Summary
An energy system model includes a set of ‘technologies’ – a broad term that encompasses all forms of energy infrastructure, including power plants, transmission lines, and storage systems. Techno-economic inputs describe the characteristics of these technologies Below is a representative list of technology groups and the specific technologies they include. The full set of technologies available in Scenario Builder is detailed below.Technology set
Technology costs
Generator Capital Costs (CAPEX)
CAPEX refers to the upfront investment needed to build new energy infrastructure. These are one-time costs for purchasing and installing technologies. The costs applied here are overnight costs - they do not include the interest during construction. This could lead to an underestimation of capital costs, especially in cases with high upfront costs, construction times, and interest rates.- Includes: equipment, engineering, procurement, construction (EPC), land, grid connection, permitting, environmental impact assessments.
- Units: typically expressed as currency per unit of capacity (e.g. $/kW for power plants and transmission, $/kWh for storage).
Operating expenditures (OPEX)
OPEX refers to the ongoing costs to operate and maintain energy infrastructure over its lifetime, after the initial CAPEX.- Variable Operating costs: proportional to the amount of electricity generated or activity level
- Includes: fuel costs (though sometimes treated separately, Commodity (Fuel) Price section), consumables.
- Units: $/MWh of electricity generated.
- Fixed Operating costs: incurred regardless of energy production level, typically time-based
- Includes: salaries, insurance, routine maintenance, property taxes.
- Units: $/MW/year (or $/kW/year).
Data sourcing standards – technology costs
Efficiencies
Efficiencies are represented by Fuel Use Rate input, which is the amount of fuel energy input required to produce one unit of energy output. Expressed as a value representing the ratio of energy input to energy output. For example:- A coal power plant with 40% efficiency has a Fuel Use Rate of 2.5 (meaning 2.5 units of fuel are needed to generate 1 unit of electricity).
- A CCGT gas plant with 60% efficiency has a Fuel Use Rate of 1.67 (meaning 1.67 units of fuel are needed to generate 1 unit of electricity).
- A battery with 85% round-trip efficiency has a Fuel Use Rate of 1.18 (meaning 1.18 units of energy input are needed to discharge 1 unit of energy).
Data sourcing standards – efficiencies
Utilisation rates (Operational constraints)
Maximum Annual Utilisation defines the highest level at which a power plant can operate within a given period, constrained by technical capability, economic viability, or regulatory requirements. For example, if a scenario sets a maximum annual utilisation rate of 80%, the model will cap the plant’s total output to 80% of its theoretical maximum capacity annually. Minimum Annual Utilisation defines the lowest operating level required for a power plant, determined by plant-specific or technology-specific operational requirements. For example, if a scenario sets a minimum annual utilisation rate of 30%, the model will ensure the plant operates at least 30% of its theoretical maximum capacity annually. Minimum Hourly Utilisation is available only for dispatch scenarios, which sets the lowest required operating level at the hourly resolution. Samples of constraining factors:- Maintenance: Planned and unplanned maintenance reduces annual output and capacity availability.
- Resource availability: Some technologies (e.g., geothermal) face natural limitations on output potential.
- Regulatory constraints: Policy can mandate minimum or maximum operating hours to balance grid supply and emissions reduction.
- Technology specification: Inflexible technologies such as coal plants have minimum operating levels to avoid excessive ramp-up and ramp-down costs.
Operational life (Lifetime)
The expected number of years a technology can operate before needing replacement. This is a key input for investment decisions. Sourced similarly to technology costs. The following table consolidates the operational lifespan data for various power plant technologies as identified from the referenced sources.Growth or Build Rates (Capacity addition constraints)
Maximum allowed increase in capacity for a given technology year on year. There are two growth rate constraints: Relative and Absolute Maximum Growth Rate. Relative Maximum Growth Rate is defined as the maximum allowed annual percentage growth in the given technology’s capacity year on year, expressed as a decimal (e.g. 0.2 for 20%). The growth rate is applied to total capacity in the preceding year. Absolute Maximum Growth Rate is expressed in absolute values. If used in conjunction with Relative Maximum Growth Rate, the model may build new capacity at this floor value, in addition to the product of the previous year’s total capacity and the Relative Maximum Growth Rate. This parameter can also act as a ‘seed’ value where no or minimal capacity exists for the technology to which a growth rate is applied. Expressed in absolute values.Emission rate
The rate at which a technology emits pollutants, especially greenhouse gases (CO₂), per unit of energy produced or fuel consumed (e.g. tonnes CO₂/MWh or tonnes CO₂/TJ). Where available, this is derived from the technology’s emission factor and heat rate. Sources include IPCC guidelines, national emissions inventories, and specific studies. These rates are critical for calculating total emissions and assessing alignment with climate targets. The following table summarizes the life-cycle GHG emission factors for various electricity generation technologies based on the IPCC AR6 WGIII.
Data sourcing standards for emission factors are detailed below.
Scenario Builder currently evaluates only CO₂ emissions and does not yet account for other regulated air pollutants such as NOₓ and SOₓ.