Energy storage and conservation Flashcards
What are 2 benefits of energy storage?
- enabled storage intermittent supplies i.e solar.
- energy production rates can be kept constant for the most economic use
What are the causes of fluctuations in energy supply?
- use of intermittent energy resources
- the cost of exploitation
- technology available
what are the causes of fluctuations in energy demand?
- Weather-related fluctuations.
- Seasonal fluctuations.
- Weekday/weekend fluctuations.
- 24 hr work fluctuations.
- Short-term fluctuations: mealtimes/TV ‘pickup’.
what is peak shaving using pumped- storage HEP?
- Surplus electricity is used to pump water uphill which stores the energy as gravitational potential
- meet sudden increases in demand
- very responsive
What is a rechargeable battery?
- enable original chemicals to be reformed using electricity so that the batteries can be reused
What is an example of a rechargeable battery?
- lead acid battery
What are 3 factors affecting rechargeable battery viability?
- recharging speed
- the number of charge discharge cycles that can be carried out
- safety issue: toxicity, fire and risk
what are fuel cells?
- a device where electrochemical process which combines oxygen and hydrogen to produce water
- therefore energy
What is compressed air?
- surplus energy can be used to drive a pump that compresses air
- released later to power machinery
What is the advantage of compressing air producing heat?
- this heat energy can be stored like in a molten salt thermal storage
What is thermal storage?
- include the use of molten salt or high volume hot water sources
what is vehicle to grid systems?
- these are systems where energy can be transferred between the national grid and vehicle batteries
- used when vehicles are plugged into the grid
What is the benefit of vehicle to grid systems?
- when there is a peak in demand for electricity, a small proportion of energy from vehicle batteries may be used
- surplus energy from the grid can also be used to recharge vehicle batteries
why is vehicle to grid systems beneficial?
- avoids the cost and environmental impacts of using rapid response high cost power stations
What is hydrogen economy?
-transportation and storage of energy in the form of liquid or gaseous hydrogen.
What are three methods used to store hydrogen?
- ammonia
- liquid ( under high pressure at very low temperatures
What is the benefit of using hydrogen?
- high energy density and therefore replace fossil fuels.
- fun fact is that hydrogen has a lot higher energy density to lithium batteries
What is the problem with hydrogen as an energy source?
- energy intensive - industrial
Why is important to improve the efficiency of energy use?
- Improvements in the efficiency of energy
use enable the same activities to be
carried out with less energy.
How can vehicle design improve energy conservation?
Aerodynamics/hydrodynamics.
* Reduce mass of vehicle
* Tyre/wheel design.
* Kinetic Energy Recovery System (KERS)/
regenerative braking.
* Use of low embodied energy materials.
- bulk transport
How does aerodynamics improve energy conservation?
- reduces friction as vehicle moves through the air.
- materials like carbon fibre
How does reducing mass improve energy conservation?
- reduces the weight of the car therefore will reduce fuel consumption
- using composite materials like carbon fibre and aluminium.
How is wheel design contributing to energy conservation?
- having solid wheels like on trains and trams are much more energy efficient
- because heat is not created by the change in shape of the tire when vehicle moves
How does KERS contribute to energy conservation?
- Regenerative braking systems convert the kinetic energy to an energy form that can be used/ stored.
- Not lost as heat like in conventional breaking where KE is converted to heat.
How can a vehicle lower its embodied energy?
- Electric car batteries can also be recycled.
- car recycled at the end of its lifetime, then its embodied emissions will be reduced as materials are shared across multiple vehicles.
How can transport infrastructure and management
systems be more energy efficient?
- Integrated transport systems road/rail/cycle i.e park and ride
- Active Traffic Management (ATM)/’Smart
motorways’
How do smart motorways help energy efficiency?
- variable speed limits can be used to prevent the serious congestion that causes delays and wastes energy
How can a car at the end of its life be useful in terms of energy conservation?
- Use of recyclable materials.
- Easier component identification.
- Easy dismantling/material separation.
How can building design conserve energy?
- Orientation/features for passive solar gains.
- Low surface area: volume ratio.
- High thermal mass materials.
What is the importance of orientation in building design?
- rooms that need to be warmer can be placed to the side of the building that gains the greatest sunlight
What is the importance of thermal mass materials in building design?
- using materials with high thermal mass can help reduce temperature extremes
- absorb heat to reduce over heating and opposite
What are two examples of thermal mass materials?
- concrete and water
What are 3 materials that are lower embodies energy materials that can be used for construction?
- lime mortar - alternative to concrete mortar
- rammed earth - alternative to concrete block walls
- limecrete is an alternative to concrete
How can earth sheltered buildings help energy conservation?
- sinking some of the building underground can reduce heat losses
What other ways can a building have high energy conservation in terms of materials and insulation?
- Double/triple glazing.
- Low emissivity glass.
- Vacuum/inert gas double/triple glazing.
- Wall/floor/roof insulation.
What are 4 examples of energy management technologies?
- Occupancy sensors.
- Improved insulation.
- Automatic/solar ventilation.
- Heat exchangers.
What is an occupancy sensor?
- detect sources of infrared energy and movement
- turn appliances off if they cannot detect occupants in the room
What materials help with insulation?
- recycled wool
- straw
What is automatic insulation?
- solar screens
- self opening windows
All helpful where there are large glazed areas with increased solar gains
What are heat exchangers?
- a device which transfers heat from one medium to another
- the counter currant flow of stale and fresh air in heat exchanger ensures efficient heat transfer
What are two examples of low energy appliances?
- Lighting: LED.
- ‘Low-energy’ white goods i.e dish washer , washing machine
How can a dishwasher and washing machine be more energy efficient.
- washing machines can have cold and low temp wash cycles which use less energy to heat water
- newer dishwashers use less water which reduces requirement for heating
4 ways industry can manage heat?
- Bulk storage of hot fluids.
- Use of heat exchangers.
- Combined Heat and Power (CHP) systems.
How can heat exchangers be used in industry?
- pass hot and cold liquids through a container
What is a CHP system?
- recover much of the heat lost in electricity generation and uses it for space heating
How can a high voltage grid help reduce energy loss?
- a high voltage means the current can be reduced to minimise energy loss
What is peak shaving/ pumped storage HEP?
- involves the storage of surplus energy so that it can be used later
explain how IT management of electricity supplies helps reduce energy loss?
- accurately predicts demand for electricity
- monitors and adjusts electricity supplies quickly
- this reduces waste of energy caused by electricity for which there is no demand.
what is the problem of new generation of energy capacity?
- will require to be in new locations for example offshore wind farms
- this will require the construction of new grid infrastructure
What is the equation for percentage change?
Final value - initial value/ final value
