Energy & Green Tech

Rooftop solar cells can be a boon for water conservation too

Electricity-generating rooftop solar cells not only save on planet-warming carbon emissions, they also save a significant amount of water, say a pair of Duke University researchers who have done the math.

Energy & Green Tech

Hawaii quits coal in bid to fight climate change

The last bits of ash and greenhouse gases from Hawaii's only remaining coal-fired power plant slipped into the environment this week when the state's dirtiest source of electricity burned its final pieces of fuel.

Energy & Green Tech

Californians told not to charge EVs as grid struggles in heat wave

Californians were told Wednesday not to charge their electric vehicles during peak hours, just days after the state said it would stop selling gas-powered cars, as the aging electricity grid struggles with a fearsome heatwave.

Energy & Green Tech

Cheaper, changing and crucial: the rise of solar power

Generating power from sunlight bouncing off the ground, working at night, even helping to grow strawberries: solar panel technology is evolving fast as costs plummet for a key segment of the world's energy transition.

Electronics & Semiconductors

Rush to build more chips puts environmental progress in peril

The CHIPS and Science Act, which President Joe Biden is poised to sign into law next week, was pitched as a once-in-a-lifetime chance to revitalize the U.S. semiconductor industry and counter Asia's manufacturing power.

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World energy resources and consumption

In 2005, total worldwide energy consumption was 500 Exajoules (= 5 x 1020 J) with 80-90% derived from the combustion of fossil fuels. This is equivalent to an average energy consumption rate of 16 TW (= 1.585 x 1013 W). Not all of the world's economies track their energy consumption with the same rigor, and the exact energy content of a barrel of oil or a ton of coal will vary with quality.

Most of the world's energy resources are from the sun's rays hitting earth - some of that energy has been preserved as fossil energy, some is directly or indirectly usable e.g. via wind, hydro or wave power. The term solar constant is the amount of incoming solar electromagnetic radiation per unit area, measured on the outer surface of Earth's atmosphere, in a plane perpendicular to the rays. The solar constant includes all types of solar radiation, not just visible light. It is measured by satellite to be roughly 1366 watts per square meter, though it fluctuates by about 6.9% during a year - from 1412 W/m2 in early January to 1321 W/m2 in early July, due to the Earth's varying distance from the sun, and by a few parts per thousand from day to day. For the whole Earth, with a cross section of 127,400,000 km², the total energy rate is 1.740×1017 W, plus or minus 3.5%. This 174 PW is the total rate of solar energy received by the planet; about half, 89 PW, reaches the Earth's surface.

The estimates of remaining worldwide energy resources vary, with the remaining fossil fuels totaling an estimated 0.4 YJ (1 YJ = 1024J) and the available nuclear fuel such as uranium exceeding 2.5 YJ. Fossil fuels range from 0.6-3 YJ if estimates of reserves of methane clathrates are accurate and become technically extractable. Mostly thanks to the Sun, the world also has a renewable usable energy flux that exceeds 120 PW (8,000 times 2004 total usage), or 3.8 YJ/yr, dwarfing all non-renewable resources.

This text uses material from Wikipedia, licensed under CC BY-SA