What happens to gas, coal and oil systems in a transition, and can carbon be removed?

Map gas networks, LNG, coal, oil, carbon capture and carbon removal; read a retirement plan and a gas-network scenario by their assumptions; compare removal methods

X2 of Energy Systems, Step by Step: what gas networks, LNG, coal plants and mines, oil, carbon capture and carbon removal do today; a year of coal retirement plans against retirements; a gas network’s cost over fewer customers; a plant’s early closure; capture against removal; removal methods by storage time, readiness, cost range and measurement. Neutral, dated, no forecasts.
  • Analyst · L2
  • 15 min guided · about 10 min practice
  • After F10 and F11

Fossil systems and carbon: what each does today, and the open question

System Today A number Open question
Gas networks and LNG Carry gas to power plants, industry and about 60% of U.S. homes; LNG ships it overseas. 15.1 Bcf a day of U.S. LNG exports in 2025, 26% of the world's Who pays for the pipes as customers leave?
Gas power plants 41% of U.S. utility-scale electricity in 2025. 0.96 lb of CO₂ per kWh of electricity generated, burning only (2023) A bridge or a lock-in?
Coal plants and mines 17% of U.S. utility-scale electricity in 2025; 512.5 million short tons mined in 2024. 8.5 GW planned to retire in 2025, 2.6 GW retired When does a plant close, and who carries what is left?
Oil About 38% of U.S. primary energy in 2025, used mostly for transport. Transport took two-thirds of the petroleum used in 2022 How exposed is an importer to one sea route?
Carbon capture and storage Captures CO₂ at a chimney or gas-processing plant and stores it underground; CO₂ that is used instead may be released again. Capture capacity of about 50 million tonnes a year worldwide (2025) Can it grow against about 38 billion tonnes of energy CO₂ a year?
Carbon removal Takes CO₂ already in the air into trees, soils, rock or minerals. Stored for decades to 10,000 years or longer, by method How long does it stay, and how is it measured?

Six ways to remove carbon (IPCC, 2022)

Method Stores carbon in Readiness (1 to 9) Cost range per tonne CO₂ Potential, billion tonnes CO₂ a year Measuring it
Direct air capture with storage (DACCS) Rock underground: 10,000 years or longer 6 $100 to $300 5 to 40 Count the CO₂ stored, less emissions from the energy and water it uses.
Bioenergy with carbon capture and storage (BECCS) Rock underground: 10,000 years or longer 5 to 6 $15 to $400 0.5 to 11 Count the CO₂ stored, less emissions and land carbon lost growing the biomass.
Enhanced weathering (crushed rock on fields) Minerals: 10,000 years or longer 3 to 4 $50 to $200 2 to 4 How fast the rock takes up CO₂ in real soils is still poorly quantified.
Biochar (charred plant matter in soil) Soils: decades to centuries (IPCC's timescale for carbon stored in soils) 6 to 7 $10 to $345 0.3 to 6.6 Count the carbon in the char, less emissions from making it.
Afforestation and reforestation Trees and soils: decades to centuries 8 to 9 $0 to $240 0.5 to 10 Carbon in growing trees; wildfire, disease or pests can reverse it.
Soil carbon in croplands and grasslands Soils: decades to centuries 8 to 9 $−45 to $100 0.6 to 9.3 IPCC: the net addition per hectare is very small and hard to monitor.
  • Readiness: 1 = basic principles described, 9 = proven in operation.
  • Cost: U.S. dollars per tonne of CO₂, IPCC's author-judgement ranges from studies in different dollar years, not adjusted to one year. A low end below zero is an estimated net saving.
  • Potential: billions of tonnes of CO₂ a year that the literature finds possible, not today's scale.
  • Why BECCS can count as removal: plants take CO₂ from the air as they grow; storing that carbon after the biomass is used can give net removal, once other emissions and land-carbon losses are counted.
  • Coal retirements in 2025: 8.5 GW planned, 2.6 GW retired (31% of the plan).
  • Capture capacity worldwide: about 50 million tonnes of CO₂ a year (IEA, December 2025). Compared with 2025's energy CO₂, about 38 billion tonnes, that capacity is about 0.13%, even running full all year.

With JavaScript on, you tap the map, check a retirement plan, try a gas-network scenario and a plant's early closure, tell capture from removal and sort the removal table.

Real and illustrative: U.S. and world numbers are dated, from EIA, IEA, LBNL and IPCC (listed under Sources). The gas network, the plant's book life and Ridge County are set for teaching and labelled so.

Need a refresher? F11 on what burning fuel does to the air; F4 on how gas and coal plants work.

What you just did, as diagrams

Roles today
Gas made 41% and coal 17% of U.S. utility-scale electricity in 2025; oil was about 38% of primary energy.
A plan is an assumption
Owners planned to retire 8.5 GW of coal in 2025; 2.6 GW retired.
Networks have fixed costs
Fewer customers can mean a higher share each, unless pipes are retired or costs are recovered another way.
Capture is not removal
Capturing fossil CO₂ and storing it durably can cut emissions; CO₂ that is used instead may be released again. Removal takes back CO₂ already in the air.
Removal differs by method
Rock and minerals store carbon for 10,000 years or longer, trees and soils for decades to centuries; readiness, cost range and measurement differ too.

Where we stop

This side topic stops at roles and open questions

Fossil systems and carbon removal enter the course as what each does for the system today, how to read a plan by its assumptions, and the questions still open; no forecasts.

This side topic covers

  • What gas networks, LNG, coal plants and mines, oil, carbon capture and carbon removal do today.
  • Reading a retirement plan or a gas-network scenario by its assumptions.
  • Removal methods compared by storage time, readiness, cost range and how they are measured.

Left to specialists

  • Forecasts of when plants close or how much gas is used.
  • Engineering design of pipelines, capture plants or storage sites.
  • Advocacy for or against any fuel or method.

Read next, three rungs

  1. Start here. EIA's plain-language pages on how the United States uses natural gas, with the latest data. EIA, Natural gas explained: Use of natural gas, last updated 31 October 2024, read 7 November 2026
  2. Go further. IPCC's assessment of carbon removal, its methods and its roles; its Chapter 6 covers energy systems. IPCC, Sixth Assessment Report, Working Group III, Chapter 12: Cross-sectoral perspectives, 2022, read 7 November 2026
  3. Go deep. Plant-by-plant trackers of coal plants, gas plants and pipelines worldwide, to test a plan against the record. Global Energy Monitor, its coal and gas trackers, cited by name, updated through the year
Go deeper · AnalystReading a retirement or gas-network scenario by its assumptions
  • Who wrote it, and when? An owner’s filing, a regulator’s order and a modeller’s scenario answer different questions; date each one.
  • Plan, scenario or forecast? A retirement plan states an owner’s intent; a scenario states “if these assumptions hold”; neither is a prediction.
  • What is held fixed? Demand, fuel prices, rules and the network’s cost: change one and the result moves.
  • Who carries the cost? Owners, customers or taxpayers, as set by regulators and contracts.
  • What would change it? An emergency order, a price swing or a new rule: in 2025, EIA counted many coal retirements delayed under emergency orders.
Go deeperWhat this lesson leaves out
  • Forecasts of plant closures, gas demand or removal at scale.
  • Engineering of pipelines, LNG terminals, capture plants and storage sites.
  • Carbon markets, credits and the rules for counting removals in an inventory.
  • Methods IPCC assesses beyond the six here, such as ocean-based removal and wetland restoration.

Check yourself

Practice, about 10 minutes: four myths, then three questions.

Myth or fact? “Capturing CO₂ at a coal plant removes CO₂ from the air.”

  • Myth
  • Fact
Answer

Myth. Stored durably, the captured share of the plant's own CO₂ stays out of the air; IPCC: capture applied to fossil fuel use is not removal, since it takes no CO₂ out of the air.

Myth or fact? “Carbon stored in new forests stays there for good.”

  • Myth
  • Fact
Answer

Myth. IPCC puts trees and soils at decades to centuries, and wildfire, disease or pests can reverse it.

Myth or fact? “LNG is natural gas cooled until it is a liquid about 600 times smaller.”

  • Myth
  • Fact
Answer

Fact. EIA: it is cooled to −260 °F, and the liquid is 600 times smaller than the gas.

Myth or fact? “When owners plan to retire a coal plant, it closes that year.”

  • Myth
  • Fact
Answer

Myth. In 2025 owners planned 8.5 GW and 2.6 GW retired; 4.8 GW was delayed and 1.1 GW cancelled (EIA).

EIA: in 2023 burning coal for power emitted 2.31 lb of CO₂ per kWh of electricity generated and burning gas 0.96. About what share of coal's is gas's?

  • About 20%
  • About 40%
  • About 60%
Answer

About 40%: 0.96 ÷ 2.31 = 0.416, or 42%. Burning only: leaks before burning are not counted.

A network costs $500 a year per customer and no pipe can be retired; a quarter of the customers leave. What does each remaining one pay for it (illustrative)?

  • $500
  • $667
  • $625
Answer

$500 ÷ (1 − 0.25) = $500 ÷ 0.75 = $667. The network's total cost has not changed; it is shared by fewer customers.

In IPCC's table, which method stores carbon for 10,000 years or longer but has the lowest readiness, 3 to 4?

  • Direct air capture with storage
  • Biochar
  • Enhanced weathering
Answer

Enhanced weathering: crushed rock on fields stores carbon in minerals, but its readiness is 3 to 4 and its uptake in real soils is still poorly quantified (IPCC).

Numbers, sources and what’s next

Numbers to remember

Number What it means Source
41% · 17% Gas and coal shares of U.S. utility-scale electricity in 2025 (our arithmetic on EIA's table). EIA, Electric Power Annual, Table 3.1.A · 2025 data
8.5 GW → 2.6 GW Coal capacity U.S. owners planned to retire in 2025, and what retired: 4.8 GW was delayed and 1.1 GW cancelled. EIA, Today in Energy, 13 April 2026 · 13 April 2026
15.1 Bcf/d U.S. LNG exports in 2025, 26% of the world's; LNG is gas cooled to −260 °F, about 600 times smaller. EIA, Today in Energy, 14 July 2026 · 14 July 2026
44,060 Average number of employees at U.S. coal mines in 2024. EIA, Annual Coal Report 2024 · released 19 November 2025
about 50 million tonnes CO₂ capture capacity worldwide, a year, two-thirds at natural gas processing; capacity is not emissions avoided. Energy CO₂ was about 38 billion tonnes in 2025. IEA, Coal 2025 · published 17 December 2025
10,000+ years How long geological formations and minerals store removed carbon; trees and soils store it for decades to centuries. IPCC AR6 WGIII, Chapter 12 · 2022

Keep going

Back to the course map

Sources and further reading

Spotted an error, or stuck? Write to hlli@ksu.edu. Corrections are made in place and dated here.

Text licensed CC BY 4.0, code MIT: teachers and students may reuse and adapt it, with credit to Honglin Li.