Energy Generation & Storage
Energy Generation & Storage
Every product that uses power needs an energy source. As a designer, you must understand how energy is generated and stored so you can select the right power system for your product. This lesson covers fossil fuels, nuclear power, renewable energy and energy storage systems.
Fossil Fuels
Fossil fuels — coal, oil and natural gas — are burned in power stations to heat water, producing steam that turns turbines connected to generators. They currently supply a large share of the UK’s electricity. Coal produces the most carbon dioxide per unit of energy, while natural gas is the cleanest of the three.
Arguments for fossil fuels: reliable, high energy output, existing infrastructure. Arguments against: finite resources that will run out, release greenhouse gases causing climate change, extraction damages habitats.
Nuclear Power
Nuclear power generates electricity through nuclear fission — splitting atoms of uranium to release heat, which produces steam to drive turbines. A small amount of fuel generates a huge amount of energy, and nuclear power stations produce no carbon dioxide during operation.
However, nuclear power produces radioactive waste that remains dangerous for thousands of years and must be stored securely. Building and decommissioning nuclear power stations is extremely expensive, and accidents (though rare) can have catastrophic consequences.
Renewable Energy
Renewable energy comes from sources that will not run out. The main types are:
Wind power uses turbines to convert kinetic energy from the wind into electricity. Wind farms can be onshore or offshore. They produce no emissions during operation but depend on weather conditions and can affect wildlife.
Solar power uses photovoltaic cells to convert sunlight into electricity, or solar thermal panels to heat water. Solar panels are silent and low-maintenance but only generate power during daylight and are less effective in cloudy climates.
Tidal power harnesses the movement of tides using barrages or underwater turbines. Tides are predictable, making this a reliable source, but installation costs are high and it can affect marine ecosystems.
Hydroelectric power uses flowing or falling water (usually from a dam) to turn turbines. It is highly reliable and can respond quickly to demand, but large dams flood valleys and displace communities.
Biomass generates energy by burning organic materials such as wood, crops or waste. It is considered carbon neutral because the plants absorbed CO₂ while growing, but it still produces air pollution and requires large areas of land for fuel crops.
The five main renewable energy sources are wind, solar, tidal, hydroelectric and biomass. All produce little or no greenhouse gas emissions during operation, but each has limitations related to cost, reliability or environmental impact.
Energy Storage Systems
Energy must often be stored for later use. Kinetic pumped storage systems pump water uphill to a reservoir when electricity demand is low (often at night). When demand rises, the water is released downhill through turbines to generate electricity almost instantly. Dinorwig in Wales is a well-known example.
Alkaline batteries are single-use batteries found in everyday products like torches and remote controls. Rechargeable batteries (such as lithium-ion) can be charged and discharged hundreds of times, making them essential for portable electronics, electric vehicles and power tools.
When selecting an energy source for a product, designers consider: the power requirement (how much energy is needed), portability (does the product move?), environmental impact, cost, availability and reliability. A portable speaker needs a rechargeable battery; a factory needs mains electricity from the grid. The choice of energy source is always a compromise between these factors.