Reasons for the variable pattern of energy supply over time (physical, economic and political)

Question 1

Physical reasons:

Answer 1

• deposits of fossil fuels are only found in a limited number of locations
• large scale hydroelectric development requires high precipitation/steep-sided valleys etc
• large power stations require flat land and geologically stable foundations
• solar power needs a large number of days a year with strong sunlight
• wind power needs high average wind speeds throughout the year
• tidal power stations require a very large tidal range
• the availability of biomass varies widely due to climatic conditions

Question 2

Economic reasons:

Answer 2

• the most accessible and lowest cost deposits of fossil fuels are developed first
• onshore deposits of oil and gas are usually cheaper to develop than offshore
• potential hydroelectric sites close to major transport routes and existing electricity transmission corridors are more economical to build than those in very inaccessible locations
• in poor countries foreign investments is often essential for the development of energy resources
• when energy prices rise significantly, companies increase spending on exploration and development

Question 3

political

Answer 3

• countries wanting to develop nuclear require permission from the International Atomic Energy Agency
• international agreementas e.g Kyoto Protocol, can have a considerable influence on the energy decisions of individual countries
• potential HEP schemes on international rivers may require an agreement of other countries to share that river
• governments may insist on energy companies producing a certain proportion of their energy from renewable sources
• legislation regarding emissions from power stations will favour the use of sources with less pollution