Updated: May 25, 2023
By Drew Schiavone
Coal Generation Plant near bay

The supply of nonrenewable energy sources is limited to the amounts that we can mine or extract from the earth. These nonrenewable energy sources come out of the ground as liquids, gases, and solids. Nonrenewable fuels are those fuels that cannot be easily made or "renewed," such as oil, natural gas, and coal. Coal, natural gas, and petroleum are called fossil fuels since they are formed over thousands of years from the buried remains of ancient sea plants and animals.

Conventional Energy Market

In 2017, about 89% of the energy consumed in the United States was from nonrenewable energy sources, which include uranium ore and fossil fuels (coal, natural gas, and petroleum). In 2018, nonrenewable energy sources accounted for about 90% of U.S. energy consumption. The top three primary energy sources consumed in Maryland are petroleum (33%), natural gas (23%), and nuclear electric power (12%); although other energy sources and their derivatives are used in the state to a lesser extent.

Maryland Energy Production and Consumption 2017-2018 graph

What is petroleum?

Petroleum is a broadly defined class of liquid hydrocarbon mixtures which include crude oil, lease condensate, unfinished oils, motor gasoline, jet fuels, kerosene, fuel oils, refined products obtained from the processing of crude oil, and natural gas plant liquids among many others. Most of the petroleum products consumed in the U.S. are made from crude oil, but petroleum liquids are also be made from natural gas and coal. Maryland has no economically recoverable crude oil reserves or production, and there are no petroleum refineries in the state. Petroleum products arrive in Maryland by pipeline from other states and by ship from abroad. The Colonial Pipeline which runs through Maryland delivers refined products (e.g., motor gasoline, kerosene, home heating oil, and diesel fuel), while Baltimore's deep-water port receives various imported petroleum products (e.g., motor gasoline, gasoline blendstocks, and residual fuel oil).

Gas pump refueling a car

Maryland's per capita petroleum consumption is among the lowest in the nation. Nearly 9 out of every 10 barrels of petroleum used in Maryland are consumed by the transportation sector. Reformulated motor gasoline blended with ethanol to reduce smog-forming and toxic pollutants is required across the densely populated Baltimore-Washington corridor in the center of the state. Counties in the mountain west and much of the rural Eastern Shore are not required to use reformulated motor gasoline. While the transportation sector accounts for the vast majority of the state's petroleum consumption, smaller quantities are used by the industrial (~6%) residential (~2%) and commercial (~2%). About 1 in 8 Maryland households use fuel oil or kerosene for heating. 

What is coal?

Coal is a readily combustible rock whose composition consists of more than 50% by weight, and more than 70% by volume, of carbonaceous material. It is formed from plant remains that have been compacted, hardened, chemically altered, and metamorphosed by heat and pressure over geologic time. Maryland holds about 0.1% of the nation's estimated recoverable coal reserves and accounts for about 0.2% of U.S. coal production. Maryland has less than 15 surface and underground coal mines, all of them located in the Appalachian Basin in the western counties. About 75% of the coal mined in Maryland is sent to electric power generators, while the rest is burned at industrial facilities.

Anthracite Coal

In the United States, 93% of coal production is used at power plants to generate electricity by powering electrical generators with the steam generated from the burning coal. As such, roughly half of the electricity supply in the United States comes from coal. While coal-fired generating plants historically supplied more than half the Maryland's net electricity generation, coal's share fell to 23% in 2018 as natural gas-fired generation increased. As of mid-2019, all but two of the 14 generating units at Maryland's seven remaining coal-fired power plants were more than 30 years old. Three of those older units were scheduled to shut down in 2019 and in 2020.

What is natural gas?

Natural gas is a gaseous mixture of hydrocarbon compounds (primarily methane) that is formed deep beneath the earth's surface. Conventional natural gas is found in large cracks and spaces between layers of overlying rock, while unconventional (shale) gas occurs in the tiny pores spaces within some formations of shale, sandstone, and other types of sedimentary rock. Maryland has few economically recoverable natural gas reserves, and the state produces very little natural gas. Most of the natural gas wells in the state are storage wells, and the few low-production wells in far western Maryland collectively produce less than 40 million cubic feet of natural gas annually. While Maryland's westernmost counties overlie part of the natural gas-rich Marcellus Shale, the state enacted a permanent ban on using hydraulic fracturing in 2017. Maryland's natural gas needs are met by supplies that enter the state by way of several interstate pipelines and a liquefied natural gas (LNG) input terminal on the Chesapeake Bay's western shore.

Stovetop flame

Maryland's residential and commercial sectors each account for about one-third of the state's natural gas consumption, and the electric power sector uses nearly one fourth; generating about 33% of Maryland's net electricity generation in 2018. The industrial and transportation sectors account for the remaining amount of the state's gas consumption. Natural gas is most commonly used for heating, with over 40% of Maryland households using natural gas as their primary fuel for home heating. Because natural gas is typically delivered through a pipeline, it is not commonly used in agricultural operations. However, natural gas is used in industrial manufacturing as an input in agriculture-related products, such as nitrogen fertilizers.

What is propane?

Propane is a by-product of natural gas processing and crude oil refining with almost equal amounts of production derived from each of these sources. Most of the propane consumed in the United States is produced in North America. Propane is a straight-chain saturated (paraffinic) hydrocarbon which forms a liquefied petroleum gas. It is a colorless gas at standard temperature and pressure. Propane is shipped from its point of production to bulk distribution terminals via pipeline, railroad, barge, truck, or tanker ship. Propane marketers fill trucks at the terminals and distribute propane to end users, including retail fuel sites.

Propane Tank

In the home, propane is used for space heating (49%), other uses (e.g., clothes drying, gas grills) (29%), water heating (16%) and cooking (6%). Agricultural operations may also use propane for various applications including livestock barn heaters or water heating in dairy barns. Because propane is linked to petroleum extraction and refining, propane pricing follows petroleum pricing. Like natural gas, the residential price will fluctuate due to delivery costs, storage, forward contracting and other factors. However, like other petroleum products, the price has escalated, especially in the past five to seven years.  

What is heating oil?

Heating oil, or fuel oil, is a petroleum product refined from crude oil. This distillate fuel is sold mainly for use in boilers, furnaces, and water heaters. Most U.S. residential sector and commercial sector heating oil consumption occurs in the New England and the Central Atlantic regions. While most states in the US Northeast have adopted ultra-low sulfur heating oil specifications (ULSHO), Maryland still allows a higher sulfur heating oil (i.e., 500 ppm) in the primary demand region. Many residential properties in Maryland have aboveground or underground oil storage tanks as a source for heating energy.  If properly maintained, a heating oil storage system will provide many years of safe energy for the home. Prices for heating oil trend with petroleum. 

Heating oil tank by house

What is nuclear energy?

Nuclear energy is produced from uranium, a nonrenewable energy source whose atoms are split (through a process called nuclear fission) to create heat and, eventually, electricity. Uranium is found throughout the earth’s crust, but most of it is too difficult or too expensive to mine and process into fuel for nuclear power plants. Nuclear energy represents approximately 22% of the US electricity supply or about 8% percent of the total energy supply. Maryland's only nuclear power plant is a two-reactor power plant located on the western shore of the Chesapeake Bay (Calvert Cliffs) which accounted for 34% of the state's electricity net generation in 2018. 

Calvert Cliffs Nuclear Power Plant from water

Additional Resources

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