XPost: misc.survivalism, alt.conspiracy   
   From: DB@cocks.net   
      
   Story by Capell Aris The Telegraph   
      
   Last Monday, the Iberian grid suffered a disturbance in the south-west   
   at 12:33. In 3.5 seconds this worsened and the interconnection to France   
   disconnected. All renewable generation then went off-line, followed by   
   disconnection of all rotating generation plant. The Iberian blackout was   
   complete within a few seconds.   
      
   At the time the grid was producing 28.4 GW of power, of which 79 per   
   cent was solar and wind. This was a problematic situation as solar and   
   wind plants have another, not widely known, downside – one quite apart   
   from their intermittency and expense.   
      
   This is the fact that they do not supply any inertia to the grid.   
   Thermal powerplants – coal, gas, nuclear, for example – drive large   
   spinning generators which are directly, synchronously connected to the   
   grid. If there are changes which cause a difference between demand and   
   supply, the generators will start to spin faster or slower: but their   
   inertia resists this process, meaning that the frequency of the   
   alternating current in the grid changes only slowly. There is time for   
   the grid managers to act, matching supply to demand and keeping the grid   
   frequency within limits.   
      
   This is vital because all grids must supply power at a steady frequency   
   so that electrical appliances work properly and safely. Deviations from   
   the standard grid frequency can cause damage to equipment and other   
   problems: in practice what happens quite rapidly when frequency changes   
   significantly is that grid machinery trips out to prevent these issues   
   and grids go down.   
      
   When a grid has very little inertia in it – as with the Iberian one on   
   Monday – a problem which a high-inertia grid would easily resist can   
   cause a blackout within seconds. Lack of inertia was almost certainly   
   the primary cause of the Iberian blackout, as Matt Oliver has opined in   
   these pages. A grid with more inertia would not have collapsed as   
   quickly, and its operators would have had time to keep it up and running.   
      
   Restoration of supplies was completed by early Tuesday morning, based on   
   reconnection to France, which facilitated progressive area reconnections   
   across Spain and Portugal.   
      
   Iberia is part of the Continental Europe Synchronous Area which   
   stretches to 32 countries. It is interconnected as a phase-locked, 50 Hz   
   grid with a generation capacity of 700 GW. To improve the stability of   
   this grid, the EU aim is that all partners will extract 10 per cent of   
   their power consumption from synchronous interconnectors – ones which   
   transmit grid inertia – helping to make the whole system more resilient.   
   France is at 10 per cent, but peninsula grids and those at the   
   geographical fringe are the least interconnected. Spain has just 2 per   
   cent from synchronous interconnectors.   
      
   But there are places where things are worse. The UK and Ireland are   
   island grids. They do have undersea power interconnectors to Europe but   
   these are non-synchronous DC links and transmit no grid inertia. There’s   
   little prospect that this will change.   
      
   Both the Irish and UK grid system operators had developed an array of   
   grid protection services that can control grid frequency, loss of load   
   or generation protection, grid phase angle and recovering from grid   
   outages. Neither country has, to date, ever experienced a total system   
   failure, even during WWII.   
      
   In 1974 construction started on Dinorwig Power Station. It is a pumped   
   storage generation plant designed specifically for the provision of all   
   the UK’s grid protection services. Dinorwig can make huge changes to its   
   output in a matter of seconds, compensating for sudden events. Operation   
   began in 1984. In 1990 all the UK’s generating stations could provide   
   inertia.   
      
   Nowadays, 55 per cent of our generation mix (wind, solar, DC imports)   
   cannot supply inertia to the grid. Are we approaching a system that   
   compares with Spain and Portugal on Monday?   
      
   It certainly looks that way. In 2012 the National Grid produced a solar   
   briefing note for the government which is still available online. In   
   that note they imagine a system that has 22 GW of solar power attached   
   to the grid. They demonstrate their concerns based on a sunny summer day   
   when demand is low. The sun rises at 5 o’clock when little or no   
   synchronous plant other than nuclear generation will be on line and at   
   midday, solar is 60 per cent of all generation. The Grid’s engineers   
   then considered that situation “difficult to manage” and concluded that   
   wind+solar power must never exceed 60 per cent of generation.   
      
   We now have 17.7 GW of grid-connected solar farms to which we must add   
   all rooftop solar installations. At midday on Tuesday according to   
   Gridwatch the UK’s asynchronous, no-inertia generation was at 66 per   
   cent of total generation.   
      
   In 2014 National Grid produced a System Operability Framework document.   
   Their objective was to outline how future scenarios of generation mixes   
   would impact upon protection services for the grid. As more and more   
   renewable generators are brought on-line, the difficulties of managing   
   the grid have become more and more onerous. For example, one service   
   titled “primary response” in 1990 called for selected generation plants   
   to increase generation within 10 seconds after a fault is detected: by   
   1,200 MW in winter and 1,500 MW in summer. In 2024 these increases are   
   required in 1.2 seconds!   
      
   After nearly 50 years of operation, Dinorwig Power Station is currently   
   shut down for major repairs and there has been no information on when it   
   will re-open. Over the next five years all of our nuclear stations, bar   
   Sizewell, will be closed. Over the same period our combined cycle gas   
   generator fleet will halve from 30 GW to 15 GW. (It takes 5 years to   
   build a new CCGT even using an existing site. The new ones are 66 per   
   cent efficient and cost less than £1 billion to build a 1 GW plant – one   
   third the cost of an offshore windmill.)   
      
   We will lose huge amounts of grid inertia. Low-inertia operation will   
   become routine. It is hard to imagine that we won’t start to suffer   
   complete national blackouts like the Iberian one.   
      
   One last piece of doom: the recovery of Spain’s grid in just one day is   
   impressive. This speed is certainly due to the assistance of a large,   
   stable grid reconnecting into the Iberian system thus allowing recovery   
   in a series of stable steps as each grid area is recovered. We will not   
   have that facility in the UK with our asynchronous interconnectors.   
      
      
   [continued in next message]   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)