The intensive margin of technology adoption Experimental evidence on Improved Cookstoves in rural Senegal

Transcription

1 The intensive margin of technology adoption Experimental evidence on Improved Cookstoves in rural Senegal Gunther Bensch, Jörg Peters RWI June 2014 A study on behalf of BMZ and GIZ s Office of Evaluation

2 Motivation Almost 40 percent of the world population rely on woodfuels as primary fuel for cooking (IEA 2010) with serious implications on People s health: According to WHO 2 Million people die every year due to cooking related smoke emissions Women s workload: Firewood has to be provided by households themselves Environment: if not extracted sustainably, wood extraction for fuels contributes to deforestation The Recipe for Success: Access to clean(er) cookstoves United Nations have proclaimed the Sustainable Energy for All goal Clean means: LPG, electricity, biogas Open Question: Also improved biomass stoves? 20/06/2014 2

3 The Improved Cooking Stove used in this study A wide variety of improved biomass cookstoves (ICS) exists ranging from simple portable ICS over bricked chimney ICS to gasifier ICS The ICS under examination is the Jambar Bois, a standard simple portable ICS that has been introduced in several African countries and has shown to curb firewood consumption by 30-50% in lab tests has no chimney still emits considerable amounts of smoke costs around 10$ 20/06/2014 3

4 Program under evaluation ICS in Senegal In urban Senegal, ICS have been disseminated for decades In rural areas, so far ICS are not available Ministry of Energy of Senegal in cooperation with Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) are now starting/intensifying ICS dissemination activities in rural areas This study. is a pilot activity to learn about take-up behaviour and impacts of ICS in rural areas Set-up: Randomized Controlled Trial in the major target region of the government program 20/06/2014 4

5 Research Questions and Literature Research questions Focus: What are the effects of ICS usage on firewood consumption, people s health and work load? Literature Focus so far has been on more sophisticated cookstoves Simple cookstoves as the one used here are not expected to deliver health benefits 20/06/2014 5

6 Study approach and data collection Randomization in Nov 2009 Out of 250 randomly selected households 100 households were randomly picked to obtain an ICS Follow-up survey in Nov 2010 Usage tracking survey in April 2013 Indicators used: Socio-economic household data dish-specific data for all meals throughout a typical day firewood collection time health status for all household members 20/06/2014 6

7 Results ICS uptake Virtually all treatment households switch from traditional stoves to ICS (although most also still use the old ones) Firewood savings Firewood consumption goes down by ~50% per prepared dish and by 30% per week Health For cooking women: respiratory disease symptoms drop by 50 % (8 pp) and eye problems by 68 % (10 pp) Other household members: no change! 20/06/2014 7

8 Results Health Health experts do not expect this ICS to improve health outcomes Why? Because smoke emission levels remain high Are these positive health effects plausible? Yes, because exposure is reduced: Outside cooking doubles in the treatment group (13% to 25%) Cooking duration is reduced substantially and significantly by 25% (70-80 minutes per day) Cooking is facilitated so that cook does not need to stay close to the stove while cooking 20/06/2014 8

9 Results What happens in the long run? Usage tracking survey 3 ½ years after randomization Decline in share of ICS users among treated households Still 49% of treated households use the ICS It is still used for 62% of prepared dishes Those who no longer use the ICS have ceased doing so because it deteriorated (and not because they lost interest) 20/06/2014 9

10 Conclusions This very simple but cheap and adapted stove yields considerable benefits for the households Even only taking into account the firewood savings (and not the public health revenues) the intervention pays back after a few months already Whether health effects can be expected is not only a question ofsmoke emission reductions, but also potential changes in exposure exposure Before ultimate decisions are taken on what is clean and how clean stoves are promoted more research is needed to explore and compare health effects of different ICS and clean fuels/stoves (LPG, advanced combustion stoves ) Different promotion policies (subsidies vs. building sustainable markets) 20/06/

11 Thanks for your attention! 20/06/

12 Discussion: Potential Weaknesses Subjectivity of indicators In particular health statements might be biased However: data is quite consistent and the alternative would be to measure smoke emissions or health status, which disturbs people even more External validity Quite high (at least for west African countries) given the fact that we are working in a typical region and with the official governmental program Hawthorne- and John-Henry-Effect People probably might change their behavior, but the effect willbe comparatively small since we declared the study to prepare an ongoing electrification project 20/06/

13 Results Time use Firewood collection Virtually all households collect firewood (instead of buying) Firewood collection time is reduced by around 15% (i.e. 2 ½hours per week) Although only borderline significant (p-values between 0.11 and 0.22), which might be due to data inaccuracies Cooking Significant reduction of cooking duration per day by 20-25% (i.e minutes per day) 20/06/

14 GIZ s Current Position towards RCTs RCTs should not be considered superior to other designs Opportunites for using RCTs remain limited given the characteristics of many GIZ programmes However there is still untapped potential in GIZ to investigate impacts with RCTs RCTs should be used if it makes sense in terms of content, strategy and funding RCTs should be used in combination with qualitative methods in order to answer the why and how questions 20/06/

15 Data Sample and participant flow Assessed for eligibility ~ 600 households in 12 villages Excluded or refused to participate 0 Randomly picked for study % 60% determined by Power Analysis November 2009 ICS users 98 Random allocation of ICS (and baseline) Control group 155 November Follow-up (endline) Analysis /06/

16 Results Impact indicators Observation field Impact indicator environment firewood consumption per dish Estimator Ordinary Least Squares (OLS) on dish level expenditures health workload household firewood consumption per week OLS on household level & Difference-in-difference cooking energy expenditures per month Propensity Score Matching on household level prevalence of respiratory diseases and eye infections time needed per week to collect firewood Probit regression for person responsible for cooking Single difference in means cooking duration per meal/ day Single difference in means 20/06/

17 Results Time use Firewood collection Virtually all households collect firewood (instead of buying) however, no strong effect on time use can be detected (which might be due to data inaccuracies) in qualitative interviews, women stated that they save time Cooking Cooking duration is substantially shorter General activities income generating activities, household duties, watching TV no significant (quantitative) impact 20/06/