This document outlines a proposed design for a new 20MW geothermal power plant in Savusavu, Fiji. The plant would use a binary cycle system to harness geothermal energy from reservoirs between 70-200 degrees Celsius. The system would include production wells to extract brine, a heat exchanger to transfer heat to a working fluid, turbines turned by the heated fluid, and 80 generators each producing 250kW of power. Electricity would be transmitted through cables to consumers. The plant aims to provide clean, renewable energy to the area at a lower cost than fossil fuels.

2. Outline
 Introduction
 Constrains
 Electricity demand/supply
 Classification
 Measurable performance indicators
 Design model
 Main parts of design model
 Transmission of electricity
 Costs
 Social, economic and environment requirements
 Life cycle system
 Conclusion
 Reference

3. Introduction
 This System Design Document has been created to outline the
proposed system design for new geothermal power plant in Savusavu.
The new system is intended for the production of electricity from the
geothermal station for the consumers of Vanualevu hoping to get a
clean and renewable energy. The new system design indented to be
build is the binary power plant, it will replace the fossil fuel driven
generators 20 to 50 MW of power would be produced in a renewable
manner. The binary power station would require the brine or the
aquifer at 70-200 degrees Celsius. The binary cycle power plant has one
major advantage over flash steam and dry steam power plants: The
water-temperature can be as low as 57°C (135°F).
 The water coming from the geothermal reservoirs through the
production wells is never in direct contact with the working fluid. After
the some of its thermal energy is transferred to the working fluid with
a heat exchanger, the water is sent back to the reservoir through the
injection wells where it regains its thermal energy.

4. Introduction (cont.)
 These power plants have a thermal efficiency rate of only 10-13%. However,
geothermal binary cycle power plants enable us, through lowering temperature
requirements, to harness geothermal energy from reservoirs that with a dry- or
a flash steam power plant wouldn’t be possible.
 Looking at the number of people living and demand for power in Vanua Levu,
it is less when compared to the demand of power in Viti Levu. Nevertheless the
population size in Vanua Levu is small but there is need for the people in
Savusavu to access electricity with minimum cost and reliable energy source for
reducing the consumption of fossil fuels. Therefore, geothermal is a renewable
energy source which can reduce the emission of carbon dioxide into earth’s
surroundings and can minimize the cost to make people in Savusavu Area get
access to electricity.
 Furthermore, to represent an engineering design of a model, each and every
components of the system should be considered and gathered information
about each parts in order to know the function of each components in the
system. As stated above, we will design the model of Binary power plant for
Savusavu Area in Vanua Levu. Therefore, different parts of this system will do
different works starting from extraction, power conversion, power
transmission/transportation and delivering of power to customers.

5. Constrains
 The people of Vanualevu demands a stable electricity
supply that is cheap and clean to use.
 A renewable energy system that is safe and provides
electricity to the people of Savusavu
 The best energy system that can be used in Savusavu is
geothermal energy system.

6. Electricity demand
Fossil fuel power source
Replacing as geothermal
energy system
Power
station
Power
source
CAPACITY
(MW)
Savusavu Binary
geothermal
plant
80 *250KW
Three
phase
induction
type
genertors
TOTAL 20

7. Electricity supply

8. Classification of geothermal energy towards
clients
 Resources classification is a key element in the characterization,
assessment and development of geothermal energy.
 Stakeholders at all levels of government, with in the geothermal
industry, and among the general public need to be able to use and
understand consistent terminology regarding issues such as location,
quality, feasibility, of development, and potential impacts.
 Terminology must encompass both the geothermal nature of
geothermal resources and the practical technological and economic
aspects of resources exploitation while reaming understandable to the
broad community of non-specialists.

9. Environment measurable performance
indicators
 Its provides information that helps evaluation and decision making
within organizations that engage in environmental efforts.
 Provides a common foundation of information for organizations and
external interested parties ( such as consumers, business, partners,
residents in local communities, shareholders and financial
institutions) and their environmental efforts.
 It also provides a common foundation of information that helps the
integration of environmental policies of the national and local
governments, such as basic environment plans and environmental
activities of organization.

10. Geothermal power plant model
 One company that can
supply this type of power
plants is FUJI ELECTRIC
LTD

11. Working fluid, Cooling fluid,
Geothermal brine
 The two working fluid primary and secondary are brine and n-pentene.
 In the selection of working fluid, It was ensured that the thermal
characteristic satisfied the binary working conditions.
 There was less adhesive effect on the environment.
 The heating of the working fluid was easy
 The properties of the liquid are equal.

12. Evaporator
functions details
 Function is to heat the
working fluid after being heat
by the Preheater
item Major
features
evaporator type Horizontal
shell-and
tube type
capacity 1990KW
Temperatur
e
inlet/outlet
N-
pentene84/
105*C
Brine
130/130*C

13. Preheater
functions details
 it heats the working fluid.
 Purpose to heat the n-pentene.
Item Major
features
preheater Type Horizontal
shell-and
tube type
Capacity 720kw
Temperatur
e
inlet/outlet
N-penten
36/84*C
Brine
130/100*C

14. Turbine
 Turbine used in this binary cycle system is radial inflow with a
diameter of 448 mm of rotor, amount of rotor 110 pieces blades, nozzle
length 35 mm, diameter 20 x 6 mm nozzle, nozzle material is AISI 304,
the number of nozzle 6 pieces, with double mechanical seal of material
stainless steel, tungsten and carbon with gear box ratio is 4 : 1.

15. Condenser
 Condenser has the function to cool the working fluid that comes out of
the turbine so that it returns to the liquid phase.

16. Generator
 The turbine that is turn by the secondary liquid is connected to the
generator. There will be 80 generators with each capacity of 250kw

17. Other parts include
 The injection well-cooled brine is pumped into the
geothermal reservoir
 The production well-heated brine is pumped out from
the reservoir.

18. Transmission of electricity
 The 20MW power will be supplied to the consumers by
electric transmission cables by the help of
transformers electricity will supplied to every
household and industries.

19. Cost
 Direct use of geothermal energy is a absolutely cheaper than other
energy sources.
 Cost of electricity generation depends upon certain factors.
1. Temperature and depth of resources
2. Type of resources ( steam, liquid, mix)
3. Available volume of resources
4. Size and technology of plant
 The initial investment is high
 But after certain time period , the cost of electricity becomes
comparable to other resources of energy.

20. social requirements of geothermal energy
 Expectations of local communities, governments, development
organizations, nongovernmental organizations (NGOs), and other
stakeholders have risen significantly regarding how effectively
companies should mitigate environmental impacts of their activities.
 These expectations have been explicitly expanded to include social
issues and impacts, which are often not seriously discussed in
environmental impact assessment reports. In developing countries,
expectations have been made complex by the challenges associated
with sustainable development. To meet these challenges, governments
through their legal systems must develop regulation on creation of a
level field for industrial competition and investment without
jeopardizing the needs of the local communities and other affected
parties.

21. Economic requirements of geothermal
energy
 Marketing analysis – size of market, distribution, market segments
 Design costs – design team computing, information retrieval
 Development costs – design detailing, supplier costs, testing costs
 Manufacturing cost - tooling, labor, overhead, assembly, inspection
 Distribution costs - packing, transport, service centres, spare parts,
warranty
 Resources – time, budget, labor, capital, machines, material

22. Environmental requirements of
geothermal energy
 Compatibility with other land-uses. Geothermal power plants
require relatively little land. The installations don’t require damming of
rivers or harvesting of forests, and there are no mineshafts, tunnels,
open pits, waste heaps or oil spills. They can be sited in farmland and
forests and can share land with cattle and local wildlife.
 Renewability of the resource. Geothermal energy has been classified
under clean and renewable resource. The resource can be described as
renewable only if the rate of extraction is less than the recharge rate.
Sustainable use of the resource can be attained through reinjection and
reservoir flow monitoring.


23. Life cycle costing of the system
 The total amount of installing the system would be
close to 50 million dollars, which will take 2.5 million
per MW. The aim of achieving this 50 million would
take approximately 30 years, with 149000KWh of
electricity 55240000 dollars of electricity would be
sold. The maintenance and operation will cost
2762000 dollars. So at this at a breakeven rate of sale of
electricity at 0.12dollars/kWh would give back
15145000 dollars for the life cycle cost of this
geothermal power plant system.

24. Conclusion
 Geothermal heating system can be replace fossil fuel heating system in
a particular area.
 Annual costs for common heating purpose can be reduced by more
than 60%.
 Continued energy shortages have created added interest in geothermal
energy for power generation.
 Geothermal energy appears to be a partial solution to our energy needs.

25. Reference
 www.worldenergy.org
 www.NEED.org
 www.wikipedia.com
 Google maps
 Energy department of Fiji
 Fuji electric LTD

27. YOU