Diploma Project Summary - Erik

In my project I had mainly two questions to be covered. The first one is about the current status on the energy supply in the area, where the goal was to get a wider view of the extent of the grid.
The other question covered was about how to make the school self-sufficient on electrical energy by using solar power. By doing this I would also examine the possibilities to apply the same solution on other buildings, equal to the school.

Solar Power
Solar energy is a powerful energy source with quite easy access. This makes it particularly beneficial for smaller independent energy systems, like the one I investigated. Furthermore the geographical position of the school has a high solar radiation with a yearly total of 1600 kWh/m2. This can be compared to Sweden which has a lower average of about 900 kWh/m2/year.

Methods used:
In my project I mainly used two methods to acquire the information. The first and most used method was interviews. During the trip to Tanzania I got the opportunity to interview personnel in the school regarding their energy usage etc, private solar companies on their products and personnel from energy authorities regarding the public electrical grid.

Ultraviolet radiation- measurements:
The measurements that I carried out on the school campus was on a specific solar radiation called ultraviolet radiation. The ultraviolet radiation only represents a small portion of the whole solar radiation that reaches earth so therefore I had to recount my results using proportionate method in my calculations.

Results:
As for the energy consumption in the school it turned out that it had a usage of about 8,5 kWh/day. This number can be compared to the average Swedish house which consumes somewhere around 55 kWh/day in average, or over six times more than the school. For the electricity from the public grid, the school payed 352 tanzanian shilling or about 1,4 sek per kWh.
The measurements gave the result of a theoretical efficiency of approximately 10W/m2. But that is only on a specific ultraviolet radiation and not the whole spectrum of solar radiation.

Electrical Grid:
In the province of Kagera, the energy authorities are importing the electricity from its neighbouring country, Uganda. The energy from Uganda is generated by hydro power plants, thus making it sustainable energy. It also showed that the energy authorities in Tanzania are planning on building large hydro power plants in the country and an energy supply consisting of only renewable energy.
Another project concerning my survey was the consisting program runned by the Rural Energy Agency. Last year this agency supplied 6500 villages in Tanzania with electricity and it is aiming to supply an equal amount this year.

Discussion:
Considering that I only measured a fraction of the total solar radiation, I had to make some calculations and finally got the result of an average solar radiation of 2 kWh/m2 per day in the school. But this number still differed from the theoretical solar radiation of 4,5 kWh/m2 per day, and this can be explained for example by inaccuracy in used equipment or inconsistency in weather and ozone layer. To get the most accurate result I went to use the theoretical number on the solar radiation on the school and used that in the calculations on the solar power system.
With the solar panels I presumed that the solar cells has an efficiency of 20%. This means that 20% of the solar energy is converted to electrical energy. This gives a theoretical daily energy conversion of 0,9 kWh/m2/day for the solar energy system.
In my calculations I also had to take in consideration that the weather could be unfavorable for a longer period of time, which would mean that more solar panels would be needed to cover the demand. Furthermore I also had to take in consideration that all the solar panels will not be fully active during all sun hours since they are placed in a fixed position. With these factors in consider, the school would need about 38 m2 of solar panels to cover its demand on electricity. To be able to supply electricity during night time, I have used a external battery in my calculations, capable of storing 13,5 kWh. A solar energy system like this, would have the capability of providing at least 17 kWh/day, which is double the amount of the usage the school has today.

Conclusion:
My conclusion on this project is that it is clearly visible that Tanzania has a great ambition on providing its whole people with electricity, and this is something that is confirmed by the large scale energy projects that is being planned and built in the country. When it comes to the school, a fully supplying solar energy system is possible and would be beneficial for the school in the long run by erasing all future energy costs and making it independent from the public grid. Though this requires an investment of at least 200 000 sek (approx. 21 000 USD), so to make this profitable for the school, it would probably need external financing, presumably from an aid organisation.