- How are the ODYSSEE data collected?
ODYSSEE data are collected by national partners and checked and harmonized by Enerdata.
- How is calculated the total energy efficiency index (ODEX)?
Energy efficiency progress for final consumers is evaluated on the basis of the different ODEX by sector for industry, transport, households and services, weighted by the share of each sector in the final energy consumption.
- How are climate corrections made?
Climatic corrections are done in a linear way on the space heating (H) or cooling (AC) consumption on the basis of the ratio between normal degree days and actual degree days:
H = Hn x (HDD/HDDn)
or H = Hn x (1-K)+ Hn x K x (HDD/HDDn) with K = share of heating consumption independent of climate fluctuations (e.g. 10%) and Hn the consumption at normal climate
AC = ACn x (CDD/CDDn)
- How energy savings are calculated in Odyssee?
Energy savings are calculated by sector from the ODEX indicator, as ODEX is equal to the ratio between the energy consumption at year t (E) and a fictive consumption that would have happened without energy savings (ES):
ODEX = E/(E+ES)*100 --> ES = E x ((100/ODEX)-1)
Example: if consumption = 50 Mtoe and ODEX = 80 --> ES = 50* ((100/80)-1) = 12,5 Mtoe
- How is calculated the unit consumption per car equivalent?
The unit consumption per car equivalent is calculated by dividing the consumption of road transport by a total stock of road vehicles measured in equivalent cars.
The stock of road vehicles is converted into a stock of equivalent cars on the basis of coefficients reflecting the difference in the average yearly fuel consumption of each type of vehicle compared to a car:
- If, for instance, a motorcycle consumes 0.2 toe/year on average and a car 1 toe/year, one motorcycle is considered to be equivalent to 0.2 cars.
- In the same way if light vehicles and trucks consume on average 5 toe/year each vehicle for road transport of goods is equivalent to 5 cars.
Default values can be used for these coefficients or national data if national surveys or evaluation exist on the consumption of cars, trucks…
- What is the best indicator to analyse energy efficiency trends of cars?
For cars three main indicators can be used to characterise their energy efficiency:
- the specific energy consumption in litres/100 km (l/100 km), also expressed in km/l in America (in miles per gallon or mpg in the US);
- the specific energy consumption in energy unit in GJ/km (or koe/km);
- the specific consumption per passenger-km in MJ/pkm (or goe/pkm).
The first indicator (litre/100 km) shows the effect of technological improvements, driving behaviour and fuel shift.
The second indicator (MJ or koe/km) takes in addition into account changes in the fuel mix (i.e. in the average calorific value of motor fuels, in Joule or toe/litre). This fuel shift can come from a substitution between gasoline and diesel or from the penetration of biofuels. If the focus is on actual vehicle improvement, this fuel shift effect should be isolated by defining separate indicators for the different fuels, e.g. for diesel, gasoline etc…
The third indicator (MJ/passenger-km) takes in addition into account changes in the average occupation rate of cars (for instance because of carpooling). The effect of changes in car occupancy can be calculated by comparing the trend of the two last indicators.
As energy efficiency should preferably be measured in energy units and as there exist policies on carpooling to improve the efficiency of cars, it is recommended to use the third indicator.
- How many branches are part from the industry sector in Odyssee?
Industry is made of mining, manufacturing, construction and electricity, gas & water. Manufacturing is made of 14 branches.
- How is the energy intensity of industry at adjusted structure calculated?
For a given country, the energy intensity of industry at adjusted structure (of a reference country) is calculated as the sum over each sub-sector i (i.e. industrial branch) of the multiplication of the observed energy intensity of sub-sector i (EIi) of that country (i.e. energy consumption per unit of value added) by the share of sub-sector i in the total value added of industry of the reference country (VAi/VA).
=∑_i▒〖(〖VA〗_(i,ref,t)/〖VA〗_(ref,t) )*〖EI〗_(i,t) 〗
- What are the different energy efficiency indicators in industry?
In industry, energy efficiency indicators should preferably be expressed in physical units (eg. toe, GJ per tonne). For industry sub -sectors (i.e. branches) for which there is not a dominant product, the energy consumption can be related to the index of production, as this index is deemed to represent the physical production of a branch. Another indicator is also used to compare the energy performance of industrial branches is the energy intensity (i.e. energy consumption per unit of value added). This is the case for the calculation of the energy intensity of industry at adjusted structure.
- How is calculated the energy efficiency index (ODEX) in industry?
The energy efficiency index in industry combines the energy efficiency trends by branch in one index (industry ODEX).
Energy efficiency trends by branch are measured from the variation of specific energy consumption, expressed in toe/t (or GJ/t) for energy intensive branches (steel, cement, pulp and paper) and toe (or GJ) per unit of production index (IPI) for the other branches.
To account for the different units used, all specific consumption is then expressed in index.
The industry ODEX is then calculated by weighting the indices of specific consumption by branch with the share of each branch in the industry sector’s energy consumption.
Up to 15 branches are considered for industry ODEX. The detail calculation is explained in http://www.odyssee-mure.eu/publications/other/odex-indicators-database-definition.html
- Is ODEX cleaned from structural changes?
As ODEX is calculated by taking into account energy efficiency trends by branch, ODEX is not affected by structural changes between the different branches. It may however be influenced by structural changes within the branches (e.g. chemicals).
- Why energy consumption by end-use does not exactly match with total households consumption?
The estimate of the consumption by end-use usually apply to permanently occupied dwellings. Total household consumption may include the consumption of summer and week-end houses and, depending on the countries, some energy consumption for heating and lighting of common spaces in multi-family buildings.
- What is the indicator used to measure energy savings in services sector in Odyssee methodology?
In Odyssee, the energy savings in services sector are calculated from the variation of the unit consumption per employee; a unit consumption per m2 of floor area would be more relevant but not enough countries can provide data on the floor area.
- How do you evaluate the semi quantitative impact?
Semi-quantitative expert estimates on measure impacts which group the measures in three categories: measures saving less than 0.1% of the sector energy consumption (low impact measures), measures saving 0.1 to less than 0.5% of the sector energy consumption (medium impact measures), and measures saving more than 0.5% (high impact measures). For measures in the cross-cutting database the percentages refer to the overall final energy consumption of the country. These estimates have been made by the National Teams in the MURE project, who have an excellent knowledge of the policy in their countries. Nearly 90% of all measures in the database have been classified in such a manner. (See http://www.measures-odyssee-mure.eu/MureScoreboardMethodology.pdf)
- When some policies are listed under several categories, how is the primary focus of the policy identified?
If policies are listed in multiple categories, the policy can be seen as a general cross-cutting measure with specifications for the category it is listed in. Those specifications will only be mentioned in the corresponding category. Policies without sector specific specifications will be listed in the “general cross-cutting” category.
- Where do I find definitions/descriptions of evaluation methods mentioned on the quantitative evaluation page of a measure?
You may find quite comprehensive descriptions of methods regarding the evaluation of energy efficiency measures in the documents linked below:
- Energy Efficiency Program Impact Evaluation Guide: https://www4.eere.energy.gov/seeaction/system/files/documents/emv_ee_program_impact_guide_0.pdf
- A guide to monitoring and evaluation of energy efficiency measures: http://www.rcreee.org/sites/default/files/a_guide_to_monitoring_and_evaluation_of_ee_measures.pdf