Energy & Green Tech

Deep learning cuts costs in building control

American buildings consume roughly 40 percent of U.S. energy, much of which is expended on heating, cooling, and ventilation. Enhanced control methods can help reduce energy consumption. Model Predictive Control (MPC) has ...

Energy & Green Tech

Data centers use less energy than you think

If the world is using more and more data, then it must be using more and more energy, right? Not so, says a comprehensive new analysis.

Engineering

Next generation of greenhouses may be fully solar powered

Many greenhouses could become energy neutral by using see-through solar panels to harvest energy—primarily from the wavelengths of light that plants don't use for photosynthesis. Those are the findings of a new modeling ...

Other

Unbuilding cities as high-rises reach their use-by date

We are entering a new world where skyscrapers and other huge buildings are becoming redundant and need significant overhaul or replacement. The process is called unbuilding or, if you're a bit highfalutin, deconstruction.

Energy & Green Tech

A smart way to predict building energy consumption

In a time of aging infrastructure and increasingly smart control of buildings, the ability to predict how buildings use energy—and how much energy they use—has remained elusive, until now.

Consumer & Gadgets

Data ownership is a recipe for better living in the city

Today, both public enterprises and private companies in the major cities collect large quantities of data about the citizens living in those cities, and most people derive little benefit from this. However, if the citizens ...

Energy & Green Tech

Comparing residential energy use on similar weather days

To better determine the potential energy cost savings among connected homes, researchers at Oak Ridge National Laboratory developed a computer simulation to more accurately compare energy use on similar weather days.

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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