📊 Detailed Case Study

Project "SunField Alpha"

Updated: March 2026

Ground-Mounted Solar Plant — 20 MWp — Southern France

Comparative analysis: technologies, configurations and profitability

20

MWp installed

32 ha

Land area

1,480

kWh/kWp/year (PVGIS)

25 yrs

Operating lifetime

This case study presents the financial analysis of a fictional but realistic solar photovoltaic project, based on verified market data. The objective is to compare different technical configurations (PERC vs TOPCon panels, fixed vs trackers) and evaluate their impact on profitability.

We analyze 4 scenarios to identify the optimal combination between investment and production, while respecting standard project finance constraints.

⚙️ Modeling Assumptions

Key parameters used for financial analysis — essential for assessing project bankability.

Sizing

  • DC Power20 MWp
  • AC Power16 MW
  • DC/AC Ratio1.25
  • Land Area32 ha (~1.6 ha/MWp)

Financial Parameters

  • WACC6.5%
  • Discount Rate7%
  • Construction Period12 months
  • IDC (Interest During Constr.)~€180k

Indexation & Provisions

  • Tariff IndexationL + 0.5×ICHT
  • OPEX Escalation2%/year
  • Decommissioning Reserve€50k/MWp
  • Inverter ReplacementYear 12

📍 Location & Solar Resource

The site is located in Southern France, benefiting from excellent solar irradiation. Solar resource was assessed using PVGIS, the European reference for yield studies.

Site Characteristics

  • LocationMontpellier (34)
  • Latitude / Longitude43.6° N / 3.9° E
  • Altitude50 m
  • Land TypeAgricultural wasteland
  • Land Area32 hectares
  • Grid ConnectionSubstation 2.5 km

Note: 32 ha corresponds to ~1.6 ha/MWp, standard ratio for trackers including access roads and technical areas.

Irradiation Data (PVGIS)

  • GHI (Global Horizontal)1,720 kWh/m²/year
  • DNI (Direct Normal)1,950 kWh/m²/year
  • Optimal Tilt33°
  • Yield (fixed 33°)1,480 kWh/kWp/year
  • Yield (1-axis tracker)1,720 kWh/kWp/year

Source: PVGIS 5.2 — European Commission (2024)

⚡ Panel Technology Comparison

Module selection is critical for long-term performance. We compare PERC monocrystalline (current standard) and TOPCon bifacial (next generation).

PERC Mono

Standard

Proven technology, best price/performance ratio today

  • Reference ManufacturerLongi / Jinko / Trina
  • Unit Power550 Wp
  • Module Efficiency21.5%
  • Number of Modules36,364 modules
  • Annual Degradation0.45%/year
  • Performance Warranty84.8% at 25 years
  • Module Price€0.11/Wp
  • Total Module Cost€2.2M

TOPCon Bifacial

Premium

Next-gen technology with passivated contact cells and bifacial production

  • Reference ManufacturerLongi Hi-MO 7 / Jinko Neo
  • Unit Power580 Wp
  • Module Efficiency22.8%
  • Number of Modules34,483 modules
  • Annual Degradation0.40%/year
  • Performance Warranty87.4% at 25 years
  • Bifacial Gain+5 to 10% (albedo dependent)
  • Module Price€0.14/Wp
  • Total Module Cost€2.8M

Analysis: The TOPCon premium (+27%) can be offset by a production gain of 5 to 10%, varying by site conditions. Bifacial gain strongly depends on ground albedo (reflectivity), mounting height, and GCR (Ground Coverage Ratio). On light-colored soil with elevated trackers: +8-10%. On dark soil with low fixed structure: +3-5%.

Sources: IRENA Renewable Power Generation Costs 2024, PV Magazine Market Survey Q4 2024

🔧 Mounting Structure Comparison

The choice between fixed structure and trackers impacts production and investment. Single-axis trackers follow the sun from East to West, optimizing energy capture throughout the day.

Fixed Structure

Economic

Simple, reliable solution with minimal maintenance

  • TypeGalvanized steel fixed tables
  • Tilt33° (PVGIS optimized)
  • OrientationSouth (azimuth 0°)
  • Minimum Height0.8 m
  • Yield1,480 kWh/kWp/year
  • Structure Price€0.05/Wp
  • Total Cost€1.0M

Single-Axis Trackers

Performance

East-West solar tracking maximizing energy production

  • TypeHorizontal N-S single-axis tracker
  • ManufacturerNextracker / Array Tech
  • Rotation±60°
  • Pivot Height1.5 m
  • Yield1,720 kWh/kWp/year
  • Gain vs Fixed+16.2%
  • Structure Price€0.10/Wp
  • Total Cost€2.0M

Analysis: Trackers double structure cost (+€1M) but increase production by 16%. With a tariff of €75/MWh, the additional production generates approximately €360k/year in extra revenue (20 MWp × 240 kWh/kWp × €75/MWh). The premium is paid back in less than 3 years, making trackers very attractive in high-irradiance locations.

🔌 Inverters & Electrical Equipment

Central Inverters

  • ModelHuawei SUN2000-330KTL
  • Unit Power330 kVA
  • Efficiency99.0%
  • Quantity60 inverters
  • MPPT12 per inverter
  • Unit Price€18,000
  • Total Cost€1.08M

Delivery Substation

  • Voltage20 kV / 400 V
  • Transformers4 × 5 MVA
  • MV Cells8 cells
  • ProtectionSEPAM Relay
  • MeteringClass 0.5
  • Substation Cost€450k

Cabling & BOS

  • DC Cables85 km (6 mm²)
  • LV AC Cables12 km
  • MV Cables3.5 km (240 mm²)
  • ConnectorsMC4 (145,000 pcs)
  • GroundingBare copper 35 mm²
  • BOS Cost€1.2M

💰 CAPEX Breakdown — 4 Scenarios

Investment cost breakdown by item. Scenarios range from lowest cost (A) to highest performance (D). The 1.25 DC/AC ratio is integrated into inverter sizing.

Item A: PERC + Fixed B: TOPCon + Fixed C: PERC + Trackers D: TOPCon + Trackers
PV Modules €2,200k €2,800k €2,200k €2,800k
Structure / Trackers €1,000k €1,000k €2,000k €2,000k
Inverters €1,080k €1,080k €1,080k €1,080k
Substation & Grid Connection €850k €850k €850k €850k
Cabling & BOS €1,200k €1,200k €1,200k €1,200k
Civil Works & Fencing €600k €600k €700k €700k
Installation & Labor €1,400k €1,400k €1,600k €1,600k
Development & Permitting €800k €800k €800k €800k
Insurance & Financial Costs €370k €390k €415k €440k
Contingency Reserve (5%) €475k €506k €542k €574k
TOTAL CAPEX €9,975k €10,626k €11,387k €12,044k
CAPEX / Wp €0.50/Wp €0.53/Wp €0.57/Wp €0.60/Wp

Sources: IRENA Renewable Power Generation Costs 2024, Berkeley Lab Utility-Scale Solar 2024, French market experience

📈 Production & Annual Revenue

Production depends on solar resource, equipment performance, and system losses. Revenue is calculated under two schemes: the CRE tender contract (secured) and spot market sales (merchant).

Production Assumptions

  • Performance Ratio (PR)82%
  • Technical Availability98%
  • Grid/Clipping Losses2%
  • Y1 Degradation2%
  • Annual Degradation0.40-0.45%/year
  • Bifacial Gain (TOPCon)+7%

Year 1 Production (P50)

  • A: PERC + Fixed29,600 MWh
  • B: TOPCon + Fixed31,680 MWh+7%
  • C: PERC + Trackers34,400 MWh+16%
  • D: TOPCon + Trackers36,800 MWh+24%

25-year cumulative production (Scenario D): ~850 GWh

CRE Tender vs Merchant Comparison

CRE Tender (Support Contract)

Secured

Guaranteed feed-in premium through PPE2 competitive tenders.

  • Average Tariff 2024€75/MWh
  • Contract Duration20 years
  • IndexationL + 0.5×ICHT (~1.5%/yr)
  • Y1 Revenue (Scenario D)€2,760k

✅ Bankable: senior debt financing up to 80%

Merchant (Spot Market)

Risky

Direct sales on EPEX Spot, exposed to volatility and solar cannibalization.

  • Average Spot Price 2024€65-85/MWh
  • Solar Capture Price~€55-65/MWh
  • Capture Rate~80-85%
  • Estimated Y1 Revenue€2,000 - 2,400k

⚠️ Cannibalization: prices drop when solar produces. Equity >40% required.

🏦 Financing Structure (Scenario D — CRE Tender)

Standard project finance structure with senior debt and sponsor equity, applicable to Scenario D (TOPCon + Trackers) under CRE tender contract.

Senior Debt

  • Amount€9,635k
  • Gearing80%
  • Rate (margin + Euribor)5.5%
  • Tenor18 years
  • Minimum DSCR1.20x

Equity

  • Amount€2,409k
  • Share20%
  • InvestorSponsor / IPP
  • Target IRR>12%

Annual OPEX

  • O&M (€12/kWp/yr)€240k
  • Insurance€60k
  • Land Lease€48k
  • Taxes (IFER, CFE)€85k
  • Asset Management€55k
  • Total OPEX€488k/year

🎯 Financial Results — 4-Scenario Comparison

Indicator A: PERC + Fixed B: TOPCon + Fixed C: PERC + Trackers D: TOPCon + Trackers
Total CAPEX €9.98M €10.63M €11.39M €12.04M
Y1 Production 29,600 MWh 31,680 MWh 34,400 MWh 36,800 MWh
Y1 Revenue (€75 tariff) €2,220k €2,376k €2,580k €2,760k
Y1 EBITDA €1,732k €1,888k €2,092k €2,272k
LCOE €42.5/MWh €41.2/MWh €39.8/MWh €38.6/MWh
Project IRR (pre-tax) 7.8% 8.2% 8.6% 9.1%
Equity IRR (leveraged) 11.2% 12.4% 13.1% 14.2%
Payback (equity) 8.5 years 7.8 years 7.2 years 6.7 years
Average DSCR 1.28x 1.35x 1.42x 1.48x

🏆 Analysis Conclusion

Scenario D (TOPCon bifacial + Trackers) delivers the best returns despite a 21% higher CAPEX versus the baseline. The 24% production gain more than compensates for the additional investment.

14.2%

Equity IRR

€38.6

LCOE / MWh

6.7 yrs

Equity Payback

⚠️ Risk Analysis

Identification and classification of project risks by mitigation level. This framework is essential for investment committees and lenders.

✅ Mitigated Risks

  • Price Risk: 20-year CRE contract with indexed tariff
  • Resource Risk: PVGIS validated data, P90 -8%
  • Technology Risk: Proven technologies, manufacturer warranties
  • Construction Risk: Turnkey EPC, performance guarantee
  • Operational Risk: Contracted O&M, 98% availability guaranteed

⚠️ Residual Risks

  • Regulatory Risk: Tax changes (IFER), permit delays
  • Interest Rate Risk: Euribor impact on debt service
  • Counterparty Risk: Off-taker solvency (if corporate PPA)
  • Grid Risk: Curtailment, network congestion
  • Tail Risk: Terminal value post-contract (years 21-25)

📚 Sources & References

IRENA — Renewable Power Generation Costs in 2023 (June 2024)

CRE — PPE2 Ground-Mount Solar Tender Results (2023-2024)

PVGIS — Photovoltaic Geographical Information System v5.2

Berkeley Lab — Utility-Scale Solar Data Update 2024

PV Magazine — Module Price Index Q4 2024

BloombergNEF — Solar PV Equipment Tracker

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