Introduction to “Conventional” Natural Gas Kenneth M. Klemow, Ph.D. BIO / EES 105 at Wilkes University

What is natural gas? Composed mainly of methane and other molecules. About methane: Energy content: 55.7 kJ/g Vaporization point: -260oF 160oC

NG has two general forms ◦ Thermogenic – From breakdown of fossil organic matter below earth’s surface  Hundreds of feet to miles below surface  Need heat and pressure ◦ Biogenic – From breakdown of organic matter at earth’s surface.  Decomposition without oxygen  Wetlands, garbage dumps

Wet Gas Vs Dry Gas Dry gas – mainly methane Wet gas – includes ethane, propane butane

Conventional vs Unconventional Natural Gas Conventional gas – Relatively easy to extract – Forms include Associated with oil Not associated with oil Can be onshore or offshore Unconventional gas – More difficult to extract – Derived from Shale, coal-bed

Geology of gas

Focus on Conventional Gas

How does thermogenic NG form? Organic matter gets buried by other sediments Breaks down without oxygen under pressure, forming hydrocarbons Temperature dependent ◦ Lower – petroleum ◦ Higher – methane Often gas mixed with petroleum, released when pressure reduced.

History of natural gas development First isolated by Chinese about 500 BC. ◦ Captured gas seeping from ground, piped it using crude pipelines. Mid-19 th Century ◦ Burned off during oil production (flaring) Early 20 th Century ◦ Pipelines constructed to capture and transport

Historic Gas Production

Conventional gas production - US

Gas utilization Energy ◦ Electrical generation ◦ Heating / cooking ◦ Transportation Feedstock for industrial processes ◦ Plastics ◦ Organic chemicals ◦ Fertilizers

Energy use of natural gas

Conventional well production Geologists find gas reservoir Drill borehole Case well in steel and concrete Gas flows upward Captured into pipeline

Wells sometimes need to be stimulated Add acid, water, or gases to promote NG flow from the well

Natural gas must be processed Remove impurities ◦ Hydrocarbons (ethane, propane, butane) ◦ Hydrogen sulfide ◦ Water vapor ◦ Nitrogen compounds

Gas distribution system

Major NG pipelines in US

NG can be compressed and liquified Both reduce volume making it easier to transport

CNG – Compressed to 1% original volume Used as a fuel for vehicles ◦ Cars, trucks, buses, locomotives ◦ Some engines run on both CNG and gasoline ◦ Common in Iran, Pakistan, Argentina, Brazil ◦ Efforts to increase use in US

LNG – Cooled to -260 o F Has 2.4 times more energy than CNG Transported via trucks and ships where pipelines not present Must be stored in cryogenic tanks Not used as fuel

Conventional gas production – worldwide

Location of conventional natural gas

Pricing natural gas Natural gas sold by volume ◦ Typical basis 1000 cubic feet (Mcf) ◦ Also used  1 million cf (MMcf)  1 billion cf (Bcf)  1 trillion cf (Tcf) ◦ 1 Mcf = 1 million BTU

Pricing natural gas Different prices often quoted ◦ Wellhead – Unprocessed NG at well ◦ Henry Hub – Port in Louisiana, used as basis for NY Mercantile Exchange  Futures price – Contract price for specified amount of gas at specified time ◦ City Gate – Price paid by utility receiving gas from major pipeline ◦ Electric Power price – Paid by electric utility ◦ Residential price – Paid by consumer

Pricing natural gas

Pricing long term trend

Pricing NG – more recently down-20-since-start-of-2013/

Pricing NG – Comparing fuels from-falling-natural-gas-prices-offsetting-higher-gasoline-prices/

Pricing NG – Effects of season

International price trends

Benefits of Conventional Natural Gas High energy density Less polluting than coal Easy to transport Does not cause radioactivity Reliable

Drawbacks of Conventional Natural Gas Burning releases greenhouse gases Drilling and pipelines impacts habitat Supplies dwindling