Gas Valorization in the Republic of Congo: Production of Electricity from National Gas Reserves

The environmental impact of greenhouse gases based on natural gas flaring influences the rate of gas recovery around the world. In the Republic of Congo, the natural gas reserve in 2019 is estimated at 90 billion cubic meters (BCM). In this study, from the Congolese gas reserve we used five gas turbines with a capacity of 150 MW each; these five turbines consume 1.69 billion cubic meters (BCM)/year for the power of 273.750 MW and consumption of 6.57 billion kilowatt-hours. The results of this study revealed that an investment capital of 192,305,137 euros was required with a net profit of 9,581,250 euros at an annual rate of return of 4.98% with an investment payback period of approximately 20 years. This will allow the Congolese government to accomplish its policy of valuing gas and developing the country; the electricity produced by the National Petroleum Company of Congo (SNPC) will be sold to the Electrical Energy of Congo (EC) at 0.06 euro/kWh.


Introduction
Despite the difficulties encountered more precisely, the lack of documents dealing with the impact of the three variables (production, utilization and flaring of gas) on economic growth at the national and international.
According to [1], the year 2019 witnessed about; we have taken stock of the and processing requests as well as the procedures for granting special and prior flaring authorizations are set by decree in the Council of Ministers, requests for special and prior authorization from flaring includes, in particular, the evaluation of alternatives for use or recovery, information on the quality and quantity of gas concerned as well as the required flaring time [2].
The main goal of this study is to make our contribution to the national gas valuation policy and environmental protection, the national petroleum company

Literature Review
One of the methods suitable for systemic reduction and elimination of gas flares is the generation of electricity with the power cycle. The basic principle of the power cycle requires the use of a gas turbine (GT) to generate electricity. Gas turbines are increasingly used for the production of electricity, especially when large quantities of natural gas are abundant [3] [4]. Turbines generate high powers with high efficiencies and low emissions and can also be used in simple cycle mode for the production of mechanical energy and electricity at baseload in the oil and gas sector where natural gas and the process gases were used as fuel, and their maintenance costs are much lower than those of liquid fuels.
According to Meetham [5], the advantages of the gas turbine are: the ability to burn various qualities of gas than other alternative engines, lower maintenance cost with few moving parts, less vibration and noise. The literature [6] and [7] has emphasized that the production of electricity from natural gas has the advantages of high energy efficiency, energy-saving, and environmental protection, as well as flexible adjustment. The development of electricity production from natural gas is conducive to the achievement of strategic energy conservation and emission reduction objectives while improving the operational safety of the network. Therefore, it is emphasized that the production of electricity from natural gas will play an important role in the low carbon transition process of the Chinese energy industry. The literature [8] has pointed out that the large-scale use of electricity generation from natural gas is an important means of building green, low-carbon cities and other environmental protection work in mega-cities.
The literature [9] [10] has emphasized that, as Chinese environmental protection standards are gradually brought into line with those of developed countries, natural gas as clean energy will be vigorously promoted and applied. The literature [11] [12] compared the effects of the production of energy from natural gas and coal on the protection of the environment and underlined that the production of energy with natural gas instead of the production with coal can assist the energy sector in achieving its strategic objective of energy conservation and emission reduction.
Therefore, China's electricity sector presented a strategic plan for the mod-  3 and gas producers use natural gas to generate electricity, which allows them to obtain profits on the sale of natural gas and the production of energy from natural gas. In China, the installed capacity for generating electricity from natural gas will represent 4% of the total installed power of electricity. Consequently, the literature [13] [14] has underlined that during the periods "Twelfth five-year plan" and "Thirteenth five-year plan", the sector of energy production from natural gas will offer good prospects for develop-  and summarized the results of these studies [26]. The characteristics of natural gas energy production projects summarize the classification methods for natural gas energy production projects and propose methods of classification approval.
These studies show that projects for the production of electricity from natural gas have been tested in many regions of China and that related theoretical and practical research has also laid the foundations for a certain development which has enabled to vigorously promote the development of energy production from natural gas during the period of the "twelfth five-year plan".
In recent years, while large traditional gas-fired plants have been constantly has analyzed the economic benefits of distributed power generation projects from a user perspective. According to analysis and research, in the current political context in China, the economic aspects of distributed energy production projects are not significant. This also limits to some extent the development of the decentralized energy production sector.
Current technology (GTW) is used all over the world for the valorization of gas, among others, we mention China and Nigeria. In Nigeria (power plant of 50 turbines), the estimated capital investment is high, the rate of return on investment is high. With a gas volume of 16,972,500,000 m 3 per year and generates 2,737,500 MW of electricity per day [33]. Therefore, GTW is a tool for gas development and economic development.

Data Collection
The data for this study were collected from various reliable sources, such as offi-

Presentation of the National Petroleum Company of Congo (SNPC) and the Electrical Energy of Congo (E 2 C)
The

Global Trend of Thermoelectricity Generation Compared with the Republic of Congo: Electricity Production from Natural Gas
Natural gas, due to its clean-burning nature, has become a very popular fuel for

Evolution and Prediction of Population
The Republic of Congo is a Central African country located on the equator, sparsely populated and dense despite an honorable size. The country reached, according to estimates, 5.3 million inhabitants in 2018. And its annual demographic growth remains very high, at +3.68% per year on average between 2010 and 2015. Figure 3 represented the growth trends of the Congolese population from 1990 to 2017.
We carried out a study to assess the demographic growth rate in the period from 1990 to 2017, following this study we noted a growth of 2,753,965 inhabitants during this period, this requires increasing the production capacity of electricity to maintain the stability of the voltage in the distribution network.
Regarding prediction, Figure 4 represented the evolution of the population for a period going from 2021 to 2035 which has been subtracted from the statistics of the growth of the total population from 1950 to 2050 [36]; with an annual growth rate of 2.61% in 2019.
Demographic changes and changes in subscribers will be the main determinants of electricity demand. Congo is expected to experience positive and faster growth in demand for electricity over the next decade. Congo's population growth will be one of its main challenges for the years and decades to come.

Electricity Production and Demand Estimation
Recently the power generation capacity in Congo has increased due to new gas power plants, for this study we will first present the history of electricity production after demand.
We have represented the variation trends in production capacity from 1990 to 2017.
From Figure 5 we can say that the Republic of Congo has the potential of production in electrical energy for a period going from 1990 to 2017, in general, the production capacity of electricity increases with an ecard of 2.81 billion kilowatt-hours, this is explained by the growth of the population and the demand for electricity in industrial areas.    Figure 7 illustrates the general situation, from natural gas extraction to recovery (production of electricity). Farm 1 whose tank is in Oil + gas form (associated gas) and Farm 2 whose tank is in gas form (no-associated gas): The first case, the crude (oil + gas) through the pipeline1 arrives at the separator, at the outlet, there is oil which is transferred to (oil stock) and gas directed to the filter then

Evaluation of GTW Technology
The economic evaluation was made using GTW technology for the production   of electricity using the ALSTOM GT13E2 turbine, the performance parameters of which are shown in Table 1.
An ALSTOM GT13E2 unit consumes a total of 0.93 million cubic meters (mcm) of gas per day and generates 150 MW of electricity [33]. Following this, we will make an economic estimate using GTW technology for the production of electricity as part of the contribution of the gas valorization policy. According to Table 1, it will be possible that 1.69 billion cubic meters (BCM) of gas could be used to produce 273.750 MW of electricity per year, using 5 units of turbines.

Estimation of Electricity and Financial Production
The estimate is based on the assumption that the availability and consistency of gas turbines are 100% throughout the year (365 days a year). We also assumed The cost of the product for sale is the retail price of electricity per kWh. The total cost of the product for sale is the financial value of all the electricity produced, which is also the total annual income.  Electrical Energy of Congo (E 2 C).
The residential sales tariff system currently in use is around 0.06 euro/kWh [34]. Therefore, it was used as the basis for calculating income from electricity sales and generate income. On this basis, the calculation is provided to demonstrate the financial output of a turbine unit with a power of 150 MW each.
The estimate has shown that GTW technology is one of the cost-effective means of upgrading gas. This is linked to the statement of revenues and return costs in Table 4 which shows an annual net profit of 9,581,250 euros with a return on investment of 4.98% per year. This initiative has a positive advantage for a long-term investment since the recovery of the latter should be around 20 years.

Conclusion and Recommendation
The main objective of this study is to apply the gas to wire technology (GTW) from gas reserves in order to contribute to the gas valuation policy.
The results show that investment capital of 192,305,137 euros was required with a net profit of 9,581,250 euros at an annual rate of return of 4.98% for an investment payback period of approximately 20 years. This project will turn the national oil company of Congo into an oil company that upgrades gas and produces electricity.
Given that gas utilization depends on gas production, there is a urge need to improve gas production capacity in the Republic of Congo, while reducing the volumes of gas flared. To do so, we suggest the following recommendations to the Congolese government: 1) Strengthen the existing legal framework, more particularly the Hydrocar- 3) Put in place fiscal/tariff policies to encourage oil operators to take an interest in gas exploitation, facilitate new investors in the gas sector.