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Energy

Introduction in Geothermal Energy

Michael Würtele

Michael Würtele Consulting

Symposium for renewable energy

Buenos Aires

27.06.2010

MW-Consulting Tel . +49 2327/972850

Robenkamp 36 Mobil +49 15111984489

D – 44869 Bochum [email protected]

Geothermal Energy


Earth diameter 12‘740 km

Earth crust 0 km – 65 kmup to 1000 °C

Earth shell 10 km – 2900 km 1000 °C to 2900 °C

Earth core 2900 km – 6370 km3700 °C to 4300 °C

Geothermal energy – inexhaustibleDevelops to approx. 70 % by the decay of radioactive particles in the underground and too approx. 30 % out of heat from the time of the earth genesis.

Geothermal energy – ecologically valuableBy the saving of the fossil fuels coal, oil and gas the immission of CO2 and other pollutants is reduced.

Geothermal energy – economical energy sourceComparatively higher capital costs amortize due to low operating costs, long life span and price stability.

Geothermal energy – available everywhereFlexibly applicable, because terrestrial heat is on every

location, at all times of day and year available.




Geothermal Systems

The choice of the right geothermal systems depends on

heat demand

cooling demand

temperature

which the customer needs.

Geothermal application are devided in

open and closed systems

as well as in

shallow and deep






peak load- and buffer boiler

pump

dense rock

heat exchanger70 °C40 °C

80 °C

2500 m

Advantages:

• only one borehole

• no risk to find an aquifer

• filled with clear water

• closed loop, therefore almost no maintenance, no abrasion,

long living, reliable in operation

• environment friendly because there is no mass exchange

The closed geothermal system




pump

aquifer

70 °C40 °C

2500 m 80 °C

Advantages:

• degree of Effenciency 8 times in comparison to a closed system

• Normally no peak boiler

• Good system for power production

The open geothermal system


buffer boiler

heat exchanger




Geothermal applications at a glance


shallow

up to -400 m

deep

below

-400 m

closed open

• Shallow borehole heat exchanger with heat pump

• Ground heat collector with heat pump

• Shallow groundwater wells with heat pump

• Deep borehole heat exchanger with peak load plant

• Deep aquifer wells

• Hot-dry-rock technology




Geothermal applications at a glance





Main geothermal applications for shallow systems

Serienschaltung

Parallelschaltung

Rohre in Graben

Verteiler im Haus

Pumpe

Grundwasser-

spiegel

horizontal loops1-2 m depth

Borehole heat exchanger 10-400 m depth

Groundwater wells 4-50 m depth

Heat pumps are required to use the heat at low, but constant temperatures

Pipes in a trench

re-injection well

groundwater level

pump

production well






Single – U Double – U

Simple coaxial Complex coaxial

Closed shallow systems – single borehole heat exchanger




Example for a shallow geothermal systems for a commerce project I

German Airtraffic Control in Langen

Office building with 44’500 m² floor space

Low-Energy-Office standard (LEO)

800 kW heating- und 650 kW cooling-power required

154 borehole heat exchangers à 90 m

Reversible heat pump

Conventional peak load coverage

Base load 330 kW heating- and 340 kW cooling-power





• 500‘000 € Investment extra costs for the

geothermal plant

• 125‘000 €/a savings on operating cost in

relation to standard WSVO 95

• 80‘000 €/a savings on operating cost in

relation to LEO without geothermal plant

• Projekt without public subsidies

• Rate of return 16%

0

50000

100000

150000

200000

250000

300000

350000

400000

4500000

LEO DFS LEO without geotherm. Standard WSO 95

Jahreskosten [€/a]

Energy costs

Maintenance costs

Capital costs


Example for a shallow geothermal systems for a commerce project II


recirculation

flow line

flow line

drive pipe

cementation

cementation

cementation

GFK-ascending pipe

insulation

Construction:

3000 m drilling depth with 24“ down to 9 5/8“ (ca. 61 down to 25 cm ) steel support

Annulus collector is filled from approx. 800 m

with thermal conducting cement (approx. 2,3 W/mK

GFK*-ascending pipe with 2 7/8“ (ca. 8 cm)

Performance data:

Flow rate 10 to 20 m³/h

Thermal engine output 250 to 350 kW

Heat amount 2,1 GWh/a with 8500 operating hours per year

Temperature spread ca. 25°C

*GFK = glass fiber reinforced plastic

Deep closed system for heat production





Deep open system for power production based on thermal water

pump pump

heat exchangers

production wellproduction well

re-injection well

Drilling depth = 3500 m, temperature > 140 °C

Construction:

3000 m drilling depth with 24“ down to 9 5/8“ steel support

Performance data:

Flow rate 65 l/s in each production well

Power output approx. 5 MW

Heat output 35 MW

8000 operating hours per year

Temperature spread ca. > 60°C

Quelle: www.hotrock.deMW-Consulting Tel . +49 2327/972850




A deep open system for power production based on hot dry rock

The concept behind hot dry rock (HDR)geothermal energy is relatively simple. Toextract this geothermal energy, boreholesare created and water is injected into thehot granite rock. The water is circulatedthrough the rocks in an engineered, artifi-cial reservoir or underground heat ex-changer. This hot water returns to theearth’s surface and it is pumped into astandard geothermal power plant. Insidethe power plant, the hot water is conver-ted into superheated steam, which drivesa turbine and generator and produceselectricity. Therefore, HDR geothermalenergy relies on existing technologies andengineering processes such as drilling andhydraulic fracturing

http://www.westernpower.com.au/


Energy demandidentification

heart amount

cooling amount

necessary temperatures

seasonal classified consumption

power

Evaluation ofGeogenic conditions

Hydrophysicalconditions at site

Petrophysicalconditions at site

Choice of the geothermal application

open / closedapplication

shallow/ deepapplication

1.

2.

3.

Modus operandi to start geothermal project I


Modus operandi to start geothermal project II

economic comparison

geothermal

vs.

conventional energy

invest costs / capital employed

cost of operation / maintenance cost

6.

Contact persons of the National Geothermal Association of GermanyGeothermische Vereinigung – Bundesverband Geothermie e.V.

Section Sciences

Prof. Horst Rüter

[email protected]

Section Shallow Geothermal

Dr. Burkhard Sanner

[email protected]

Section Deep Geothermal

Dr. Horst Kreuter

[email protected]


http://www.geothermie.de/typo3temp/pics/2f09084ff5.jpg




Thank you for your attention!


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