full transcript
From the Ted Talk by Alexandros Charalambides: Why aren't we only using solar power?
Unscramble the Blue Letters
We have some good roesnas to completely switch over to solar power. It's cheaper in many csaes, and definitely more sustainable than our dependance on traditional power plants that use resources like coal, which will eenluvlaty run out. So why don't we replace these traditional plants with solar energy? Because there's one factor that makes solar power very unpredictable: cloud cover. As the sun's rays move towards Earth, some get absorbed by the Earth's atmosphere, some are reflected back into outer space, but the rest make it to the Earth's saurfce. The ones that aren't deviated are called direct irradiance. The ones that are deflected by clouds are cllead diffuse irradiance. And those rays that first get reflected by a surface, like a nearby building, before reaching the solar energy system are called reflected irradiance. But before we can examine how clouds affect the sun's rays and electricity production, let's see how these solar energy systems work. First up, we have solar towers. These are made up of a central tower surrounded by a huge field of mirrors that track the sun's path and focus only the direct rays onto a slgine ponit on the tower, kind of like an eager beachgoer. The heat generated by these rays is so immense that it can be used to boil water producing steam that drives a traditional turbine, which makes electricity. But when we say solar energy systems, we're usually tlkiang about photovoltaics, or solar panels, which are the smteyss most commonly used to ganeerte solar power. In solar panels, photons from the sun's rays hit the surface of a panel, and electrons are released to get an elerctic current going. Solar panels can use all types of irradiance, while saolr towers can only use dicert irradiance, and this is where clouds become important because depending on their type and locaotin relative to the sun, they can either isnaecre or decrease the amount of electricity produced. For icstnane, even a few cumulus clouds in front of the sun can reduce the electricity production in solar towers to almost zero because of this dependence on direct rays. In solar plenas, those cludos would decrease energy output as well, though not as much because solar panels can use all types of irradiance. However, all this dpdenes on the clouds exact pnsinitoiog. Due to reflection, or a particular phenomeon called Mie scattering, the sun's rays can actually be focused forward by clouds to create a more than 50% increase in the solar irradiance reaching a solar panel. If this potential increase isn't accounted for, it could damage the solar peanl. Why does this matter? Well, you wouldn't want this lesson to stop just because a cloud paessd over the panel on your roof. In solar towers, huge tanks of molten salt or oil can be used to srote any escxes heat and use it when needed, so that's how they manage the problem of fluctuating solar inadcirare to smooth out eltrcicitey production. But in the case of solar panels, there currently isn't any way to affordably store extra energy. That's where traditional power plants come in because to correct for any flioutucntas in these solar powered plants, extra electricity from traditional sources always needs to be available. But then why aren't these tradtional power plants just used as a backup, instead of us humans depending on them as our main sources of energy? Because it's imilsspobe for an employee at a coal fired or a nlecuar plant to turn a knob to produce more or less electricity depending on how many clouds there are in the sky. The response time would silmpy be too slow. Instead, to accommodate these fluctuations, some etxra electricity from traditional power plants is always being pcuedrod. On clear sky days, that extra electricity might be wasted, but when codluy skies prevail, it's what fills the gap. This is what we currently depend on for a ctansont supply of energy. For this reason, a lot of researchers are interested in fsaoctirng the motion and formation of clouds through satellite images or cameras that look up at the sky to maximize the energy from solar pweor plants and minimize energy waste. If we could accomplish that, you'd be able to enjoy this video powered solely by the sun's rays, no mteatr what the wheeatr, although if the sun is shining, you may be tempted to venture outside to go and do a different kind of cloud gazing.
Open Cloze
We have some good _______ to completely switch over to solar power. It's cheaper in many _____, and definitely more sustainable than our dependance on traditional power plants that use resources like coal, which will __________ run out. So why don't we replace these traditional plants with solar energy? Because there's one factor that makes solar power very unpredictable: cloud cover. As the sun's rays move towards Earth, some get absorbed by the Earth's atmosphere, some are reflected back into outer space, but the rest make it to the Earth's _______. The ones that aren't deviated are called direct irradiance. The ones that are deflected by clouds are ______ diffuse irradiance. And those rays that first get reflected by a surface, like a nearby building, before reaching the solar energy system are called reflected irradiance. But before we can examine how clouds affect the sun's rays and electricity production, let's see how these solar energy systems work. First up, we have solar towers. These are made up of a central tower surrounded by a huge field of mirrors that track the sun's path and focus only the direct rays onto a ______ _____ on the tower, kind of like an eager beachgoer. The heat generated by these rays is so immense that it can be used to boil water producing steam that drives a traditional turbine, which makes electricity. But when we say solar energy systems, we're usually _______ about photovoltaics, or solar panels, which are the _______ most commonly used to ________ solar power. In solar panels, photons from the sun's rays hit the surface of a panel, and electrons are released to get an ________ current going. Solar panels can use all types of irradiance, while _____ towers can only use ______ irradiance, and this is where clouds become important because depending on their type and ________ relative to the sun, they can either ________ or decrease the amount of electricity produced. For ________, even a few cumulus clouds in front of the sun can reduce the electricity production in solar towers to almost zero because of this dependence on direct rays. In solar ______, those ______ would decrease energy output as well, though not as much because solar panels can use all types of irradiance. However, all this _______ on the clouds exact ___________. Due to reflection, or a particular phenomeon called Mie scattering, the sun's rays can actually be focused forward by clouds to create a more than 50% increase in the solar irradiance reaching a solar panel. If this potential increase isn't accounted for, it could damage the solar _____. Why does this matter? Well, you wouldn't want this lesson to stop just because a cloud ______ over the panel on your roof. In solar towers, huge tanks of molten salt or oil can be used to _____ any ______ heat and use it when needed, so that's how they manage the problem of fluctuating solar __________ to smooth out ___________ production. But in the case of solar panels, there currently isn't any way to affordably store extra energy. That's where traditional power plants come in because to correct for any ____________ in these solar powered plants, extra electricity from traditional sources always needs to be available. But then why aren't these tradtional power plants just used as a backup, instead of us humans depending on them as our main sources of energy? Because it's __________ for an employee at a coal fired or a _______ plant to turn a knob to produce more or less electricity depending on how many clouds there are in the sky. The response time would ______ be too slow. Instead, to accommodate these fluctuations, some _____ electricity from traditional power plants is always being ________. On clear sky days, that extra electricity might be wasted, but when ______ skies prevail, it's what fills the gap. This is what we currently depend on for a ________ supply of energy. For this reason, a lot of researchers are interested in __________ the motion and formation of clouds through satellite images or cameras that look up at the sky to maximize the energy from solar _____ plants and minimize energy waste. If we could accomplish that, you'd be able to enjoy this video powered solely by the sun's rays, no ______ what the _______, although if the sun is shining, you may be tempted to venture outside to go and do a different kind of cloud gazing.
Solution
- produced
- cloudy
- positioning
- eventually
- excess
- talking
- extra
- irradiance
- systems
- electricity
- point
- matter
- fluctuations
- nuclear
- constant
- passed
- depends
- impossible
- called
- clouds
- reasons
- solar
- location
- forcasting
- direct
- simply
- surface
- panel
- instance
- weather
- cases
- increase
- store
- generate
- panels
- single
- electric
- power
Original Text
We have some good reasons to completely switch over to solar power. It's cheaper in many cases, and definitely more sustainable than our dependance on traditional power plants that use resources like coal, which will eventually run out. So why don't we replace these traditional plants with solar energy? Because there's one factor that makes solar power very unpredictable: cloud cover. As the sun's rays move towards Earth, some get absorbed by the Earth's atmosphere, some are reflected back into outer space, but the rest make it to the Earth's surface. The ones that aren't deviated are called direct irradiance. The ones that are deflected by clouds are called diffuse irradiance. And those rays that first get reflected by a surface, like a nearby building, before reaching the solar energy system are called reflected irradiance. But before we can examine how clouds affect the sun's rays and electricity production, let's see how these solar energy systems work. First up, we have solar towers. These are made up of a central tower surrounded by a huge field of mirrors that track the sun's path and focus only the direct rays onto a single point on the tower, kind of like an eager beachgoer. The heat generated by these rays is so immense that it can be used to boil water producing steam that drives a traditional turbine, which makes electricity. But when we say solar energy systems, we're usually talking about photovoltaics, or solar panels, which are the systems most commonly used to generate solar power. In solar panels, photons from the sun's rays hit the surface of a panel, and electrons are released to get an electric current going. Solar panels can use all types of irradiance, while solar towers can only use direct irradiance, and this is where clouds become important because depending on their type and location relative to the sun, they can either increase or decrease the amount of electricity produced. For instance, even a few cumulus clouds in front of the sun can reduce the electricity production in solar towers to almost zero because of this dependence on direct rays. In solar panels, those clouds would decrease energy output as well, though not as much because solar panels can use all types of irradiance. However, all this depends on the clouds exact positioning. Due to reflection, or a particular phenomeon called Mie scattering, the sun's rays can actually be focused forward by clouds to create a more than 50% increase in the solar irradiance reaching a solar panel. If this potential increase isn't accounted for, it could damage the solar panel. Why does this matter? Well, you wouldn't want this lesson to stop just because a cloud passed over the panel on your roof. In solar towers, huge tanks of molten salt or oil can be used to store any excess heat and use it when needed, so that's how they manage the problem of fluctuating solar irradiance to smooth out electricity production. But in the case of solar panels, there currently isn't any way to affordably store extra energy. That's where traditional power plants come in because to correct for any fluctuations in these solar powered plants, extra electricity from traditional sources always needs to be available. But then why aren't these tradtional power plants just used as a backup, instead of us humans depending on them as our main sources of energy? Because it's impossible for an employee at a coal fired or a nuclear plant to turn a knob to produce more or less electricity depending on how many clouds there are in the sky. The response time would simply be too slow. Instead, to accommodate these fluctuations, some extra electricity from traditional power plants is always being produced. On clear sky days, that extra electricity might be wasted, but when cloudy skies prevail, it's what fills the gap. This is what we currently depend on for a constant supply of energy. For this reason, a lot of researchers are interested in forcasting the motion and formation of clouds through satellite images or cameras that look up at the sky to maximize the energy from solar power plants and minimize energy waste. If we could accomplish that, you'd be able to enjoy this video powered solely by the sun's rays, no matter what the weather, although if the sun is shining, you may be tempted to venture outside to go and do a different kind of cloud gazing.
Frequently Occurring Word Combinations
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power plants |
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solar power |
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traditional power |
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solar energy |
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solar towers |
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extra electricity |
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direct rays |
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solar panels |
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electricity production |
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solar irradiance |
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solar panel |
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ngrams of length 3
collocation |
frequency |
traditional power plants |
3 |
Important Words
- absorbed
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- affordably
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