The incredible dam / L’incroyable barrage

One evening, as every evening, the inhabitants lit their torches. Suddenly there was light, all the inhabitants wondered if it was the operation of the dam that provided them with this electricity

A dam is designed to regulate the flow or to store the water. In particular for flood control, irrigation, industry, hydroelectricity, fish farming, a supply of drinking water, etc. In nature there are also beaver dams.

We are in the vicinity of the hydroelectric dam of Kaléta, in a small village. The role of a dam is very important because it serves has to produce some electricity. The role of a dam is also to regulate the outflow or to store the water. It can be used for irrigation, industry, hydropower, fish farming, or as a supply of drinking water. The function of Kaléta is to produce some electricity for Guinea.

Catchment basin of Kaleta / bassin de retenue d’eau de Kaleta
Valve for collecting water / vanne pour capter de l’eau

First of all the dam holds back the natural flow of water. Large amount of water accumulate and form a reservoir (the normal Lake is 110 M²). Once the water is stored, they open valves so that the water rushes into penstocks. These pipes lead the water to the hydraulic plant below. This central force of water turns a turbine (there are 3 turbines, which have a capacity of 80MW each with facilities of 180 m 3 per second). Alternators work with the energy provided by the turbine, the generator produces an alternating electric current (an alternating electric current is a current that reverses direction twice per period and carries some amount of electricity), which is sent to a transformer. (A transformer modifies the values of tensions and strength of current delivered by the alternator). The more there is water the more there is power. The transformer raises the tension of the electric current produced by the alternator so that it can be more easily transported in the very high-voltage lines.

Very high voltage lines leaving Kaleta / Lignes à très haute tension partant de Kaleta

Abstract / Résumé

Un barrage hydroélectrique est un ouvrage d’art construit en travers d’un cours d’eau. On dit que la guinée est le château d’eau d’Afrique mais paradoxalement, nous n’avons ni eau ni électricité. Ce scandale ne pouvait pas durer voila pourquoi les Chinois ont construit le barrage hydroélectrique de Kaléta. Avec une puissance de 240,5 mégawatts. Il a fallut à l’état guinéen investir 526 millions de dollars.

Written by / écrit par:

Mamoudou Condé, Chérif Diallo, Moustapha Ndiaye

Photos: Christine Soumah

And then there was light… a dream come true! / Et la lumière fut! Un rêve devenu réalité…

We lived in darkness without an exit door, we were desperate. When as if by magic came a hero which drove away the darkness in our city. It is called Kaleta.

Kaleta was a dream for the government for thirty years. After a lot of statistics and studies and calculations, the government decided to invest money in the project. Guineans decided to collaborate with French and Chinese companies for the construction. The companies who participated in the construction of the Kaleta dam are CIW (China International Water and Electricity Corporation).

the dam of kaleta / le barrage de Kaleta

Kaleta was built between 2013 an 2015, in 3 years and a half instead of 4 years and a half. It is the first big dam in Guinea and there will be a second one soon. Kaleta is located more than 70 km away from Conakry. In the plant there are 8 levels underground and the dam is 53 meters high.

In the control room, there are computers and screens which are necessary to control all the machines, such as the alternators, the turbines and the alternators.

shaft of the turbine / arbre de la turbine

The alternator is
used to convert mechanical energy into electrical energy. The transformer can be used to change the voltage of the current. A hydraulic turbine is a rotating machine that produces mechanical energy from moving water (stream or tide) or potentially moving (dam). It is the essential component of hydroelectric power plants to produce electricity from a water flow.

Today, the electricity that is produced is not enough for the whole country. The Guineans need roughly 270 megawatts on the network. During the rainy season (from June to September), there is a lot of water, but during the dry season there is less water. So the dam cannot work at full capacity. Today in Kaleta only 2 turbines are working, they produce between 100 and 150 megawatts. The power of the dam depends on the quantity of water.

location of the Souapiti dam / site du barrage de Souapiti

A second dam will soon be built to supply Kaleta with a constant flow of water and to produce more electricity for the whole country. Guinea will then sell energy to neighboring countries. That second dam will be called Souapiti.

 

Abstract / Résumé

Kaleta un rêve devenu réel

Un projet conçu en 2013 et terminé en 2015. Aujourd’hui la centrale de Kaleta nourrit une partie de la Guinée en électricité, cette source est située au village de Kaleta dont le barrage tient son nom. Le fonctionnement des machines comme les générateurs, les turbines, est contrôlé par de nombreux ordinateurs depuis la salle de contrôle. Kaleta ne peut pas fournir assez d’énergie pour alimenter toute la Guinée. Elle a besoin d’une forte pression pour faire fonctionner les 3 turbines, ce qui est uniquement possible pendant la saison de pluie. Un nouveau barrage est en cours de construction, qui alimentera aussi Kaleta en eau, donc il permettra a Kaléta de produire plus d’électricité. Ce nouveau barrage se trouve à Souapiti.

Written by / écrit par

Mariam, Alice, Salematou et Tess

Souapiti, THE big dam/ LE grand barrage

Rejoice men of Guinea ! Soon you will be able to watch a classico without being interrupted by a power cut ! What is going to make this miracle possible ?

The dam of Souapiti will create an artificial lake of 6.3 billions of m3. Its construction will be completed in 2020.

Needs in electricity in Guinea today are equivalent to 240 MW on average and 270 MW during peak hours on the interconnected network. For the moment the dam of Kaleta can produce 100 to 240 MW. Souapiti will provide an extra 450 MW, and will allow Kaleta to be supplied by a regular flow of water, thus to work at full capacity.

The location of the future dam of Souapiti / site du futur barrage de Souapiti

The  dam of Souapiti is being built by a Chinese society CWE (the China international water and electricity company) and the works  will cost 1,400,000,000$. 15% will be paid by the Guinean state and the rest will be borrowed from a Chinese bank (Exim bank). The dam of Souapiti is under construction on the river of the Konkoure.

One difficulty encountered in the construction of the dam of Souapiti was the removal of people. To relocate these people, two new villages have been created with brand new housing, electricity for 1500 people. The relocation of people took place peacefully.

The village of the workers, very similar to the new villages / Le village des travailleurs, très similaire aux nouveaux villages

Guinea will possibly sell 30% of the production of Souapiti to neighboring countries or Guinea will sell 165 MW,  to Senegal (20%), Guinea Bissau (6%), and Gambia (4%). Which could represent  2 to 10 millions Euros a year.

Souapiti will solve the electricity problem in Guinea… If the barrage is correctly kept the daily life of Guineans will be way better and easier.

Even the government will have benefits in it, Souapiti will be a major source of revenue for Guinea’s economy.

Abstract / Résumé :

Le barrage de Souapiti est en construction par la société chinoise CWE pour combler le manque d’électricité en Guinée. Le barrage de Souapiti entrainera la création d’un  lac artificiel de 6 milliards m3. Il sera achevé en 2020. Le barrage de Souapiti est en construction sur la rivière du Konkouré.  Il fournira à la Guinée 450 MW et il permettra au barrage de Kaleta situé en aval de produire davantage d’électricité.

Les travaux du barrage coûteront 1 milliard 400 millions de dollars. La Guinée payera 15% et le reste sera prêté par une banque chinoise. La Guinée pourra ensuite probablement vendre jusqu’à 30% de la production de Souapiti à ses pays limitrophes.

Souapiti règlera bientôt la plupart des problèmes d’électricité Guinéens.

written by / écrit par

Noah ALAO, Radi CHAIB, and Kalil BOUZIGUES

Photos: Christine Soumah