Solar Energy
Introduced| English | Meaning |
|---|---|
| Solar/ˈsəʊlə/ | Energy obtained from radiation emitted by the Sun. |
| Active/ˈæktɪv/ | Active |
| Passive/ˈpæsɪv/ | Passive |
| Photovoltaic/ˌfəʊtəʊvəʊlˈteɪɪk/ | Photovoltaic |
| intermittent/ˌɪntəˈmɪtənt/ | Occurring with interruptions or gaps rather than continuously. |
Power from the sun
- The sun pours more energy on Earth in an hour than we use in a year.
- Solar 太阳能 power captures some of that free energy.
- It makes no smoke and no CO2 while running.
- There are two main ways to use it: active and passive.
Active solar
- Active 主动式 solar uses equipment to collect and move energy.
- Photovoltaic 光伏 (PV) panels turn sunlight straight into electricity.
- Solar water heaters use pumps to move sun-warmed water.
- These systems have parts, wiring, and sometimes pumps.
A solar farm. The panels are tilted toward the sun and spread over a large area of land
Solar photovoltaic (PV) panels make…
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Photovoltaic cells turn sunlight straight into electricity, with no burning and no moving parts.
Passive solar
- Passive 被动式 solar uses smart design, with no equipment.
- South-facing windows let winter sun warm a room.
- Thick walls and floors store daytime heat and release it at night.
- Roof overhangs shade the windows in summer.
Active or passive solar?
Sort each example by whether it uses equipment (active) or just smart design (passive).
Passive solar design uses…
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Passive solar uses clever design — windows, thick walls, overhangs — to catch and hold heat with no devices.
While running, solar power produces no CO2 and no air ____.
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Solar power makes electricity with zero emissions while it runs — a major clean-energy advantage.
The catch
- Solar only works when the sun shines — it is intermittent 间歇性.
- Output drops at night and on cloudy days.
- Cloudy or high-latitude places get far less.
- To use solar at night, you need batteries to store it.
A drawback of solar power is that it makes no electricity at night.
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Solar depends on sunlight, so output drops at night and on cloudy days — it is intermittent.
Select all advantages of solar power.
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Solar is clean, renewable, and rooftop-ready — but it works far better in sunny places than cloudy or high-latitude ones.
Keep active and passive straight. Active = equipment (PV panels, pumps) that collects or converts solar energy, often into electricity. Passive = design (windows, thick walls, shade) that captures heat with no moving parts. If it has a panel, wire, or pump, it's active; if it's just the shape and materials of the building, it's passive.
One sunny house:
- On the roof, active PV panels feed electricity to the lights and fridge.
- Inside, big south-facing windows and a thick stone floor are passive — they soak up the sun's warmth all day and release it after dark, with no machine at all.
- Both cut the fuel bill; only one has moving parts.
Solar power captures the sun's energy with zero emissions while running. Active solar uses equipment — photovoltaic panels for electricity, pumps for hot water. Passive solar uses building design — windows, thick walls, overhangs — with no moving parts. Its main drawback is being intermittent: no power at night or under heavy cloud.