Energy Sources & Sustainability (DP IB Environmental Systems & Societies (ESS))

Renewable & Non-renewable Energy Sources

• Energy sources are classified into renewable and non-renewable categories

  • This is based on their ability to regenerate within a human lifespan

What are renewable energy sources?

• Renewable energy comes from energy sources that will not run out and includes:

  • Wind energy

  • Solar energy

  • Tidal energy

  • Biomass (wood)

  • Geothermal energy

  • Hydropower

• Once in place, these renewable energy sources do not produce any greenhouse gas emissions (except for biomass)

  • It is important to note that greenhouse gases may be emitted in the production, construction and transport of the equipment required for renewable energy sources

• Advantages of all:

  • Reduces dependence on fossil fuels and foreign energy sources

    • This promotes energy independence and security

  • The renewables industry creates jobs in manufacturing, installation, operation and maintenance of renewable infrastructure

Wind energy

• Wind energy harnesses the kinetic energy of moving air to generate electricity

  • It involves the use of wind turbines

  • These have large blades that spin when the wind blows

  • The rotating blades transfer kinetic energy to a generator, which converts it into electrical energy

• Advantages:

  • Abundant energy source

  • No greenhouse gas emissions or air pollutants produced during operation

  • Land beneath turbines can often still be used for farming or other purposes

  • Can be installed offshore (in the sea) to minimise land use conflicts

  • Installation and running costs have decreased significantly, making it competitive with non-renewable energy sources

  • Can be small- or large-scale

• Disadvantages:

  • Intermittent (non-constant) energy source dependent on wind availability

  • Visual and noise pollution can affect local communities

  • Initial high capital investment for turbines and infrastructure

  • Potential impact on wildlife, particularly birds and bats flying into the turbine blades

  • Wind farms require large areas of land, which can have an impact on agricultural or natural landscapes

Solar energy

• Solar energy uses photovoltaic (PV) panels that transfer energy from sunlight to produce an electrical current, generating electrical power

• Advantages:

  • Abundant energy source

  • No greenhouse gas emissions or air pollutants produced during operation

  • Suitable for various scales of application (from house rooftops to very large solar farms)

  • Can be integrated into existing buildings and infrastructure

  • Solar is progressively becoming less expensive and more efficient

  • Solar energy can be generated in remote places where they don't have electricity (e.g. to power solar street signs in rural areas)

• Disadvantages:

  • Intermittent (non-constant) energy source dependent on sunlight availability

  • Initial high capital investment for solar panels and equipment

  • Requires significant land area for solar farm installations (which could otherwise be used for agriculture)

  • Energy storage solutions needed for night-time or cloudy days

  • Potential environmental impact during manufacturing and disposal of panels (electronic waste)

  • Some people dislike the appearance of large solar farms (visual pollution)

Tidal energy

• Tidal energy uses the energy of rising and falling tides to turn a turbine and generate electricity

• Advantages:

  • Abundant energy source

  • No greenhouse gas emissions or air pollutants produced during operation

  • Predictable and reliable source of energy due to regular tidal patterns

  • Can produce a large amount of electricity at short notice

  • Minimal visual impact when installed underwater

  • Long lifespan of tidal turbines with minimal maintenance

• Disadvantages:

  • High initial costs

  • Limited availability of suitable sites

  • Potential environmental impact on marine ecosystems and fish migration

  • Maintenance challenges and costs due to underwater installations

  • Possible interference with shipping lanes and navigation

Biomass (wood)

• Biomass energy uses organic materials such as wood to generate heat or electricity

• Advantages:

  • Renewable resources and carbon neutral if managed sustainably

  • Readily available in many regions, especially rural areas

• Disadvantages:

  • Carbon dioxide and air pollution from combustion emissions

  • Deforestation risk and habitat loss if not sustainably managed

  • Impact on indoor air quality if not properly ventilated

Geothermal energy

• Geothermal energy harnesses heat from within the Earth's crust for electricity generation or heating purposes.

  • The Earth's interior is extremely hot

  • Water can be poured into shafts below the Earth's surface

  • The water is heated and returned via another shaft as steam or hot water

  • Steam can be used to turn a turbine and generate electricity

  • The hot water can also be used to heat homes

• Advantages:

  • Sustainable energy source

  • Reliable and stable source of energy available at all times

  • Small land footprint compared to other renewable sources (e.g. wind and solar)

  • Geothermal power stations are usually small compared to nuclear or fossil fuel power stations

  • Long lifespan of geothermal plants with low operating costs

• Disadvantages:

  • Site-specific; limited to regions with near-surface geothermal activity

  • High initial drilling and exploration costs

  • Can result in the release of greenhouse gases from underground

  • Geological risks such as earthquakes or ground subsidence

Hydropower

• Hydropower uses flowing water to generate electricity through turbines in dams

• Advantages:

  • Reliable and predictable source of energy

  • Low greenhouse gas emissions during operation

  • Multi-purpose benefits, including flood control and irrigation

  • Long lifespan of hydroelectric plants with low operating costs

  • Can respond to demand quickly, generating large scale amounts of electricity in a short period of time

• Disadvantages:

  • Disruption of river ecosystems and fish migration routes

  • High initial capital costs for dam construction and infrastructure

  • Dam construction and reservoir formation floods habitats and can require relocation of human communities

  • Climate change impacts on water availability is affecting reservoir levels, making them less reliable

What are non-renewable energy sources?

• Non-renewable energy comes from energy sources that will eventually run out, including:

  • Fossil fuels

  • Nuclear energy (using uranium as a fuel)

Fossil fuels

• Fossil fuels include:

  • Coal

  • Crude oil, which is refined into petrol, diesel and other fuels

  • Natural gas (mostly methane), which is used in domestic boilers and cookers

• Fossil fuels are formed from the remains of plants and animals

  • Chemical energy stored in fossil fuels originally came from sunlight

  • Energy from the sun was transferred to chemical energy stores within plants through photosynthesis (plants use energy from sunlight to make food)

  • Animals ate the plants and the energy was then transferred to their chemical store

• Advantages

  • The current systems of transport and electricity generation used by human societies rely heavily on fossil fuels

    • These fossil fuels are generally readily available on a daily basis

  • In the past, fossil fuels have been reliable for large-scale energy production (although this is changing as supplies start to become depleted and prices rise)

  • Efficient—fossil fuels typically have a high energy density (they produce a large amount of energy per kilogram)

• Disadvantages

  • It takes millions of years for fossil fuels to form:

    • This is why they are considered a non-renewable energy resource

  • The increasing demand for decreasing supply causes prices to increase

    • Fossil fuels are predicted to completely run out within the next 200 years

  • Burning fossil fuels pollutes the atmosphere with harmful gases such as:

    • Carbon dioxide, which contributes to the greenhouse effect

    • Sulphur dioxide, which produces acid rain

    • Both carbon and sulphur can be captured upon burning, preventing them from being released into the atmosphere, but this is expensive to do

  • Oil spills can occur during transport of fossil fuels, which damage the marine environment and wildlife over very large areas

  • Prices fluctuate rapidly

  • Conflict and political disagreements (such as the war in Ukraine) can have an impact on supplies

Nuclear Energy

• Energy stored in the nucleus of atoms can be released when the nucleus is broken in two:

  • This is known as nuclear fission

• Nuclear power stations use fission reactions to create steam to turn turbines to generate electricity

• Nuclear power is a low-carbon, low-emission, non-renewable resource

  • However, it is controversial due to the radioactive waste it produces and the potential scale of any accident

• Advantages

  • No pollution released into atmosphere

  • Nuclear reactors are perfectly safe as long as they are functioning properly (rigorous safety checks must be routinely carried out and rigorous safety procedures followed)

  • Nuclear power stations can generate electricity reliably on a large scale to be available as needed

  • Small amounts of uranium are needed, and large reserves are available

  • Reduces reliance on fossil fuels

  • Increases energy security

• Disadvantages

  • There is a finite supply of uranium ore, so nuclear power is a non-renewable resource

  • Nuclear fuels produce radioactive waste, which needs to be stored for thousands of years

  • Safe ways of storing radioactive waste are very expensive

  • If an accident occurs at a nuclear reactor, radioactive waste can leak out and spread over large areas

  • The cost of decommissioning (shutting down) nuclear power plants is very high

Sustainability of Energy Sources

• Energy sustainability refers to meeting current energy demands without compromising the ability of future generations to meet their needs

• The sustainability of energy sources can vary greatly depending on:

  • Whether they are renewable or non-renewable

  • Their environmental impact

Environmental cost of non-renewable energy

Fossil fuels

• Extraction: mining for coal and drilling for oil and gas can destroy habitats and lead to soil erosion and water contamination

• Refining crude oil: this process releases harmful chemicals and contributes to air and water pollution

• Liquefaction of natural gas: turning gas into liquid for easier transportation emits carbon dioxide and other greenhouse gases

Nuclear energy

• Mining of uranium: extracting uranium for nuclear power plants is energy-intensive and leaves behind radioactive waste

• Nuclear waste: long-term storage of nuclear waste is difficult, as it remains hazardous for thousands of years

Environmental cost of renewable energy Sources

• Renewable energy comes from sources that can be naturally replenished, such as the sun, wind and water

• These sources tend to have a lower environmental impact

• However, they can still have significant (sometimes 'hidden') environmental costs, including:

  • Manufacturing: producing renewable energy devices requires energy and raw materials, leading to environmental damage

  • End-of-life management: recycling components from solar panels, wind turbines and batteries is often expensive and not always efficient, leading to waste and pollution

Examples of renewable energy devices

• Wind turbines

  • Challenges:

    • Wind turbines require rare earth elements for magnets and motors, such as neodymium

    • At the end of their life, turbine blades are difficult to recycle and often end up in landfills

• Solar panels

  • Challenges:

    • The production of solar panels requires mining for materials like silicon and rare earth elements

    • Solar panels have a limited lifespan (20-30 years) and need careful disposal to avoid chemical pollution

• Tidal barrages

  • Tidal barrages use the movement of tides to generate energy

  • Challenges:

    • Building tidal barrages can disrupt local ecosystems, affecting fish and marine life

    • Barrages are large and expensive to construct and maintain

Rare earth elements in renewable energy

• Renewable technologies, like electric vehicles (EVs) and wind turbines, rely on rare earth elements for efficient energy conversion

• However, these elements are difficult to mine and refine, leading to sustainability issues, including:

  • Energy-intensive extraction:

    • Extracting rare earth elements requires significant energy (e.g. for mining machinery), contributing to greenhouse gas emissions

  • Mining impacts:

    • Mining for rare earth elements can cause severe environmental damage, including:

      • Water contamination: mining processes release toxic chemicals into nearby water sources, affecting both surface water and groundwater

      • Habitat destruction: clearing land for mining operations and access routes can destroy local ecosystems, disrupt wildlife habitats and cause deforestation

      • Dust pollution: dust from cutting, drilling and blasting rocks accumulates in surrounding areas, leading to air pollution and increasing the risk of respiratory diseases for nearby communities