Spain's grid operator denied on Wednesday dependence on solar power was to blame for the country's worst blackout, while Prime Minister Pedro Sanchez came under increasing pressure to explain what went wrong.

The blackout across Spain and Portugal knocked out communications and transport systems, shut down industry and offices and brought commerce to a virtual standstill. The blackout could have shaved 1.6 billion euros ($1.82 billion), or 0.1%, off GDP, Spain's business lobby estimated.

Monday’s devastating blackout in Spain is raising questions about the country’s massive reliance on solar and wind power for electricity — and whether the new power sources may have played a role. Spain’s socialist government has faced increasing pressure to explain what went wrong on Monday,