Abstract
Carbon capture is often praised as a key step toward decarbonization — but few talk about its hidden side effect: the massive energy it consumes.
Every tonne of CO₂ captured means less power for the grid, forcing plants to burn more fuel just to stay even.
This article unpacks that paradox and explains why smart heat recovery and integration are crucial for making CCS truly sustainable.
The big picture: energy producers under pressure
Carbon capture and storage (CCS) is widely discussed in power generation, especially in waste-to-energy (WtE) facilities and conventional fossil-fuel plants such as coal and gas.
These producers still rely on combustion — and therefore unavoidably emit carbon dioxide.
In WtE, the picture is more nuanced. Only part of the emitted CO₂ is of fossil origin; a significant share comes from biogenic fractions of municipal waste.
Capturing that portion can even result in net-negative emissions, provided the CO₂ is permanently stored or used without re-emission.
Yet whatever its origin, carbon capture comes with a steep energy penalty.
The process requires low-pressure steam for solvent regeneration and electricity for pumps, fans, and compressors.
The more CO₂ we capture, the less electricity reaches the grid — that’s the paradox at the heart of CCS.
How carbon capture affects net output
Imagine a 70 MW net waste-to-energy plant running at full capacity.
A typical amine-based capture system requires around 40 MWₜₕ of 4-bar steam for solvent regeneration and 7 MWₑ for auxiliaries such as solvent pumps, cooling, and CO₂ compression.
The 4-bar extraction steam no longer contributes to power generation.
For most turbines, that’s roughly 0.25–0.35 MWₑ of lost power per 1 MWₜₕ of steam.
Using a mid-range value, the penalty equals ≈ 11 MWₑ from the reboiler, plus 7 MWₑ from auxiliaries — about 18 MWₑ total.
That reduces net output from 70 MW to about 52 MW, a 25% drop in electricity available to the grid.
And it’s not an outlier — numerous studies report 20–30% efficiency losses in both WtE and fossil-fuel plants once CCS is installed.
The paradox: more fuel to stay the same
If the plant tried to maintain its original 70 MW output, it would need to burn more fuel.
To offset a 25% penalty, thermal input must increase by about 33% (1 / (1−0.25) − 1 ≈ 0.33).
But more fuel produces more CO₂, requiring more capture energy — a self-reinforcing loop.
The system tends toward an asymptotic increase in fuel demand; full compensation by burning more is not practically achievable.
You simply can’t burn your way out of the energy penalty.
Economics: why subsidies are critical?
CCS reduces the amount of electricity plants can sell while raising operating and capital costs.
Without incentives, it would make most projects financially impossible.
That’s why carbon pricing, emission credits, and subsidies are critical.
In Europe, this support comes from EU ETS allowances, the Innovation Fund, and national CCUS programs.
They are not political luxuries — they are what makes low-carbon power financially viable.ents, “recovery” becomes just a number — disconnected from reality.
From one plant to the entire grid
If every fossil-fuel and WtE plant added CCS without improving efficiency or recovering heat,
the grid’s net deliverable electricity would drop by roughly 20–30%.
To maintain supply, new generation capacity — ideally renewable or low-carbon — would be required.
In WtE, capturing the biogenic share can even deliver net-negative emissions, but the energy cost remains:
every MWh consumed for capture is one less for consumers.
CCS thus represents both a decarbonization tool and an energy-supply challenge.
Looking ahead: from penalty to opportunity
The energy penalty isn’t entirely unavoidable.
The capture process generates large amounts of low-temperature waste heat — from flue-gas cooling and solvent condensation.
Using absorption or mechanical heat pumps, this heat can be upgraded and reused within the plant or exported to district heating networks.
Done right, this can recover part of the lost energy and even turn a capture unit into a useful heat source.
The next article in this series will explore how waste heat from CO₂ capture can be recovered and reused — turning a major efficiency loss into an opportunity for energy circularity.
Key takeaway
CCS is vital for decarbonizing combustion-based energy, but typically a quarter of net power is consumed by the capture process itself.
Maintaining the same output means burning more fuel — and creating more CO₂.Recognizing this paradox is the first step toward better design.
With heat recovery, smart integration, and realistic carbon pricing, carbon capture can move from energy liability to a sustainable bridge to climate neutrality.