Opinion of the European Economic and Social Committee on The use of geothermal energy
Date: 2005-02-09
Institutions: European Economic and Social Committee
Subjects: EU programme, energy policy, energy supply, geothermal energy, research and development, scientific research

C 221/22

EN

Official Journal of the European Union

8.9.2005

Opinion of the European Economic and Social Committee on The use of geothermal energy

(2005/C 221/05)

On 1 July 2004, the European Economic and Social Committee, acting under Rule 29(2) of its Rules of
Procedure, decided to draw up an opinion on the use of geothermal energy.

The Section for Transport, Energy, Infrastructure and the Information Society, which was responsible for
preparing the Committee's work on the subject, adopted its opinion on 17 January 2005. The rapporteur
was Mr Wolf.

At its 414th plenary session of 9 and 10 February 2005 (meeting of 9 February 2005), the Committee
adopted the following opinion by 132 votes, with 2 abstentions:

This opinion supplements earlier Committee opinions on
energy and research policy. It describes the development and
use of geothermal energy, as an energy source which, given the
extent of reserves, meets the criterion of sustainability, does not
contribute to global warming through CO2 emissions, and can
therefore be considered as a renewable energy source. The
opinion includes a brief overview and evaluation, set in the
context of the global energy issue, of current development and
use of geothermal energy,
its potential, and the problems
connected with launching it commercially.

The need for a secure,

1.2
inexpensive, environmentally
sound and sustainable supply of usable energy is at the heart of
the Lisbon, Gothenburg and Barcelona European Council deci-
sions. EU energy policy is thus pursuing three closely related
and equally important objectives, namely to safeguard and
enhance (1) competitiveness, (2) security of supply and (3) the
environment — all of them linked by the common thread of
sustainable development.

Table of contents:

1. The energy issue

2. Geothermal energy

3. Current situation

4. Future development and recommendations

5. Summary

1. The energy issue

Usable energy (1) is the mainstay of our contemporary
1.1
way of life and culture. Its ready availability opened the door to
our present-day standard of living. Unprecedented strides have
been made in the major and emerging industrialised countries
in terms of life expectancy, food supply, overall prosperity and
Insufficient energy supply would severely
personal freedom.
jeopardise these achievements.

(1) Energy is not actually consumed, but merely converted and, in the
process, used. This happens through conversion processes such as
coal combustion, the conversion of wind energy into electricity, and
nuclear fission (conservation of energy; E = mc2). However, the
terms ‘energy supply’, ‘energy production’ and ‘energy consumption’
are also used.

In several opinions (2), the Committee has noted that
1.3
supplying and using energy puts a strain on the environment,
presents risks, depletes resources and involves the problem of
external dependence and imponderables, as in the case of
current crude oil prices. The Committee has also pointed out
that the most important measure for reducing the risks asso-
ciated with the security of energy supply, economic crises, and
other risks is to ensure the most diverse and balanced possible
use of all types and forms of energy, including all efforts to
conserve energy and use it rationally.

1.4
In technical terms, however, none of the potential future
energy supply options and technologies is perfect. None is
wholly free of damaging environmental impacts. None is suffi-
cient to cover all needs, and it is difficult to adequately gauge
their long-term potential. Moreover, current trends and the
rising costs of both conventional and alternative energy sources
clearly indicate that future energy supply costs are unlikely to
be as advantageous as current costs of using fossil fuels (3), such
as crude oil, coal, and natural gas.

(2) Promoting renewable energy: Means of action and financing instruments;
Proposal for a Directive of the European Parliament and of the Council on
the promotion of cogeneration based on a useful heat demand in the
internal energy market; Draft proposal for a Council Directive (Euratom)
setting out basic obligations and general principles on the safety of nuclear
installations and Draft proposal for a Council Directive (Euratom) on the
management of spent nuclear
fuel and radioactive waste; The issues
involved in using nuclear power in electricity generation; Fusion energy.
(3) Future use of which will have to be increasingly restricted in view
of both the limited reserves of such fuels and also the need to
reduce CO2 emissions (Kyoto Protocol).

8.9.2005

EN

Official Journal of the European Union

C 221/23

1.5
Nor, therefore, can a forward-looking, responsible Euro-
pean energy policy bank on being able to secure an adequate
energy supply along the lines of the objectives set out above by
using only a small number of energy sources.

1.6
Thus, no secure, long-term, environmentally sound and
economically viable energy supply exists — either in Europe or
elsewhere in the world (1). The key to potential solutions can lie
only in further intensive research and development, which
should include setting up pilot plants and evaluating them
from both a technical and an economic perspective, gradually
working towards commercial launches of new energy sources.

1.12
Even within the EU Member States, there are consider-
able differences of approach to the energy issue. However, both
at national and European levels, there is broad consensus as to
the need to continue developing all possible energy sources
(with the exception, in some Member States, of nuclear energy).
To this end, numerous R&D programmes and other support
programmes, some of which are funded from multiple sources,
have been launched both by individual Member States and at
European level.

1.13
One of the EU's main objectives in this field is to
achieve a significant medium- to long-term increase in the use
of renewable energy sources, which can also help protect the
climate. In this context, geothermal energy can make a signifi-
cant contribution.

The Committee has also made the point that, given the
1.7
that
slow pace of change in the energy industry,
climate (greenhouse) gas emissions are a global, not a regional
issue, and the expectation that the problem will further worsen,
particularly in the second half of the century, the approach to
the energy issue should be more global in scale and cover a
substantially longer time period.

the fact

2. Geothermal energy

The problems of

1.8
finite resources and emissions are
compounded by the forecast two- or even three-fold increase in
global energy requirements by 2060 as a result of population
growth and the need for less developed countries to catch up.
increased efficiency and
On the basis of current knowledge,
energy savings alone will not be enough to offset these very
substantial additional requirements.

Technologies for tapping into and using thermal energy
2.1
flows from the earth's interior, which is very hot,
to the
surface, are referred to as geothermal energy production. Water
(in liquid form or as steam) is used as the heat carrier.

Any strategy (2) and prospects for development must

1.9
therefore look beyond the timeframe of 2060.

However, the density of such thermal energy flows is
2.1.1
very low, and temperatures rise only slowly as distance below
the earth's surface increases, at an average rate of around 3oC
per 100 m. Geological zones in which the temperature gradient
is steeper are referred to as geothermal anomalies.

As the Committee has also noted, public perceptions
1.10
and open debate in this area reflect a broad range of opinions
that veer between over- and underestimating the risks and
opportunities involved.

The heat balance of geological

layers close to the
2.1.2
earth's surface can also be affected by solar radiation; however,
in the following paragraphs this energy is included in the cate-
gory of geothermal energy.

1.11
There is therefore still no sufficiently consistent global
energy policy. An additional problem is the fact that the EU
needs to compete on a level playing field in the global
economy.

2.2

There are two options for using geothermal energy.

(1) The overall problem has been foreshadowed by previous oil crises
in 1973 and 1979), current increases in oil prices, and the
(e.g.
current controversy – centred on the trade-off between economy
and environment – about the allocation of emissions certificates.

(2) However, see 2.2.1.2 and 2.2.2.2.

2.2.1
The first of these is using geothermal energy for
heating purposes. Currently, about 40 % of the total energy
supply in the EU is used for heating purposes; this generally
requires relatively low (water)
temperatures (e.g. as low as
< 100° C).

C 221/24

EN

Official Journal of the European Union

8.9.2005

2.2.1.1
For heating purposes alone, so-called geothermal
probes are used among other things. (These involve a coaxial
tube, the lower end of which is sealed, and through which
water flows down to a depth of 2.5-3 km, then up and out
again, thereby absorbing useable heat of up to approximately
500 kWth.

2.3.1
At the same time, the costs of tapping and using such
reservoirs increase significantly with depth, and therefore,
depending on how the energy is to be used, a balance must be
struck between bore depth, efficiency and heat output.

2.2.1.2
One option for tapping energy very close to the
earth's surface is to use geothermal pumps (‘reverse cycle chil-
lers’) to heat buildings (from around 2 kWth to 2 MWth); these
also require a refrigerant (1). There are several types, tapping
energy from depths of as little as 1 metre up to several
hundred metres, depending on which technology is used.

2.2.2
The second option is to generate electrical energy.
temperatures (e.g. > 120° C):
This requires higher (water)
usually, there are two boreholes, some distance apart; the water
to be heated is fed underground through one borehole and
flows out from the other. A greater amount of heat — 5 to 30
MWth — can be achieved in this way.

For this reason, earlier stages of the search for useable
2.4
heat
areas with
reservoirs
geothermal anomalies.

concentrated on geological

High geothermal gradient anomalies (so-called high-
2.4.1
enthalpy (2) reservoirs) are mostly located in areas of intensive
volcanic activity (Iceland, Italy, Greece, Turkey). The therapeutic
properties of thermal water heated by high-enthalpy reservoirs
have been known since ancient times, and they were first used
to generate electricity about one hundred years ago (Larderello,
Italy, 1904).

However, even these (water) temperatures are still
2.2.2.1
insufficient to achieve the requisite thermodynamic efficiency
(to transform heat energy to electricity), and in view of the
temperatures required to reach boiling point within the turbine
circuit.

By contrast,

2.4.2
low geothermal gradient anomalies (so-
called low-enthalpy reservoirs), i.e. areas in which the tempera-
ture gradient is only slightly higher than usual, are located in
areas of intensive tectonic activity (Rhine Graben, Tirennian
Sea, Aegean Sea, etc.), and more generally in sedimentary aqui-
fers (Pannonian Basin in Hungary and Romania, North German
— Polish Basin).

For this reason, substances with a lower boiling
2.2.2.2
point than water such as perfluorpentane (C5F12) are used for
preference as the working fluid in turbine circuits. Special
turbine circuits such as the Organic Rankine Cycle (ORC
process) or the Kalina process are being developed for that
purpose.

Due to the limited number of areas with geothermal
2.5
anomalies,
since the mid-1980s efforts have increasingly
concentrated on tapping the heat stored in ‘normal’ geological
formations, in order to cope with the rising demand for energy
and to be able to match the supply of heat or power more
closely to demand in the surrounding areas.

2.2.3
to
One particularly advantageous arrangement
combine both applications (heat and electricity) and to use
the residual heat arising during or in connection with electricity
thus providing heat and
generation for heating purposes,
power at the same time.

is

2.5.1
As a result, geothermal reservoirs in areas without
geothermal anomalies began being used for energy production
in the 1990s, mainly in German-speaking countries. Electricity
generation only began in Altheim and Bad Blumau (Austria)
and in Neustadt-Glewe (Germany) during the last 4 years.

2.3
However, in order to supply energy which is technically
useable for electricity generation in particular, geothermal
reservoirs have to be located sufficiently deep, usually several
kilometres below the earth's surface, requiring costly deep dril-
ling.

(1) In future e.g. CO2 could be used.

2.5.2
preferably 4-5 km or more, deep drilling is necessary.

As this takes place at depths of at least 2½ km, but

(2) Enthalpy, which is a term used in thermodynamics,
energy content (internal energy plus expansion energy).

is useable

8.9.2005

EN

Official Journal of the European Union

C 221/25

Technologies for producing geothermal energy have the

2.6
following advantages:

extended to electricity generation using water at higher
temperatures. The medium for heat transfer is the under-
ground water from the reservoir;

— unlike wind or solar energy, geothermal energy does not
depend on the weather, time of day, or season, enabling it
to contribute to all-important baseload capacity;

— pre-existing heat only needs to be brought from the reser-
voir at a depth of several kilometres to the surface, elimi-
nating the processes involved in primary heat production
(such as combustion or nuclear processes) and the conco-
mitant economic and environmental costs involved;

— thermal reservoirs are an almost inexhaustible and renew-
able source of heat, which could in theory make a substan-
tial contribution to energy production.

— the hot dry rock (HDR) process involves deep boreholes
being sunk into suitable geological formations and exten-
sive stimulation. Surface water is injected underground and
used to extract stored heat by cooling the heat exchange
surfaces, which are artificially created by stimulation of
deep layers of rock;

— pressurised hot water

reservoirs, with a water/steam
mixture at temperatures of up to 250oC or more (however,
such high temperatures are of rare occurrence) which can
be used to generate electricity or for heating.

2.7

However, they also have the following disadvantages:

In addition, ground-level technologies (2) are being developed
to improve heat exchange and efficiency.

— the temperatures are too low to achieve a satisfactory level
of thermodynamic efficiency for electricity generation;

— to ensure that heat exchange takes place and that

the
reheating capacity of
the underground reservoir is not
exceeded, very large volumes need to be tapped and used
so that, at high heat extraction rates, the reservoir does not
display signs of exhaustion that could force it to be aban-
doned earlier than planned;

3.2
In the EU, geothermal capacity for generating electricity,
most of which is located in Italy, and which generally uses
geothermal anomalies, is currently about 1 GWel, or about 2 %
of total EU electricity generating capacity. Geothermal capacity
for direct heating is about 4 GWth, but is forecast to rise to 8
GWth or more by 2010.

— when reservoirs are used,

it is essential to prevent any
potential
environmentally
harmful and/or corrosive substances (such as CO2, CH4, H2S
and salts) and to keep equipment corrosion in check;

release of

from or

impact

— the costs and economic imponderables (such as prospecting
risks and the possibility of exhaustion) associated with
tapping and using geothermal reservoirs are still relatively
high.

3. Current situation

3.3
Therefore, neither form of geothermal energy use has
yet made a substantial contribution to EU energy supply, and
they represent a negligible proportion even of
renewable
energy use.

However, thanks to support from both Member States
3.4
and the EU, use of geothermal energy has increased substan-
tially over the last few years. Provided the heat output ranges
from just a few to several tens of MWth geothermal energy still
makes a contribution to decentralised energy supply.

Basically, there are three technologies, with variations,
3.1
for tapping and using deep geothermal energy; these usually
require at least two boreholes (a doublette) (1):

In the view of the Committee, this development is posi-
3.5
tive and well worth supporting.
In many such cases, pilot
plants are needed in which various methods can be tested and
developed.

— hydrothermal reservoirs are used as a source of under-
ground, non-artesian (i.e. not pressurised) water, which is
brought to the surface, and up till now has generally been
technique is being
used for heating. At present,

this

(1) However, see 2.2.1.1 on sealed geothermal probes and 2.2.1.2 on

geothermal heat pumps.

(2) See 2.2.2.2 on turbine circuits.

3.6
Comparing the costs per 1 KWel of electricity generated
from various renewable sources, geothermal energy (even if
heat and power generation can be combined) currently costs
about twice as much to use as wind energy, and half as much
as solar energy.

C 221/26

EN

Official Journal of the European Union

8.9.2005

3.6.1
However (see above) geothermal energy supplies can
be largely matched to demand. This advantage will become
increasingly significant as renewable energy takes a larger share
of the energy market: using the fluctuating output from wind
and solar energy will
increasingly require technologies for
buffering and regulating energy, and it is likely that energy-
consuming and costly storage media such as hydrogen will be
needed.

4. Future development and recommendations

Provided that it is no longer restricted to geothermically
4.1
anomalous areas (see also points 2.4 and 2.5), geothermal
energy has the potential to make a significant contribution to
environmentally sound and sustainable energy supplies (see
also point 4.13).

4.2
In order to use and develop this potential for economic-
ally viable electricity generation, boreholes need to be sunk to a
depth of at least 4 or 5 km, to reach rock layers in which
temperatures are at the threshold of about 150° C. In addition,
rock at this level needs to be treated (stimulated) so as to
enable a sufficient quantity of water to circulate and sufficient
heat exchange to take place between the hot rock and the
water which is naturally present or pumped through.

However (see also point 2.2.1.1), lesser bore depths of
4.2.1
e.g. 2-3 km are sufficient if the energy is to be used solely for
heating purposes.

well as work on preparing the market are needed, in order to
bring down production-related costs.

4.6
In the medium term, making geothermal energy compe-
titive means enabling it to compete with wind energy in terms
of costs. There is a high probability of this happening, given
that the disadvantages of wind energy are becoming increas-
ingly apparent: wide fluctuations in output result in major addi-
tional costs and emissions from other sources, wind farms can
be unsightly, and the noise can disturb people living in the vici-
nity; in addition, they increasingly require repair and mainte-
nance. The costs borne by consumers or the public purse must
also be included in any overall assessment.

4.7
In the long term, given that prices of crude oil and
natural gas are likely to continue rising, and reserves may
possibly begin running out, general competitiveness will
become an issue for geothermal energy. The question to be
answered is when, if ever — taking into account external costs
of all energy production technologies — geothermal energy
will achieve long-term competitiveness, without any form of
subsidy or market-distorting preferential treatment.

4.8

In the meantime, the following measures are needed (1):

— effective R&D programmes at national and European levels
to bring scientific and technological development in the
field to the point where technologies and individual stages
of the various processes can be developed and tested at an
adequate number of test sites,

4.3
Appropriate technological solutions are already being
developed and tested at several locations in Europe (e.g. Soultz-
sous-Forêts, Gross Schönebeck) with varying geological forma-
tions. The development of geothermal technologies which are
as independent as possible of location and are therefore suitable
for export offers the main scope for progress, but this still
requires considerable R&D work.

— legislation to promote private investment (e.g. laws on the
sale of electricity to the grid, heating and air-conditioning
systems) designed to provide initial, tapered support for
commercial launches so as to make energy sales during the
launch stage attractive for a limited period, not least in
order to test, enhance and evaluate economic potential. In
particular,
this also applies to contractual arrangements
between energy supply companies and consumers,

On the one hand, development of the various technolo-
4.4
gies which already exist
in a rudimentary form needs to
continue in order to make them viable, at the same time as
checking compliance with the previously mentioned criteria for
sustainable use of geothermal energy.

4.4.1
One particularly important question is whether the
hydraulic and thermodynamic criteria for adequate sustain-
ability of a stimulated reservoir can actually be met.

On the other hand, the individual stages of the process
4.5
need to be gradually improved and made more efficient in
order to bring costs down to a competitive level (see below). At
the same time, research and development (see point 1.6), as

— action to offset the risks associated with prospecting and
tapping geothermal reservoirs, e.g. in sinking boreholes and
locating viable sources.

4.9
The Committee is pleased to note that considerable
progress has already been made in this field. It fully endorses
the Commission's existing and planned R&D projects, and also
its intention to again substantially increase its activity in this
area in its next R&D framework programme. It also endorses
the relevant R&D programmes of Member States and their
efforts, by adopting appropriate support measures, to facilitate
and encourage the commercial launch of geothermal energy on
a trial basis.

(1) See: Promoting renewable energy: Means of action and financing instru-

ments

8.9.2005

EN

Official Journal of the European Union

C 221/27

4.10
In this connection, the Committee reiterates its earlier
recommendation that the opportunities offered by the Euro-
pean Research Area should be utilised through a comprehen-
transparent and coordinated energy research strategy,
sive,
supported by all the players involved. This strategy should be
made
seventh R&D framework
the
programme and the Euratom programme.

a key element of

This strategy should give appropriate emphasis to the
4.11
R&D measures which are required to develop geothermal
energy, until it becomes possible, in the context of a changing
energy market, to provide a more accurate estimate and evalua-
tion of the long-term costs and the achievable potential of such
technology.

4.12
The Committee also recommends that all geothermal
energy R&D programmes, i.e. including those which until now
have been solely supported at a national level, be integrated as
far as possible into a European energy research programme, to
operate on the basis of open coordination. This would have the
benefit of promoting European cooperation in the field.

4.13
In this context, the Committee sees the participation of
new Member States in the EU R&D framework programme as
an opportunity. Demonstration plants and pilot plants should
be set up in these countries also, in the course of the forth-
coming renewal of their existing energy systems.

In addition,

the Committee recommends

the
4.14
Commission sufficiently harmonise the effective measures
taken within the EU to promote commercial
launches (e.g.
legislation on the sale of electricity to the grid) to enable EU-
wide competition, at least in regard to actual geothermal tech-
nology, to take place on a level playing field.

that

4.15
Given that geothermal energy lends itself particularly
well to combined heat and power generation, the Committee
also recommends that
the Commission look into suitable
heating networks and use of geothermal heat.

5. Summary

Technologies for tapping into thermal energy flows
5.1
from the earth's interior, which is very hot, to the surface, are
referred to as geothermal energy production.

5.2
This energy is mainly used for heating purposes, but it
can also be used to generate electricity, or combined heat and
electricity.

Brussels, 9 February 2005

5.3
Geothermal energy is already being used in areas with
geothermal anomalies, but it still represents an insignificant
proportion of overall energy supply.

Technologies which allow areas without geothermal
5.4
anomalies to be tapped offer the potential
for geothermal
energy to make a significant contribution to sustainable energy
supply, and to base-load supply in particular. However, they
require boreholes to be sunk to depths of about 4–5 kilo-
metres, together with additional ‘stimulation’.

5.5
However, there is also considerable potential for devel-
opment in the use of heat pumps to tap geothermal energy
close to the surface for the purposes of heating and air-condi-
tioning.

5.6
The potential to contribute to baseload capacity distin-
guishes geothermal energy from sources with fluctuating
(e.g. wind and solar energy), which are becoming
output
increasingly dependent on technologies for regulating, buffering
and storing energy and which are meeting public opposition
due to the amount of land they require and their aesthetic
impact on the countryside.

5.7
The Committee reiterates its recommendation that the
opportunities offered by the European Research Area be
utilised through a comprehensive energy research strategy.

This strategy should include R&D measures which are
5.8
needed to develop geothermal energy, continuing and, as
appropriate, building on existing programmes.

5.9
The Committee recommends that all geothermal energy
R&D programmes, which until now have been solely supported
at a national level, be integrated into such a European energy
research programme and the measures which it comprises, to
operate on the basis of open coordination.

5.10
The Committee recommends initial, tapered incentives
and legislation in all Member States (e.g. a law on the sale of
electricity to the grid) for commercial
launches and private
investment,
in order to make the production and sale of
temporarily subsidised energy more attractive and thus also to
help test, enhance and evaluate the economic potential of this
energy form.

The Committee

5.11
such support
measures should be sufficiently harmonised within the EU to
ensure that EU-wide competition in regard to geothermal tech-
nology takes place on a level playing field.

recommends

that

The President

of the European Economic and Social Committee

Anne-Marie SIGMUND