Red alerts for much of UK.

Met office red alert for extreme heat has been issued for London and for parts of the Midlands. This is the first ever met office red warning for heat.

Government red warnings for heat health alert now cover all of England. I think that this may be the first such alert, it is undoubtedly the first ever to affect all of England.

Are significant consequences expected for electricity generation and distribution ?

  • folk buying portable aircon units and not realising they need to put the hot air out the window probably.  Buildings with air con installed finding out if it is adequately sized or not as it runs at full chat for the first time.

    I wonder how many of our cables and transformers will be running warmer than the designers expected, and if it will cause a few on the edge to fail.


  • Well, now we have a better idea, and perhaps  compared to the fires, the drownings, and the disruption to road and rail, the loss of nearly 15000 houses electricity supply is probably small beer. Sagging cables and overheating transformers apparently. Northern Powergrid map here



  • One wonders how the TGV can keep running in France without a problem.  I blame the media for being prophets of doom and exaggerating almost any small hiccup into a scary disaster.

    OK rail disruption reports.  Some optic cables were damaged by grass fires which can cause signal failures but these can be fixed in a few hours once identified.  Electric overhead catenary can be disconnected and diesel electric engines used instead. Agreed this all causes delays but is not the massive problem the BBC is broadcasting.

    Stay at home is good for some but what about the NHS and essential workers? Scare stories have an  economic cost as it causes a lost in production of the national wealth. 

    Government panic reactions can cause much distress to everyone.  Just think of the Covid panic overreaction we have just been through. .


  • there may be an element of over reacting in the UK, but also under design., but the overhead line problem for our railways is that they expand and drop, and then snag and we have seen them occasionally get ripped out by the passing  train. diesels may not solve that. More frequent tension points would, but is not quick.


  • Electric overhead catenary can be disconnected and diesel electric engines used instead.

    And where are these fleets of diesel electric locomotives, sitting around for 363 days a year, ready for those two days when it's too hot to run electric ones?

    Our rail network is designed to handle typical British weather.

  • Network rail seem to suggest that some of the overheads already have some form of autotensioning on more recently electrified lines (I have no idea about railways but wonder if it's to do with those stacks of concrete slabs hanging on line-ends running over pulleys at some of the stations near me) and it's the older overheads that are more affected.

  • train overhead lime problems happen in  Spain too

    recent news item


  • I do wonder whether the assumed ambient outside air and soil temperatures used in the UK for cable selection (either by default in BS7671, or specified in BS IEC 60287-3-1) are due a review.

    For sure 40°C mightn't happen every Summer (I hope), not all loads will be at full load for sufficient duration in Summer to be bothered, and no, things don't suddenly burst into flames 0.1K over 70/90°C... but we've exceeded 30°C quite a few times already this year, some loads (e.g. HVAC) are at max in these conditions and not everyone takes account of solar radiation either, so I do wonder if operating lives have been unduly reduced.

  • Despite some failures, it seems that electricity transmission and distribution generally held up very well. 

    Very hot weather increases the load as compared to mild or warm weather, but even the peak load on the hottest ever day was less than that prevailing in winter weather.

    That however is the position nationally, I suspect that in London that new records may have been set for load. AFAIK nothing major blew up  which is reassuring.

  • Slight correction. Designed to handle what used to be typical British weather.

    For example, no heated points. Every time it gets really cold, people are dispatched to known "cold spots" to unfreeze the points (and they rarely manage to reach all of them). German rail has heated points, because conditions when you need it are more frequent. Britain is currently more worried about heavy rains and about heat spells than about extremal cold spells, probably because that is the way the likelihoods pan out. 

    Almost all prophylactic environment measures cost more (installation, maintenance, maybe running costs). So you have to figure out if/when you need them, in advance. A decade-plus ago, there was a cold-snow ("powder snow") storm in Northern France, Belgium, Germany, in January I think. The Eurostar trains (1st gen) could not run because the filters in the traction cars could not cope. We are talking some two decades after service introduction - this really was new. In contrast, in Sweden such circumstances occur regularly, so engine filters routinely cope. But they had real trouble in winter with their first tilt trains. And now with trying to run trains at higher speeds, there are issues with "snow clouds" with operations over 200kph in winter. For example  Was it considered worth retrofitting the 1st ten Eurostar traction cars? Nope. Obviously, nope. We haven't had the chance yet to see if the 2nd gen Siemens multis behave better.