Environmental Engineering Reference
In-Depth Information
ing station fired with natural gas. The heat is distributed by two independently
operated district heating systems as shown in Table 10.1.
In the following the investment and operation costs as well as the heat production
costs for these geothermal heating stations are discussed in detail.
Table 10.1
Technical data of geothermal reference plants
District heating system
DH-II
DH-III
in GJ/a
a
Heat demand
26,000
52,000
Heat at heating station
g
in GJ/a
b
32,200
64,400
50,6
c
Geothermal share
in %
85
Base-load heating station
2.1
c
geothermal capacity
in MW
3.4
32,600
c
geothermal heat free heating station
in GJ/a
27,400
production temperature
in °C
100
62
in m
3
/h
maximum flow rate
60
72
production/injection well depths
in m
2,450 / 2,350
1,300 / 1,250
CHP station / heat pump
d
auxiliary units
Peak-load heating station
fuel
light fuel oil
natural gas
burner technology
Low-NO
x
Low-NO
x
heating capacity
in MW
5
2 x 5
Boiler efficiency
in %
92
92
District heating network
length
in m
6,000
2 x 6,000
feeding/return temperature
e
in °C
70 / 50
70 / 50
network efficiency
in %
85
85
house substations efficiency
f
in % 95 95
a
heating demand of the consumers connected to the district heating system (see Chapter 1.3);
b
including losses of the heat distribution network and house substations / hot water intermediate
storage;
c
direct heating transfer and geothermal share of heat provided by heat pumps;
d
two natural
gas-fired CHP stations each (630 kW thermal capacity, 450 kW electric capacity and a ther-
mal/electric efficiency of 52 respectively 38 %) and heat pumps driven by electric motor (coefficient
of performance of 4 at a thermal capacity of 1,450 kW);
e
annual average;
f
average efficiency (80 %
domestic hot water systems and 98 % for space heating systems;
g
including the losses of the heat
distribution network and the building substations).
Site-specific impact factors and local conditions (such as temperature, salinity,
production rates of geothermal fluid, local consumer structure and demand behav-
iour) result in considerably different designs for such geothermal heating systems.
And such differences are responsible for significantly different costs of geother-
mal heating plants. Due to these uncertainties the costs outlined below can there-
fore only describe general magnitudes. This is the reason why, depending on the
individual case, more or less favourable heat production costs may be achieved.
Investments.
Besides the applied technology, investment costs of geothermal heat-
ing plants (Table 10.2) are mainly influenced by the system size. Specific costs
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