9 Key Variables
10.3 Activity Analysis
In this, the default methodology, energy consumption is calculated as the product of an activity level and an annual energy intensity (energy use per unit of activity). Overall activities are defined as the products of the individual activities entered along a complete branch of the Demand tree. Typically, activities are specified as a single absolute value (e.g. number of households) multiplied by a series of shares or saturations/penetrations (e.g. the percent share of urban households, the penetration of an end-use such as air conditioning), and the penetration of each technology that meets the end-use.
Total energy consumption is thus calculated by the equation:
Energy consumption = activity level x energy intensity
There are two basic variations to this methodology: in a Final Energy Demand Analysis you specify energy intensities at the device level as the amount of fuel used per unit of activity; in a Useful Energy Demand Analysis you specify useful energy intensities at the next highest branch level (typically the end-use level), and then specify the efficiencies of each device.
Note: this method can also be used to project energy consumption directly (i.e. not per unit of activity). To do this, simply enter "No data" for the units in the Activity Level variable.
Tip: use the methodology tab on the Demand Branch Properties screen to set-up an
10.3.1 Final Energy Demand Analysis
In conducting a final energy demand analysis, a typical approach is to disaggregate your demand data structure into four levels representing sectors, subsectors, end-uses and devices. An example of this approach showing the Activity Level table in the Analysis View is given below.
Activity levels for one of the four hierarchical levels are typically described in absolute terms (in this case the number of households is 8 million in the Current Accounts year), while the other three levels are described in proportionate (i.e. percentage share or percentage saturation) terms. In the example shown above, urban households are 30% of the total number of households in 2000, of these 95% have some type of refrigerator, and all refrigerators are existing (less efficient) models. None of the new, more efficient models have been introduced in the base year. Notice that at the top level, the user chose an absolute unit for the activity level (households). At lower levels, LEAP keeps track of the units, and hence knows that the percentage number entered at the second level is the share "of households". In general, LEAP lets you choose the numerator units for activity levels, whilst automatically displaying the denominator unit. When selecting an activity level unit, you can choose from any of the standard non-energy units. Use the Units screen (Main Menu: General Parameters: Units) if you need to add additional units. The above data are shown for the Current Accounts year, but all values can be altered for future years in scenarios. This allows the planner to capture the combined effects of separate changes at many levels, such as, for example, the growth in the total number of households, the rate of urbanization, the penetration of refrigeration, and the market share of less efficient vs. more efficient refrigerator models. To
project these data, you first use the Manage Scenarios option to create one or more scenarios. Then, in the Analysis View, you override the default (constant) expressions entered in Current Accounts for each branch, with new expressions that describe how each value changes over time.
The tree structure for this type of final energy analysis is shown on the right. Notice that all of the branches are created as category branches ( ) except for the bottom-most nodes, which are always created as technology branches ( ). For these bottom-level branches, you also define the annual energy intensities per unit of activity level (in this case per household) and specify the fuels used by the device (see below).
When editing energy intensities, first select the fuel used by each device and then set the scale and units in which you want to enter the intensity. The scale and units columns can only be edited in Current Accounts. Changes to the energy intensity units’ column subsequent to entering an intensity value will cause LEAP to offer to convert the value to the new units.
10.3.2 Useful Energy Demand Analysis
Tip: use the Demand Branch Properties dialog to set-up a useful energy demand
analysis.
For cases in which you wish to explicitly consider demand-side efficiency improvements and fuel switching independently of the evolution of useful energy demands (e.g. the heat demand in a building), you may wish to use LEAP's useful energy analysis methodology instead of the default final energy analysis.
A useful energy analysis lets you independently consider three important trends: a) how the overall useful demand might change over time (for example as incomes rise and people consume more, or as building standards improve affecting heat demand per square meter), b) how the market penetration of different devices changes over time, and c) how the efficiencies of devices (i.e. final energy demand per unit of useful energy provided) is likely to evolve over time.
To configure a useful energy analysis, do the following:
1. Add an end use branch ( ) at the end-use level (e.g. heating, cooling, cooking). 2. On the Demand Branch Properties screen, check the box marked "useful energy
Note that useful energy branches are always immediately above the technology branches in a demand tree. Only technology branches may be added below them. In the example shown on the right, three substitute fuels (fuel oil, electricity and natural gas) area used to provide commercial heating.
Current Accounts
When conducting a useful energy analysis, Current Accounts data can be specified in two different ways:
1. In the default method, you specify final energy intensities for the end-use, along with the fuel shares and efficiencies for each fuel or device level. Notice that device fuel shares are not the same thing as the activity shares entered in a final energy analysis. Fuel shares are the share of total final energy consumed by each device, while activity shares reflect the number of "activities" (e.g. the share of floor space heated by different boiler types). The percentage efficiencies you enter for each device are used to calculate the overall useful energy intensity for the end-use, and the activity shares for each device in the Current Accounts year. This first approach is most useful when you have Current Accounts data describing the total fuel consumed in the base year, and you wish LEAP to calculate the useful energy demand.
2. In the second method, you specify useful energy intensities directly in Current Accounts. This approach is useful in cases where you have data describing the useful demand for a branch (e.g. the heat demand in buildings).
Tip: use the Demand Branch Properties dialog to select between these two
alternatives. Notice that you can mix and match methods freely in different branches
Scenarios
Irrespective of the method you choose for Current Accounts, in scenarios you project the useful energy demand, device efficiencies and activity shares into the future.