Shadowing Practice: How to fix clean energy’s storage problem - Learn English Speaking with Video
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This is the typical demand for electricity on a spring day in California.
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It starts growing around 6 a .m., then rises again around 6 p .m.
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Now, this line shows when wind power feeds the California power grid.
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Wind is variable, but often picks up at night.
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Solar panels, on the other hand, kick into gear around 7 a .m., generate a lot of electricity until the sun sets around 7 p .m.
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On most days, neither comes close to meeting the peak demands of the day.
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So, the power company relies on fossil fuels, like natural gas, to make up for the gap, which widens significantly when people use electricity the most.
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Since the power company can't store the solar and wind energy, it has to use fossil fuels at these times,
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which can be stored in barrels and tanks.
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It's kind of the big gap in our renewable energy system right now.
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If we don't figure out a way to store renewable energy, there's a chance that we're going to be still dependent on fossil fuels.
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So, how do we store some of this solar and wind energy for later?
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Right now you might be thinking, just use a battery.
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And you're not wrong.
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Batteries have improved immensely over the past few years, particularly lithium -ion batteries, which use a chemical reaction to store energy.
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Individual homes that have solar panels often use lithium -ion batteries to store energy.
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But there's a few reasons lithium -ion isn't perfect for the grid.
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This is Neil Dinesha, a founding writer at Heatmap, a climate news site, and he wrote about this for Vox in 2022.
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One is just the scale that's needed.
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We would need a lot at a level that we just don't really have right now.
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That's a challenge because lithium is only found in a few places on earth.
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But more importantly, like we need lithium -ion batteries for other things.
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Lithium -ion battery is really good for stuff that moves because it's relatively light.
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Meaning it's better suited for things like electric cars and portable electronics, not power grids that stay still.
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Luckily, there's another energy storage solution that's actually been around for a long time.
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This is the site for the first pump storage hydroelectric station in Southern Ireland.
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This is a type of energy storage called pump storage hydro.
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They were first built in Europe.
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The U .S built one in 1929.
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And many more were built in the 1970s and 80s as a way to store nuclear power.
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Today, these facilities are all over the world.
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There are 39 of them in the U .S.
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And they store energy in a really fascinating yet simple way.
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When energy demand is low,
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renewable or fossil fuel energy is used to pump water from a reservoir or river up a mountain into a higher reservoir.
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Basically converting this energy into what's called potential energy.
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So potential energy, you might kind of remember from high school physics.
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When a thing is up at a height, it has stored potential energy.
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When it's let go, it turns into kinetic energy.
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When that energy is needed, the water is released down the mountain,
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where it's converted into kinetic energy that spins a turbine and generates electricity for the grid.
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It's a way of combining water, a mountain, and gravity into a battery, and it can be about 90 % efficient,
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meaning only 10 % of this energy is lost in the process.
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Pump storage hydro works really well, but it's difficult to build more.
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Well, for starters, you need a mountain, and you need to haul out a mountain to put pumps inside it,
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and it takes a lot of money, and we don't have mountains everywhere.
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So the ideal way to store renewable energy would be something that's cheaper and smaller than a pump storage hydro plant,
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but works in roughly the same way.
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One company, Energy Vault, is also using gravity to store renewable energy, but without the water or mountain.
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Instead, renewable energy is used to lift heavy blocks of concrete up into the air, where it becomes potential energy.
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Then when it's needed, the blocks are released, spinning a turbine, which converts the potential energy back into electricity.
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Energy Vault calls this gravity energy storage, and while it's still being tested, the company claims it could be more than 80 % efficient.
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A company called QuidNet is working on a different version of the same principle.
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Their geomechanical pump storage unit uses renewable energy to pump water underground into a pressurized hole, where it can be stored as potential energy,
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then released back up to the surface to spin a turbine and generate electricity.
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Both techniques are betting on potential energy as a solution for storing renewable energy for the grid.
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I think this partly because potential energy has shown itself to be pretty efficient.
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Also, realistically, fewer moving parts.
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If all you're doing basically is using gravity to work with you, you have a pretty massive force of nature on your side right there.
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But potential energy isn't the only possible solution.
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Other companies are using renewable energy to superheat salt, insulating it, then releasing that heat to create steam or hot air to drive a turbine.
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Basically storing renewables by converting them to thermal energy.
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Then there's a company that's betting on rusted iron.
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They're called iron air batteries and what they do is they utilize the chemical reaction
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that creates rust to store and discharge energy.
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This thing
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that we all sort of think of as an inconvenience could be really useful is just kind of beautiful to me.
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Right now these ideas are all in various stages of development, but they are attracting investors.
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And the hope is that several will work because one might not fit every power grid.
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The grid, renewable energy overall, is going to be a sort of patchwork solution.
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And so the more we try these solutions,
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the closer we get to figuring out exactly what the right mix is for what we need for the greater future.
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Vocabulary and speaking notes for this lesson
This speaking lesson is built on the video “How to fix clean energy’s storage problem”. The speaker keeps coming back to these words: energy, renewable, store, potential, pump. This video has 72 sentences and 1011 words to shadow. The speech runs for 5:21. The speaker talks fast, about 189 words per minute, so expect linked and reduced sounds. Only 79% of the words are among the 3,000 most common in English, so the vocabulary is demanding.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| renewable adjective | /ɹɪˈnu.ə.bl̩/ | Able to be renewed; capable of renewal. |
| pump noun | /pʌmp/ | A device for moving or compressing a liquid or gas. |
| grid noun | /ɡɹɪd/ | A rectangular array of squares or rectangles of equal size, such as in a crossword puzzle. |
| electricity noun | /ɪˌlɛkˈtɹɪsɪti/ | Originally, a property of amber and certain other nonconducting substances to attract lightweight material when rubbed, or the cause of this property; now… |
| lithium noun | /ˈlɪθi.əm/ | The simplest alkali metal, the lightest solid element, and the third lightest chemical element (symbol Li) with an atomic number of 3 and atomic weight of… |
| gravity noun | /ˈɡɹævɪti/ | Of an activity such as a ceremony, a person's conduct, etc.: the quality of being deeply serious and solemn, especially in a dignified manner; seriousness… |
| convert verb | /kənˈvɝt/ | To transform or change (something) into another form, substance, state, or product. |
| fossil noun | /ˈfɑsl̩/ | The mineralized remains of an animal or plant. |
| turbine noun | /ˈtɜː.baɪn/ | Any of various rotary machines that use the kinetic energy of a continuous stream of fluid (a liquid or a gas) to turn a shaft. |
| efficient adjective | /ɪˈfɪʃənt/ | Making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy. |
| spin verb | /spɪn/ | To rotate, revolve, gyrate (usually quickly); to partially or completely rotate to face another direction. |
| generate verb | /ˈd͡ʒɛn.ə.ɹeɪt/ | To bring into being; give rise to. |
| hydro noun | /ˈhaɪdro/ | Electrical power supply; specifically, electrical power provided by a utility (as a publicly-owned one); payment or bills for this. |
| reservoir noun | /ˈɹɛz.ə(ɹ).vwɑɹ/ | A place where anything is kept in store. |
| rust noun | /ɹʌst/ | The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous… |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| figure out verb | To come to understand; to discover or find a solution; to deduce. |
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | can be stored · is only found · were built |
| Present perfect have/has + past participle — a past action that still matters now | have improved · that's actually been · has stored |
Pronunciation to watch
The speaker uses 10 contractions and reduced forms, such as don't, isn't, you're. Say them the short way, as you hear them.
- The “th” sounds: lithium /ˈlɪθi.əm/, thermal /ˈθɜːməl/
- The “sh” and “zh” sounds: efficient /ɪˈfɪʃənt/, pressurize /ˈpɹɛʃəɹaɪz/
- Long words — get the stress right: electricity /ɪˌlɛkˈtɹɪsɪti/, electronics /ɪˌlɛkˈtɹɑ.nɪks/, importantly /ɪmˈpɔɹ.tənt.li/, inconvenience /ɪnkənˈvinjəns/, hydroelectric /ˌhʌɪdrəʊɪˈlɛktrɪk/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like renewable, pump, grid.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.