Energy Storage & Conservation (DP IB Environmental Systems & Societies (ESS))

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

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