US-REGEN Documentation

Resource and Technology Assumptions / Carbon Management

Direct Air Capture

Summary

Direct air capture (DAC) technologies use energy and capital inputs to produce a high purity CO2 stream from ambient air that can be either utilized for fuel synthesis or geologically stored. There is significant uncertainty about the achievable cost and energy consumption of direct air capture, which are in general higher per ton of CO2 than capture from more concentrated flue gas streams. The most promising emerging technologies use engineering designs optimized for air capture. These fall into two main categories: (a) high-temperature liquid-solvent technologies; and (b) low-temperature solid-sorbent technologies.

US-REGEN includes four representative DAC technologies:

  1. High-temperature with heat provided by natural gas (with flue gas capture)
  2. High-temperature with heat provided by electricity
  3. Low-temperature with both gas and electric energy inputs
  4. Low-temperature with all-electric energy inputs

These technologies are characterized in terms of capital cost per net carbon removal capacity, fixed and variable operating cost, energy requirements, and gross capture rate (i.e. total CO2 captured from air and flue gas per net CO2 removed from air).

Technology Cost and Performance

US-REGEN model assumptions for the costs and performance of direct air capture technologies over time are shown in the chart and table below. Use the buttons to choose a parameter to compare.

Capital Cost by Direct Air Capture Technology and Year
  • Chart
  • Table
Data Definitions

Measures

  • Capital Cost ($/tCO2): Cost to bring a new direct air capture system into operation, normalized to the system's net CO2 removal capacity
  • Fixed Cost ($/year per tCO2): Annual fixed cost to operate and maintain the system, normalized to the system's net CO2 removal capacity
  • Variable Cost ($/tCO2): Non-fuel variable cost to operate and maintain the system per net tCO2 removed
  • Natural Gas Input (MMBtu per tCO2): Natural gas energy input per net tCO2 removed
  • Electricity Input (MMBtu per tCO2): Electric energy input per net tCO2 removed

Direct Air Capture Technology

  • High-temp (gas): High-temperaure using gas and electricity
  • High-temp (elec): High-temperature using all electric heat (from grid)
  • Low-temp (gas): Low-temperature using gas and electricity
  • Low-temp (elec): Low-temperature using all electric heat pumps