LNG and NH3: Energy Carriers for decarbonized energy system

As the world handles climate change and seeks to transition to cleaner energy sources, energy carriers that can store and transport cleaner energy will become increasingly important. 

Two potential energy carriers that are gaining more attention are liquefied natural gas (LNG) and ammonia (NH3). 

LNG is natural gas, mainly methane CH4 , that has been cooled to ultra-low temperatures ( -162 Celsius) , liquefying it for easier storage and transportation. 

Ammonia is a compound made from nitrogen and hydrogen that can be used as a dense source of hydrogen for fuel cells and internal combustion engines.

Both LNG and NH3 have promising properties as energy carriers. They are dense sources of energy that can be stored and transported, and when used they produce virtually little or no emissions.

 They can help solve renewable energy's intermittency problem, ammonia for example can provide a means to store and distribute energy from sources like solar and wind power. 

Although there are still challenges to overcome regarding cost, safety, and acceptance, LNG and NH3 may represent key pieces in the shift to a cleaner energy future with greater energy security and flexibility.

Overall, these two energy carriers deserve a closer look as potential pathways to a net-zero emissions economy.

Let’s take a closer look into the two energy carriers.

Starting with a comparison between the physical and chemical properties of NH3 and LNG 

Apparently, LNG has a higher energy density than NH3, which means that it can store more energy per unit of volume or mass.

The higher energy density of LNG means that it can provide the same amount of energy as NH3 while occupying less space or having less mass.

This makes it more convenient for transportation and storage. For example, a given volume of LNG can store about 2.8 times more energy than the same volume of compressed NH3 gas at the same pressure and temperature.

The physical and chemical properties of LNG and NH3 affect the design and operation of engines and storage in a number of ways. For example, LNG facilities must be designed to operate at cryogenic temperatures (below -150 °C, while NH3 facilities must be designed to handle the corrosive properties of ammonia. LNG storage tanks must be designed to prevent leaks, while NH3 storage tanks must be designed to prevent explosions.

Regards climate change, LNG and NH3 are both considered to be cleaner-burning fuels than conventional fuels, such as heavy fuel oil and gas oil. This is because they produce lower emissions of greenhouse gases, such as carbon dioxide (CO2). LNG produces about 25% fewer CO2 emissions than heavy fuel oil, and NH3 produces about 40% fewer CO2 emissions than gas oil.

In addition to lower CO2 emissions, LNG and NH3 also produce lower emissions of other pollutants, such as sulfur dioxide (SO2) and nitrogen oxides (NOx). SO2 and NOx can contribute to acid rain and smog, and they can also be harmful to human health. LNG produces about 90% fewer SO2 emissions and about 70% fewer NOx emissions than heavy fuel oil. NH3 produces about 90% fewer SO2 emissions and about 80% fewer NOx emissions than gas oil.

The climate benefits of using LNG and NH3 as alternatives to conventional fuels are significant. If LNG and NH3 were to be used to replace all of the heavy fuel oil and gas oil used in the world today, it would be the equivalent of taking about 1.5 billion cars off the road. This would have a major impact on reducing greenhouse gas emissions and mitigating climate change.

LNG and NH3 can also contribute to the decarbonization of the energy system. Decarbonization is the process of reducing the amount of carbon dioxide and other greenhouse gases emitted into the atmosphere. LNG and NH3 can be used to power a variety of applications, including power generation, transportation, and industrial processes. As the demand for clean energy grows, LNG and NH3 are expected to play an increasingly important role in decarbonizing the global energy system.