Welcome to Energy Generation and Storage!

Hello future Product Designers! This chapter is incredibly important because every product, from your smartphone to a washing machine, needs power to function. As designers, we need to know where that power comes from and how we can store it efficiently and sustainably.
Don't worry if terms like 'photovoltaic' sound scary—we'll break down every concept into simple, understandable pieces! Let's get started on powering up your knowledge!

Quick Review: Energy and Products

Energy is the ability to do work. In product design, we focus on electrical energy because it is clean, easy to transmit, and powers modern electronics.
We need to consider two main things:
1. How we generate electricity (the source).
2. How we store electricity (batteries and capacitors).

1. Sources of Energy: Renewable vs. Non-Renewable

When we talk about energy generation, we separate the sources into two big groups. The choices designers make here have huge impacts on the environment.

1.1 Non-Renewable Sources

These sources cannot be easily replaced once they are used up. They are finite (limited) and often release harmful gases when used, contributing to climate change.

  • What they are: Sources that took millions of years to form and are being depleted much faster than nature can replace them.
  • Examples: Fossil Fuels (Coal, Oil, Natural Gas) and Nuclear Power (uses Uranium).
  • Designer's View: While reliable and powerful, using products that rely heavily on non-renewable sources is increasingly discouraged due to environmental responsibility.

Analogy: Think of Non-renewable energy as the petrol in your car's tank. Once you use that tank up, it's gone, and you must refill it from a finite supply.

1.2 Renewable Sources

These sources are naturally replenished, meaning they won't run out. They are considered much more sustainable and usually have a lower environmental impact.

  • What they are: Energy derived from natural processes that are continuously occurring.
  • Examples: Solar, Wind, Hydroelectric (Water), Geothermal, and Tidal power.
  • Designer's View: Product designers actively look for ways to integrate renewable sources into their products (e.g., solar charging pads, wind-up torches).

Analogy: Think of Renewable energy as the sun shining every day or the wind blowing. It keeps coming back!

Key Takeaway:

Sustainable design prioritises Renewable energy sources to minimise environmental damage and ensure long-term availability.

2. Generating Power in Product Design

For product designers, we aren't usually building massive power stations, but we integrate small-scale renewable systems directly into our products.

2.1 Solar Power (Photovoltaics - PV)

Solar cells convert light directly into electricity.

  • How it works: Light hits the photovoltaic (PV) cells, which causes electrons to move, creating an electric current.
  • In Products: Used in small devices where power requirements are low or intermittent (e.g., solar-powered garden lights, calculators, portable phone chargers).
  • Advantage: Clean, silent, and works anywhere there is sunlight (even cloudy days, though less effectively).
  • Disadvantage: Only works during the day, requires backup storage (like a battery), and can be bulky.

2.2 Wind Power (Small-Scale)

We often use small turbines in remote areas or attached to specific products.

  • How it works: Wind turns the blades, which spin a generator, producing electricity.
  • In Products: Used for small-scale power generation, such as lighting for campsites or weather monitoring equipment.
  • Advantage: Clean, powerful source when the wind is blowing.
  • Disadvantage: Requires wind (unreliable), can be noisy, and needs physical space.

2.3 Human Power (Kinetics)

This is energy generated by the user's movement.

  • How it works: Movement (e.g., cranking, shaking, or pressing) drives a small generator.
  • In Products: Wind-up radios, crank flashlights, or generators built into exercise equipment.
  • Advantage: Power is available anywhere, anytime, without external sources.
  • Disadvantage: Limited power output; requires effort from the user.

Quick Tip: Look around your home. Which products use solar cells? Which ones require you to physically turn a switch or crank them?

3. Energy Storage: Batteries and Capacitors

Since the sun doesn't always shine and the wind doesn't always blow, products need a way to save energy for later use. This is where storage devices come in.

3.1 Batteries (The Power Reservoir)

Batteries store energy chemically. When you connect them, the chemicals react to release electrical energy.

3.1.1 Primary Cells (Non-Rechargeable)

These batteries are designed for a single use. Once the chemical reaction is complete, they are thrown away (and should ideally be recycled!).

  • Examples: Standard AA, AAA, and D size alkaline batteries.
  • Use: Low-drain devices or devices used infrequently (e.g., TV remote controls, smoke detectors).
3.1.2 Secondary Cells (Rechargeable)

These cells use reversible chemical reactions, allowing them to be recharged many times.

  • Examples: Lithium-Ion (Li-ion) cells (used in phones and laptops) and Nickel-Metal Hydride (NiMH) cells.
  • Key Consideration: Cycle life—how many times a battery can be successfully charged and discharged before its capacity drops significantly.
  • Designer Focus: Li-ion batteries offer excellent energy density (a lot of power in a small size), making them ideal for modern portable products.

Common Mistake to Avoid: Never try to recharge a primary (single-use) battery. They can leak, overheat, or even explode!

3.2 Capacitors (The Quick-Fire Storage)

A capacitor is like a very small, temporary battery that stores energy electrostatically rather than chemically.

  • How they work: They consist of two metal plates separated by an insulator. They store energy by collecting electrical charge on these plates.
  • Speed is Key: Capacitors charge and discharge extremely quickly.
  • Use in Products:
    • To provide a large, quick burst of power (e.g., camera flash units).
    • To smooth out power supply fluctuations.
    • As a temporary backup to keep memory running when the main power is briefly disconnected.
  • Limitation: They store far less total energy than a battery of the same size.

Analogy: A Battery is a large water reservoir that releases energy steadily over a long time. A Capacitor is like a quick-release balloon—it fills up fast and releases all its stored energy in a powerful burst.

Key Takeaway:

Designers choose between batteries (high capacity, slow release) and capacitors (low capacity, fast charge/discharge) based on the product’s function. Rechargeable batteries (secondary cells) are preferred for sustainability.

4. Energy Efficiency in Product Design

It doesn't matter how sustainable your energy source is if the product wastes most of the energy it receives. Efficiency is a crucial part of responsible design.

4.1 Reducing Energy Consumption

Designers must select components that use minimal power.

  • Lighting: Choosing LEDs (Light Emitting Diodes) over older incandescent bulbs is essential, as LEDs use far less electricity to produce the same amount of light.
  • Motion: Using efficient motors and ensuring moving parts have low friction.
  • Power Management: Programming products to enter a low-power sleep mode or shut down automatically after a period of inactivity.

4.2 Minimising Standby Power

Many products, like televisions or chargers, continue to draw small amounts of power even when 'off'—this is called phantom load or standby power.

  • Designer’s Responsibility: Designing internal circuits that drastically reduce the power drawn when the product is in standby mode, ideally close to zero.

4.3 Energy Rating Labels

In many countries, products like appliances (fridge, washing machine) must carry an energy efficiency rating (often A+++ down to D).

  • Importance: This helps consumers choose the most efficient model, encouraging manufacturers to design better products.

Did you know? If every household cut its standby power consumption by half, it would save enough electricity to power many small cities!

Key Takeaway:

Efficiency means getting the most 'work' out of the least amount of energy. Sustainable design focuses on both clean generation and minimal consumption.

Chapter Review: Core Concepts Checklist

You should now be able to confidently explain these concepts:

  • The difference between Renewable (Solar, Wind) and Non-renewable (Fossil Fuels) energy sources.
  • How Photovoltaic (PV) cells convert light into electricity for small products.
  • The difference between Primary (disposable) and Secondary (rechargeable) batteries.
  • The function of a Capacitor (fast charge/discharge) compared to a battery.
  • Why product designers must consider energy efficiency (e.g., using LEDs, reducing standby power).