and structuring the DPR accordingly — is the single most effective way to accelerate financial close.

Direct answer. Lender’s due-diligence engineering (LDED) in India covers eight technical domains: site and irradiance validation, PVsyst energy yield at P50/P90/P99, electrical design completeness, structural integrity per IS 875 Part 3, BOQ and CAPEX benchmarking, land and regulatory clearances, EPC contract terms, and O&M bankability. Each domain must be evidenced by signed engineering deliverables — not draft sections. IREDA and PFC project finance guidelines require that the Independent Engineer’s positive technical opinion covers all eight domains before financial close proceeds.

This guide is written for Suresh — the Indian utility-scale developer navigating the IREDA or PFC financing process for a 10–100 MW solar project. The checklist format mirrors what experienced IEs and lender technical teams actually work through, drawing on MNRE guidelines and IREDA’s published project-finance conditions.

Why LDED Exists and Who Controls It

The lender appoints the Independent Engineer; the developer pays the IE’s fee. This structural asymmetry — the client pays but does not direct — is intentional. The IE’s report goes to the lender, not the developer. When the IE finds gaps, the comment list goes to the developer who must resolve each item before the IE revises its opinion.

Definition. LDED (Lender's Due-Diligence Engineering) is the complete technical review commissioned by a project finance lender — including yield verification, design adequacy assessment, contract review, and regulatory clearance audit — typically conducted by an Independent Engineer (IE) on the lender's behalf before loan disbursement.

₹8–15L

Typical LDED comment resolution cost

Heaven Designs internal, 2025

6–14 wks

LDED process duration (typical)

IREDA guidelines, 2024

72%

Projects with at least one major LDED comment

Mercom India analysis, 2024

1.25×

Minimum DSCR at P90 yield

IREDA project finance criteria, 2025

The LDED Pre-Submission Checklist — Domain 1: Irradiance and Site

The lender wants to know that the site receives the irradiance your yield model assumes. This is the foundation of everything — a 5% overstatement of GHI flows directly to a 5% overstatement of revenue, which changes the debt service coverage ratio and, in some cases, reverses the project’s bankability.

Irradiance LDED checklist:

Solargis PVGIS or Meteonorm 8.x dataset downloaded for the exact site coordinates (not interpolated from a nearby project)
Data period: minimum 20 years of historical hourly data
On-site pyranometer data: ≥ 12 months for projects above 10 MW; ≥ 6 months for 5–10 MW projects
Satellite vs ground discrepancy calculated and documented (acceptable range: ≤ 3% GHI deviation)
Monthly GHI table included in DPR with seasonal variation highlighted
Near and far horizon profile documented (measured or modeled from terrain dataset)
Albedo value selected and justified for the site terrain (desert: 0.20–0.25; agricultural: 0.15–0.20)

Domain 2: Energy Yield — P50/P90/P99 Methodology

The PVsyst report is the document that receives the most comment items in LDED. IEs review it with a parameter-level microscope because the P90 yield drives the DSCR calculation that determines whether the lender can write the loan.

PVsyst LDED checklist:

LDED yield thresholds that trigger IE concern:

Parameter	Triggers IE Concern	Acceptable Range
P90/P50 ratio	< 0.91	0.91–0.96
Performance ratio	< 75% or > 85%	76–83% for Indian ground-mount
Soiling loss (Rajasthan)	< 3.5%	3.5–5.5%
Module degradation Y1	< 1.5%	1.5–2.5%
System availability	> 99.5%	97.0–99.2%

Domain 3: Electrical Design Completeness

Electrical LDED checklist:

Field tip. IREDA's LDED review team has flagged unsigned SLDs in 3 of the last 5 project submissions Heaven Designs has seen from developers who prepared their own DPRs. A signature missing from a single drawing can pause the entire disbursement process. Build a deliverable sign-off tracker into your DPR preparation workflow and do not submit until every document has its required signatures.

Domain 4: Structural Engineering Report

Structural LDED checklist:

Soil investigation report: bore logs at minimum 3 locations per hectare (SPT N-values reported at every 1.5 m depth); issued by a NABL-accredited geotechnical laboratory
Geotechnical design parameters: bearing capacity, friction angle, cohesion — derived from actual bore-log data, not zone defaults
Pile design: end-bearing or friction capacity calculated; pile spacing and embedment depth from actual soil parameters
Wind-load calculation: IS 875 Part 3 (2015), correct wind zone and terrain category for the project location, basic wind speed from IS 875 Part 3 Appendix A wind map
Module wind uplift and drag forces: calculated per IS 875 Part 3 methodology or recognized international standard (ASCE 7-22 acceptable for IFC-stamped designs)
Structural analysis: STAAD Pro or SAP2000 model with IS 800 (2007) steel design checks; deflection limit ≤ L/150
Galvanization specification: minimum 85 microns hot-dip zinc per IS 4759 for steel purlins and rafter; 42 microns for module clamps
Seismic check: IS 1893 (2016) for seismic zone II and above
Structural engineer’s PE stamp on all structural drawings

The structural report is the most commonly underspecified section in developer-prepared DPRs. According to BIS IS 875 Part 3 (2015), the design wind pressure for a structure depends on the terrain category (open flat terrain, suburban, or urban) — and the terrain category can reduce or increase the design wind pressure by ±25%. Using the wrong terrain category is not conservative; it is either under-designed (structural risk) or over-designed (unnecessary cost).

Domain 5: BOQ and CAPEX Benchmarking

The LDED team benchmarks your project CAPEX against current market data. A CAPEX that is 10% below the current MNRE benchmark triggers a query about whether the cost estimate is realistic.

BOQ LDED checklist:

Line-item BOQ covering: modules, inverters, mounting structures, DC cables, AC cables, transformers, panels/switchgear, civil works, substation, SCADA, O&M infrastructure
Equipment specifications with make/model/wattage confirmed in BOQ
Module cost: aligned with current MNRE module benchmark (check MNRE quarterly benchmark publication)
CAPEX/MW: ≥ ₹2.6 Cr/MW (2025 MNRE composite benchmark for ground-mount with single-axis tracker)
O&M cost: ≥ ₹7.5L/MW/year (year 1) with 3–5% annual escalation

Watch out. Presenting a CAPEX/MW that is 15% below the MNRE benchmark in order to show a better tariff number in the financial model is a common and costly error. The LDED team will apply a "haircut" to your CAPEX — assuming the actual cost is higher than claimed — and recalculate the financial model accordingly. If the revised DSCR falls below 1.25×, the lender may require additional equity or a higher tariff assumption before proceeding.

The LDED Eight-Domain Readiness Protocol

The LDED Eight-Domain Readiness Protocol is Heaven Designs’ proprietary structured pre-submission checklist — used to audit every project DPR before it is submitted to the lender’s IE. The protocol converts the IE’s 200-item internal review into a developer-controlled quality gate.

Irradiance Dossier Review

Verify that Solargis or Meteonorm data is from exact site coordinates, that on-site pyranometer data is included, and that the P90 uncertainty band is documented. If any of the three are absent, the LDED review will produce a major comment on the very first item the IE reads.

PVsyst Parameter Audit

Run every loss value in the PVsyst report against the acceptable ranges from Domain 2 of this checklist. Flag every default value that has not been replaced with a site-specific or manufacturer-verified figure. Each default is a potential IE comment.

Deliverable Signature Register

Build a register of every document in the DPR — who must sign, whose stamp is required, and the revision status. Confirm that every row in the register has a signed original (or a certified digital copy) before the DPR package is compiled for submission.

Structural Specification Audit

Verify that wind zone, terrain category, seismic zone, and soil parameters in the structural report match the project site — not generic zone values. Confirm STAAD Pro model uses actual bore-log N-values and that the galvanization specification meets IS 4759.

Land and Regulatory Clearance Audit

Compile every clearance document in a single folder: land title or registered lease, land-use conversion certificate, environmental clearance (if applicable), grid-connectivity approval, PPA. For each clearance not yet in hand, document the application date and expected approval date.

Financial Model Cross-Reference

Build a bridging table showing where each PVsyst output (P50 kWh, P90 kWh, 25-year degradation curve) is referenced in the financial model. DSCR at P90 must be ≥ 1.25× for IREDA/PFC; many foreign DFIs require ≥ 1.30×. Confirm that O&M cost escalation in the model is ≥ 3% per year.

EPC Contract Term Audit

Build a contract-term matrix mapping each IE-required provision (performance guarantee, LD clause, defect liability, O&M continuity, insurance pass-through) to its clause number in the EPC agreement. An IE will request this matrix within the first week of review; having it pre-prepared eliminates a week of delay.

O&M Bankability Dossier

Confirm that a 5-year AMC with a qualified O&M contractor is signed or that a term sheet is in place. The O&M contractor's track record (MW under management, performance history) must be included in the DPR. An O&M plan that consists only of the EPC contractor's self-agreement is unlikely to satisfy an IE appointed by a DFI or international bank.

Domain 6: Land and Regulatory Clearances

Land documentation LDED checklist:

Land ownership: registered sale deed (freehold), or registered lease agreement with ≥ 25 years remaining term from commissioning date
Land-use: agricultural land-to-commercial/industrial conversion order from revenue authority (if applicable)
Land-use conversion: applicable in states that require it (Rajasthan, Maharashtra, Karnataka, Telangana — check the specific state revenue code)
Environmental clearance (EC): required for projects above 25 MW in most Indian states under the EIA Notification 2006; confirm with MOEF/SPCB for your project state
Grid-connectivity approval: executed LTA or MTOA agreement from SECI or the state DISCOM
PPA: fully executed between developer and off-taker (SECI/DISCOMS/private buyer)
Forest clearance: if any portion of the project land intersects reserved or protected forest — confirm with the Forest Department

Note. A grid-connectivity application letter is not the same as a connectivity approval. IREDA requires an executed LTA or MTOA agreement before financial close. If the DISCOM or SECI has not yet executed the agreement, IREDA may proceed to financial close with a condition precedent — but only if the application date and expected execution timeline are documented and accepted by the lender's credit committee.

Domain 7: EPC Contract Review for Bankability

The LDED team reviews the EPC contract for these minimum provisions:

Contract Term	IREDA Minimum Requirement	DFI Minimum Requirement
Performance guarantee	P50 annual yield, 25 years	P75 annual yield, 25 years
LD for performance shortfall	12 months tariff shortfall	24 months tariff shortfall
LD cap	20% of EPC contract value	30% of EPC contract value
Delay LD	0.1%/week, min 26 weeks	0.1%/week, min 52 weeks
Defect liability period	5 years (modules), 2 years (balance of plant)	10 years (modules), 5 years (balance of plant)
Performance testing protocol	IEC 61724 or equivalent	IEC 61724-1 specific
Insurance pass-through	CAR + ALOP; PI from designer	CAR + ALOP + PI; named insured includes lender

Domain 8: O&M Plan and Contractor Bankability

The lender’s LDED team evaluates the O&M plan because an under-resourced O&M program is a risk to long-term plant performance and thus to debt service.

O&M LDED checklist:

O&M contractor: minimum 3 years’ experience managing solar plants > 1 MW in India
MW under management: minimum 20 MW portfolio for IREDA projects; 50 MW for DFI projects
AMC scope: cleaning (frequency defined per soiling level), preventive maintenance schedule, corrective maintenance SLA (< 48 hours for inverter failures), SCADA monitoring
O&M cost: ₹7.5–9.5L/MW/year (year 1); annual escalation 3–5% documented
Insurance: O&M contractor must carry professional indemnity (PI) insurance ≥ ₹2Cr per event

Download an LDED-ready DPR engineering sample

See what a bankable PVsyst report and CEIG-ready SLD package look like — structured to pass IREDA's technical review on first submission.

Get the sample pack →

LDED Comment Categories — Frequency Analysis

Based on Heaven Designs’ review of LDED comment logs from 80+ Indian solar projects financed through IREDA, PFC, and REC between 2022 and 2025:

Comment Category	Frequency (% of projects)	Average Resolution Time
PVsyst loss values using defaults	64%	8–14 days
Missing signed deliverables	58%	3–7 days
Structural report not site-specific	51%	14–21 days (requires new bore logs)
Financial model inconsistency with PVsyst P90	48%	4–8 days
Land-use conversion certificate absent	44%	30–90 days (revenue authority processing time)
EPC contract LD cap insufficient	41%	7–21 days (contract renegotiation)
Grid connectivity approval outstanding	38%	30–60 days (DISCOM/SECI processing)
O&M plan absent or unpriced	35%	7–14 days

The resolution time column reveals the asymmetry: PVsyst and financial model corrections take days; structural reports requiring new soil investigation take weeks; land and regulatory clearances take months. This is why the LDED Eight-Domain Readiness Protocol prioritizes land and regulatory clearances as Domain 5 — if these are missing, start the resolution process immediately. Everything else can be fixed in parallel.

According to IREDA’s project finance framework, all technical reports submitted in support of a loan application must be prepared by qualified engineering professionals and, where applicable, bear the stamp of a licensed engineer or recognized technical institution. IREDA reserves the right to reject any technical report that does not meet these standards, and the loan processing period is suspended until compliant reports are received.

How Heaven Designs Helps

The LDED process is, at its core, an engineering documentation quality problem. Developers who prepare DPRs in-house with small engineering teams consistently produce documents that return with 15–30 comment items — not because their projects are technically flawed, but because the documentation does not meet the format and rigor standard that IEs expect. Heaven Designs’ LDED-ready engineering packages are structured specifically to pass IE review on first submission.

Bankable PVsyst Reports — IE-ready P50/P90/P99 yield studies with full loss justification, Solargis/Meteonorm data integration, and .PVC file archiving
Electrical CEIG Drawings — CEIG-approval-ready SLDs with signed electrical calculations for IREDA/PFC projects
STAAD Pro Report & Calculations — Site-specific structural reports with IS 875 Part 3 wind calculations and bore-log-based pile design
Solar Ground Mount Design — Complete IFC-grade engineering package for utility-scale projects
MW-Scale Project Management Consultancy — Owner’s engineer covering DPR preparation, LDED management, and IE interface
Download a sample deliverable — Redacted PVsyst report and SLD from a recently LDED-cleared 20 MW project

FAQ

What is LDED in solar project finance?

LDED stands for Lender’s Due-Diligence Engineering — the technical review process that a solar project’s financier (IREDA, PFC, SBI, or a DFI) commissions before disbursing project finance. It is typically conducted by an Independent Engineer appointed by the lender. The IE reviews the DPR across eight domains: irradiance, energy yield, electrical design, structural engineering, BOQ, land and regulatory clearances, EPC contract, and O&M plan. A positive IE technical opinion is a condition precedent to loan disbursement.

How long does the LDED process take for an Indian solar project?

The LDED process from DPR submission to positive IE opinion typically takes 6–10 weeks for a well-prepared first submission. Projects with significant comment items — missing signed documents, default PVsyst loss values, structural reports without site-specific soil data, or outstanding land clearances — extend the LDED cycle to 12–20 weeks. The most time-consuming comment resolutions are those requiring new regulatory approvals or additional site investigations, which can take 1–3 months.

What PVsyst parameters do LDED reviewers most frequently question?

The four parameters most frequently flagged are: soiling loss (default values are too optimistic for dry-climate sites), module degradation year 1 (using manufacturer marketing figures rather than LID-corrected values), system availability (assuming 100% availability with no planned maintenance downtime), and near-shading modeling (using the unlimited-shading approximation rather than the 3D shading scene model). Each of these can reduce the simulated P90 yield by 1–4%, which may change the DSCR from bankable to sub-threshold.

Does IREDA require a specific PVsyst report format?

IREDA does not prescribe a specific PVsyst report template, but it does require that the report cover: the data source and period for irradiance, all loss values with their justification, P50/P90/P99 annual yield, the simulation methodology, and the engineer’s certification. IREDA’s panel IEs have developed a set of expected disclosure items that they check systematically. The independent engineer DPR checklist covers all IE-expected items in detail.

What is the minimum DSCR that IREDA requires for solar project finance?

IREDA requires a minimum debt service coverage ratio (DSCR) of 1.25× calculated at the P90 annual energy yield. This means that the project’s revenue at P90 yield (which occurs in 9 out of 10 years statistically) must be at least 1.25 times the annual debt repayment obligation. Some IREDA facilities for specific green energy schemes allow a 1.20× DSCR with enhanced security. DFI lenders (AfDB, IFC, ADB) typically require 1.30–1.40× DSCR at P90.

Can a DPR be submitted to IREDA without an executed PPA?

IREDA does not process a loan application without an executed PPA. The PPA is one of the core conditions precedent to financial close. A term sheet or letter of intent from the off-taker is not sufficient — the PPA must be a fully executed, legally binding agreement. For SECI-scheme projects where SECI acts as the intermediary off-taker, the PSA (Power Sale Agreement) between SECI and the state DISCOM must also be in place.

How does the LDED process differ for DFI-financed projects compared to IREDA?

DFI lenders (AfDB, IFC, ADB, KfW) apply more demanding LDED standards in three areas: (1) environmental and social impact assessment — DFIs require an ESMP (Environmental and Social Management Plan) conforming to IFC Performance Standards or Equator Principles, which IREDA does not require; (2) EPC contract terms — DFIs expect stronger performance guarantee and LD provisions (see the table in Domain 7 of this guide); and (3) O&M contractor credentials — DFIs typically require an O&M contractor with minimum 50 MW under management and a track record of 5+ years. See the lender acceptance register guide for a comparison of IREDA vs DFI acceptance standards.

According to IFC’s Performance Standards (2012), all IFC-financed projects must comply with Environmental and Social standards that go beyond what Indian regulatory law requires. Developers seeking DFI financing for Indian solar projects should engage an ESMS (Environmental and Social Management System) consultant during the DPR preparation stage, not after the LDED review has started.

India’s Central Electricity Authority provides regulatory context for all grid-connected solar projects. According to the CEA Grid Connectivity Regulations, the technical documentation requirements for projects above 11 kV include protection scheme diagrams, earthing design reports, and commissioning test protocols — all of which must be at IFC-grade quality before DISCOM clearance is issued.