producing and validating small area estimates of household electricity demand

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

@dataknut

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

@dataknut

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

@dataknut

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

@dataknut

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

@dataknut

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

@dataknut

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

@dataknut

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

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Validation: Electricity Total weekly £

Observed @LSOA

DECC 2010

Spearman: 0.509

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Small Area Estimates of Electricity Consumption

@dataknut

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

@dataknut

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:– b.anderson@soton.ac.uk