As humanity began to spread to all corners of the globe in a desperate attempt to find living space for the growing population, they started running into energy problems.  The colder areas of land where they began to move needed huge amounts of power, and technological improvements in energy production couldn't keep up.  Even relatively small cities required small nuclear plants just to cover their needs.  Soon, however, the power companies decided to use the most powerful reactor in the system, the Sun, to generate all of the power they needed.  In partnership with private space agencies, they launched a series of satellites to orbit the sun and beam power back to Earth.

They discovered that they could get much more efficient power transfer rates if they beamed the power to satellites, so they put several in polar orbit and a large one at the L1 Lagrange point.  The L1 Station collects the diffuse energy being beamed toward Earth and focuses it to send it to one of the satellites in polar orbit.  From there the power would be split and relayed through the other satellites to whoever needed it.

While this could provide enough power for the people of Earth to survive, they still experienced massive shortages of power, as well as resources such as metals and food.  Millions of people began moving into space where energy and metals were in much higher supply.  They colonized Venus, Mars, and the asteroid belt, with smaller colonies even further out in the system and on Mercury.

L1 station grew from being a simple engineering station where the crew which maintained and expanded the station could live into a massive trade hub which most of the trade in the system between the sunward colonies and the Earth.

The colonies soon began to declare independence from Earth, and the Earth, lacking the resources to keep them, let them leave.  This lead to a technology boom on both Earth and the colonies, and the creation of the warp drive, though it was too slow to be used for rapid interstellar travel, taking more than a month to get to the Alpha Centauri system.  It did, however, attract the attention of aliens to the system, many of which decided to stay to trade with humanity.  Their main trade base with humans is L1 Station.