225 kV interconnection between Mali and Ivory Coast : done !

A bit of history

Segou switchgearOn November 11, 2012, the high voltage power systems of Mali and Ivory Coast were connected for the first time. The new 225 kV overhead lines connection between Ferkéssédougou in the North of Ivory Coast and Ségou in Mali, via Sikasso and Koutiala, was put in operation. Not only the two countries are now interconnected in a single power system, but also Senegal, Mauritania, Burkina Faso, Ghana, Togo, Benin, Nigeria and Niger.

Ferke-SegouThe 520 km of new lines, that costed EUR 125 mio, were indeed the missing link between the 225 kV OMVS system and the 330 kV coastal backbone network from Nigeria to Ghana. The two networks, joined together in one, now constitute one of biggest power system in Africa, stretching over 3,000 km from Mauritania to Nigeria, as promoted by the WAPP (West African Power Pool) since decades.

The OMVS (Organisation pour la mise en valeur du fleuve Sénégal, in French) is the Senegal River Basin Development Authority. It was established in 1972 by the governments of Guinea, Mali, Mauritania, and Senegal.

Personal emotion

I am personally happy that the line is finally in operation. I remember my first power system planning study, back in 1997. It was precisely the feasibility study for the interconnection between Mali and Ivory Coast, performed by Lahmeyer Int. The interconnection was already defined in a regional master plan performed in the eighties.

SLD Mali Ivory CoastFor ten years, there had been no significant progress. Finally, in 2007, I had again to revisit the study. India came to help the two countries to finance the project and the feasibility study had to be updated, again by Lahmeyer Int. The lines were then built accordingly to the detailed design prepared in the study. Now, they are online. It is always a great feeling for a planner to see that what he recommended years ago is finally built.

The construction wasn’t easy, taking into account the political uncertainties and security issues in both countries. I would like to pay respect to the engineers and workers who built the line in extremely tough conditions.

A smart move

Building overhead lines is not especially what one understand in the term “Smart Grid”. But taking into account the lack of high voltage network in Africa, the investment is really smart. Let’s continue to interconnect countries in West Africa. The next interconnection could be Ghana-Burkina Faso-Mali (Bolgatanga-Bobo Dioulasso-Sikasso – 600 km) or Guinea-Mali (N’Nzérékoré-Fomi-Fomi-Bamako – 920 km).

Gauthier Dupont
Dupont Energy Consulting GmbH

The wind in Mauritanian sails

The first wind farm in West Africa, Act II 

In a previous article we have seen that Nigeria and Mauritania are competing for the first wind farm in West Africa, respectively with a 10 and 4.4 MW project. Now it seems that Mauritania is taking the lead with a second project, but this time in premiere-league with 30 MW.

The Mauritanian industry and mining company SNIM, which hired Valorem to prepare the studies and to supervise the construction of the 4.4 MW wind farm in Nouadhibou at the extreme North of the country, is now planing to commission in October 2013 a second 30 MW wind farm south to the capital Nouakchott. Valorem offers again the engineering and consulting services. One can estimate the total investment to 45 million €, taking into account a nominal cost of 1,500 €/kW.

An ambitious project

The 2011 peak load of the Mauritanian interconnected network reached only 70 MW. At night during the cool season the load drops down to 25 MW, less than the wind farm installed capacity.

OMVS HV network

Hopefully Mauritania is interconnected with Senegal and Mali through a 225 kV single circuit overhead line being part of the OMVS network that was built to export the energy produced at the 200 MW hydro power plant located at Manantali in Mali (see opposite map).

There is therefore no technical issue to export the excess energy to the two neighboring countries, at the condition that the single HV circuit overhead line is available, which is not always the case.

For some people in Mauritania there is no need for export. Major industrial projects would soon grow in the desert. New factories would add enough electricity consumption so that there will be no excess energy to export. Fifteen years in Africa have shown me that projects developers and officials are extremely too optimistic when it concerns industries development. It would take years to start running the first factory in Mauritania.

One might object that same optimistic attitude is often adopted when estimating power plants project schedule. Fair enough. But SNIM particularly need more energy to develop its mining activities. Raw material international market prices are high. It is the right time to SNIM to invest in increasing its production. An incentive stronger than investing in factories in Mauritania. SNIM needs power to develop. They then have to build new power plants.

Two missing links

First, the Mauritanian utilities Somelec does not have a National Load Dispatch Centre (NLDC). The operation of the network is done manually (the operator uses a computer mouse to control active and reactive power production as well as circuit breakers. There is no automation) and power plants operators communicate on the phone. Yes, we live in the XXI Century. Shocking, isn’t it?

The good news is that another project of a new 120 MW power plant located north to Nouakchott is undergoing and also requires a NLDC. Somelec is well aware of the situation and is doing everything he can to find a solution to fund the  construction of the NLDC. One can reasonably hope that the NLDC will be ready before the wind farm.

Second, there is no network close to the wind farm location. 33 kV underground cables or overhead lines must be installed to connect it to Arafat substation, the closest one located 11 km away. The problem is that the substation is very old and in bad shape, and no spare feeders are available. Additionally it belongs to Somelec, not to SNIM. A new switchgear must then be installed. It wouldn’t be technically difficult because there is enough free space inside the substation fence. But an agreement shall be achieved between Somelec and SNIM (who pays for what? What belongs to whom?) Negotiation could require much more time than building the wind farm.

So, nothing technically insurmountable, but not easy to manage.

Missing business case

The major threat shall be searched out somewhere else. At which tariff shall be sold the energy produced by SNIM to Senelec and/or EDM, the Senegalese and Malian utilities? How much shall be paid to SOGEM, the OMVS operator, for using its network? And Somelec, what would be its share?

None of these crucial questions was yet raised. Why? Because they are extremely difficult to answer. On one hand, the legal frame is complicated, not only because of the implication of three countries, but mainly because the laws applicable to the energy sector are not prepared to address such a case.

On the other hand, it took ten years to the Senegalese, Malian and Mauritanian authorities to agree on energy tariff and respective allocation of the energy produced by Manantali. One can hope this time the negotiations between SNIM, Somelec, SOGEM, Senelec and/or EDM and the three national authorities will not last as long. But I am not sure it can be done before the wind farm produces its first kWh.

Gauthier Dupont
Dupont Energy Consulting GmbH

Related articles

Looking for wind in Africa

Unfavorable wind pattern

Prevailing wind pattern found in the tropics is not very favorable for power generation. Mean wind speed is globally smaller than in Europe and the USA (see the map), except along some coasts (clockwise): North of Senegal, Mauritania, Morocco, Egypt, Somalia, Kenya, South Africa and Namibia. Best spots are predominantly remote, inhabited, and without infrastructures (road and power network).

Global wind speed

Optimistic wind maps

Wind maps, like the one displayed opposite, are created by models based on mathematical equations that describe the physics and dynamics of the atmosphere, calibrated from observational data. The more measurements, the higher the accuracy.

Wind measurement at wind generator height is a scare resource in Africa. Few measurement campaigns were performed, expect at some best spots. In vast areas, in particular the Sahara, calculated mean wind speed entirely relies on atmospheric model calibrated from data measured thousands kilometers away. Such results cannot be seriously used.

Higher vertical and horizontal resolution, as well as few measurements at 40 m were recently used to produce detailed wind maps for Mali and Senegal. Results confirm that global models overestimate wind speed in the Sahara. Wind potential is limited in a narrow band along the coast, where 8 m/s can be found. Wind speed dramatically declines when entering the continent. Best spots in Mali benefits for a mere 5.5 m/s.

Another wrong solution for Africa

Before the national wind map was available, Canadian wind developers supported by the Canadian development cooperation administration convinced the government of Mali to install an hybrid system (small wind turbine & diesel generator) in a remote small town reputed being windy. But the wind people feel is not the one needed for power generation. The wind turbine stands useless most of the time. Inhabitants are frustrated. They were told that the system would produce electricity mainly from wind, but now they have to pay for the fuel. Finally the wind turbine was dismantled and installed in another small town, leaving the diesel generator producing electricity and greenhouse gases. By the way, the same story was repeated in the other town.

Accurate wind map wanted

There is therefore an imperative need in Africa for wind measurements (typically at two thirds of hub height, i.e. 60 m to reach a high of 90 m for the wind turbines) and accurate wind maps. Global maps like the one above, as well as feelings and hearsay, cannot anymore be the only sources of information for decision makers to define investment policy.

Gauthier Dupont
Dupont Energy Consulting GmbH