Micro:bit Related ProductsJacdac SeriesJacdac Energy Practice KitCase 3: Hydroelectric Power StationOn this pageCase 3: Hydroelectric Power StationIntroductionSpeak, clap, or make sounds toward the micro:bit V2 board — the louder the sound, the brighter the LED light ring and the faster the 360° building-block servo drives the water turbine generator model, simulating stronger water flow and higher power generation. The quieter the sound, the dimmer the LED and slower the servo. In complete silence, the LED turns off and the servo stops, simulating a dry-season shutdown. The sound represents the "force of the water current."Learning ObjectivesLearn about hydroelectric power stations and understand the basic principle of converting the potential energy of water into electrical energy.Understand the energy conversion chain — water potential energy → water kinetic energy → turbine rotational kinetic energy → generator electromagnetic induction → electrical energy.Understand the advantages and disadvantages of hydroelectric power, developing a comprehensive perspective on renewable energy.Required MaterialsItemImageQuantitymicro:bit V21Jacdac Expansion Board1Jacdac 10cm Connector Cable1Jacdac 25cm Connector Cable1Jacdac Servo Module1Jacdac LED Ring1360° Building-Block Servo1USB Cable1Sensor PrincipleThis case uses the built-in microphone of the micro:bit V2 as the sensor. It captures ambient sound levels (0–255) in real time and maps them to both the servo rotation speed and the LED ring brightness.Assembly StepsModel Principle360° Building-Block Servo and the Water Turbine Generator ModelThe 360° building-block servo provides continuous rotational power and is mounted on the central axle of the water turbine generator model. As the servo rotates, it drives the turbine blades, simulating the process of water flow striking a turbine to spin it, which in turn drives a generator to produce electricity. The servo speed corresponds to the "water flow intensity" — the faster the rotation, the stronger the water flow and the higher the power generation.Hydroelectric Power Station — The Energy Code of a DamThe core principle of a hydroelectric power station is using the drop height (head) of water to generate electricity. As water flows from a higher elevation to a lower one, its gravitational potential energy is converted into kinetic energy — this high-speed water flow strikes the turbine blades, causing them to rotate. The turbine then drives a generator, which converts the rotational kinetic energy into electrical energy via electromagnetic induction. The entire process burns no fuel and produces zero carbon emissions.Key Formula: Hydroelectric power ≈ water density × gravitational acceleration × water flow rate × head height. The higher the head (drop height) and the greater the flow rate, the greater the power generated. With a 100-meter head, each ton of water falling can generate approximately 0.27 kWh of electricity.Connection DiagramAs shown below, insert the micro:bit V2 board into the Jacdac expansion board, and use cables to connect the servo module and LED ring to the Jacdac expansion board's edge connector via daisy-chaining.Programming SoftwareMicrosoft MakeCodeMakeCode ProgrammingStep 1: Adding the Jacdac ExtensionGo to Microsoft MakeCode and click "New Project".Enter a project name in the pop-up window and click "Create".Click "Extensions" in the code drawer.In the pop-up interface, type "Jacdac" and click the search icon, then select the Jacdac software library as shown.Step 2: Connecting the HardwareUse a USB cable to connect the micro:bit V2 board to the computer.Note: If this is the first time running a Jacdac program on the micro:bit V2, please pre-load a blank Jacdac program onto the board first. Otherwise, skip this step.Connect the sensors. MakeCode will automatically detect and simulate them in the simulator area, where sensor status is displayed in real time.Click "ADD BLOCKS" to add the sensor extension module.Note: When connecting a new sensor, repeat the "click 'ADD BLOCKS'" workflow once.Write the Program as ShownReference Program Linkhttps://makecode.microbit.org/_1gAhi03bcemxYou can also download the program directly from the webpage below. Once downloaded, you can start running the program.ResultSound level is correlated in real time — the louder the sound, the faster the 360° building-block servo rotates and the brighter the Jacdac LED ring shines; the quieter the sound, the slower the servo and the dimmer the LED ring. This simulates a hydroelectric power station in operation.ThinkBoth hydroelectric power generation and waterwheel water lifting (the noria case) use the power of water — how are they different?If you live in a place without large rivers, what other methods of power generation could you use?Program LogicTrigger ConditionActionSourceSound level detected360° building-block servo rotates at a speed mapped from the sound value, driving the water turbine generator; LED ring brightness varies with sound levelmicro:bit Sound SensorKnowledge Extension: Hydroelectric Power — From a Single Drop of Water to Lighting Up a CityI. Where Does Water's Energy Come From — The Science of Energy ConversionWhat exactly happens to a drop of water falling from a reservoir hundreds of meters high? Below is the complete energy conversion chain in hydroelectric power generation:Solar radiation Evaporation Cloud precipitation Mountain reservoir(Nuclear fusion) → (Thermal) → (Gravitational PE) → (PE storage) ↓ Water falls from height ↓ Water kinetic energy (High-speed water flow) ↓ Strikes turbine blades ↓ Turbine rotational KE (Mechanical rotation) ↓ Generator electromagnetic induction ↓ Electrical energy (To homes everywhere)Conversion StageEnergy Form ChangeWhere It HappensEfficiencyStage 1Gravitational PE → Water kinetic energyPenstock (water rushes down from dam height)~95%Stage 2Water kinetic energy → Rotational kinetic energyTurbine (water flow strikes blades)~90–95%Stage 3Rotational kinetic energy → Electrical energyGenerator (rotor cuts magnetic field lines)~95–98%Overall Efficiency~85–92%The comprehensive energy conversion efficiency of hydroelectric power reaches 85%–92%, among the highest of all power generation methods. For comparison: thermal power ~35–45%, solar photovoltaic ~15–22%, wind power ~35–45%. One ton of water falling from a height of 100 meters can theoretically generate about 0.27 kWh — enough to keep an LED light on for 10 continuous hours.II. How a Hydroelectric Power Station Is BuiltA large hydroelectric power station typically includes the following core components: ┌─────────────────────────────┐ │ Hydroelectric Station │ └─────────────┬───────────────┘ │ ┌─────────┐ ┌─────────┐ ┌───────┴───────┐ ┌──────────┐ │Reservoir│ │ Dam │ │ Powerhouse │ │Transmission│ └────┬────┘ └────┬────┘ └───────┬───────┘ └─────┬────┘ │ │ │ │ Stores water Blocks river Turbine + Gen Power to grid Provides head Creates drop Water→Electricity Homes everywhereComponentFunctionInteresting FactReservoirStores large volumes of water, provides stable head and flowThree Gorges Reservoir capacity: 39.3 billion m³, equivalent to 2,800 West LakesDamBlocks the river, creating a water level dropThree Gorges Dam: 181 m tall, ~2.3 km long — as tall as a 60-story buildingPenstockGuides water from the high reservoir to the low turbineWater speeds can reach tens of meters per second with enormous impact forceTurbineConverts water flow kinetic energy into rotational mechanical energyA single turbine runner can exceed 10 m in diameter and weigh hundreds of tonsGeneratorUses electromagnetic induction to convert rotational kinetic energy into electricityA single Three Gorges generator: 700 MW — enough for a medium-sized cityTailraceDischarges spent water back into the downstream riverEnsures downstream river ecology is not interruptedIII. Global Hydropower — A Giant in NumbersKey Data PointValue2024 global installed hydropower capacity1,283 GW2024 global hydropower generation~4,200 TWh, ~14.3% of global electricityGlobal hydropower generation cost~$0.057/kWh (among the lowest of all renewables)World's largest hydroelectric stationChina's Three Gorges Dam, 22.5 GW capacity, ~80–100 TWh annuallyCountries with hydropower134Oldest still-operating hydro stationSome over 100 years (extremely long lifespan)China's installed hydropower capacityOver 420 GW, #1 globally for many consecutive yearsRankCountryInstalled CapacityShare of National Electricity1China~420 GW~16%2Brazil~110 GW~63%3USA~102 GW~6%4Canada~83 GW~60%5Russia~56 GW~17%In countries like Brazil, Canada, Norway, and Venezuela, hydropower provides over half of all electricity. Norway generates almost 100% of its electricity from hydropower — the most "water-powered" country in the world.IV. The Two Sides of Hydropower — No Perfect Energy Source✅ AdvantagesAdvantageDescriptionExtremely high efficiency85%–92%, far exceeding thermal (~40%) and solar PV (~20%)Zero-carbon operationNo fossil fuels burned during generation, no greenhouse gas emissionsDispatchable / fast responseHydro units can go from shutdown to full power in minutes — much faster than thermal or nuclear, ideal for peak load balancingExtremely long lifespanDams and stations can operate for 50–100 years; excellent long-term ROILow operating costOnce built, the "fuel" is free (water falls from the sky); O&M costs far lower than thermalMulti-purpose utilizationOne dam can simultaneously provide: power generation, flood control, irrigation, water supply, navigation, tourism, aquacultureBeyond power generation, the Three Gorges Project raised the Yangtze River's middle and lower reaches' flood protection standard from "once in 10 years" to "once in 100 years," safeguarding approximately 15 million people.❌ DisadvantagesDisadvantageDescriptionReal-World ExampleSubmerges large areas of landReservoir inundation floods upstream farmland, forests, villages, and even ancient townsThree Gorges Reservoir submerged 1,084 km² — roughly half the area of ShenzhenPopulation displacementEstimates suggest up to 80 million people worldwide have been displaced by dam constructionThree Gorges displaced ~1.3 million people — the largest reservoir resettlement in human historyEcological damageDams block fish migration, alter river temperature and water quality, disrupt aquatic ecosystemsThe Chinese sturgeon is critically endangered due to blocked migration routes from Gezhouba and Three Gorges DamsSediment trappingSediment trapped behind dams deprives downstream deltas of replenishment, causing coastal retreatAfter Egypt's Aswan Dam, the Nile Delta has retreated tens of meters annuallyReservoir greenhouse gasesIn tropical regions, submerged vegetation decomposes to produce methane (25× the greenhouse effect of CO₂)Some tropical reservoirs in early filling stages produce significant methane — but this is limited to specific regions and initial periods, not a universal hydro characteristicClimate vulnerabilityDroughts cause significant drops in generationGlobal drought in 2021 reduced hydropower output by 0.4%, with some countries seeing drops over 20%Core Dilemma: Hydropower is clean — but the process of dam building is not "clean." Hydropower is green — but the forests it submerges are also green. Whether hydro is truly "green energy" depends on how we balance the benefits of generation against the ecological costs.V. The Future of Hydropower — From Mega-Dams to "Micro-Hydro"TrendDescriptionPumped storageUse surplus electricity (e.g., nighttime wind power) to pump water back to a higher reservoir, then release it to generate during peak demand — essentially a giant "water battery." Currently accounts for over 90% of global energy storageSmall / micro hydropowerUses natural stream drops without large dams to generate (tens to thousands of kW), minimal ecological impact, suitable for remote mountainous areas and villagesRetrofitting aging stations~40% of global hydro equipment has operated for over 40 years; technology upgrades can boost efficiency 10%–20%Improved fish passagesDesigning more fish-friendly ladders and passages to help migratory fish bypass damsEnvironmental flow mandatesRequiring stations to release minimum ecological flows downstream to keep rivers from running dryReflection: Your servo model simulates a turbine rotating to generate power, but the greatest real-world challenge is this — how to generate electricity without inflicting irreversible harm on rivers and the people who live alongside them. Future engineers, this puzzle awaits your solution.
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