$28,000 Solar System in San Antonio: How the Domestic Content ITC Bonus Saves Cash and Loan Buyers $2,800 That Lease and PPA Customers Never See
The scenario: a $28,000 quote on your San Antonio roof
Say you got a quote this month for an 8 kW rooftop system in San Antonio — $28,000 before incentives, $3.50 per watt installed. Your installer's proposal shows "30% federal tax credit" and calls it a day. What it probably doesn't mention: there's a second federal credit sitting on the table worth another 10% of system cost, and whether you can claim it — or your lease company claims it instead — depends entirely on how you finance the system.
That's the real story buried in this week's solar manufacturing news. Solar Power World reported that OCI appears to be bringing its Elite Solar panel line into Mission Solar Energy's manufacturing site in San Antonio — one of the longest-running U.S. panel assembly plants, running since 2014. Around the same time, PV Magazine USA reported First Solar dropped its Section 337 patent complaint against TOPCon manufacturers now that new Section 232 import tariffs are doing similar work at the border. Put those two stories together and you get a practical, dollar-denominated question for anyone in South Texas shopping for solar this fall: does more domestic panel supply in your own backyard actually change your payback math? It does — but only if you own the system.
Based on Elovane's analysis of the EIA electricity price dataset, NREL's county-level solar irradiance data, and the DSIRE incentive program database (part of the 10,850-row dataset we maintain across seven sources), here's the full comparison — cash, loan, lease, and PPA — run against real San Antonio numbers.
Translating the jargon first
Before the math: four ways to pay for solar, and what each one actually means for who owns what.
- Cash purchase — you pay the full cost, you own the system, you claim every tax credit and utility incentive directly.
- Solar loan — you still own the system (and claim the credits), but you're paying it off over time with interest, like a car loan secured against the equipment.
- Solar lease — a third party owns the system; you pay a fixed monthly rent for the electricity it produces. The third party keeps the tax credits.
- PPA (power purchase agreement) — same third-party ownership, but instead of a flat rent, you pay per kilowatt-hour actually produced, usually at a rate below your utility's retail price.
The credits at stake here are the federal Investment Tax Credit (ITC) — 30% of system cost — plus a domestic content bonus of an additional 10% if enough of the steel, iron, and manufactured components (inverters, racking, and in some structures, the panels themselves) are U.S.-made. That's a combined 40% credit, but it only flows to whoever legally owns the system on the day it's placed in service. Own it, and you get up to $11,200 back on a $28,000 system. Lease or PPA it, and the third-party owner gets that money — priced (maybe) into your monthly rate, or maybe not.
Why San Antonio's manufacturing news actually matters here
Meeting the domestic content threshold has historically been the hard part — installers often couldn't source enough qualifying components to hit the percentage requirement, so many buyers left that second 10% on the table even when they legally owned their system. That's the part the manufacturing news touches directly: with Mission Solar Energy's existing San Antonio line and OCI reportedly adding Elite Solar production at the same site, local installers get an easier path to specifying enough domestically-produced content to actually qualify. Meanwhile, First Solar backing off its TOPCon patent fight — a fight it can now let the newer Section 232 tariffs handle instead — signals continued upward pressure on imported panel pricing, which nudges the economics further toward domestic supply chains being price-competitive, not just compliance boxes to check.
Translation for your quote: ask your installer, by name, which panel and inverter models they're proposing and whether the system as designed actually qualifies for the domestic content adder. It's a single question that's worth up to $2,800 on this system size — but only if you're the owner of record.
The worked numbers
Assumptions, all sourced from our internal datasets:
- System: 8 kW DC, $28,000 installed ($3.50/W)
- Production: ~11,500 kWh/year, based on NREL's county-level solar irradiance data for Bexar County, TX, south-facing roof, minimal shading
- Utility rate: $0.13/kWh residential (CPS Energy, San Antonio's municipal utility, running below the Texas statewide EIA average of roughly $0.152/kWh)
- Export credit: $0.055/kWh for excess production, reflecting CPS Energy's avoided-cost buyback structure (Texas has no state-mandated net metering requirement — worth noting since net metering rules vary enormously by state)
- Combined credit for owned systems: 30% base ITC + 10% domestic content = 40%, or $11,200
- Net cost, cash or loan: $16,800
- Solar loan rate: 7.75% APR, 15-year term — consistent with the elevated financing environment reflected in our FRED financial rates dataset this year
Year-one bill savings, blending self-consumption and export credit at roughly an 85/15 split, come out to about $1,365. That single number is the input for everything below — and it's exactly the kind of figure that changes on every roof, every rate schedule, and every utility territory, which is the whole reason a generic "solar pays for itself in 7 years" headline is useless for your specific house. You can model this for your specific situation at Elovane rather than eyeballing it from a national average.
Payback at three rate escalation scenarios (cash purchase)
Utility rates don't sit still for 25 years, and your escalation assumption swings the payback year more than almost anything else in the spreadsheet. Running the $16,800 net cost against cumulative savings at three EIA-informed escalation rates:
| Rate escalation | Cumulative crossover point |
|---|---|
| 2%/year | ~11.1 years |
| 4%/year | ~10.2 years |
| 6%/year | ~9.5 years |
That's a real swing — nearly two years of payback difference — driven entirely by an assumption most installer quotes bury in fine print or skip altogether. Given that this week's utility-scale roundup from PV Magazine USA shows continued large-scale buildout (300 MW in Utah, corporate PPAs tied to Texas tech-sector power demand, California microgrid and storage expansion) layered on top of AI data centers forming their own demand-management alliance to soak up grid capacity, betting on flat or declining electricity rates over the next decade looks optimistic. We've written previously about how rising loan rates and utility rate escalation interact to move payback by years, not months — this San Antonio example is a smaller-scale version of the same dynamic.
NPV over 25 years: cash vs. loan vs. lease vs. PPA
Here's where financing choice stops being a preference and becomes a dollar figure. Using a 5% discount rate and 4% utility rate escalation, modeling the loan at 7.75%/15-year, a lease at a fixed monthly payment escalating 2.9%/year, and a PPA priced at $0.115/kWh (also escalating 2.9%/year, versus a 4%-escalating utility rate):
| Financing method | Net present value over 25 years |
|---|---|
| Cash purchase | $12,233 |
| Solar loan | $9,342 |
| PPA | $6,830 |
| Solar lease | $5,811 |
That's a $6,422 gap between cash and lease on the exact same roof, exact same panels, exact same production — purely a function of who owns the asset and who captures the 40% tax credit. The loan sits in between: you pay roughly $2,900 in present-value terms for the convenience of not writing a $16,800 check upfront, but you still keep the full incentive stack because you still own the system. This is the kind of analysis Elovane runs for you — so you don't have to build the spreadsheet yourself, and you don't have to take an installer's best-case lease pitch at face value. If you want the fuller national picture on how these four financing paths stack up, we've broken it down in more depth in our solar loan vs. lease vs. cash comparison.
The ownership question that's about to matter even more: who gets paid for the RECs?
There's a newer wrinkle worth flagging, even though it's currently playing out at utility scale rather than on residential roofs. PV Magazine USA reported this week on a Google-backed pilot — Quintrace, esVolta, and LevelTen Energy time-shifting 9.2 GWh of battery storage output to sell granular, carbon-free environmental attribute certificates (EACs) for corporate 24/7 energy matching. It's the first commercial proof that a battery can earn extra revenue simply by shifting when it discharges clean electricity, not just how much.
That revenue stream belongs to whoever owns the underlying renewable energy certificates — which, on a residential system, means whoever owns the system. Cash and loan buyers keep their RECs by default. Lease and PPA contracts routinely sign those RECs over to the third-party owner as boilerplate. It's not a large dollar figure for a single home today, but as residential VPP and REC-aggregation platforms mature — and they're moving that direction fast, following the same playbook this pilot just validated commercially — owned systems (especially paired with a battery) are positioned to capture that value and leased systems structurally are not. If you're weighing a battery alongside this system, our TOU rate spread battery payback analysis for Texas walks through how CPS Energy's rate structure specifically affects that math.
What to actually check before you sign
- Ask who owns the system. If it's a lease or PPA, you are not eligible for the 30% ITC or the 10% domestic content bonus — full stop, regardless of what the salesperson implies.
- Ask for the specific panel and inverter models and their manufacturing origin. With Mission Solar Energy and potentially OCI's Elite Solar line both producing locally in San Antonio, domestic-content-qualifying equipment is more available in this market than it was two years ago — but it's still not automatic on every quote.
- Get your installer's utility rate escalation assumption in writing. A 2% vs. 6% assumption moved this example's payback by nearly two years; on a larger system or higher-usage household, the swing is bigger.
- Compare the NPV, not just the monthly payment. A lease that "starts saving you money on day one" can still leave $6,000+ in present-value savings on the table over 25 years compared to owning the same system outright.
None of these numbers are yours until you run them against your actual roof, your actual utility rate, and your actual financing offer — San Antonio's numbers won't match Austin's, and CPS Energy's buyback rate won't match a neighboring co-op's. Run your own numbers at Elovane before you sign anything.
Data behind this post
The figures above are computed from the product's own reference tables, last refreshed 2026-04-15:
- 3,672 rows from eia_electricity_prices
- 51 rows from nrel_solar_irradiance
- 6,287 rows from nrel_county_solar
- 648 rows from nrel_atb_system_costs
- 171 rows from dsire_incentive_programs
- 7 rows from fred_financial_rates
- 14 rows from nrel_solar_defaults
Sources
- What role will renewable energy play in the AI Energy Management Alliance? — PV Magazine USA
- Utility-scale project roundup: Utah solar, Texas tech power, California microgrids and storage, and Massachusetts community solar — PV Magazine USA
- Google-backed pilot unlocks first environmental certificate revenue stream for battery storage — PV Magazine USA
- First Solar drops TOPCon patent complaint — PV Magazine USA
- Texas records suggest OCI is bringing Elite Solar to Mission Solar Energy manufacturing site — Solar Power World