Throughout this project, I explored where carbon capture technologies might be most geographically and geologically feasible in the U.S. — first through Direct Air Capture (DAC) powered by renewables, then through Point Source Capture (PSC) at major industrial sites.
However, given the magnitude and complexity of reversing atmospheric carbon buildup, scientists are increasingly coming to the conclusion that no single solution will suffice. A realistic carbon capture strategy must blend both PSC and DAC technologies, tailoring them to regional strengths. Where large industrial emitters overlap with accessible storage geology, PSC offers an efficient, near-term path to emissions reduction. Meanwhile, DAC’s ability to operate independently of emissions hotspots will likely be crucial for reaching net-negative targets in the long run. Together, alongside careful reservoir management, these complementary technologies offer the best shot at addressing the climate challenge at scale.
In this final installment, I compare the two approaches directly and reflect on where a blended strategy is not only possible, but necessary.
DAC vs. PSC: A Summary Comparison
| Aspect | DAC | PSC |
|---|---|---|
| Capture Source | Atmospheric CO₂ | Industrial stack emissions |
| CO₂ Concentration | ~420 ppm (very dilute) | 5–20% (much higher) |
| Energy Intensity | High | Lower |
| Siting Flexibility | High (can be placed anywhere with clean energy) | Limited (must be co-located with emission source) |
| Tech Maturity | Emerging | Mature (demo plants exist) |
| Best Fit Regions | Land-rich, high-renewables (e.g., West Texas, Midwest) | Industrial clusters near geology (e.g., Midwest, Gulf Coast) |
Revisiting DAC: West Texas as a Contender
Stephen Whitley, my supervisor from Whitley Digital Consulting, pointed out that my earlier DAC analysis used a wind speed threshold (≥10 mph) based on surface-level measurements — which may have inadvertently excluded regions like West Texas, where wind farm activity is extensive.
According to Stephen:
“At 100m — where modern wind turbines operate — wind speeds are often 40–70% faster than surface readings. That shift makes places like West Texas viable for wind-powered DAC, especially when you factor in available land.”
This feedback highlights how even areas that fell short of my initial raster thresholds can still make economic sense when terrain, height, and infrastructure are considered. With both solar irradiance and wind speeds at turbine height, West Texas emerges as one of the few regions where DAC could be supported by multiple renewable sources — a key advantage in siting large-scale atmospheric carbon removal.
Narrowing PSC: Midwest Plants With Dual Storage Access
In Part 2, I identified numerous power plants emitting over 1 million tons of CO₂ annually that sit directly atop either saline reservoirs or depleted oil fields.
But when filtering even further, a set of Midwestern power plants stood out for their proximity to both types of storage. These sites — clustered in states like Illinois, Indiana, and Ohio — represent ideal PSC targets: they’re high-volume emitters and strategically located near geologic storage options.
These dual-access sites could:
- Begin with enhanced oil recovery to help fund retrofits (oil reservoirs)
- Transition to long-term saline injection as oil capacity is exhausted
Sector Suitability: Where PSC Has the Edge
Based on global emissions rankings, PSC is most viable in sectors where emissions are concentrated and process-based:
| Sector | % of global emissions | Suitability for PSC |
|---|---|---|
| Power Generation | ~31% (#1) | Ideal target (stack emissions) |
| Cement | ~8% (#3) | High emissions per facility |
| Iron & Steel | ~7% (#4) | Capturable, large-scale sites |
| Chemicals | ~5% (#6) | High CO₂ purity, centralized plants |
As Stephen pointed out, distributed emissions (like cars, cows, or residential heating) aren’t good PSC candidates — these are precisely where DAC would be needed to achieve net-negative outcomes.
Conclusion: Toward a Blended Strategy
The data — and the geography — point to a clear conclusion:
We need both DAC and PSC to meet climate goals.
Point Source Capture is the low-hanging fruit — especially in the industrial Midwest and Gulf Coast where emitters and storage align. But Direct Air Capture will be vital for reaching deep decarbonization and atmospheric drawdown, especially in rural regions with abundant renewable potential and no concentrated emissions sources.
Rather than treating these technologies as competitors, it’s time to view them as complementary tools in a national CCS portfolio — tailored to regional strengths, and deployed with urgency.