Energy triangle
In supplying society with energy, a balance must be struck between three key dimensions: competitiveness, security of supply, and the environment and climate. No single energy source is optimal from all dimensions. This energy triangle illustrates the pros and cons of hydro power.
Climate and environment: Hydro power is a renewable energy source that causes almost no emissions that impact the climate or the environment. However, power plants are a significant encroachment on the landscape and impact river ecosystems. A power plant may also affect animal and plant life in the vicinity.
Security of supply: Hydro power plants provide large-scale and stable electricity generation. But sustained high generation levels are dependent on precipitation. Hydro power also functions as balancing power, since capacity can be rapidly changed to compensate for differences in generation and consumption in the mains supply.
Competitiveness: Hydro power has no fuel costs and competitive generation costs. Constructing a new power plant requires a substantial investment, but its economic life is long.