Suganya Paskaran

The use of decentralized Concentrated Solar Power (CSP) systems in Sri Lanka

The Government of Sri Lanka estimates that Sri Lanka's annual electricity demand will
increase by 4%-6%. This comes at a time when the country had already reached its potent ial
for t raditional renewables. Fossil fuels are being used to meet the additional demand,
accounting for 60% of the current energy mix and 25% of the import expenditure. The shift
towards fossil fuel based energy has also resulted in the gradual increase of C02 emissions.
These issues can be addressed by investing in Non-Conventional Renewable Energy (NCRE),
for which Sri Lanka has ample resources. Solar power is the least deployed NCRE in Sri Lanka
due to high capital costs and lack of research and development .

This research aims to assess the feasibility of deploying decentralized Concent rated Solar
Power (CSP) plants in Sri Lanka to cater to the increasing demand while developing a low cost,
simple design. Hence, this research has two objectives, first, assessing the potential for CSP
to provide a significant fraction of Sri Lanka's future energy needs, second, recognizing the
crit ica l importance of costs, to further develop previous work done in the Cambridge
University, Engineering Department which was aimed at reducing the cost of the major capital
element, the mirrors.

The feasibility assessment includes the estimation of electricity demand growth and the
corresponding land and investment required to satisfy this demand with CSP plants. A suitable
upper limit for the Levelised Cost of Electricity (LCOE) was also estimated. It was concluded
that CSP plants can be used for rural electrification in Sri lanka, given that capital costs were
reduced.

The cost of CSP can be reduced by making design changes to the mirror and the supporting
structure, which accounts to 40% of its total cost. Previous work suggested a r ibbed structure
for the mirror structure. Even though this method was successful in achieving the target price,
the sophisticated design led to the use of specialised labour and equipment thus defeating
the primary design target of being simple.

Therefore, a simple approach to structural design was explored using commonly available
materials such as corrueated steel sheets with simple assembly techniques. The idea was to
attach facing sheets to the corrugated sheet with pop-rivets to improve the stiffness of the
cross section. Sample sections were made to demonstrate the possibility of fabricating the
cross-section with minimum labour and equipment and experiments were conducted to
assess the structural performance.

The fabrication process revealed that it was possible to produce the cross section with nonspecialised
equipment and labour. The results showed that the facing sheets improved t he
st iffness, both in bending and torsion but they were not as good as what the theory predicted.
It was concluded that the corrugate composite can be used for the mirror structure after
further modifications.