TU / e
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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
TU / e
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Eindhoven University of Technology
Contents
• Backgrounds
• Rebound effects
• Exploratory research
• Conclusions
Wim Heijs
TU / e
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Eindhoven University of Technology
Wim Heijs
Backgrounds: world energy production
TU / e
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Eindhoven University of Technology
Wim Heijs
Backgrounds: world electricity production
TU / e
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Eindhoven University of Technology
Wim Heijs
Backgrounds: household energy use Neth.
household energy use
Gj per person
other sources
natural gas
(temp. corrected)
electricity
apparent stagnation
despite technological
and psychological
efforts ...
TU / e
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Eindhoven University of Technology
Wim Heijs
Backgrounds: reasons for stagnation
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)
TU / e
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Eindhoven University of Technology
Wim Heijs
Rebound effect in general
- energy efficiency measures
- monetary savings
- increased consumption
(direct or indirect through production)
- backfire: total elimination of saving (or worse)
TU / e
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Eindhoven University of Technology
Wim Heijs
Rebound effect: types
- direct rebound effects:
increased use when costs are lower
e.g. higher room temperature, leave lights on,
or take longer showers
Wonderful, this new boiler!
Now it takes twice as long
before Norman gets angry...
TU / e
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Eindhoven University of Technology
Wim Heijs
Rebound effect: types
- 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!
TU / e
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Eindhoven University of Technology
Wim Heijs
Rebound effect: types
- reinforced by marketing / technology push
(especially electric appliances)
Finally, you CAN afford
the dryer you never had,
AND save energy!!!
TU / e
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Eindhoven University of Technology
Wim Heijs
Exploratory research: existing studies
- contradictory: estimated 1 - 80% (max. 170%)
- large diversity of relevant behaviors
many intervening factors
- changes over time: longitudinal approach
- problems concerning reliability
TU / e
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Eindhoven University of Technology
Wim Heijs
Exploratory research: design
- 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.
TU / e
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Eindhoven University of Technology
Wim Heijs
Exploratory research: results
- 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
TU / e
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Eindhoven University of Technology
Wim Heijs
Exploratory research: main indicators
- higher living room temperature night/day* 15/5
- more rooms heated simultaneously*
12
- higher temperatures when absent*
10
- computer / tv on longer
10/5
- increased number of lights indoors
7
- new freezer (not a replacement)
7
- more frequent use of dishwasher
6
- garden lighting on longer
6
- new garden lighting (not a replacement)
5
- more lights left on for security
5
- more frequent / longer showers
4/4
* to some extent natural / recommended
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TU / e
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Eindhoven University of Technology
Wim Heijs
Conclusions
- 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
TU / e
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Eindhoven University of Technology
Wim Heijs
Conclusions
- 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?
TU / e
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Eindhoven University of Technology
Thank you for
your attention
Questions and
discussion...
Wim Heijs