Energy Conservation - Scientific Assessment of Projects

Energy Conservation - 

Scientific Assessment of 

Projects 

Evaluation, Training and Education 

Dipl. Ing. Hans Hertle 

ifeu – institute Heidelberg, Germany 

www.ifeu.de 

We are here! 

ifeu - Institute Heidelberg German-Sino Workshop January 23rd and 24th of 2007 URUMQI, Xinjiang, China 1

SUMMARY 

� TECHNICAL IMPLEMENTATION 

(Pilot Project Hannover Kronsberg) 

� EVALUATION OF EXPO 2000 

ENERGY CONSERVATION PROJECT 

� AUDIT OF ENERGY CONSERVATION 

IN GERMAN BUILDINGS 

� TRAINING PROGRAMMES AND 

PUBLIC EDUCATION PROGRAMMES 


Hannover Kronsberg: 

The new Vision of Sustainable Development 

Source: Hannover Kronsberg Handbook 

Kronsberg 

reserve areas 

EXPO 2000 

1980 

2050 


Key Data of Kronsberg 

2890 apartments 6475 inhabitants 213000 m 2 living area 

Source: ifeu 2003 

ifeu - Institute Heidelberg German-Sino Workshop January 23rd and 24th of 2007 URUMQI, Xinjiang, China 4 

N

Typical Structure: Multifamily Housing 

Source: Hannover Kronsberg Handbook 

http://www.hannover.de/ 

http://www.sibart.org/pdf/handbook_big_en.pdf 


Ecological Optimization at Kronsberg 

� Soil management 

� Waste management 

� Water concept 

� Communications networking 

� Public relation 

� Energy concept (main focus) 


Energy Concept of Kronsberg 

N 

1 

5 

3 

1 

4 

2 

Basic principles for all areas: 

low energy houses 

and district heating from 

CHP stations 

1) energy plants (CHP) 

plus innovative projects 

for some areas: 

2) passive houses 

3) atrium elements 

4) solar heating 

5) photovoltaic installations 

6) wind turbine generators 


CO 2 emissions of Kronsberg area (households) 

Energy Concept: Expected CO 2 -Emissions 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

Reference (100%): CO 2 emissions of reference scenario according to 

german insulation regulation 1995 with separate gas condensing boilers 

quality assurance Quality assurance (-7%) (-7%) 

quality assurance (-7%) 

Low Energy House Standard (-17%) 

Low-energy house standard (-17%) 

CHP & district heating (-23%) 

CHP and district heating (-23%) 

electricity savings (-13%) 

electricity saving (-13%) 

wind 

energy 

(-20%) 

wind 

energy 

(-20%) 

Source: KUKA (Kronsberg Environmental Liaison Agency GmbH) 1998 

microclimate zone, 

microclimate 

zone, photovoltaic, 

photovoltaic, solar 

district heating, 

passive houses 

(5 15% 

solar district heating. 


index for space heating [kWh/(m 2 *yr)] 

Actual Energy Consumption Indices for Space Heating 

Target 

Kronsberg 

standard: 

50 – 55 

kWh/(m 2 *yr) 

reference actual target passiv 

scenario consumption indices house 

Passive house 

standard: 

13 

kWh/(m 2 *yr) 



Energy consumption indices for heating and electricity 

energy indices [kWh/(m 2 *yr)] 

reference actual target 

scenario consumption indices 

electricity 

distribution 

losses 

hot water 

demand 

space heating 

demand 



CO 2 indices [kg/(m 2 *yr)] 

CO 2 indices from the evaluation of Kronsberg 

development 

reference actual target 

scenario indices 

electricity 

distribution 

losses 

hot water 

demand 

space heating 

demand 



CO 2 in tons per resident per year 

Actual CO 2 -Emissions per Resident per Year 

100% = 1.7 t CO 2 = reference scenario 

quality assurance and 

low energy house standard: -26.6% (-24%) 

CHP and district heating: 

-18.8 % (-23%) 

electricity 

savings 

-1.1% (-13%) 

wind energy: 

-27.7% (-20%) 

avarage public 

transport to and from work 



long distance flight ( up to 6 tons CO 2 )

Audit of energy conservation in German buildings 

Questions: 

� In which way is the german energy saving ordinance from 

2002 (EnEV 2002) implemented in common practice? 

� What are the long term target standards of EnEV (2010) 

Evaluation projects: 

� Beiträge der EnEV und des KfW - CO 2 – Gebäudesanierungsprogramms 

in Deutschland 

� Evaluation und Begleitung der Umsetzung 

der EnEV 2002 in Baden-Württemberg 

http://www.ifeu.org/index.php?bereich=ene&seite=enev 


CO 2 emissions [kg/(m 2 *yr)] 

Source: 

ifeu / IWU 

2004 

Necessary long term target standards 

of the German energy saving ordinance (EnEV) 

80 

70 

60 

50 

40 

30 

20 

10 

0 

68 

Due to rapidly increasing energy prices 

and according to German objectives of 

climate protection, 

EnEV target standards 

had to be strengthened! 

34 

24 

existing buildings new passiv house passiv house target 2050 

buildings renovated buildings „KfW 60“ „KfW 40“ for all 

efficiently (EnEV 2002) buildings 


12 

8 

10

Saving potential in percent 

Saving potential of German building stock 

by EnEV 2002 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

Insulation of 

window 

Fenster 

basement 

Kellerdecke 

roof / ceiling 

Dach bzw. OG - Decke 

Außenwand 

1 2 

theoretical real 

saving potential saving potential 


wall

Reasons for the lack of implementation 

� Conservation standards are not yet adapted 

to the present energy price on the national level. 

� Also external costs of energy use are not included. 

� With the implementation of EnEV 2002 control systems 

on state level do not exist any longer. 

� Private market partners submit to competiton and are 

looking for the cheapest offer. 

� There is a lack of information on cost effective 

measures of architects, engineers and craftsmen. 

� Not enough well trained actors are able to realise 

ambitious standards (like the passive house standard). 


To ensure good practise construction, auditing 

actors‘ compliance and quality assurance is required. 

I.e. Hannover Kronsberg Management included the 

following objectives into land sale contracts: 

� compulsory low energy house standard 

� airtight construction and minimisation of 

thermal bridges 

� comfortable accommodation 

� consitant planning and construction 

� quality guarantees for the owner and user 


The following quality assurance scheme was 

applied as a five-stage process throughout the 

entire construction period in Hannover Kronsberg : 

stage 1: check the required energy index 

stage 2: check detailed plans 

stage 3: check work on site and documentation 

stage 4: measure airtightness 

stage 5: certification 


To improve knowledge of all actors 

training programmes are neccessary 

Best practise: Impulsprogramm NRW BAU und ENERGIE 

� training programmes for architects, ingenieers, 

craftsmen, owners and consumers. 

� including about 30 education units from 

energy management to solar applications. 

� „Wissensportal Energie“: Web Based Trainings 

�„Solar – and Energy check NRW“: about 2000 

handcrafts in NRW have been educated 

systematically. 

Energy agency NRW: http://www.ea-nrw.de/ 


Quality labels guarantee independant and 

professional consulting services 

Best practice: GIH Qualitiy Label (Home energy consulting of 

engineers and craftsmen) 

� commited to independant consulting 

� commited to constant training of staff members 

� verification of consulting reports 

� evaluation by the customer 

� random tests of consulting activities 

http://www.gih-bw.de/ 


Conclusions 

� The economic saving potential remains largely untouched. 

� The energy saving ordinance (EnEV) needs to be adapted to 

recent developments in energy prices. 

� Random checks of actual EnEV-implementation should be 

introduced and carried out by governmental authorities. 

� In order to implement sustainable renovation standards, 

members of the building sector need intensive training. 

� In combination with the energy pass for buildings, we 

suggest to introduce a quality label for independant energy 

consulting services. 


Thank you for your attention! 

Lao Tse: Liebt die Dinge der Welt, aber verliert euch nicht an sie.

Energy Conservation - Scientific Assessment of Projects

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