Economic & Environmental Aspects of Power Generation
Economic Aspects
Cost and Types
The cost of a product is the sum of the various expenses incurred to produce it. For power plants, the product is electrical energy supplied to the network (kWh).
Internal Costs relate to the economic costs passed on to the productive process, which can be divided into:
- a) Depreciation costs of investment: fixed annually
- b) Fuel costs: variable
- c) Cost of operation and maintenance (O&M): fixed (staff) and variable (lubricants, waste management, etc.)
This analysis of internal costs does not usually include the costs of transmission and distribution of energy (e.g., electricity losses in the network and taxes), since it considers the cost of energy (e.g., kWh) at the point of exit from the plant.
External Costs relate to the social cost impacts on the environment caused by emissions and waste generated in this process, which can be passed on as eco-taxes on the product.
Specific Investment Cost of an Installation
Cost base of the plant: This is what it would cost if built and paid for instantly. This includes direct costs (land, civil works, installation, and equipment) and indirect costs (engineering services, inspection, etc.).
The total investment cost is equal to the cost base multiplied by a factor that increases with higher finance costs and longer construction periods.
The total investment cost divided by the rated power of the plant (e.g., in kWe) represents the cost per unit of installed power. This parameter is important because the cost of installed power is not constant for each plant type.
Specific Fuel Costs
This is obtained by dividing the total cost of fuel consumed by the plant during one year of operation by the energy generated by the plant during that year.
This cost varies significantly depending on the type and size of the plant. The cost of fuel in a hydroelectric power plant is almost negligible, low in nuclear power plants, and very high in thermal coal, fuel oil, and gas plants.
Specific O&M Costs
This is obtained by dividing the total cost of O&M for one year of plant operation (cost of staff and ancillary costs) by the energy generated by the plant during that year.
This cost does not change significantly with the size of the plant or between different types of plants.
Total Cost
The total cost of generation is the sum of the three types of costs (investment, fuel, and O&M).
Environmental Aspects
1 Particulate Emissions
Particulate emissions are associated with combustion. However, thanks to the use of electrostatic precipitators and electrofilters, removal efficiencies of between 95% and 99% are achieved.
Particulate emissions remain an environmental problem for developing countries with less restrictive environmental legislation. The most dangerous particles from a health perspective fall between 0.01 and 1 mm in size.
2 Radiological Contamination
Source: Nuclear energy.
The amounts of various types of radioactive contaminants depend on the type of reactor, its design, and the specific treatment of effluents installed.
Contamination of coolant by activation can occur. To achieve very low emission levels, radioactivity in the primary coolant circuit (reactor) must be reduced by continuous and efficient purification.
During normal operation of a nuclear plant, small amounts of radionuclides are released into the environment in the form of liquid effluent, vapor, or gases.
The damage caused by radiation is associated with two types of effects:
- Stochastic: Cancer and genetic errors, which have no threshold dose.
- Non-stochastic: Biological changes that occur only above a threshold dose.
The reduction of radionuclides released into the environment requires an adequate effluent treatment system, which is present in almost all nuclear power plants.
3 Thermal Pollution
Due to the condensation of steam in electricity generation systems, waste heat is released into the environment. The water used for cooling is returned to its source with an increased temperature.
This temperature increase can be minimized if the cooling circuit is closed and uses cooling towers.
4 Noise Pollution
Only wind and geothermal power generation have been considered “noisy.”
5 Land Occupation
The problems arising from the construction of hydroelectric plants should be noted. While cleaner from a chemical perspective (they do not release pollutants into the environment), they require changes to the course of rivers and the flooding of large areas of land, which almost inevitably alters existing ecosystems.
The use of mini-hydro power plants mitigates this problem, as they do not require large structures for their development. This is why their use has been promoted in recent years.
Wind and solar power also require significant land occupation. Wind farms, consisting of a large number of wind turbines, can cause bird deaths, although some may consider their “lack of aesthetics” to be their main drawback.
Nuclear, fossil fuel (coal, fuel oil, and gas), and geothermal power plants have a medium level of land occupation. The remaining energy sources have the lowest land occupation requirements.