Title: Feasibility study of geothermal utilization of Yangbajain field in Tibet Autonomous Region, P.R. China

Abstract

This study investigates the feasibility of the renewable energy utilization in Tibet, which is known as
the “world roof” with highest elevation and splendid natural scenery. Based on the available energy
assessment and market analysis, a technical and economic feasibility study is carried out on
geothermal utilization of Yangbajain field with the objective of solving both electricity shortage and
lack of space heating so as to improve the Tibetan people’s living condition.
The technical feasibility study is to set up thermodynamic model of proposed different power
generation scenarios and long distance district heating system to analyze and optimize each scenario
by using EES and Matlab programmes. Four alternative scenarios optimized for new power plant
design are double flash cycle (Scenario 1), hybrid single flash and ORC cycle with isopentane as
working fluid (Scenario 2), pure ORC cycle with isobutane as working fluid (Scenario 3), and hybrid
single flash and Kalina cycle (Scenario 4). The conceptual design of district heating system with about
90km distance from Yangbajain to Lhasa is as well carried out. The results indicate that all power
cycles are technically feasible at different efficiency and heating system can be put up under
appropriate design and construction.
A financial viability evaluation is performed for all scenarios using engineering economic Present
Worth (PW) value analysis method with objective to figure out Internal Rate of Return (IRR) of each
system. The most optimum power cycle scenario is Scenario 1 with IRR value of 31.84%, followed by
Scenario 2 with IRR value of 22.15%. The district heating system has low IRR value of 3.13% due to
the high investment cost of long distance transmission pipeline. However, as an entire system of CHP
power plant, the optimum system can yield 8.92% IRR value at pure commercial investment level.
Since it will be a subsidized programme from the central government, it can reach 10.78% of IRR
value without loan interest payment. If the expected IRR of the investment company is 10.00%, it
proves this project is economically feasible.
The environmental protection in Tibet is the most important to be emphasized to carry out such a big
infrastructure project. As a renewable energy application, this project will benefit the region and local
people. At the same time, environmental protection should be conducted during the whole process of
proposal, designing and implementation for sustainable development.