1. TU / e Eindhoven University of Technology Wim Heijs Exploring energy rebound effects Wim Heijs Richard Adrians contact: w.j.m.heijs@tue.nl Department of Architecture, Building and Planning ERES 2011 Eindhoven 1

2. TU / e Eindhoven University of Technology Wim Heijs 2 Contents Backgrounds Rebound effects Exploratory research Conclusions

3. TU / e Eindhoven University of Technology Wim Heijs Backgrounds: world energy production 3

4. TU / e Eindhoven University of Technology Wim Heijs Backgrounds: world electricity production 4

5. TU / e Eindhoven University of Technology Wim Heijs Backgrounds: household energy use Neth. 5 household energy use Gj per person other sources natural gas (temp. corrected) electricity apparent stagnation despite technological and psychological efforts...

6. TU / e Eindhoven University of Technology Wim Heijs Backgrounds: reasons for stagnation 6 Real estate, e.g.: - quality of existing stock - investment, pay back time Occupants, e.g.: - knowledge - motivation, bad examples (industry, city) - strong habits, behavioral patterns rebound effects (or take back effects)

7. TU / e Eindhoven University of Technology Wim Heijs Rebound effect in general 7 - energy efficiency measures - monetary savings - increased consumption (direct or indirect through production) - backfire: total elimination of saving (or worse)

8. TU / e Eindhoven University of Technology Wim Heijs Rebound effect: types 8 - direct rebound effects: increased use when costs are lower e.g. higher room temperature, leave lights on, Wonderful, this new boiler! Now it takes twice as long before Norman gets angry... or take longer showers

9. TU / e Eindhoven University of Technology Wim Heijs Rebound effect: types 9 - indirect rebound effects: opportunity to purchase new goods/services e.g. dryer, waterbed, more illumination indoors or in the garden... Don’t worry, dear. It’s energy efficient lighting!

10. TU / e Eindhoven University of Technology Wim Heijs Rebound effect: types 10 - reinforced by marketing / technology push (especially electric appliances) Finally, you CAN afford the dryer you never had, AND save energy!!!

11. TU / e Eindhoven University of Technology Wim Heijs Exploratory research: existing studies 11 - contradictory: estimated 1 - 80% (max. 170%) - large diversity of relevant behaviors many intervening factors - changes over time: longitudinal approach - problems concerning reliability

12. TU / e Eindhoven University of Technology Wim Heijs Exploratory research: design 12 - limited time, opportunity (MSc R. Adrians) - to find indications while maximizing chance: most noticeable after significant change in energy use, move to a low energy dwelling - survey N=451, list of possible direct (30) and indirect (10) rebound effects controls:- no income change, drop energy costs - equal dwelling / household size - different energy-related features, etc.

13. TU / e Eindhoven University of Technology Wim Heijs Exploratory research: results 13 - return rate 12% (N=54, holidays) - some controls unusable (hh / energy costs) unreliable answers, change of provider, no or dissimilar bills (no more natural gas, additional costs electricity heat pump, etc.) - others usable (income, situation) removed: changed household size (22), dwelling size, other intervening effects (11) - remaining for analyses: 21 cases

14. TU / e Eindhoven University of Technology Wim Heijs Exploratory research: main indicators 14 - higher living room temperature night/day* 15/5d - more rooms heated simultaneously* 12d - higher temperatures when absent*10d - computer / tv on longer 10/5d - increased number of lights indoors 7d/i - new freezer (not a replacement) 7i - more frequent use of dishwasher6d - garden lighting on longer6d - new garden lighting (not a replacement)5i - more lights left on for security5d - more frequent / longer showers4/4d * to some extent natural / recommended

15. TU / e Eindhoven University of Technology Wim Heijs Conclusions 15 - provisional indications (in)direct rebound effects to some extent mitigated by ‘normal usage’ - low energy houses, energy-conscious people: more frequent in ‘normal’ population? - main lessons learned: > control intervening factors very difficult > statistical correction of situational differences using large samples > longitudinal design, objective measures

16. TU / e Eindhoven University of Technology Wim Heijs Conclusions 16 - rebound effects plausible, inevitable - partly responsible for slow progress - disregard: transformation of problems instead of solution - difficult to prevent, inherent to economy - awareness necessary first step - research on prevalence, strategies - what about larger users (industry, government)? - renewable sources the only real way out?

17. TU / e Eindhoven University of Technology Wim Heijs 16 Thank you for your attention Questions and discussion...