Energy Generation & Storage

Renewable and non-renewable energy sources

There are two types of energy sources — renewable and non-renewable.

• Renewable energy sources include wind, solar, tidal, geothermal, biomass and hydro-electric.
• Non-renewable energy sources include coal, oil, gas and nuclear.

Renewable energy sources are often referred to as ‘clean’ or ‘green’ energy sources, because they come from a natural supply that is continuously replaced.

Non-renewable energy sources are often called ‘dirty’ and ‘fossil fuels’. Coal, oil and gas are available in different parts of the world, but in limited amounts. Non-renewable energy sources often need to be extracted from the earth and sometimes processed, which can give off pollution and be very damaging. We currently depend highly on non-renewable energy sources, so a shift to ‘greener’ sources is underway and developing more and more.

Advantages and disadvantages of renewable energy

Wind power

• Advantages: Relatively little impact on the environment; reliable when there is wind
• Disadvantages: Some people consider turbines to be unsightly (‘visual pollution’); expensive to install; can affect wildlife, particularly birds

Solar energy

• Advantages: Clean, free energy source once set up; some electricity generated even on cloudy days
• Disadvantages: Expensive to set up; very dependent on sunny weather conditions; home solar panels can be space-consuming; storing solar energy can be difficult and expensive

Tidal energy

• Advantages: Around 80% efficient — better than solar or wind-based systems; generates power for around 10 hours per day
• Disadvantages: Expensive to set up; can damage ecological coastlines and harm marine life

Geothermal energy

• Advantages: Uses ‘hot spots’ where molten rock close to the earth’s crust generates hot water; allows broader access to energy through drilling
• Disadvantages: Very high-cost resource; risks triggering earthquakes; limited to specific locations

Wave energy

• Advantages: renewable; waves are fairly predictable; no fuel costs.
• Disadvantages: expensive to build; equipment can be damaged by storms; can affect marine life and shipping; only suitable for some coastlines.

Hydroelectric energy

Water stored behind a dam flows through turbines to generate electricity.

• Advantages: reliable; can start quickly when demand rises; pumped storage schemes can store energy by pumping water back uphill.
• Disadvantages: very expensive to build; flooding valleys destroys habitats and homes; limited suitable locations.

Wood and biomass

Organic material (wood, crops, food and animal waste) is burned or turned into biofuel.

• Advantages: renewable if new trees and crops are planted; uses waste products.
• Disadvantages: burning releases CO₂ and smoke; needs large areas of land; can lead to deforestation if not managed.

Nuclear energy (non-renewable)

• Advantages: large, reliable output; no CO₂ produced while generating.
• Disadvantages: radioactive waste must be stored safely for thousands of years; risk of serious accidents; very expensive to build and decommission.

Issues with fossil fuels

Burning coal, oil and gas releases CO₂ (contributing to global warming) and other pollutants such as sulphur dioxide (acid rain). They are finite and will run out, and extracting them damages landscapes.

Manufacturing using renewable energy

Industrial and commercial manufacturing plants and factories around the world are implementing alternative methods of power generation from renewable energy sources, in order to increase production and reduce their energy usage.

Currently, about 66% of the energy used by the industry and manufacturing sector is fossil fuels, with a small percentage of renewable energy and biofuels.

Government targets

The UK government has made a commitment for the UK to be net zero emissions by 2050.

This includes:

• Increasing clean wind energy
• Slashing carbon emissions
• Increasing offshore wind capacity

Fossil fuel powered road vehicles

From 2030, the sale of new petrol- and diesel-powered cars will be banned in the UK. Some new hybrid vehicles that use both electricity and petrol or diesel can still be sold until 2035.

In addition to some cities having congestion charges to help reduce congestion and pollution:

• Electric vehicles and hybrids are becoming a more popular choice for motorists
• There is often reduced or no road tax, as these vehicles are very clean and some produce zero emissions
• Lots of car manufacturers are now producing fully electric cars, however battery technology and charging facilities remain problematic

Renewable energy for products

• Photovoltaic (PV) cells can be used as power supplies and ‘trickle chargers’, converting free sunlight into electricity — used in calculators, garden lights, and solar-powered chargers.
• Wind-up technology uses mechanical movement to generate and store energy without the need for batteries. A wind-up torch uses the energy from turning the handle to power the device.

Energy storage in household products

• Disposable batteries (e.g. alkaline) — cheap and convenient, but create waste and contain harmful chemicals.
• Rechargeable batteries (e.g. lithium-ion, NiMH) — cost more at first but can be reused hundreds of times; used in phones, laptops, power tools and electric cars.
• Mains electricity — constant supply for products that are not portable.
• Solar / PV — free energy from sunlight, often used to recharge a built-in battery.