According to these results, the Eritrean coastline has an outstanding wind resource, particularly in the Aseb area. Of the two sites monitored at Aseb, the Aseb Airport site appears to be the more promising. Existing data sources indicate mean annual wind speeds of over 9 meters per second at the Aseb Airport, with a theoretical capacity factor exceeding 50%. These values indicate that Aseb could generate over 200 kilowatts for each 20-meter diameter turbine installed at 30 meters height.
Due to the plentiful and inexpensive land resources in the Aseb area, a wind farm using available land could generate far more power than the current demand in the entire country. Without storage, Aseb could integrate only about 3 megawatts of wind power into the existing power grid (Van Buskirk 1997). Options for transmitting power generated at an Aseb wind farm to the more populated areas near Asmera are currently being investigated.
There are several factors that might justify Eritrea taking a relatively advanced position regarding wind energy development. First and foremost, Eritrea has some unquestionably favorable wind resources. The analysis presented here indicates that there are unusually high wind speeds along the southern coast. Other good sites have been found in highland passes in central Eritrea (see Appendix B). In addition, some of the physical properties of the wind flows at these sites increase its potential value. These include a highly periodic wind pattern with low variability and a positive correlation between wind power availability and electricity demand in the highlands.
Wind energy in Eritrea is an economically attractive option. In economically advanced nations, the main constraint on wind energy development is the competition from natural gas generators (Grubb and Meyer 1993). This is not the case in Eritrea. Because of the high capital costs of transportation and distribution facilities for natural gas, such generators are not expected to be an option for Eritrea within the next decade at least. In addition, diesel-generated electricity costs 6.5 cents per kilowatt-hour, while electricity generated at good wind sites should be significantly less expensive.
Currently, Eritrea's economic development is constrained by the lack of long-term investment capital. Due to international concern about global carbon emissions, wind energy development is likely to provide access to grants or loans at subsidized interest rates that otherwise would not be available for electricity development. Also, since energy supply is one of the main constraints on national economic development, such investments would increase the pace of national reconstruction, further improving the economic situation in Eritrea.
Finally, Eritrea has already taken steps to perform an evaluation of wind resources. A major constraint on wind energy development is the wind resource assessment (Grubb and Meyer 1993), while lack of expertise is another major barrier in developing countries. This work, along with current monitoring activities and other work examining institutional barriers in Eritrea, are rapidly removing these impediments.
Due to these unusually favorable factors for Eritrean wind energy development, it may be to Eritrea's advantage to plan a relatively high level of wind power penetration for the energy sector. What remain are questions involving the technical, economic and physical feasibility of wind energy development in the Eritrean context.
In developing wind power for the electric grid in Eritrea, the primary considerations are economic. Currently, only the southern coastal region of Eritrea has been shown highly promising for wind energy development. Yet the main electricity load in Eritrea is currently in the central highlands region. Therefore, for extensive wind power development, either economical wind sites closer to the load center in the Eritrean highlands must be found, or transmission from the southern coast to Mitsiwa'e needs to be considered.
The main factors constraining Aseb wind power development are the relatively low demand and small size of the existing grid. Since the combined capacity of the Aseb power system is currently about 17 megawatts, the Aseb utility could accommodate only about 3 megawatts of wind. Due to the abundant wind resource at Aseb, this could easily be supplied by between 5 and 10 small to medium size turbines.
Another problem with the wind resource at Aseb is that the peak supply is in the winter, while the peak demand in the summer. One plan that would both further exploit the wind resource and level the seasonal loads is a cooperative effort with Ethiopia, in which winter wind power from Aseb is traded for summer hydropower from the Blue Nile region. However, this option may no longer feasible because of recent political conflict between the two countries.
Another option for distributing excess supply may be to connect the power system at Aseb to the national grid in the central highlands. Although this option is preferable in many respects, construction of transmission lines along the 500 km route may be prohibitively expensive and power losses unacceptably high. It may be possible, however, to find high-quality coastal wind power sites that are closer to the central grid.
Based on the promising results obtained from this preliminary resource assessment, wind power could be an attractive future source of energy for Eritrea. To realize this potential, the following work needs to be pursued:
Complete the Physical Resource Assessment
Procedures adhering to international sampling standards for station monitoring and maintenance need to be developed and a data processing and distribution system needs to be established and institutionalized. Wind site prospecting should continue, with considerations for factors such as ease of access, distance to transmission and distribution facilities, logistical impediments to maintenance and technical support, land use and land availability, security, and local community reactions. The completed physical resource assessment should result in the identification of several candidate sites for future pilot projects. Progress is occurring on several of these fronts.
Since 1996, the Eritrean Department of Energy has been conducting a wind prospecting and wind survey program that has employed a variety of tactics to find and evaluate wind energy sites with high potential. Preliminary results of this program are provided in Appendix B. Although these spot measurements were not conducted as part of this thesis work, the results are linked to this study through the collaborative effort and are included for completeness.
Further funding for the coastal component of this assessment has been procured from the Global Environment Facility (GEF), a joint program between the United Nations Development Program (UNDP), the United Nations Environment Program (UNEP) and the World Bank. This new project will include dedicated on-site monitoring, the results of which are expected in 1999.
Improve the Aseb power system
For full exploitation of the wind energy potential at Aseb, measures need to be taken to increase the reliability of the city power distribution system (Van Buskirk 1997). Although wind prospecting continues in the Eritrean highlands, further investigation into power transmission from Aseb to the highland is also warranted.
Implement pilot projects
One or more pilot projects should be implemented to demonstrate feasibility and to develop skills. A pilot project of this scale requires careful preparation and planning in order to be successful. Essential components in pilot project formulation and implementation include: cost and performance data from wind turbine manufacturers; information about current electricity generation; preliminary and final project designs; project evaluation criteria; financing options; operational procedures; and project staff training. The final decision on pilot project implementation is dependent on site assessment completion; however, as site evaluation awaits the year of data collection, pilot project formulation can proceed simultaneously. It is unclear at this point whether the GEF funded project described above will include pilot projects.
Conduct a thorough economic assessment of wind power integration
Wind data collected in the prospecting effort should be used to perform a detailed economic evaluation of wind power at each site. Prior to the availability of such data, any economic predictions are highly speculative.
Initiate a joint utility and government plan for wind development
Given the successful outcome of the previous stages, the government and utility can initiate an orderly plan and institute appropriate institutional mechanisms for the development of wind resources in Eritrea. Issues to be settled include: wind energy development priorities and policy goals; evaluation of wind power based on comparisons with competing fuel options; incorporation of environmental and energy security concerns; reliability; technical requirements; and social acceptability. In addition, possible institutional barriers of wind energy development in Eritrea should be considered.
If these steps are actively pursued, Eritrea will soon be in a good
position to take advantage of its indigenous wind energy resources in an