Visualizing the Changing Patterns of Daylight In One Year
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Soaking up the Sun: Visualizing the Changing Patterns of Daylight in One Year

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The darkest days are upon the residents of the Northern Hemisphere as daylight dwindles and the night lingers longer. Meanwhile, those in the Southern Hemisphere bask in their warmest and longest days—and those at the Equator continue to observe consistent days and nights.

These changing lengths of days and nights depend on where you are on Earth and the time of year. The tilt of the Earth’s axis and its path around the sun affect the number of daylight hours.

Today’s post highlights two simple and elegant animations that help demonstrate how different latitudes experience the sun’s light over the course of one year. The first comes from Reddit user harplass, while the second comes from data scientist Neil Kaye.

Longer and Shorter Days

The Ancient Greeks envisioned the movement of the sun as a Titan named Helios who rode across the sky in a horse-drawn chariot, illuminating the known world below. A rosy-fingered dawn would herald his imminent arrival, while the arrival of the dusk god Astraeus, ever on Helios’ heels, marked the passage of day into night.

Today, time is not at the whims of Greek mythology but by the measurable and consistent movement of celestial bodies. A day on Earth is 24 hours long, but not every day has 12 hours of daylight and 12 hours of night. The actual time of one Earth rotation is a little shorter–about 23 hours and 56 minutes.

Daytime is shorter in winter than in summer, for each hemisphere. This is because the Earth’s imaginary axis isn’t straight up and down, it is tilted 23.5 degrees. The Earth’s movement around this axis causes the change between day and night.

During summer in the Northern Hemisphere, daylight hours increase the farther north you go. The Arctic gets very little darkness at night. The seasonal changes in daylight hours are small near the Equator and more extreme close to the poles.

Length of a Rotation: Equinoxes and Solstices

There are four events that mark the passing stages of the sun, equinoxes and solstices.

The two solstices happen June 20 or 21 and December 21 or 22. These are the days when the sun’s path in the sky is the farthest north or south from the Equator. A hemisphere’s winter solstice is the shortest day of the year and the summer solstice the year’s longest.

Equinoxes and Solstices

In the Northern Hemisphere the June solstice marks the start of summer: this is when the North Pole is tilted closest to the sun, and the sun’s rays are directly overhead at the Tropic of Cancer.

The December solstice marks the start of winter when the South Pole is tilted closest to the sun, and the sun’s rays are directly overhead the Tropic of Capricorn.

The equinoxes happen around March 21 and September 23. These are the days when the sun is exactly above the Equator, which makes day and night of equal length.

Stand in the Place Where You Are

It is always darkest before the dawn, and every passing of solstice marks a time of change. As the Northern Hemisphere heads into the winter holiday season, it also marks the advent of longer days and the inevitable spring and summer.

The lengths of days and nights are constantly changing, but every one will get their time in the sun, at some point.

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Energy

Visualizing the Range of Electric Cars vs. Gas-Powered Cars

With range anxiety being a barrier to EV adoption, how far can an electric car go on one charge, and how do EV ranges compare with gas cars?

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The Range of Electric Cars vs. Gas-Powered Cars

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EV adoption has grown rapidly in recent years, but many prospective buyers still have doubts about electric car ranges.

In fact, 33% of new car buyers chose range anxiety—the concern about how far an EV can drive on a full charge—as their top inhibitor to purchasing electric cars in a survey conducted by EY.

So, how far can the average electric car go on one charge, and how does that compare with the typical range of gas-powered cars?

The Rise in EV Ranges

Thanks to improvements in battery technology, the average range of electric cars has more than doubled over the last decade, according to data from the International Energy Agency (IEA).

YearAvg. EV RangeMaximum EV Range
201079 miles (127 km)N/A
201186 miles (138 km)94 miles (151 km)
201299 miles (159 km)265 miles (426 km)
2013117 miles (188 km)265 miles (426 km)
2014130 miles (209 km)265 miles (426 km)
2015131 miles (211 km)270 miles (435 km)
2016145 miles (233 km)315 miles (507 km)
2017151 miles (243 km)335 miles (539 km)
2018189 miles (304 km)335 miles (539 km)
2019209 miles (336 km)370 miles (595 km)
2020210 miles (338 km)402 miles (647 km)
2021217 miles (349 km)520 miles* (837 km)

*Max range for EVs offered in the United States.
Source: IEA, U.S. DOE

As of 2021, the average battery-powered EV could travel 217 miles (349 km) on a single charge. It represents a 44% increase from 151 miles (243 km) in 2017 and a 152% increase relative to a decade ago.

Despite the steady growth, EVs still fall short when compared to gas-powered cars. For example, in 2021, the median gas car range (on one full tank) in the U.S. was around 413 miles (664 km)—nearly double what the average EV would cover.

As automakers roll out new models, electric car ranges are likely to continue increasing and could soon match those of their gas-powered counterparts. It’s important to note that EV ranges can change depending on external conditions.

What Affects EV Ranges?

In theory, EV ranges depend on battery capacity and motor efficiency, but real-world results can vary based on several factors:

  • Weather: At temperatures below 20℉ (-6.7℃), EVs can lose around 12% of their range, rising to 41% if heating is turned on inside the vehicle.
  • Operating Conditions: Thanks to regenerative braking, EVs may extend their maximum range during city driving.
  • Speed: When driving at high speeds, EV motors spin faster at a less efficient rate. This may result in range loss.

On the contrary, when driven at optimal temperatures of about 70℉ (21.5℃), EVs can exceed their rated range, according to an analysis by Geotab.

The 10 Longest-Range Electric Cars in America

Here are the 10 longest-range electric cars available in the U.S. as of 2022, based on Environmental Protection Agency (EPA) range estimates:

CarRange On One Full ChargeEstimated Base Price
Lucid Air520 miles (837 km)$170,500
Tesla Model S405 miles (652 km)$106,190
Tesla Model 3358 miles (576 km)$59,440
Mercedes EQS350 miles (563 km)$103,360
Tesla Model X348 miles (560 km)$122,440
Tesla Model Y330 miles (531 km)$67,440
Hummer EV329 miles (529 km)$110,295
BMW iX324 miles (521 km)$84,195
Ford F-150 Lightning320 miles (515 km)$74,169
Rivian R1S316 miles (509 km)$70,000

Source: Car and Driver

The top-spec Lucid Air offers the highest range of any EV with a price tag of $170,500, followed by the Tesla Model S. But the Tesla Model 3 offers the most bang for your buck if range and price are the only two factors in consideration.

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Green Steel: Decarbonising with Hydrogen-Fueled Production

How will high emission industries respond to climate change? We highlight industrial emissions and hydrogen’s role in green steel production.

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This infographic highlights industrial emissions and hydrogen's role in green steel production.
The following content is sponsored by AFRY
This infographic highlights industrial emissions and hydrogen's role in green steel production.

Green Steel: Decarbonising with Hydrogen-Fueled Production

As the fight against climate change ramps up worldwide, the need for industries and economies to respond is immediate.

Of course, different sectors contribute different amounts of greenhouse gas (GHG) emissions, and face different paths to decarbonisation as a result. One massive player? Steel and iron manufacturing, where energy-related emissions account for roughly 6.1% of global emissions.

The following infographic by AFRY highlights the need for steel manufacturing to evolve and decarbonise, and how hydrogen can play a vital role in the “green” steel revolution.

The Modern Steel Production Landscape

Globally, crude steel production totalled 1,951 million tonnes (Mt) in 2021.

This production is spread all over the world, including India, Japan, and the U.S., with the vast majority (1,033 million tonnes) concentrated in China.

But despite being produced in many different places globally, only two main methods of steel production have been honed and utilised over time—electric arc furnace (EAF) and blast furnace basic oxygen furnace (BF-BOF) production.

Both methods traditionally use fossil fuels, and in 2019 contributed 3.6 Gt of carbon dioxide (CO2) emissions:

Steel Production MethodMaterials UtilisedCO2 Emissions (2019)
EAFScrap0.5 Gt
BF-BOFScrap, iron ore, coke3.1 Gt

That’s why one of the main ways the steel industry can decarbonise is through the replacement of fossil fuels.

Hydrogen’s Role in Green Steel Production

Of course, one of the biggest challenges facing the industry is how to decarbonise and produce “green” steel in an extremely competitive market.

As a globally-traded good with fine cost margins, steel production has been associated with major geopolitical issues, including trade disputes and tariffs. But because of climate change, there is also a sudden and massive demand for carbon-friendly production.

And that’s where hydrogen plays a key role. Steel traditionally made in a blast furnace uses coke—a high-carbon fuel made by heating coal without air—as a fuel source to heat iron ore pellets and liquify the pure iron component. This expels a lot of emissions in order to get the iron hot enough to melt (1,200 °C) and be mixed with scrap and made into steel.

The green steel method instead uses hydrogen to reduce the iron pellets into sponge iron, metallic iron that can then be processed to form steel. This process is also done at high temperature but below the melting point of iron (800 – 1,200 °C), saving energy costs.

And by introducing non-fossil fuels to create iron pellets and renewable electricity to turn the sponge iron and scrap into steel, fossil fuels can be removed from the process, significantly reducing emissions as a result.

The Future of Green Steel Production

Given the massive global demand for steel, the need for hydrogen and renewable energy required for green steel production is just as significant.

According to AFRY and the International Renewable Energy Agency, meeting global steel production in 2021 using the green steel method would require 97.6 million tonnes of hydrogen.

And for a truly carbon-free transition to green steel, the energy industry will also need to focus on green hydrogen production using electrolysis. Unlike methods which burn natural gas to release hydrogen, electrolysis entails the splitting of water (H2O) into oxygen and hydrogen using renewable energy sources.

Full green steel production would therefore use green hydrogen, electrolysers running on renewables, and additional renewables for all parts of the supply chain:

Steel Production SourceAnnual Steel ProductionGreen Hydrogen RequiredElectrolyser Capacity RequiredTotal Renewables Capacity Required
Base Reference1 Mt50 kT0.56 GW0.7 GW
U.S.85.8 Mt4.3 Mt48 GW60 GW
Europe103 Mt5.2 Mt58 GW72 GW
China1032.8 Mt51.6 Mt581 GW726 GW
Global1951 Mt97.6 Mt1,097 GW1,371 GW

Currently, green hydrogen production costs are higher than traditional fossil fuel methods, and are dependent on the levelised costs of renewable energy sources. This means they vary by region, but also that they will reduce as production capacity and subsidies for renewables and green hydrogen increase.

And many major European steel manufacturers are already leading the way with pilot and large scale facilities for green steel production. Germany alone has at least seven projects in the works, including by ArcelorMittal and ThyssenKrupp, two of the world’s 10 largest steelmakers by revenue.

AFRY is a thought leadership firm that provides companies with advisory services and sustainable solutions, in their efforts to fight climate change and lead them towards a greater future.

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