Energy Supply Chains: Where Your Electricity Comes From

May 8, 2023

Depending on where you live, your electricity is generated primarily by:

Burning carbon and hydrocarbon fuels like coal and natural gas (fuel oil is only used sparingly)
Nuclear power
Hydro power (dams)

And fractionally by
Burning bio-mass (normally wood and wood-based products)

Its journey from the generator to your meter is shown on your bill.

Supply: generation and transmission.  Generated power is transmitted at high voltage over long distances (steel towers) to a transmission sub-station owned by your serving utility.  These are deregulated components and can be purchased by you together or separately from your utility or from a competitive supplier.

Distribution: when electric power is transformed to a lower voltage at the substation, the utility distributes it to your meter using infrastructure (poles, wire and terminal transformers) that it owns and maintains.

Where Your Natural Gas Comes From

Supply: natural gas is a mixture of various hydrocarbon compounds, but primarily methane (CH4) and is found underground and extracted by drilling.  Raw gas is then processed to remove water and add the odorant (the rotten egg smell that allows you to detect gas leaks).  It is then sent through a large and complex network of regional and interstate pipelines to a terminal interface with your distributing utility called the “city gate.”

Distribution: the utility takes gas from the city gate and distributes it to your meter using pipelines and controls that it owns and operates.

Burning Natural Gas

When you burn natural gas, you produce heat and products of combustion by breaking molecular bonds.  Like any hydrocarbon fuel, the products of combustion (exhaust gas) ideally is made up of carbon dioxide (CO2) and water vapor (H2O), but the world isn’t ideal, so you have to be cautious with carbon monoxide (CO), that is toxic in small concentrations.  Natural gas is considered clean burning because it has a low proportion of carbon to hydrogen so it’s products of combustion have a lower proportion of carbon dioxide to water vapor.

For illustration, compare methane, CH4 to octane (ideal gasoline), C8H18.  The proportion of carbon to hydrogen in octane, 8/18 is higher than methane, 1/4.  The heat content of methane is about 20,000 BTU/Lb. vs. Octane, about 10,000 BTU/Lb.