Methodology note on modelling impacts

Transcription

1 Methodology note on modelling impacts What changes? This note sets out the modelling we have undertaken to obtain our UK-level estimates of the impacts of changes to domestic ovens and hobs minimum efficiency requirements coming into force on 20 February 2015 (Regulation No 66/2014). This measure is part of the European Commission s eco-design directive, which seeks to realize the high electricity savings potential of domestic appliances. The way this specific regulation seeks to limit the supply of energy efficient gas and electric hobs and ovens options on the market is by phasing out less efficient products. This is done in three steps between 2015 and 2019, for the exact details of the changes see the regulation. General approach Based on data on the characteristics of the average UK ovens and hobs and the most recent available market data, we were able to build a simple stock and flow model. This is used to estimate the impact of the policy by comparing to what would have otherwise happened in the baseline case (the business as usual scenario). The impact is the difference between the two scenarios in terms of aggregate electricity consumption of UK hobs and ovens. Data on the domestic cooking appliance market and the appliances characteristics and usage (life span, average electricity consumption, number of cycles and so on) are extremely scarce, both at the European and the country level. It was therefore necessary to make some assumptions. Where possible we followed the assumptions made in the Preparatory Study for Lots 22 (domestic and commercial ovens) and Lot 23 (Domestic and commercial hobs and grills) commissioned by the European Commission. The stock and flow model To estimate the UK impacts of these new rules we built a stock-flow model that allows appraisal of the effects of the regulatory change. In our modelling we are drawing upon market intelligence data (number, type and energy efficiency class of to stock and sales of domestic cooking appliances in the UK) and some assumptions are borrowed from the Preparatory Study, DECC and Defra s data from the Market

2 2 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements Transformation program (growth and replacement rates, distribution of new purchases by energy efficiency class as well as life spans of different types of domestic cooking appliances). Combining these data allows us to estimate the number of hobs and ovens in the UK and the level to which the whole stock has been replaced each year after the regulation comes into force on February 20, What this means is that after establishing the stock using market intelligence data we draw up sales forecasts for each of the appliance types by energy efficiency class (gas hob, electric hob, gas oven, electric oven) using data available from DECC. The growth rates of different domestic cooking appliances and their average lifetime were used in the stock model to calculate the flows (exits and entries into the stock). Both were taken from the Preparatory Study for Lots 22 (domestic and commercial ovens) and Lot 23 (Domestic and commercial hobs and grills), which estimate the products average lifetime as 19 years. This is then used to forecast the stock in the future and the point at which the stock has been fully replaced. However, there is a lack data on gas hobs and gas ovens by energy efficiency class as these products were previously not labelled (both for the present stock and new purchases). We work around this by assuming that gas hob and oven purchases are similarly distributed to their electric counterparts. In the absence of data this is the fairest assumption we can make. Estimating the impacts To estimate the impact of the changes we compare the electricity consumption in the BAU scenario and the policy scenario. The difference between the two in any given year constitutes the electricity saving. The latest year for which we make these estimates is 2030 when the stock has almost been replaced completely. Using the estimate of electricity savings under the policy we are also able to estimate the carbon emissions avoided and the impact on household bills. To be able to calculate this difference in electricity consumption we needed to know current usage patterns of UK domestic appliances (average consumption per running cycle and number of cycles run per year by energy efficiency class). Changes to the length of the running cycle or number of cycles are not expected and thus remain static in our comparison of baseline and policy scenario. Modelling the BAU scenario In the base-case current hob and oven models remain the only products sold on the market over the outlook period. However, for ovens we are able to take into

3 3 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements consideration efficiency improvements that are likely to occur in the market in the absence of the regulation (by extrapolating the past 20 years trend using data on electric ovens from DECC and assuming the development is similar for gas ovens). For hobs (both electric and gas) this is unfortunately not possible as DECC does not hold suitable data on the past trends in energy efficiency improvement of new hobs. This is the best option to incorporate incremental improvements in the market in our modelling. This scenario is then used as a baseline in order to compare the results with the policy scenario. Estimating the policy scenario To estimate the policy scenario we combine the data on the stock of hobs and ovens today (2015) and in any year up to 2030 (inclusive) and the changes the minimum energy efficiency requirements mean for sales. Effectively, we are taking out the hobs and ovens from the new purchases that are now no longer on sale in any respective year and redistribute these purchases to the available categories (based on the observed splits). This way we can calculate how much lower the energy consumption of all hobs and ovens in the stock is without those phased out under the regulation on sale.

4 4 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements Appendix 1 Stock and flows, Table 1: Ovens, stock and flows, Year Electric ovens Gas ovens Stock Sales Stock Sales ,290,000 1,089,535 9,160, , ,570,000 1,119,990 9,080, , ,840,000 1,130,830 8,980, , ,100,000 1,156,676 8,880, , ,370,000 1,179,118 8,780, , ,640,000 1,197,703 8,680, , ,925,667 1,222,643 8,588, , ,215,489 1,248,102 8,497, , ,509,527 1,274,091 8,408, , ,807,842 1,300,622 8,319, , ,110,496 1,327,705 8,231, , ,417,551 1,355,352 8,145, , ,729,073 1,383,574 8,059, , ,045,127 1,412,384 7,974, , ,365,777 1,441,795 7,890, , ,691,091 1,471,817 7,807, ,147

5 5 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements Table 2: Hobs, stock and flows, Year Electric hobs Gas hobs Stock Sales Stock Sales ,152, ,114 15,458, , ,155, ,813 15,632, , ,144, ,781 15,794, , ,130, ,232 15,957, , ,115, ,523 16,123, , ,099, ,057 16,289, , ,091, ,327 16,463,047 1,020, ,083, ,316 16,638,154 1,042, ,076, ,051 16,815,122 1,064, ,068, ,555 16,993,973 1,087, ,060, ,856 17,174,727 1,111, ,052, ,979 17,357,403 1,135, ,044, ,953 17,542,021 1,159, ,037, ,807 17,728,604 1,184, ,029, ,571 17,917,171 1,210, ,021, ,274 18,107,744 1,236,578

6 6 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements Appendix 2 Total impacts Table 3: Ovens (electric and gas), annual impacts, Year Electricity saved Financial savings CO2 savings ,106 52, , ,234, ,704 2,129, ,089,423 1,424,477 4,106, ,028,525 2,135,286 6,123, ,731,924 8,408,848 22,822, ,551,954 14,626,809 39,676, ,255,104 21,710,864 56,888, ,581,409 28,905,068 74,407, ,543,847 35,753,019 92,242, ,155,664 43,683, ,397, ,430,381 52,326, ,880, ,381,802 61,287, ,697, ,024,018 68,829, ,856, ,371,414 76,903, ,363, ,438,674 84,735, ,226, ,240,787 94,148, ,452,825 Total 3,549,475, ,629,326 1,471,440,581

7 7 Methodology note: modelling impacts of ovens & hobs minimum efficiency requirements Table 4: Hobs (electric and gas), annual impacts, Year Electricity saved Financial savings CO2 savings ,458 45, , ,062,296 99, , ,111,126 1,205,276 3,786, ,476,717 2,342,133 7,355, ,615,126 7,349,838 22,230, ,464,413 12,370,336 37,399, ,574,554 18,091,294 53,008, ,980,471 24,008,904 69,070, ,718,105 29,538,246 85,599, ,824,438 36,140, ,608, ,337,531 43,349, ,114, ,296,556 50,916, ,130, ,741,827 57,576, ,672, ,714,835 64,636, ,756, ,258,286 71,719, ,398, ,416,138 80,029, ,617,314 Total 4,338,113, ,418,610 1,383,241,011