The FEAR in Europe is that Moscow will not re-open the pipeline due to economic sanctions over the Ukraine Special Military Operation.

As European countries find themselves without inbound natural gas, they are relying upon stored gas in tanks to keep power plants running and industry operating.   But at this time of year, the amount of natural gas in storage is not what it has to be for the Winter months when gas usage soars for heating, and so the stored supply can only last maybe a month or two.

If Russia does NOT turn the NordStream One pipeline back on, then Europe will run out of natural gas at varying stages, depending upon the country involved.

In anticipation of Russia NOT turning the gas back on, Germany is in what they call "Stage Two" natural gas emergency.  They are limiting how long people can take showers (hot water), dimming street lights to reduce electricity demand and warning the public that natural gas may be completely cut off.