The production of electric power
Thanks to its several economic and environmental benefits, in the latest years natural gas has converted into the main fossil fuel for the production of electricity. During the 70s and 80s, energy production was oriented towards coal and nuclear plants, but a series of economic, environmental and technological factors has provoked a shift towards the gas.
Vapour plants
Natural gas can be used as a fuel in vapour electric plants in order to produce vapour that, at a high pressure, activates a turbine, which makes the alternator turn. In order to create high- pressure vapour, water is superheated in a boiler: by hemertically closing the container, the vapour pressure increases and then violently gets out towards the turbine. With reference to the performance of these plants, approximately 40% of the energy contained in the fuel is transformed into electricity. The remaining 60% is lost during energy conversion from chemical to thermal, mechanical and electric.
Turbo-gas plants
Natural gas can also be used in turbo-gas electric plants. These thermoelectric plants directly exploit the energy produced during methane (or gas oil) combustion and work without boiler, in order to transform the water into vapour and without condenser in order to reconvert the vapour into water. A turbo-gas plant consists of:
- A compressor: it sucks air up from the atmosphere, compresses it and sends it to the combustion chamber.
- Combustion chamber: this is where the combustion between the air and the fuel occurs (methane or gas oil).
- Gas turbine: the air and gas mixture, at high temperature, gets into a turbine where the expansion of combusted gases makes the rotor blades rotate and subsequently activates the alternator therefore generating electricity.
The advantages of turbo-gas plants are: the low costs of the plant, they start rapidity even if there is no energy in the network and the fact that these plants do not need cooling water. It is possible to build them in any place, even far from the rivers and the sea. The disadvantage is the very low output (around 30%) and therefore the very high energy cost.
Combined-cycle plants
Combined-cycle and co-generation systems are the most efficient technologies to produce electricity from natural gas. Both use the heat that would normally be lost. Combined-cycle plants exploit the heat they generate to produce electricity. These systems associate a turbo-gas plant with a vapour group: the residual heat of fumes going out from the turbo-gas group is used to produce vapour, increasing the performance by 56%. Moreover combined-cycle plants have lower building and maintenance costs, and a higher functioning reliability.
Combined cycle plants represent the most sustainable solution for thermoelectric power generation, guaranteeing a low overall impact on natural resources. In particular, the use of natural gas has a very limited environmental impact in terms of local atmospheric pollution. Respect to coal and oil, in fact, using natural gas eliminates sulphur dioxide and dust emissions and reduces nitrogen oxide emissions thanks to the introduction of state-of-the-art combustion technology. In terms of global atmospheric pollution, the combination natural gas/combined cycle represents one of the most efficient alternatives to reduce greenhouse gas emissions. Natural gas is the fossil fuel whose combustion to produce a unit amount of energy generates the smallest amount of carbon dioxide: the “emission factor” amounts to 2.35 tCO2/tep, around 26% lower that of petroleum-based products and around 41% lower than coal.
Special reports
-
13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
-
18 January 2016
Ten years of oil demand
Eni has recently published the 14th edition of the 2015 World Oil and Gas Review...
10 September 2020
A simple and ingenious invention
There are objects so simple and ordinary that we forget their existence when we don't need them. Their presence is…
17 March 2020
Energy and renewable sources: what is the current status?
The unstoppable growth of renewable sources continues…
-
23 September 2019
Everything is transformed
At primary school we learn that nothing is created and nothing is destroyed. We have heard this phrase so many…
17 January 2019
What Are Solar Cells? Everything You Wanted To Know
When you think of renewable energy, what comes to mind? Water? Wind? Indeed, these two examples have proven the most…
1 June 2018
Is lithium the new petroleum?
Today petroleum vies for the title of “contemporary gold” with several competitors, one of those is certainly lithium...
-
13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
18 January 2016
Ten years of oil demand
Eni has recently published the 14th edition of the 2015 World Oil and Gas Review...
-
10 September 2020
A simple and ingenious invention
There are objects so simple and ordinary that we forget their existence when we don't need them. Their presence is…
17 March 2020
Energy and renewable sources: what is the current status?
The unstoppable growth of renewable sources continues…
-
13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
From the Multimedia section
Facts
-
Some curiosities about methane hydrates
The melting of the ice cells, not only brings about the release of methane gas, but it also produces another…
Orimulsion
In order to improve supply security, and therefore the diversification of sources to produce electric energy...
Cracking operations
At the end of the fractional distillation, long hydrocarbon molecules can be transformed into lighter molecules by means of more…
-
Where does energy come from?
Every day the Earth receives enough solar energy to satisfy the global energy need...
Electricity and electrons
In all electric plants, excluding photovoltaic solar plants, mechanic energy is transformed into electric energy through the same basic procedure...
Peat and peat-bogs
The age of coal starts towards the mid 1600s, stimulated by the need for finding an alternative energy source to…
-
Geographical distribution of energy
Every day the Earth receives enough solar energy to satisfy the global energy need. Unfortunately we cannot exploit all this…
An artificial geyser
Electric and thermal power produced from geothermal energy depend on the existence of underground infiltrations...
A hydrogen house
In Settimo, a municipality close to Turin, the first Unité d’Abitation has been created...
-
14 June 2011
Some curiosities about methane hydrates
The melting of the ice cells, not only brings about the release of methane gas, but it also produces another…
2 March 2011
Orimulsion
In order to improve supply security, and therefore the diversification of sources to produce electric energy...
-
Cracking operations
At the end of the fractional distillation, long hydrocarbon molecules can be transformed into lighter molecules by means of more…
Where does energy come from?
Every day the Earth receives enough solar energy to satisfy the global energy need...
-
Electricity and electrons
In all electric plants, excluding photovoltaic solar plants, mechanic energy is transformed into electric energy through the same basic procedure...
Peat and peat-bogs
The age of coal starts towards the mid 1600s, stimulated by the need for finding an alternative energy source to…
-
14 June 2011
Some curiosities about methane hydrates
The melting of the ice cells, not only brings about the release of methane gas, but it also produces another…
-
2 March 2011
Orimulsion
In order to improve supply security, and therefore the diversification of sources to produce electric energy...
-
Cracking operations
At the end of the fractional distillation, long hydrocarbon molecules can be transformed into lighter molecules by means of more…