High Penetration of Wind Energy in the Cape Verde Islands




Location
Cape Verde

Responsible
Organisation
Empresa Pública de Electricidade e Água (ELECTRA)
Funding
The Cape Verde and the Danish governments

Project Period
1992-1995

Contact
Name:



Address:




Phone:

Fax:

E-mail:

www:
Risoe National Laboratory
Wind Energy and Atmospheric Physics Department
Att. Jens Carsten Hansen

Building VEA-762
P.O. Box 49
DK-4000 Roskilde
Denmark

+45 4677 5074

+45 4677 5083

carsten.hansen@risoe.dk

http://www.risoe.dk/amv/

Description
Introduction:

In Cape Verde, electric power has until recently been almost entirely supplied from diesel power stations using gasoil
and heavy fuel. This situation changed in 1994 when wind farms with a total capacity of 2.4 MW - called the Step 1
Wind Farms - were installed at the three major island grids as a project jointly funded by the Cape Verdean and the
Danish governments.

Cape Verde has wind energy resources from the trade-winds providing a strong north-easterly flow for most of the
year. Projects since the early 80\'es have documented the technical and economic feasibility of today\'s wind energy
technology for Cape Verde.

Step 1 Wind Farms:

Below are the operation statistics for Step 1 Wind Farms at Sal, Mindelo and Praia power systems average for 3
years 1995-1997:

Island
Sal
Sao Vicente
S. Tiago
Power system
Sal
Mindelo
Praia
Available diesel capacity (MW)
Gas oil
Heavy fuel
Gas oil
Installed wind turbine capacity (kW)
600
900
900
Avg. wind speed at hubheight (m/s)
87.4
10.4
7.8
Annual wind energy production
(MWh)
1440
4390
2500
Annual power system load (MWh)
10120
32800
39870
Avg. wind energy penetration %
14
14
6.3
Avg. wind turbine capacity factor %
27
56
31
Annual diesel fuel savings (t)
340
970
615



Lessons Learned:

Evidence has been provided from the operation of the Cape Verde Step 1 Wind Farms:


That wind power is technically and economically feasible at the present wind energy penetration levels, which
for the first 6 months of 1995 were 24%, 19%, and 11% in Sal, Mindelo and Praia respectively

That on average for the 3 years, 1995-1997, the wind energy penetration in Mindelo has been 14% with a
record high average capacity factor of the three wind turbines for the total period of 55.6%, i.e. average
power output for each of the three Nordtank 300 kW wind turbines has been 167 kW

That comparison with actual data shows that modelling of power system performance with relatively high wind
energy penetration is possible with acceptably low uncertainties

Accurate power system modelling at conservative assumptions show good prospects for expanding the Step 1 Wind
Farms at Cape Verde with a step 2. The Step 2 Wind Farm sizes giving the least cost of energy have at the given
assumptions been determined to be 1.8 MW at Praia, 1.2 MW at Mindelo and 0.6 MW at Sal giving a wind energy
penetration of 25-30% in the first year of operation.

Implementation of these three wind farms will reduce Cape Verde\'s dependence on imported fuel oil significantly and
contribute to reducing the cost of electricity in the country. The project will serve as a demonstration showing that
power systems may be expanded with wind energy up to significant penetration levels without adding expensive
control systems and without jeopardising power system reliability.

Globally, implementation of the Step 2 project will contribute to reducing emissions of greenhouse gasses. Although
the environmental impact is small on a global scale, it should be included in evaluation of each project. The proposed
internalisation of the external savings due to environmental benefits improve the economics of the proposed project
by 40% measured as the increase of the projects internal rate of return when including external environmental savings
of 0.10 DKK/kWh.

It is seen from the results of the economic analysis, that the optimum wind farm sizes for the Cape Verde are even
larger than the proposed sizes. Due to the lack of international experiences with wind energy to these high
penetration levels in MW size power systems, the uncertainties and project risks may seem too high for commercial
investors. However, in view of the international need for such pilot and demonstration project, attempts should be
considered to attract funding from international organisations.

Finally, island power systems exists world wide, which are similar to the Cape Verdean with relatively high costs of
conventional electricity generation and sites with sufficient favourably wind conditions to make wind power feasible.
Keeping the uncertainties of these preliminary studies in mind, it has found that even in areas, which traditionally have
been considered low wind areas, there may be found locally sufficient wind resources to make wind power feasible.