# Energy Service Demands 

TIAM comprises 42 energy-services in the five end-use sectors (see Table 1).

Table 1: Energy service demands in the TIAM model
| Residential segments | Commercial segments | Industrial segments  | Transportation segments | Other segments   |
|---------------------------|-------------------------|--------------------------|------------------------------|------------------------------|
| Space heating             | Commercial cooling          | Chemicals           | Domestic Aviation                         | Agriculture                  |
| Space cooling             | Commercial cooking          | Iron and steel       | International Aviation                          | Non-energy uses in transport |
| Water heating             | Commercial space heat           | Pulp and Paper | Road Bus Demand                  |                              |
| Lighting                  | Commercial hot water                | Non-ferrous metals           | Road Commercial Trucks Demand             |                              |
| Cooking                   | Commercial lighting                 | Non Metals                | Road Three wheels Demand                 |                              |
| Refrigeration             | Commercial office equipment           | Other Industries       | Road Heavy Trucks Demand                  |                              |
| Clothes washing           | Commercial refrigeration      | Industrial and Other Non Energy Uses         | Road Light Vehicle Demand                  |                              | 
| Clothes drying            |        |                        Other non-specified consumption  | Road Medium Trucks Demand       |                              |
| Dish washing              |                         |                          | Road Auto Demand            |                              |
| Electric appliances       |                         |                          | Road Two Wheels Demand                 |                              |
| Other energy uses         |                         |                          | Rail-Freight     |                              |
|                           |                         |                          | Rail-Passengers                
|                           |                         |                          |Domestic Internal Navigation          |                              |
|                                                           |                         |                          |International Navigation          |                              |
|                                 
                          
                       
To fulfill each energy-service demand, a number of technologies exist. The technologies vary in terms of input fuel(s), efficiency and costs. 
In fact, each of the energy-services is treated as a function that consumes energy to satisfy the demand for a service (e.g., demand for auto transport, measured in billion vehicle kilometers). Similar to other bottom-up models, the energy-service demands in TIAM are projected exogenously. They are specified at the regional level based on a range of exogenously-given drivers such as GDP, GDP per capita, GDP per household and population. The energy-service demands are linked to the underlying drivers, using elasticity factors. The elasticity factors reflect the sensitivity of energy-service demands to a change in their underlying drivers. Usually, the assigned elasticities are less than one, highlighting that the energy-service demands grow slower than the underlying drivers.
As the energy-service demands in the TIAM model are projected exogenously, they are independent to their prices. This means that the projection of an energy-service demand is fixed unless either the driver or the elasticity parameter changes. Therefore, although TIAM shows how the energy-service demands can be satisfied at the lowest possible cost, it is not able to reflect the ‘price effect’ which refers to the impact of a change in energy prices on the demand of energy services (Parkin et al., 2005). Hence, although the model provides a detailed technological representation of the energy system, it is not able to address the contribution of (price- dependent) energy-service demands in tackling climate change. 

### References
Babak Mousavi, “Analysis of the relative roles of supply-side and demand-side measures in tackling global climate change: Application of a hybrid energy system model,” vol. 2018.