Solar Project Financing Guide
CAPEX · PPA · Lease · PACE · Bonds (2026)
The B2B playbook: how corporate developers, EPCs, and commercial buyers structure solar project financing. 5 financing models compared, IRR/NPV/LCOE benchmarks, and how module sourcing affects project economics.
5 Financing Structures Compared
Each with pros, cons, typical IRR, and minimum project size.
CAPEX (Self-Financed)
Corporate buyer with strong balance sheet, wanting 100% asset ownership & full savings
Customer pays upfront CAPEX (typically $0.50-1.20/Wp turnkey). Full tax depreciation + all savings to customer.
Highest IRR (15-25% unlevered), no long-term contracts, full ownership, instant balance-sheet asset.
Large upfront cash outlay; opportunity cost of capital.
PPA (Power Purchase Agreement)
C&I buyer wanting no CAPEX, stable electricity cost, off-balance-sheet
Developer owns + operates system on customer's site. Customer buys solar kWh at agreed $/kWh (typically 10-30% below grid). Contract 15-25 years.
Zero CAPEX, instant savings day 1, O&M handled by developer, off-balance-sheet.
Lower lifetime savings vs CAPEX, long-term lock-in, complex contract, transfer risk on property sale.
Solar Lease
Commercial/municipal buyer wanting predictable fixed monthly payment
Customer leases equipment; fixed monthly payment (5-25 years). Own system at end (EBO) or buyout/renewal option.
Predictable cost, no CAPEX, simpler than PPA structure, may qualify for tax advantages.
Tax credits sometimes captured by lessor not lessee; total cost higher than CAPEX.
PACE Financing (USA)
US commercial property owners with long hold period
Loan attached to property tax bill, 10-30 year term. Transfers with property sale. Available in C-PACE-enabled states.
Long tenor, transfers with property, 100% financing possible, off-balance-sheet.
USA-only (C-PACE), subject to state/local adoption, mortgage lender consent required.
Green Bonds / Project Finance
Utility-scale 20+ MW projects, developer with track record
Non-recourse project finance. 70-80% debt, 20-30% sponsor equity. Debt tenor 15-22 years. Requires BNEF Tier-1 module, bankable EPC, offtaker PPA.
Capital-efficient, scalable to hundreds of MW, developer retains control.
Bankability requirements exclude smaller/newer developers; long due-diligence cycle.
Financial Metrics Cheat Sheet
Σ(CAPEX + OPEX_t) / Σ(Energy_t) ÷ discount factor
$20-45/MWh utility; $50-90/MWh C&I rooftop (2026)
Rate where NPV = 0
15-25% unlevered CAPEX; 10-18% levered project finance
Σ Cash Flow_t / (1+r)^t − CAPEX
Positive NPV @ 8-10% discount rate = go decision
CAPEX / Annual Savings
4-7 years C&I rooftop; 6-10 years utility-scale depending on PPA
Solar Financing FAQ
What's the #1 mistake B2B buyers make in solar financing?▼
Underestimating the cost of non-production time. Every week delay between CAPEX signing and commissioning = 1/52 of first-year revenue lost (never recovered). For a $1M project generating $200K/yr, that's ~$4K per week. Rushing equipment selection or cutting corners on EPC contract terms to save 1% CAPEX often loses 3-5x that in delays. Budget 10-15% more contingency + pick proven suppliers.
How do I calculate LCOE for my project?▼
LCOE = (Total Lifetime Cost) ÷ (Total Lifetime Energy) ÷ Discount factor. Total lifetime cost = CAPEX + sum of OPEX over project life, discounted. Total lifetime energy = Year-1 output × (1 - degradation)^t summed. Use our free ROI calculator which computes LCOE automatically once you enter system size, location, and CAPEX.
When should I use a PPA vs CAPEX?▼
CAPEX (buy outright) when: you have cash or cheap debt; want maximum long-term savings; plan to own the property 10+ years; in a market with valuable tax incentives. PPA when: zero CAPEX is mandatory; you want instant guaranteed savings without capital outlay; you need off-balance-sheet treatment; you don't want O&M responsibility. For most C&I buyers with capital, CAPEX produces better 25-year NPV by 30-50%.
How much does the module $/W affect project IRR?▼
Significantly. Modules are typically 25-35% of total CAPEX. A $0.02/W savings on modules (e.g. JUSTSOLAR factory-direct vs Tier-1 distributor) on a 1 MW project = $20K CAPEX saved. At 20% IRR baseline, that's equivalent to adding ~1.2 percentage points to IRR. Over 25 years, compounds to $50-80K NPV improvement. Hence the rationale for sourcing modules direct from factory vs branded distributors.
Can I finance module purchases separately from EPC?▼
Yes — this is called equipment finance or trade finance, common for larger orders. JUSTSOLAR can provide lender documentation for project review, but payment terms are confirmed only in the formal PI or signed contract. For new buyers and most first orders, standard is 100% T/T before shipment. Any bank-instrument or milestone-payment exception requires written approval from Frank.
What's the typical bankability requirement for utility-scale?▼
For project-financed utility-scale (20+ MW): (a) BNEF Tier-1 module (currently ~30 brands qualify), (b) 25+30 year warranty backed by manufacturer, (c) PPA with creditworthy offtaker, (d) bankable EPC contractor with performance guarantees. JUSTSOLAR is Tier-1 adjacent — we can supply as sub-supplier under a Tier-1 branded module wrap for bankability if needed. For C&I and distributed generation (under 20 MW), we supply directly without the bankability constraint.
Financing Ready? Start With Module Sourcing.
Modules are 25-35% of CAPEX. Factory-direct sourcing from JUSTSOLAR saves 10-15% $/W vs Tier-1 distributors — directly improving project IRR by 1-2 percentage points.
Also see: Wholesale Prices · B2B Buyer's Guide