How is Natural Gas formed?
Natural gas is formed from the decomposition of organisms such as plants, animals and multi cell bacteria. Over hundreds of millions of years, this layer of organic matter mixes with sand and silt. It is then exposed to intense heat and pressure under the Earth’s surface. Over time this causes the carbon bonds in these organisms to collapse leaving behind loose carbon and hydrogen. This process changes the matter into hydrocarbons such as coal, petroleum or natural gas.
Where is Natural Gas found?
Typically natural gas is found in reservoirs. These reservoirs can be beneath the ocean floor, or under the Earth’s surface. It can be found close to the surface as well as deep below the Earth’s crust. Natural gas could be found by itself or in wells of crude oil. The deeper we drill the higher the chances of finding natural gas instead of oil.
Most reserves are found in the Middle East and Russia. The middle eastern countries account for over 40% of the worlds natural gas supply and Russia accounts for about 24%. The United States and Canada combined have around 8% of the world’s natural gas supply.
Types of Natural Gas
Conventional Natural Gas – Pure natural Gas found under a permeable layer of rock. Usually found in larger deposits of oil, floating on top to create a layer. Conventional wet gas or associated gas is when the gas is not purely methane and has other hydrocarbons with in it. Unconventional Natural Gas – Found deep (4500 meters or more) underneath the Earth’s surface. Extracting this gas is more difficult and thus more costly. Though technology is making this easier and less expensive over time.
Types of Unconventional Natural Gas
- Shale: Found within Shale, a type of sedimentary rock that is composed of mud and acts like a large mineral. It is a tough material that is difficult to drill into.
- Tight Gas: Found underground within impermeable rock. Can only be extracted through fracking.
- Coal-bed Methane: Found sometimes alongside coal mines. Historically, this was a waste product of coal mining, but has now become a significant source of energy.
- Bio-gas: Produced when organic matter decomposes without oxygen being present, typically it is man made. Generally contains less methane than conventional natural gas thus is not as energy efficient though more environmentally friendly.
How is Natural Gas Extracted?
The first step is to perform a well test to determine whether there is a significant amount of natural gas in the deposit found. If there is enough in the deposit to justify the cost of extracting the resource, then new production wells will be built.
Once a site has been selected for extraction, depending on the type of natural gas or oil found there are a couple of different extraction methods. Since natural gas is found alongside oil the extraction methods are similar for both. Once a well has been drilled, concrete and metal casings are installed into the well, with a collection pump built above the surface. Occasionally, natural gas will be injected back into the well for future extraction.
Types of Extraction
- Vertical Drilling: The first and only type of natural gas production until 1980. Efficient when conventional natural gas is close to the surface. vertical wells are on average 300-800 meters. Limited to gas reserves that are only accessible from above.
- Horizontal Drilling: Flexible and cost efficient, can broaden the possibilities of drill sites. Requires less drilling sites as the drill bits can move horizontally through natural gas deposits.
- Hydraulic Fracturing/Fracking: Starts off by generating a ‘micro-earthquake’. High pressure streams of water, sand, and corrosive chemicals help break up the formation of rocks. Then natural gas can flow up the gathering pipelines to wells on the surface. This method is banned in some places as it requires large quantities of water that can overwhelm the environment as well as creates large amounts of radioactive wastewater which can affect the environment if not managed correctly.
- Acidizing: Refers to the use of corrosive chemicals to remove blockage of rocks on the way to the reserve
Natural Gas Paving the way towards a Green Future
Natural gas can be thought of as a bridge towards a zero carbon future. This means natural gas can be used to achieve lower carbon emissions until renewable energy technologies are efficient enough to become the primary source of energy. As fossil fuels have been our primary fuel source throughout history, there is significant infrastructure in place to ensure natural gas is both accessible and reliable throughout North America.
Natural Gas Compared to Other Fossil Fuels: On a small scale, burning 1 MMBtu of coal releases 200-230 pounds of CO2. While diesel and heating oil releases about 160 pounds of CO2. The same amount of Natural gas only produces about 100 pounds of CO2.
Newer technologies to transport and extract Natural Gas are also becoming more prevalent. Liquefied Natural Gas (LNG) is fast becoming one of North Americas top energy exports. When gas is in its liquid form it is much easier to transport across oceans. As seen in the map above indicating the various pipelines throughout Canada. We can see that there are LNG stations dedicated to the cooling and heating of Natural gas to move it between it’s liquid (cool) state and Gas (warm) state, in order to efficiently import and export it worldwide. The extraction technologies of today are also more sophisticated than before. There is less environmental damage done by the rigs of today compared to the rigs in the 70s-2000s.
Methods of Producing Electricity: Renewable VS Natural Gas
Using Solar Power: Producing Solar Power depends first most on how much direct sunlight your panel will receive. Next we need to think about the size and wattage capabilities of the panels themselves. Generally in 2022 Solar panels are about 12-15% effective, as in only 12-15% of the solar power received from the sun is converted into energy.
This translates into a solar panel with 15% efficiency and 1 metre surface would produce around 150 Watts of electricity. This is enough to power small electronics such as led lights and charging your phone or tablet.
Unless you have a large (and costly) solar panel system setup, solar power is not a very reliable power source.
Using Wind Power: Wind generally produces more power than solar. Wind turbines are much larger and have a range of electricity storage capabilities. Still the power produced is dependant on the speed of the wind. Turbines in 2022 generally have capacity between 250 Watts and 7MW (Million Watts). They are also more efficient than solar panels, with wind power being 20-40% efficient at converting the wind into energy. Still in North America Wind power faces challenges such as cold weather making the turbines icy and permits for optimal wind farm locations being difficult to obtain.
In ideal conditions a turbine with 3MW capacity can produce more than 6 million kWh of electricity per year. this means over 16,666 kWh per day. That means it is enough to power 3 average households per day!
Using Hydro Power: Hydro-power is the most efficient renewable energy source. Hydro has an astonishing efficiency of 90%, as in 90% of the available energy is successfully turned into electricity. Hydro-power plants have very large storage capacities. There are also downsides to hydro-power. Building and maintaining a hydro-power plant is quite expensive, it is also dependant on the body of water available. To create a steady flow of rushing water, oftentimes dams are built on existing lakes or rivers, then the water flowing out of those dams is used to generate power. The creation of a dam on an otherwise flowing body of water creates a build up of methane gas in the stagnant side that is released into the atmosphere. Methane of course, is far worse than carbon dioxide in terms of green house gases.
In Canada hydro-power is the number one method to generate electricity, about 60% of all electricity generation is through hydro.
Using Natural Gas: Natural Gas has a high efficiency of around 60% when used to convert Electricity. Of course during this conversion there is a significant amount of CO2 emissions. If Natural gas was used instead of electricity the overall energy the user receives is much higher.
As we can see in the illustration above, using just Natural Gas to power your home would give you almost 3x as much energy as using renewable to generate electricity.
Pressure, Temperature and Gas Distribution
In North America majority of our reserves and sources of natural gas are located in the southern United States (Texas) and in western Canada. In order to bring the gas from those regions to the rest of the continent, we rely on natural gas pipelines. For there to be a steady stream of gas flowing through these pipelines three things need to be balanced, the volume of gas in the pipe, the temperature and the pressure inside gas storage facilities.
In colder months there is a higher demand for energy, thus the overall volume of gas to be moved is higher. The temperature of course is much lower. When temperatures are low the movement of gas molecules are slower making it that much more difficult to move gas throughout the pipeline system. In warmer months we see the opposite, overall demand for gas is lower, there is less gas that needs to be moved on a daily basis. In higher temperatures the movement of gas molecules is faster and so it is less difficult to move through pipelines.
We are able to offset this issue through gas storage. In the summer months when the demand is lower, unused gas is injected into storage to be stored for when demand is higher in winter weather. As moving the gas is easier under warm temperatures.