Macrogeneration

What Macrogeneration covers

Macrogeneration is examined in Unit AS 1, The Earth's Capacity to Support Human Activity, a written examination. It covers conservation of energy and the simple generator, thermal power stations and steam turbines, direct and indirect renewable electricity, electricity transmission through the National Grid, smart grids and interconnectors and combined heat and power.

The 6 subtopics

Each one has its own page. CCEA AS Environmental Technology students sit this topic in the first year.

• Conservation of energy and the simple generatorThe conservation of energy and wasted energy, efficiency and kilowatt-hour calculations, Sankey diagrams, electromagnetic induction, the parts of an alternating current generator and how a simple wind generator works.Open →
• Thermal power stations and steam turbinesThe boiler, steam turbine, generator and condenser, cooling water and pulverised coal, energy changes and efficiency calculations, why heat cannot all become electricity, combined cycle gas turbines and Northern Ireland's stations.Open →
• Direct and indirect renewable electricityDirect and indirect generation, the energy changes in wind, solar, hydroelectric, tidal, wave and biomass power, hydroelectric power and capacity factor calculations, and which sources depend on the Sun.Open →
• Electricity transmission through the National GridThe grid from power station to home, high-voltage transmission and worked power-loss calculations, step-up transformers, alternating current, Northern Ireland's network and operators, the Single Electricity Market and baseload and peak.Open →
• Smart grids and interconnectorsSmart grids, smart meters and demand-side response, wind curtailment, the Moyle and other interconnectors, the North–South Interconnector, high-voltage direct current, and the environmental and economic case for interconnection.Open →
• Combined heat and powerHow CHP recovers waste heat, efficiency calculations against separate generation, district heating, suitable sites and fuels, heat-led operation, carbon savings, limitations and trigeneration.Open →

What you need to know

Answer each one before you reveal it.

Take Macrogeneration further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Transmission vs Distribution

  Transmission: carrying bulk power at very high voltage over long distances. Distribution: delivering power at lower voltages to local homes and businesses.

• Step-up transformer vs Step-down transformer

  Step-up transformer: a device that raises voltage before long-distance transfer. Step-down transformer: a device that lowers voltage for safe local supply.

• Baseload vs Peak demand

  Baseload: the minimum level of electricity use that persists around the clock. Peak demand: the highest level of electricity use, typically on winter evenings.

Questions from this topic

Each one with the model answer underneath.

1. 1

   State the Law of Conservation of Energy.

   Model answer

   Energy cannot be created or destroyed, only transferred or converted from one form to another. The total energy of a closed system stays constant.

2. 2

   If energy is always conserved, why is some energy described as wasted?

   Model answer

   Wasted energy is not destroyed but spread into the surroundings, mostly as low-temperature heat. Energy in that dissipated form can no longer do useful work.

3. 3

   How is the efficiency of an energy conversion calculated?

   Model answer

   Efficiency equals useful energy output divided by total energy input, multiplied by 100 for a percentage. The same ratio can be calculated with power instead of energy.

4. 4

   An electric motor takes in 500 J and delivers 400 J of useful kinetic energy. Calculate its efficiency and the energy wasted.

   Model answer

   The motor is 80% efficient and wastes 100 J. The working is 400 ÷ 500 × 100 = 80%, and 500 − 400 = 100 J, lost as heat and sound.

5. 5

   Why can no machine have an efficiency above 100%?

   Model answer

   An efficiency above 100% would mean the machine delivers more energy than it receives. The machine would then be creating energy, which the Law of Conservation of Energy forbids.

6. 6

   How many joules are there in one kilowatt-hour?

   Model answer

   One kilowatt-hour equals 3.6 MJ. A power of 1,000 W for 3,600 s gives 3,600,000 J.

What is inside Levo

Six ways to work the same material.

Macrogeneration revision questions

Is Macrogeneration 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 Macrogeneration cover in CCEA AS-Level Environmental Technology?

6 subtopics: conservation of energy and the simple generator, thermal power stations and steam turbines, direct and indirect renewable electricity, electricity transmission through the national grid, smart grids and interconnectors and combined heat and power. Each one has its own page with questions and model answers.

How is Macrogeneration organised?

By the CCEA 3930 specification, subtopic by subtopic, so it matches the order you are taught it in.