National research program on the effects of Underground

Thermal Energy Storage (UTES)

- use of the subsoil in a sustainable way -

Benno Drijver – IF24 september 2010

Content

1) UTES– Why UTES?– What is UTES?– Application in the Netherlands

2) Research program– Organization– Approach– First results

3) Conclusion

1) UTES – Why UTES?

• Fossil fuels are finite

• Security of energy supply (reduce dependence on fossil fuels)

• Reduce global warming

Urgent need to reduce the use of fossil fuels

Trias Energetica:I. Reduce energy demand (energy-saving)II. Use renewable sources instead of fossil fuelsIII. Use the most efficient techniques to produce/use energy

UTES saves energy (and energy costs)

1) UTES – What is UTES?

TES = thermal energy storage UTES = using the underground for TES

TES using ice has been used for hundreds of years

1) UTES UTES – What is UTES?

What is UTES?

Aquifer TES (ATES): Open loop systemsGroundwater is extracted from and infiltrated in the aquifer

Borehole TES (BTES):Closed loop systems

1) UTES – What is UTES?

ATES – Types Doublet

Monowell Recirculation

1) UTES – Application in the Netherlands

• ATES permits in the Netherlands: 1990, 2000, 2009

1) UTES – Application in the Netherlands

Growth ofATES and BTES in theNetherlands

Applications of ATES in the Netherlands

2) Research program – Why a research program?

• Government wishes to stimulate UTES

(less stringent regulations, faster permit procedures, etc.)

• Growth has to take place in a sustainable way Research on the remaining concerns

- Impact on groundwater chemistry and microbiology - Interference between UTES systems- Claim on subsurface space- Perforation of protecting clay layers- Potential leakage of fluids from BTES-systems

Investigating opportunities: combination conceptsUTES/Remediation and UTES/other concepts in the watercycle

2) Research program – Organization

Research parties

Specialist in (bio)remediationCombination UTES – remediation

Research institute on the subsurfaceGeohydrology, geochemistry, remediation

Consultant specialized in UTES> 20 years of experience

Fundamental researchUTES, remediation, microbiology

2) Research program – Organization

Made possible by our participants

– Foundation for Knowledge Development and Disseminiation on Soil (SKB)

– National government (ministries of Economic Affairs and of Housing, Spatial Planning and Environment)

– All 12 provinces

– Municipalities (Almelo, Amersfoort, Apeldoorn, Den Bosch, Deventer, Haarlem, Hengelo, Tilburg, Utrecht, Zwolle)

– Water boards (Groot-Salland, Regge en Dinkel)

– Drinking water companies/organizations (Brabant Water, Vitens, VEWIN)

– Agency NL, Arcadis, Essent (Energy company), Port of Rotterdam, Dutch association for UTES (NVOE), Dutch horticultural association (PT), Dutch Railways Foundation for Soil Remediation (SBNS), Rendo

2) Research program – Approach

Literature review

Direct impact ATES:(hydrological, thermal)

Indirect impact ATES(compaction, chemistry, microbiology)

BTES (anti-freeze liquids)

Combination concepts (UTES – remediation/other concepts)

2) Research program – Approach

Field measurements at 9 UTES-projects

Different types of UTES systems: BTES, different ATES types, high temp., contaminated sites

Relatively old projects (long term impact) Availability of a reference well Existing data set Different geochemical (redox) conditions Temperature difference > 2 °C Geographical distribution

1x 3x 1x 1x 2x

2) Research program – Approach

Field measurements at 9 UTES-projects

Clean sites: 3 monitoring wells (warm zone, cold zone, reference well)

Contaminated sites: 5 monitoring wells

Parameters: Physical - hydraulic head, temperature, EC, pH Chemical - main and trace elements, redox parameters,

pollutants, nutrients, substrates Microbiological - numbers, diversity, species, functional

groups, pathogens, remediating species

2) Research program – Approach

Laboratory experiments

Step 1: Batch experiments to investigate mobilisation of organic matter from aquifer sediment. Static and dynamic (shaken) tests at 10, 20, 30, 50 ºC.

Step 2: Batch experiments on bioremediation at different temperatures (with and without stimulation) to investigatie the influence of temperature on remediation kinetics.

Step 3: Column experiments to investigate the influence of flow velocity on bioremediation kinetics.

2) Research program – First results

Geochemistry – Results from literature review

Conclusions impact of temperature on main elements seems insignificant below 25 ºC > 40 ºC precipitation of carbonates can occur > 45 ºC fulvic acids are mobilized from organic matter in aquifer sediments

Little research was found on: The impact on trace elements The impact of (vertical) mixing

2) Research program – First results

Microbiology – Results from literature review

Conclusions Microbiologic growth is limited by the amount of assimilible organic carbon =>

Limited temperature increases seldom lead to microbial growth Organic matter mobilized at high temperatures might stimulate microbial

growth Temperature changes can cause shifts in the composition of the microbiologic

population to species that are adapted to these temperatures Pathogens are not expected to grow in aquifers used for UTES

Little research was found on: The impact on functional groups (e.g. denitrifiers, sulfate reducers) The impact on microbial diversity

2) Research program – First results

Laboratory experiments

Step 1 (Static and dynamic (shaken) batch experiments at 10, 20, 30, 50 ºC) is finished

Conclusions: -Temperatures up to 30 ºC do not

influence COD;- Increasing temperature to 50 ºC

leads to elevated COD levels;

This indicates mobilisation of organic matter between 30 and 50 ºC

0,00

50,00

100,00

150,00

200,00

250,00

300,00

10 20 30 50

CZ

V ,

amm

oniu

m (

mg/

l)

Organisch stof (6,3%)

Statisch CZV (gefiltreerd) Statisch ammonium

Dynamisch CZV (gefiltreerd) Dynamisch ammonium

2) Research program – First results

Interference

Projected interference risk: growth to 2250 ATES systems

The Hague

Amersfoort

Amsterdam

2) Research program – First results

Interference: Factors influencing interference

Calculated temperatures after 20 years of ATES:

Energy balance Large energy imbalance

2) Research program – First results

Interference: Factors influencing interferenceHydrological impact ATES (well configuration)

Extraction without re-injection (I) Extraction with re-injection (ATES – A,B,C)

B C

A

A

I

3) Conclusion

Questions that lawmakers have to deal with are:

- To what extent should other groundwater users (e.g. drinking water companies) be protected against UTES?

- Should high temperature storage be allowed and under which conditions?

- Which monitoring prescriptions should be demanded in permits?

- What requirements should be made to reduce the risk of leakage of fluids from BTES systems and limit the consequences?

- Is legislation necessary to minimize interference? (how bad is interference?)

Goal of the research program (2009- end of 2011):

- Provide scientific information on the effects of UTES

- This information must help lawmakers to develop new legislation

www.meermetbodemenergie.nl

Thank you for your attention