Natural gas is one of the most widespread and demanded primary energy carriers on the planet Earth. According to the forecast of the International Energy Agency, the consumption of natural gas in the world could grow to 4 trillion cubic meters by 2022.
This energy carrier, unique in its ecological and economic properties, is effectively used for the production of heat and electricity, cooking, lighting, as a fuel for vehicles and stationary engines.
The basis of natural gas (up to 98%) is methane (CH4). It is colorless and odorless; lighter than air; chemically inactive, easily dissolves in gaseous and liquid media, such as air, water or oil. Natural gas is primarily of organic origin.
It took hundreds of millions of years, high temperatures, enormous pressures, and a lack of oxygen to form fossil fuels.
Natural gases based on methane accompany other fossil fuel deposits: associated gas is adjacent to oil; coal bed methane or firedamp is present in coal deposits, coal gas; coal bed methane; Marsh gas is born in the swamps.
In the United States, the development of such a resource as shale gas has recently become widespread.
There is a possibility of artificial production of natural gas. For example, biogas is obtained from sewage (sewage gas), landfills (landfill gas), livestock and poultry farms. There are also a number of synthetic gas technologies.
EXPLORED OIL AND GAS RESERVES
There is no consensus on the world’s oil and gas reserves. Various methods are used for calculations. In general, the assessments of specialists from various organizations are quite close.
Oil and gas reserves are distributed very unevenly across the countries of the world. At the same time, some countries got more oil, some – more gas, some a little bit of everything, and some – neither one nor the other (see fig; redraw the drawing using graphic icons). The question of how many years the reserves of certain minerals will last also does not have an unambiguous answer. It is necessary to consider the actual volume of reserves of different categories, the level of production, demand and its change over time, and other parameters.
At today’s production levels, the world’s provision of hydrocarbon reserves based only on proven resources is, on average, about 50 – 55 years for oil, and up to 60 years for natural gas. It should be borne in mind that the natural gas reserves in question include only traditional resources that do not include slate gas and other sources.
USING GAS AS MOTOR FUEL
The widespread availability of natural gas, its environmental and economic qualities have made it possible to successfully use it as a fuel in the transport sector. Two natural gas-based energy carriers are used as motor fuel: compressed natural gas (CNG) and liquefied natural gas (LNG).
CNG and LNG are “siblings”. And nevertheless, as often happens in a family, they all have different characteristics. More precisely, physical and chemical properties. These differences determine the design features of gas vehicle engines, on-board fuel storage systems, and filling stations.
Liquefied petroleum gas (LPG) fuels are also widely used in the world. LPG is a mixture of propane and butane, and natural gas is based on methane. Therefore, for simplicity, LPG is often referred to as “propane”, while CNG and LNG are often referred to as “methane”. In some countries, propane is also called “car gas = auto gas”.
Methane is lighter than air and dissolves quickly in the air when leaked. And propane is heavier and tends down to the ground. It can fill technological wells, service pits in garages and form explosive mixtures with air. One spark is enough to cause an explosion.
NATURAL GAS AS AN ENVIRONMENTALLY FRIENDLY FUEL
The use of natural gas is one of the keys and most effective solutions to combat climate change and improve air quality. It is the most commercially viable solution for the transport sector. Today, transport accounts for up to 85% of harmful emissions in cities. The use of CNG and LNG is a viable solution to instantly reduce emissions of greenhouse gases and particulate matter into the atmosphere.
A 2017 study that assessed the environmental impact of natural gas using a well-to-the-neck approach found that CNG could reduce greenhouse gas emissions by 23% compared to gasoline and 7% compared to diesel in passenger cars. For heavy trucks, the emission reductions are even more impressive: 16% compared to diesel.
When emissions, other than greenhouse gases, are taken into account, the use of a methane car becomes even more attractive. Burning natural gas in an engine result in a 95% reduction in particulate matter and a 70% reduction in nitrogen oxides compared to diesel and gasoline even within the limits.
Comparison of emissions from internal combustion engines running on CNG, gasoline and diesel (Euro 6) strict EU environmental standard “Euro 6”. The emissions from the use of natural gas are free from other harmful and carcinogenic particles.
Even within the framework of estimating emissions that are not subject to today’s regulation (gases with ozone-depleting potential, aldehydes), natural gas is the optimal fuel for improving air quality in cities. In maritime transport, the use of natural gas is also the optimal solution to reduce sulfur oxide emissions.
Research firm “Naby” estimates that cruise ferry passengers can be exposed to air pollution levels 60 times higher than normal. Using LNG as a bunker fuel reduces potential harm to zero.
Gas can be ‘green’
CNG and LNG can be produced from a wide range of renewable energy sources using a variety of technologies:
“Biogas can be obtained using an anaerobic process from organic waste and biomass”;
“In the process of gassing, organic waste with a high carbon content is converted into carbon monoxide, hydrogen and carbon dioxide, from which synthetic gas is then obtained”;
“Electricity to gas” is a process in which surplus electricity generated by renewable energy sources is converted into hydrogen, and later, through the methanization process, into methane.
All “renewable” gas can be mixed with natural gas and used as fuel for transportation. Thus, even a small amount of “renewable” gas in the mixture can increase the positive effect on the environment. The use of “renewable” gas can achieve zero CO2 emissions in the transport sector.