Every Tuesday I go to a two hour French Conversation Class.  It’s at my daughters’ tea time so I am invariably late and flustered when I arrive, but I so enjoy my chance to speak French.  We are a motley crew of people, all of whom have a deep love of France and many of whom have lived there for short periods, or married into the country.  One young man comes with his mother.  Several are retired.  We include a general practitioner, a renegade Czech who allegedly fled his country during the Revolution and reads everything through a magnifying glass the size of a plate, an engineer at the local nuclear powerstation, a telecommunications research engineer, a retired polyglot and a couple of local businessmen.  I continually count my blessings that a class so perfectly suited to my language ability should be offered in my provincial home town. 

Our tutor is French and the Head of Languages at the local college of further education.  He is … excellent, no other word for it.  Full of enthusiasm, very organised, flexible and approachable.  And probably prevented from running this course next year because it is technically run by our local council, not the college that employs him, even though it takes place in a room provided by the college, and even though it is one of the high points of the tutor’s week to teach a group of such an ability.  This year he managed to arrange the course without anyone noticing until it was too late.  Next year he thinks he will be more closely watched.  We have spent several weeks talking about student demonstrations in France, so are already collecting our cauliflowers to use as weapons if need be.  We are all very keen to continue such a wonderful opportunity.

last week we had to give a short presentation to our peers on a chosen subject.  I chose to talk about the recent wedding I attended in Burgundy – lots of material, and little preparation.  Other people chose subjects as diverse as a novel and a film called “The Diving Bell and the Butterfly” and the Tour de France.  Then we adjourned to the language lab to hear an extract from a radio programme about an event which happened in November 2006 and which threw millions of people into the dark. 

A large newly built cruise liner, the Norwegian Pearl, was navigating the river Ems in North Western Germany and as a precaution the German electricity supply company decided to suspend operation of a very high voltage cable that crossed above the river.  The German network is part of a pan-European network comprising 27 countries currently, with a list of wannabees, such as Syria, Jordan and Libya, queueing up to join.  It notified its nearest neighbour, France, of its intention to shut down the line, but there was inadequate co-ordination amongst other suppliers and distributers of electricity with the result that the electricity which could not be routed via the German cable caused a surge in other networks.  The surge threatened to cause the other lines to overheat, and so emergency shutdowns occurred.  Each shutdown reduced the capacity of the network, producing futher surges and shutdowns.  In all 10 million households were left without electricity, of whom half were in France.  The breakdown highlighted both the interdependence of so many countries and also the poor communication between suppliers. 

The Norwegian Pearl

The disruption was, however, also a reflection of an inherent drawback with electricity: it is impossible to store.  A Gas pipeline may suffer catastrophic disaster interrupting supply, but gas may also be stockpiled so that a few day’s supply is kept in hand.  At this point our Czech friend piped up.  He told us about a pumped-storage hydroelectric station in the Czech republic which uses electricity in slack periods to pump water uphill to a storage lake.  In periods of high demands the water is then allowed to flow downhill again, operating turnbines which generate cheap hydroelectric power.   At least, our Czech friend gave us the outline, but the engineer at the nuclear power station gave us the detail.  He told us about two power stations in Wales that operate the same system, and there are another two in Scotland.  Although each centre uses more electricity than it produces, the output is produced at peak times when it can be sold at peak rates, whilst the electricity is consumed mostly during the night when it can be bought at cheap rates, close to zero often.  What is being stored is not the electricity, but the capacity to generate electricity cheaply.  Elecricity is not “stockable“.  Electricity output of these plants is about 70-85% of the electricity input. 

There is an additional benefit of these hydroelectric stations to the grid as a whole – they even out demand.  That is to say, they increase demand on conventional power stations during slack periods (because they call for electricity to pump the water uphill) and they reduce the demand in peak times.  This ensures that convention powerstations, which operate best when kept running consistently, may continue to operate at peak efficiency. Demand can be very quickly satisfied too. The Welsh power plant at Dinorwig can supply 1320 MW of power to the national grid in only 12-16 seconds if there is a sudden surge. This is quick enough to rescue a network in meltdown and compares with a conventional power station which takes at least 12 hours to reach full power from cold and needs 45 to switch to the grid if they are on “hot standby”

Pumped storage was first used as long ago as the 1890s in Italy and Switzerland.  The Czech Republic had one of the earliest plants built on modern lines at Stechovice in 1947 although this original station was closed in 1991 and a newer plant with reverse turbine technology built in its place.  Globally Europe has a 32GW capacity for pumped storage hydroelectricity.  This compares with a capacity of 19.5 GW in the US.  Twice as much electricity in Europe is accounted for by pumped storage hydroelectricity (5.5%) than in the US.   Centres are expensive to produce, especially if the optimum geographical conditions do not exist naturally: ideally there will be a large body of water close to a mountain with a good connection to the national grid.  All possible sites have been exploited in the UK and similarly in the United States.  Further suitable sights may exist in the developing world, but the huge capital costs remain a disadvantage.

Et voilà!  A la prochaine fois.

More: Wikipedia

Dinorwig

 

Vocabulary

une panne d’électricité – powercut

à tres haute tension – very high voltage

sauter – to trip

un reseau – network

des moyens d’urgence – emergency measures

une centrale électrique – power station

un black-out

une coupure – interruption to supply

en surcharge – overloaded

l’effet domino/l’effet papillon –

délesté – taken out (electricity … of the network, from le lest, ballast)

la capacité de production – generating capacity

stockable – storeable

la kyrielle – chain (of events)

 

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