Key term
CCEA AS-Level Environmental Technology 3930
Fossil Fuels
Global Action on Energy Conservation and Climate Change
Macrogeneration
Microgeneration
Energy From Wind
Topic overviewHorizontal and vertical axis wind turbinesKinetic energy, wind power and the Betz limitPower curves, rated output and energy lossesSwept area, blade length and turbine massAir density, hub height and turbine sitingPower control, yawing and survival speedChoosing a location for a commercial wind farm
Energy From the Sun
Topic overviewSolar radiation, tracking and concentrating solar powerFlat plate and evacuated tube collectorsSizing a domestic solar thermal systemPhotovoltaic cells and semiconductor wafersTypes of photovoltaic module comparedPlanning regulations and solar incentivesPassive solar design in new and existing buildings
Energy From Biomass
Energy Storage
Plastics for the Future
Topic overviewCrude oil as a fuel and a feedstockRefinery gases and the making of polymersPersistent plastic waste and the Great Pacific Garbage PatchToxic gases from incinerating plasticsBiodegradable, photodegradable and compostable plasticsTesting photodegradable plastic against polytheneBio-derived polyethylene and a sustainable plastics future
Renewable Energy Investigations
Energy Storage
- 4 subtopics
- 12 things to know
- AS 1
What Energy Storage covers
Energy Storage is examined in Unit AS 1, The Earth's Capacity to Support Human Activity, a written examination. It covers intermittency and reliability of renewable supply, why renewable energy needs storing, pumped hydro and compressed air energy storage and where energy storage is most beneficial.
Where it is assessed
AS 1
The Earth's Capacity to Support Human Activity — a written examination.
Check the CCEA specification ↗The 4 subtopics
Each one has its own page. CCEA AS Environmental Technology students sit this topic in the first year.
- Intermittency and reliability of renewable supplyIntermittency against reliability, wind forecasting, solar output through the year, wave and tidal patterns, the spring–neap cycle, backup generation, combining sources and wind curtailment in Northern Ireland.Open →
- Why renewable energy needs storingTime-shifting, reducing curtailment and fossil backup, grid stability, large-scale storage technologies, power rating and energy capacity, round-trip efficiency, and run time, energy returned and storage profit calculations.Open →
- Pumped hydro and compressed air energy storageHow pumped hydro works, a stored energy calculation, reversible pump-turbines and round-trip efficiency, Turlough Hill, compressed air storage, diabatic and adiabatic designs, caverns, Huntorf and McIntosh, and the Larne proposal.Open →
- Where energy storage is most beneficialThe sites pumped hydro and compressed air need, storage near wind farms and congested grids, islands and the island of Ireland, batteries at substations, cost-effectiveness, and where Northern Ireland might locate new storage.Open →
What you need to know
Answer each one before you reveal it.
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Key term
Discuss where Northern Ireland might best locate new large-scale energy storage.
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What is meant by the intermittency of a renewable energy source?
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Relate the intermittency of renewable sources to the need for large-scale energy storage.
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What is meant by the reliability of a renewable energy source?
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What is time-shifting in energy storage?
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Outline how pumped hydro storage works.
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What physical features does a site need for pumped hydro storage?
Key term
Distinguish between intermittency and reliability using tidal power as an example.
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How does energy storage reduce curtailment of wind farms?
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In what form does pumped hydro storage hold energy?
Key term
Why are steep upland areas favoured for pumped hydro?
Take Energy Storage further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Intermittency vs Reliability
Intermittency: output that stops and starts with natural conditions. Reliability: confidence that output will be available when it is needed.
Pumped hydro storage vs Compressed air energy storage
Pumped hydro storage: lifting water to an upper reservoir to release later through turbines. Compressed air energy storage: forcing pressurised gas into underground caverns to drive a turbine later.
Diabatic CAES vs Adiabatic CAES
Diabatic CAES: a scheme that discards compression heat and burns natural gas to reheat the released flow. Adiabatic CAES: a scheme that keeps compression heat in a thermal store and reuses it.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by the intermittency of a renewable energy source?
Model answer
Intermittency means the source does not produce energy continuously, but stops and starts with natural conditions. Solar output stops every night, and wind output drops in calm spells.
- 2
What is meant by the reliability of a renewable energy source?
Model answer
Reliability is how far output can be depended on to be available when it is needed. A reliable source is predictable and can be planned around.
- 3
Distinguish between intermittency and reliability using tidal power as an example.
Model answer
Tidal power is intermittent, because output falls to zero at slack water several times a day. Tidal power is also highly reliable, because the timing of tides can be predicted years ahead.
- 4
Why is wind power both intermittent and unreliable?
Model answer
Wind speed changes from minute to minute and with passing weather systems. Output stops in calm spells and when turbines shut down in storms.
- 5
How far ahead can wind power output be forecast?
Model answer
Weather forecasts allow wind output to be predicted fairly well a day or two ahead. Longer-range forecasts are much less accurate, so reserves must be kept available.
- 6
Why is solar power poorly matched to UK electricity demand through the year?
Model answer
Solar output is highest in summer, but UK electricity demand peaks on dark winter evenings. Solar panels produce nothing at the time of the daily winter peak.
What is inside Levo
Six ways to work the same material.
Energy Storage revision questions
- Is Energy Storage examined at AS in CCEA Environmental Technology?
- Yes. It sits in AS 1, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.
- What does Energy Storage cover in CCEA AS-Level Environmental Technology?
- 4 subtopics: intermittency and reliability of renewable supply, why renewable energy needs storing, pumped hydro and compressed air energy storage and where energy storage is most beneficial. Each one has its own page with questions and model answers.
- How is Energy Storage organised?
- By the CCEA 3930 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Energy Storage, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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