49 Fun Facts About Renewable Energy

Which physical effect lets a solar cell turn sunlight directly into an electric current, with no moving parts?

The photovoltaic effect is a semiconductor producing an electric current when light hits it, which is why solar cells are also called PV cells.

Which country held the largest installed wind power capacity globally at the end of 2024?

By the end of 2024, China significantly led the world in wind energy, with an installed capacity exceeding 520 GW, far surpassing other nations.

Which type of hydroelectric power plant stores water in a large artificial lake behind a dam?

An impoundment plant dams a river to store water in a reservoir; a penstock carries it down to the turbine, and the height difference, the head, sets the power output.

Which geothermal plant technology uses a low-boiling secondary fluid to turn a turbine?

Binary cycle geothermal plants operate by using the heat from geothermal fluid to vaporize a separate working fluid with a lower boiling point, whose vapor then drives a turbine to produce electricity.

What biological process breaks down organic matter in the absence of oxygen to produce biogas?

Anaerobic digestion is microbes breaking down organic matter without oxygen; the biogas it yields is mostly methane and carbon dioxide and can be burned or upgraded to pipeline-quality biomethane.

What is the primary natural force responsible for creating tides, which are harnessed for tidal energy?

The gravity of the Moon and Sun pulls on the oceans to raise tides; at new and full moon the two pulls line up, producing the largest spring tides roughly twice a month.

What solar technology uses mirrors to focus sunlight on a receiver, heating fluid to make steam for a turbine?

Concentrated Solar Power (CSP) systems use mirrors to concentrate sunlight, generating high temperatures that heat a fluid to produce steam, which then powers a turbine to create electricity.

What is a key advantage of offshore wind farms compared to onshore wind farms?

With no obstacles at sea, winds are stronger and steadier, giving a higher capacity factor. Offshore breezes are also often strong in the afternoon, when demand peaks.

Which of these is a documented environmental impact of building a large dam and reservoir?

Blocked fish migration routes are a classic dam impact: salmon and other migratory fish cannot pass the wall without ladders. Dams also trap sediment that would otherwise build deltas downstream.

Enhanced Geothermal Systems extract heat from rock that conventional plants cannot use because it lacks what?

Hot dry rock lacks the natural water and permeability a conventional plant needs, so Enhanced Geothermal Systems pump high-pressure water down an injection well to shear open cracks and create an artificial reservoir.

Which of these is a common feedstock used in the production of bioethanol?

Corn is the main bioethanol feedstock in the United States: its starch is broken into sugars, fermented into ethanol and blended into gasoline, most commonly as E10.

What billing mechanism credits solar-panel owners for excess power sent back to the grid?

Net metering is an electricity billing mechanism that credits owners of renewable energy systems, such as solar panels, for the surplus electricity they feed back into the public utility grid.

What hydrogen production method uses renewable electricity to split water with zero emissions?

Green hydrogen is produced through electrolysis, a process that uses electricity from renewable sources like solar or wind power to split water into hydrogen and oxygen without generating greenhouse gas emissions.

Which type of silicon solar panel is known for its high efficiency and a uniform, dark appearance?

Monocrystalline panels get their uniform dark look because each cell is cut from a single high-purity silicon crystal, which is also what gives them their high efficiency.

What component atop a wind turbine tower houses the gearbox, generator and control systems?

The nacelle is the housing atop the tower that holds the gearbox, generator and control systems; the word is borrowed from aviation, where it means an engine pod.

Which of these is a direct use of geothermal heat, without converting it to electricity?

Heating greenhouses is a direct use: geothermal water at only 25–90 °C warms the soil and air, far below what a power plant needs. Iceland grows tomatoes and cucumbers this way.

What chemical process is most commonly used to produce biodiesel from vegetable oils or animal fats?

Biodiesel is primarily produced through transesterification, a chemical reaction where vegetable oils or animal fats react with an alcohol in the presence of a catalyst to form fatty acid methyl esters (biodiesel) and glycerol.

Which technology stores energy by pumping water uphill and releasing it through turbines at peak demand?

In 2021 pumped-storage schemes provided almost 85% of the world's 190 GW of grid energy storage.

When a company buys a carbon offset to cover its own greenhouse gas emissions, what is it paying for?

Funding reductions elsewhere only works if the world ends up at least as well off as if the buyer had cut its own footprint; programs issue their own credit labels, such as the CDM's Certified Emission Reductions.

Which type of hydroelectric plant diverts part of a waterway's flow through a penstock with little or no storage?

A run-of-river plant diverts part of the river's flow through a penstock with little or no storage; any small pond it keeps is called pondage, so output follows the river's natural flow.

Second-generation biofuels are primarily derived from which category of feedstocks?

Second-generation biofuels come from non-food biomass and crop residues such as straw, corn stover and woody energy crops grown on marginal land, avoiding the food-security worries of diverting food crops into fuel.

What name is given to an electricity network that uses two-way digital communication to integrate renewables and respond to faults?

A smart grid moves information as well as electricity in both directions, letting it fold in distributed renewables and respond to faults faster than the one-way 20th-century grid.

Solar and wind are called 'intermittent' renewables because, unlike hydro, they are not what?

Solar and wind are not dispatchable on demand: their output follows the weather rather than the operator, unlike reservoir hydro, which can be ramped when needed. Storage and interconnection are the usual fixes.

In which country did James Blyth build the first electricity-generating wind turbine in 1887?

Blyth's 10-metre cloth-sailed turbine charged batteries at his holiday cottage in Marykirk, Kincardineshire, Scotland, in July 1887, months before Charles Brush's machine in Ohio.

Under the Betz limit, what is the most of the wind's kinetic energy a turbine can capture?

Albert Betz showed in 1919 that no turbine can capture more than 16/27, about 59%, of the wind's kinetic energy; the best modern rotors reach roughly 75–80% of that ceiling.

Who built the first solar cell, in the 1880s?

Charles Fritts coated selenium with a thin layer of gold in 1883 to make the first solar cell, about 1% efficient; Edmond Becquerel had only observed the photovoltaic effect in 1839.

In which Italian town did Prince Piero Ginori Conti test the first geothermal generator in 1904?

At Larderello in Tuscany in 1904, Conti's generator lit four light bulbs; the world's first commercial geothermal power station was built there in 1911.

Which Californian geothermal field hosts the largest group of geothermal power plants in the world?

The Geysers, north of San Francisco, is the world's largest complex of geothermal plants: more than a dozen units with about 1.5 GW of installed capacity, running on dry steam since 1960.

Which dam overtook Hoover Dam in 1942 as the world's largest hydroelectric station?

Grand Coulee on the Columbia River passed Hoover in 1942 and was later expanded to 6,809 MW; hydropower was nicknamed 'white coal' in that era, and Itaipu took the title in 1984.

The low-head Kaplan hydro turbine is named after an engineer from which country?

Austria: Viktor Kaplan, an Austrian engineer teaching in Brno, patented his adjustable-blade propeller turbine in 1913; its design lets low-head, high-flow hydro plants run efficiently.

The Three Gorges Dam, the world's largest power station by capacity, spans which river in central China?

The Yangtze's Three Gorges Dam packs 22,500 MW of turbines, enough for around 95 TWh a year, and set a world record of nearly 112 TWh after the 2020 monsoons.

The 14 GW Itaipu Dam sits on the Paraná River along Brazil's border with which country?

Half its 20 generators run at 50 Hz for Paraguay and half at 60 Hz for Brazil, and most of the Paraguayan share is exported back across the border.

The Sihwa Lake station, the world's largest tidal power plant at 254 MW, is in which country?

Sihwa Lake in South Korea, completed in 2011 with 254 MW, narrowly beat France's 240 MW Rance plant, which had held the tidal record since 1966.

The world's first tidal power station opened in 1966 on the Rance estuary, in which region of France?

Brittany's Rance barrage was picked for its 8 m average tidal range; Charles de Gaulle opened it in November 1966, and a road across the dam links Dinard and Saint-Malo.

Bhadla Solar Park, a 2,200 MW Indian solar plant, lies in which desert?

Bhadla sits in the Thar Desert of Rajasthan's Jodhpur district, covering 56 square kilometres; it was built in four phases from 2015, partly funded by the Climate Investment Funds.

Which Danish company built Hornsea 2, the world's largest offshore wind farm when it opened in 2022?

Ørsted, called DONG Energy until 2017, built the 1.3 GW Hornsea 2 off Yorkshire; its 1,000th UK turbine was one of the Hornsea 2 machines, fifteen years after its first at Barrow.

The first practical photovoltaic cell was publicly demonstrated in 1954 at which laboratory?

At Bell Laboratories in 1954, Calvin Fuller, Daryl Chapin and Gerald Pearson unveiled a silicon cell of about 6% efficiency, the ancestor of every rooftop panel.

Under the Shockley–Queisser limit, what is the top efficiency of a single-junction solar cell?

The Shockley–Queisser limit is about 34% (33.7% at a 1.34 eV band gap); silicon's own cap is about 32%, and stacking several junctions is the way past it.

IRENA, the intergovernmental renewable energy agency founded in 2009, is headquartered in which oil-rich Gulf city?

Abu Dhabi's Masdar City hosts IRENA, the first international body devoted solely to renewables; Bonn keeps its innovation centre and Vienna its UN liaison office.

Hywind Scotland, the world's first commercial floating wind farm, lies 29 km off which town?

Hywind Scotland's five floating turbines sit 29 km off Peterhead in Aberdeenshire; they averaged a 54% capacity factor and rode out Hurricane Ophelia and Storm Caroline in 2017 by shutting down.

The Hornsdale Power Reserve, the world's largest lithium-ion battery in 2017, is in which state?

Tesla built the A$90 million 'Tesla Big Battery' beside the Hornsdale Wind Farm in South Australia after the state's 2016 storm blackout; at 100 MW it was the world's largest in 2017.

How many solar power towers does the Mojave Desert's Ivanpah plant focus its mirrors on?

Ivanpah's 173,500 heliostats aim at boilers atop three 140-metre towers. When it opened in 2014 it was the world's largest solar thermal plant, with Google among its investors.

The 510 MW Noor Ouarzazate concentrated solar complex is in which country?

Morocco's Noor Ouarzazate complex, opened in stages from 2016 on the edge of the Sahara, pairs 510 MW of parabolic-trough and tower CSP with molten-salt storage for after-dark output.

Roughly what share of Iceland's homes are heated by geothermal energy?

About 90% of Iceland's homes are heated geothermally; the first was in 1907, when a farmer piped hot-spring steam into his house, and Reykjavík's first district pipeline followed in 1930.

The Olkaria geothermal complex in the Great Rift Valley lies inside which national park?

Olkaria lies inside Hell's Gate National Park near Naivasha, Kenya; underground temperatures reach about 340 °C, and the field's estimated 2,000 MW potential was almost double Kenya's 2008–09 peak demand.

In July 2015, Danish wind turbines briefly supplied what share of national power demand?

140%: on the windy night of 9–10 July 2015 Danish turbines covered 116% of demand at the evening peak and 140% by 3 a.m., with the surplus exported to Germany, Norway and Sweden.

Brazil's decades-old ethanol fuel programme is built on which crop?

Sugarcane: Brazil's Proálcool programme began in 1975; leftover cane fibre, bagasse, is burned for heat and power, and flex-fuel cars that run on any petrol–ethanol blend took about 94% of new sales by 2013.

Germany's Renewable Energy Sources Act (EEG) of 2000 originally relied on which support mechanism?

The EEG's feed-in tariff gave producers a guaranteed grid connection and a fixed price for 20 years, funded by a surcharge on consumers' bills; competitive auctions replaced it for most technologies under the 2017 reform.

The 'duck curve' of solar-heavy grids was named in 2012 by the grid operator of which US state?

CAISO, California's grid operator, named the duck curve in 2012: net demand after solar sags at midday and spikes at sunset, a shape that grid batteries charged at noon help flatten.