The Amprion control room in Brauweiler, Germany. Photographer: picture alliance/Getty Images Germany’s largest power-grid operator said that the country may have to restrict electricity exports this winter as a last resort to avoid blackouts. Amprion GmbH said such a measure would be an “ultima ratio” in a critical grid situation, as Europe’s biggest economy faces possible gas rationing amid the continent’s worst energy crisis in decades. Cutting exports could affect neighboring countries such as France and Austria — the biggest buyers of German power last year. Germany is especially vulnerable to the surge in energy costs triggered by Russia’s war in Ukraine due to a heavy reliance on imported gas. To tackle the crisis, it’s extending operations at two lignite-fired power units until the end of next winter. It has also postponed its nuclear phase out, blaming shutdowns in France that has cut reactor availability there to below 50%. […]