Energy from the deep subsurface, potentials of geothermal for a sustainable supply of

increasing energy demands

Annamária NádorGeological and Geophysical Institute of Hungary

3rd European Energy Conference, October 27-30, 2013, Budapest

Current energy consumption is unsustainable - actions are urgently needed!

growing energy demand

restricted and uneven distribution of fossil fuels → supply security

climate change debate: enhanced use of fossil fuels → increased atmospheric CO2 concentration → global warming, extreme events

increase of renewables in the energy mix: integrated economic development

innovative and competitive technologies

structural changes in the industry and agriculture

new working places

decentralized → rural development

Kyoto Protocol

20/20/20 by 2020 COM(2006)848 cut energy consumption (fossil fuels) and CO2 emisssions increase energy efficiency increase renewable energy sources (RES)

National characters

Import dependency: ~ 83% of hydrocarbons Security supply, focus on own resources

Main aim: ensure the longterm sustainability, security, and

economic competitiveness of energy supply in Hungary

Increasing the share of renewables

New Energy Strategy of Hungary 2011-2030

Russian import20 billion m3/y

European market4,5 billion m3/y

Total consumption:12 billion m3/y

Own production:1,8-2,0 billion m3/y

4,1 bn m3/yr

4,5 bn m3/yr

6,5 bn m3/yr

RES Directive (2009/28/EC): 13% RES for Hungary

Hungary: not an obligation but a POSSIBILITY for economic growth: 14,65% RES by 2020 (120,57 PJ)

2010 2020

Distribution of RES in the Electricity and Heating-Cooling sectors

Contribution of geothermal

energy

2010

9% of total RES

2020

17% of total RES

Direct heat (PJ) 4,23 14,95

Electricity production (MW)

0 57

Geothermal energy: definition and basic concepts

Geothermal energy is energy stored in the form of heat below the surface of the solid earth (shallow – stored solar and deep)

Origin of heat: decay of radioactive isotopes: U238, U235, Th232, K40

4300°C

3700°C

1000°C

Total volume of the Earth

Heat flow

Crust (rich in radioactive isotopes)

2% 8 x 1012 W

mantle 82% 32.3 x 1012 W

Core (no radioactive isotopes)

16% 1.7 x 1012 W

Heat content of the Earth: 12,6∙1024 MJ

Takes over 109 years to exhaust via global terrestrial heat flow

high enthalpy (el. power)

high temp. basins (el. power, district heating)

medium temp. basins(district heating)

everywhereshallow geothermal

Main geothermal provinces of Europe

EGEC

heating → thermal expansion of stored groundwater → lower density, rise and replaced by colder meteoric water of high density coming from the margins of the system

artificially enlarged fractures as „heat exchangers” in deep lying hot rock bodies

Hydrogeothermal (convectional) systems

Enhanced Geothermal Systems

Lindal diagram

Cascade utilization of geothermal energy

>150°C: high enthalpy - electricity generation< 150°C: low-medium enthalpy - heating-cooling + many others

Thermal bath of Caracalla, Thermae Antoninianae

1904: the world’s first geothermal power station with a 10kW generator at the Larderello dry steam field, Italy, Tuscany

Geothermal potential of Hungary

Favorable conditions due to Miocene basin formation (10-12 My ago)

Average terrestrial heat-flow: 100 mW/m2

Geothermal gradient: 45 °C/km

Thickness of the lithosphere

Subsurface temperature distributions (°C)

-1500 m

-2500 m

Zilahi Sebess et al. 2012

1

Pannonian basin - hot sedimentary aquifer (convectional flow system): utilization of geothermal energy ≈ thermal

groundwater / fluid abstraction

Main geothermal reservoirs

Paleo-Mesozoic fractured, karstified basement rocks

Mio-Pliocene porous basin fill: multi-layered sandstones, shales

depth (top) >2-3000 m 600-1500 m

temperature >100-150 °C 50-100 °C

prospect power, CHP direct heat, balneology

high heat flux thermal „insolation” of basin fill sediments regional groundwater flows driven by hydraulic potential between recharge and discharge areas

Current utilization schemes in Hungary

Nádor et al.2013

595 thermal wells (outflow T > 30 °C)Annual production: 68,44 million m3 (2011)

No. of thermal wells

Abstracted amount of thermal water

(million m3)

Installed capacity

(MWth)

Annual use (TJ/y)

Balneology 249 36,8 265 5285Agriculture - animal husbandries, other 68 2,09 56,3 750Agriculture-heating of greenhouses and plastic tents 86 7,25 185,54 2050Heating (DH, town-heatnig and individual buildings) 51 6,76 132,97 1350Industry 15 1,44 8,3 170Other- drinking water 87 10,8 25,56 350Other - sanitary water 22 2,73 18,4 220Other-undefined 17 0,57 5,41 80TOTAL 595 68,44 697,48 10255

Current utilization schemes

Nádor et al.2013

Renewability vs. sustainability

Renewability – attribute of the energy source

The energy extracted from a renewable energy source is always replaced in a natural way by an additional amount of energy and the replacement takes place on a similar time scale as that of the extraction” (Axelsson et al., 2001)

Geothermal energy: replacement of heat and fluid

Sustainability – how we use it?

„... for each geothermal system and for each mode of production there is a certain level of maximum energy production, below which it will be possible to maintain a constant energy production for a very long time (100 - 300 years)” (Axelsson et al., 2004)

Balanced heat-fluid production

High production rates exceeding long-term rate of recharge can lead to depletion of the reservoir, which can be avoided by reinjection of used fluids.

Balanced fluid/heat production (not producing more than the natural recharge re-supplies) is fully sustainable.

These rates are limited and often not economical for use

Hydrogeological models: different scanarios

only SK

csak SK

only HU

SK, HU, SLO present

SK, HU, SLO 5X

TRANSENERGY project: transboundary hydrogeothermal systems

Tóth, 2012

Hydraulic heads field in Upper Pannonian geothermal aquifer, pumpig wells scenario

Hydraulic heads field in Upper Pannonian geothermal aquifer, doublets scenario

TRANSENERGY project, Danube basin pilot area (SK-HU)

Svasta, 2013

Concluding remarks

Geothermal energy is an important RES and has huge potentials for growth

Geothermal energy is renewable on time-scales of technological /societal systems, though it is an exhaustible energy source

Production should be limited to sustainable levels which secures the longevity of the resource (not exceeding natural re-charge and/or re-injection)

Due to the favorable geological setting, the geothermal potential of Hungary is very good

In the current utilization balneology is overwhlemming, direct use in agriculture is significant, but much beyond the potentials in district heating

Ambitious NREAP numbers forecast a 3,5 times growth in direct heat and establishment of power production by 2020

Responsible for the RDI in Hungary (establishing the national RDI strategies and policies, their implementation and monitoring.

Supports the uptake of local innovations in the Hungarian and international the market.

Promote and help the foreign investments in innovation area. Coordinates and is responsible for the international and bilateral cooperations in the area of technology and science.

Incubation of the young innovative enterprises and RDI activities of the SME-s.

National Innovation Office

Thank you for your attention!

nador.annamaria@mfgi.hutel: +36-30-924-6823