Syllabus Edition
First teaching 2024
First exams 2026
Energy Storage & Conservation (DP IB Environmental Systems & Societies (ESS))
Revision Note
Written by: Alistair Marjot
Reviewed by: Bridgette Barrett
Energy Storage
Energy storage is important for managing the supply of energy, especially from renewable sources
This is because many renewable sources do not produce a consistent flow of energy
By storing energy, countries can ensure a reliable supply even when renewable sources like wind or solar power are not generating electricity
The need for energy storage
Some renewable energy sources, such as wind and solar, produce energy intermittently
This means they only generate power when conditions are right:
Wind power: only produces electricity when the wind is blowing
Solar power: only generates electricity during the day when there is sunlight
Because of this, there can be times when energy supply does not meet demand
Energy storage systems help solve this problem by:
Storing excess energy when production is high
Releasing it when demand exceeds supply
Energy storage solutions
There are several ways to store energy to ensure supply can meet demand, including the following:
Batteries
Store electricity as chemical energy, which can be released when needed
Uses: common in electric vehicles and home solar systems
Example: Tesla Powerwall batteries store energy from solar panels and can supply power to homes during outages or high demand periods
Pumped hydroelectricity storage (PHS)
PHS stores energy by pumping water to a higher reservoir when there is surplus electricity
When electricity demand is high, the water is released back down to a lower reservoir, turning turbines to generate electricity
Uses: large-scale energy storage used by national grids
Example: Dinorwig Power Station in Wales is one of the largest PHS systems and is used to balance electricity supply in the UK
Advantages of PHS:
Large capacity: can store huge amounts of energy from excess electricity generated during periods of high renewable energy production (e.g. when the wind is blowing strongly or during peak solar energy generation)
Reliable: provides quick response to sudden demand increases (known as peak-shaving)
Long lifespan: PHS plants can operate for decades with low maintenance, contributing to their sustainability
Disadvantages of PHS:
Geographic limitations: requires specific landforms (mountains, valleys) and large reservoirs, limiting where it can be built
Environmental impact: constructing dams and reservoirs can damage ecosystems and disrupt local wildlife
Economic costs: can have very high initial costs to build
Awaiting image: Pumped hydroelectricity storage
Image caption: Pumped hydroelectricity storage
Fuel cells
Fuel cells convert stored chemical energy (often hydrogen) directly into electricity
Uses: used in transportation (e.g. hydrogen-powered vehicles) and backup power systems
Example: Japan is investing in hydrogen fuel cells for its energy transition, particularly for powering vehicles and buildings
Thermal storage
Stores heat energy, which can be used to generate electricity later or provide heating
Uses: often used with solar power plants, where excess solar energy is stored as heat and converted to electricity during low sunlight
Example: the Crescent Dunes Solar Energy Project in the US uses molten salt to store solar energy as heat, which is then used to generate electricity after sunset
Managing energy demand: peak-shaving
Energy storage systems can be used for peak-shaving
This is the process of levelling out periods of high demand to ensure supply meets demand
When there is a peak in electricity usage (like during cold winter evenings), stored energy can be released to meet the extra demand
This avoids blackouts or the need to turn on extra power plants
Energy Conservation & Efficiency
What is energy conservation?
Energy conservation means changing our behaviour to use less energy
It includes small daily actions such as:
Turning off lights when not in use
Reducing the use of heating or air conditioning by wearing appropriate clothing or using natural ventilation
Travelling less by fuel-driven vehicles and opting for walking, cycling or public transport instead
What is energy efficiency?
Energy efficiency means using technologies and designs that require less energy to perform the same task
This can include:
Installing low-energy LED lighting in homes and buildings
Using energy-efficient appliances (e.g. the latest washing machines and fridges with high energy-efficiency ratings)
Developing fuel-efficient transportation methods, such as electric vehicles (EVs)
Designing buildings to conserve heat through better insulation, reducing the need for heating and cooling
For example, the use of double-glazed windows in homes increases energy efficiency by keeping heat inside, reducing the need for heating systems
The importance of energy conservation and efficiency
Energy conservation and efficiency help reduce energy demand and waste
These strategies make countries less dependent on importing energy resources
This reduces costs and improve energy security
They also contribute to reducing carbon emissions
This helps combat climate change
Examples of energy conservation and efficiency
Smart lighting systems
Energy-efficient lighting like LED bulbs and motion sensors are designed to reduce electricity use
Motion sensors ensure that lights are only on when needed, reducing waste in public spaces and large buildings
Effectiveness:
LEDs use up to 80% less energy than traditional bulbs, making them a cost-effective solution for reducing electricity use
Passive solar building design
Passive solar design uses natural sunlight to heat buildings, reducing the need for artificial heating
Buildings are designed with large windows facing the sun and materials that store and release heat efficiently
Effectiveness:
Passive solar design is effective in regions with consistent sunlight, helping reduce energy bills and making homes more energy-efficient
Designing goods to be easily recycled
The circular economy aims to reduce waste by designing products that can be easily reused, repaired or recycled
By creating products with longer lifespans and using recyclable materials, less energy is needed for producing new items
Effectiveness:
Designing goods to be recycled reduces the energy needed for producing new materials, cutting down energy demand in industries
Commercial shipping with sails
One innovative way to improve energy efficiency in the shipping industry is by designing ships with sails (wind-assisted propulsion)
Modern ships can use large, automated sails, known as rotor sails or kite sails, to harness wind energy and reduce fuel consumption
This reduces greenhouse gas emissions
Effectiveness:
Ships using wind-assisted propulsion can reduce fuel consumption by 10-30%, depending on wind conditions
Examiner Tips and Tricks
Remember that energy conservation focuses on behaviour change, while energy efficiency focuses on technology and design improvements. Energy efficiency practices can be used and implemented to achieve energy conservation.
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