producing and validating small area estimates of household electricity demand
DESCRIPTION
Paper presented at the 4th General Conference of the International Microsimulation Association, 11-13 December, CanberraTRANSCRIPT
Producing and validating small area estimates of household electricity
demand
IMA 2013Canberra, December 12th 2013
Dr Ben AndersonSustainable Energy Research Centre
University of Southampton
@dataknut
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Small Area Estimates of Electricity Consumption
@dataknut
Contents
What & Why
How?
Results– Overall consumption– Consumption inequalities
Conclusions & future Directions
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Small Area Estimates of Electricity Consumption
@dataknut
Contents
What & Why
How?
Results– Overall consumption– Consumption inequalities
Conclusions & future Directions
?
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Small Area Estimates of Electricity Consumption
@dataknut
Digression: Geography
Southampton (UK)
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Small Area Estimates of Electricity Consumption
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Digression: What’s a small area?
In this case…– English Lower Layer
Super Output Areas– Census 2001 LSOAs– c. 630 households
each– 148 in Southampton
City
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Small Area Estimates of Electricity Consumption
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What & Why
Basically we want something for nothing– Small area estimates of energy demand– Without a bespoke energy census
Why?– Infrastructure planning– Energy efficiency intervention analysis– Politics!
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Small Area Estimates of Electricity Consumption
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The problem:
Small area summaries exist
But they are aggregates– Or averages
And we want a micro-level model– To micro-simulate change…
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Small Area Estimates of Electricity Consumption
@dataknut
What can we do?
A bespoke energy census– ££££££££££££££££££££
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Small Area Estimates of Electricity Consumption
@dataknut
What can we do?
A bespoke energy census– ££££££££££££££££££££
A large sample energy survey covering all LSOAs– ££££££££££
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Small Area Estimates of Electricity Consumption
@dataknut
What can we do?
A bespoke energy census– ££££££££££££££££££££
A large sample energy survey covering all LSOAs– ££££££££££
Small Area Estimation– Take existing area level data– Take (ideally) an existing large n survey– Combine £
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Small Area Estimates of Electricity Consumption
@dataknut
Small Area Estimation
Econometric approaches– Well known– Multi-level Models– Usually requires census microdata for anything
other than means
Re-weighting (and other) approaches– Increasingly well known– 'Spatial microsimulation'– Does not require census microdata
Income, income deprivation,income inequality
smoking prevalence, obesity,
consumption expenditure,CO2, water…
Innovation Network:“Evaluating and improving small
area estimation methods”
http://eprints.ncrm.ac.uk/3210/
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Small Area Estimates of Electricity Consumption
@dataknut
Contents
What & Why
How?
Results– Overall consumption– Consumption inequalities
Conclusions & Future Directions
Estimation
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Small Area Estimates of Electricity Consumption
@dataknut
Data
Data– Living Costs and Food Survey 2008-2010
· Consumption proxies (reported energy expenditure)
– Census 2001 (2011)
Projection– Projected ‘surveys’– Projected ‘census’
So far…
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Small Area Estimates of Electricity Consumption
@dataknut
Conceptually…
LSOA 2.1(Region2)
Survey data cases
LSOA 1.1(Region1)
Iterative proportional fittingBallas et al (2005)
If Region = 2
Weights
LSOA census ‘constraint’ tables
If Region = 1
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Small Area Estimates of Electricity Consumption
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Key First Job:
Choose your constraints
Census data
Survey data
You may have little choice
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Small Area Estimates of Electricity Consumption
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Key First Job:
The constraints– Selected by stepwise regression
Expenditure Share of expenditure
Most important Number of persons Employment Status
Accommodation type
Number of earners
Age of HRP Age of HRP
Employment Status Composition
Number of rooms
Number of children
Least important Ethnicity (non-white)
R sq 0.136 0.01
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Small Area Estimates of Electricity Consumption
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IPF…
Well known! Deming and Stephan 1940
– Fienberg 1970; Wong 1992 A way of iteratively adjusting statistical tables
– To give known margins (row/column totals) In this case
– Create weights for each case so LSOA totals ‘fit’ constraints
– Weighting ‘down’
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Small Area Estimates of Electricity Consumption
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Internal Validation methods
Use of constraints to re-create the Census tables
Difference = Absolute Error
– Total Absolute Error (TAE) = sum of all errors
– Standardised AE = TAE/(n persons x n constraint categories)
Smith et al:
– SAE of less than 20% and ideally less than 10%
– in 90% of the areas is desirable.
Consumption Mean SAE p90
Ethnicity 2.18% 3.05%
Number of children 0.11% 0.22%
Number of rooms 0.05% 0.10%
Employment status (HRP) 0.88% 1.22%
Age (HRP) 0.34% 0.75%
Tenure 0.07% 0.14%
Accomodation type 0.21% 0.51%
Number of persons 0.00% 0.00%
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Small Area Estimates of Electricity Consumption
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Preliminary results: Electricity Mean weekly £
Modelled
Census 2001
LC&F Survey 2008-2010
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Small Area Estimates of Electricity Consumption
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Validation: Electricity Mean weekly £
Observed @LSOA
DECC 2010
Spearman: 0.317
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Small Area Estimates of Electricity Consumption
@dataknut
Preliminary results: Electricity Total weekly £
Modelled
Census 2001
LC&F Survey 2008-2010
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Small Area Estimates of Electricity Consumption
@dataknut
Validation: Electricity Total weekly £
Observed @LSOA
DECC 2010
Spearman: 0.509
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Small Area Estimates of Electricity Consumption
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What is causing the error? Heating!
– 2011 data
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Small Area Estimates of Electricity Consumption
@dataknut
What is causing the error? Heating!
– 2011 data
Housing growth
Combined
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Small Area Estimates of Electricity Consumption
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Consumption inequality Area level gini
R = -0.413– (p < 0.001)
DRAFT
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Small Area Estimates of Electricity Consumption
@dataknut
Consumption inequality Area level gini
R = 0.463– (p < 0.001)
DRAFT
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Small Area Estimates of Electricity Consumption
@dataknut
My big worry
Data quality
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Small Area Estimates of Electricity Consumption
@dataknut
Contents
What & Why
How?
Results– Overall consumption– Consumption inequalities
Conclusions & Future Directions
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Small Area Estimates of Electricity Consumption
@dataknut
Conclusions
Outliers and errors are informative
Reported consumption data– Could be dangerous
Census 2011 central heating– Critical new constraint
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Small Area Estimates of Electricity Consumption
@dataknut
Future directions
Update for 2011 data
Census projection 1981 -> 2021
Use measured energy consumption
Contact:– [email protected]