Sunday, August 31, 2014

"The secret world of power generation, and the arrival of Earth-spanning super grids"

From ExtremeTech, 30July:
A long, long time ago, before the wind, before the snow — well, the middle of the 1800s to be exact — electricity was an intriguing but mostly useless thing. Some factories and residences toyed with early electric lights and motors powered by on-site generators, but most of the world used piped steam and natural gas to heat their homes and drive their machines for decades after electrification began. That would all change, however, with Nikola Tesla’s invention of three-phase high-voltage power distribution at the end of the 1800s and the creation of the world’s first synchronized national electricity grid in Great Britain in 1938.

Overnight, electricity became cheap and constantly available — it became a utility — and the number of users in the UK shot up dramatically, from around 750,000 in 1920 to 9 million in 1938. Synchronized electricity — 50Hz from every socket in the country — meant that devices (radios, TVs, motors) worked everywhere, and the production and sales of those early electric devices boomed accordingly. Other countries would soon follow, and eventually, thanks to intra- and international interconnections between networks, the world’s power grids are now mostly synchronized at either 50 or 60Hz.
Power line pylons, at sunset

A modern power grid is a wondrous thing. Basically, through the magic of high-voltage direct-current (HVDC) cables, electricity generation and consumption can be balanced across an entire country — or even an entire continent. If you need power down south, you can spin up a hydroelectric generator in the north; if you have excess power in the south, you can use it to pump water back up to the top of the dam in the north. If it’s particularly windy or sunny, you can turn off a few coal and combined cycle gas turbine (CCGT) power plants. If a neighboring country or state is being hit by a heatwave, you can pump power into their grid via an interconnector. If you have a lot of constant nuclear power generation (like France), you can export surplus power to other countries  – and then, during peak times, import power from those same countries if you ever need it.

Perhaps most impressively, though, it’s important to remember that the world’s electricity grids have almost no energy storage at all. With the exception of pumping water back to the top of a hydroelectric dam — an option that’s only available in limited quantities and only in some countries — all electricity generated must be consumed immediately. As you can imagine, spinning up exactly the right number of turbines to match the power needs of millions of people is rather difficult — and in the UK, it’s all done by a single person....MUCH MORE

Electric Avenue in Brixton, London: The first market street to be illuminated by electric street lights (1895)
Electric Avenue in Brixton, London: The first market street to be illuminated by electric street lights (1895)

And, of course, Eddy Grant's song about Brixton 1981: