The single biggest barrier to commercial solar adoption is not technology — it is capital. A Power Purchase Agreement (PPA) removes the upfront investment entirely, but trades it for decades of contractual obligations. Direct ownership maximises long-term returns but requires capital. Understanding the trade-offs is the first step in any C&I solar decision.
How each model works
Direct ownership (outright purchase or loan)
The business purchases the solar system outright or finances it through a bank loan or green finance facility. The business owns the asset, captures all energy savings, and takes all depreciation and tax benefits available in their jurisdiction. After loan repayment (typically 5–8 years), energy is effectively free for the remaining 17–20 years of the system's life.
Power Purchase Agreement (PPA)
A third-party investor (Independent Power Producer, or IPP) owns, installs, and operates the solar system on the customer's roof or land. The customer signs a long-term contract (typically 10–25 years) to purchase electricity from the system at a fixed or escalating rate, which is lower than the grid tariff. The customer pays zero upfront and zero for maintenance — but also owns nothing and cannot easily exit the contract.
Solar lease
Similar to a PPA but the customer pays a fixed monthly fee for use of the system rather than a per-kWh rate. Less common in commercial applications than PPAs or direct purchase.
Side-by-side comparison
| Factor | Direct ownership | PPA |
|---|---|---|
| Upfront cost | High (or loan repayments) | Zero |
| Long-term savings | Maximum (100% of bill reduction) | Partial (spread with IPP) |
| Asset on balance sheet | Yes — improves asset base | No (off-balance-sheet) |
| O&M responsibility | Owner's responsibility | IPP's responsibility |
| Technology risk | Owner bears degradation risk | IPP bears performance risk |
| Flexibility | Full control, can modify/expand | Contract terms restrict changes |
| Tax benefits | Owner captures depreciation | IPP captures depreciation |
| Property sale impact | System transfers with property | PPA must transfer or be terminated |
| Typical contract length | Owned forever | 10–25 years |
| Best for | Businesses with capital access and long tenure | Businesses with no capital or credit constraints |
The financial case for direct ownership
For a business with access to capital or green financing at reasonable rates, direct ownership almost always produces better long-term economics. Consider a 500 kWp rooftop system in a market with a $0.12/kWh grid tariff:
- System cost: ~$350,000 (installed)
- Annual generation: ~650,000 kWh
- Annual savings: $78,000/year
- Simple payback: 4.5 years
- 25-year savings (no escalation): $1,950,000 — a 5.6× return on investment
Under a PPA at $0.09/kWh, the same business saves $0.03/kWh over the grid tariff — $19,500/year, or $487,500 over 25 years. The IPP captures the other $1,462,500 in value. Direct ownership delivers 4× more lifetime value than a PPA in this scenario.
When a PPA makes sense
Despite the long-term economics favouring ownership, PPAs serve a real need in several situations:
- Capital constraint: The business has no budget for capital expenditure and cannot access debt financing at reasonable rates
- Credit quality: The IPP can access cheaper capital than the business, making the overall project viable at a rate that still beats the grid tariff
- O&M expertise: The business does not want to manage solar maintenance — a legitimate concern for companies without facilities management expertise
- Short lease / short tenure: If the business is unlikely to occupy the property for 10+ years, direct ownership is risky — the system may not achieve payback before a move
- Public sector: Government entities often cannot capitalise assets or take depreciation benefits, making the ownership model unattractive relative to PPAs
PPA contract terms to scrutinise
If a PPA is the right choice, the contract terms matter enormously:
- Escalation rate: Many PPAs include annual rate escalations of 1–3%. Over 20 years, a 2% annual escalation on a $0.09/kWh PPA rises to $0.134/kWh — which may exceed future grid tariffs if energy markets evolve. Negotiate a fixed rate or a cap.
- Minimum generation guarantee: Without a performance guarantee, the customer has no recourse if the system underperforms. Insist on a minimum annual generation guarantee with liquidated damages.
- Termination clause: Terminating a PPA early can cost 10–30% of remaining contract value. Review the buyout schedule annually and understand the exit cost before signing.
- Property transfer: If the business sells the property, the PPA must transfer to the new owner, who may not accept it. This can complicate or block a property sale.
- Technology ownership at end of term: Many PPAs allow the customer to purchase the system at fair market value (often near zero) at contract end. Others require the IPP to remove the system. Clarify this upfront.
Green financing: the middle path
For businesses that want the ownership economics but lack liquidity, green loans and sustainability-linked credit facilities increasingly bridge the gap. In markets like Southeast Asia and the Middle East, development finance institutions (DFIs) and green banks offer concessional loans at 3–6% for solar projects, dramatically improving the ownership ROI versus commercial lending rates.
At 5% financing over 7 years, the 500 kWp system in the example above costs approximately $5,600/month in debt service — equivalent to about $0.026/kWh — leaving a net saving of about $0.094/kWh versus the grid, or $61,100/year. Full ownership after year 7 delivers the remaining 18 years at near-zero cost.