There are no gas pumps in space, nor will there be.

How do you get electricity 220 miles above Earth? (click here) No extension cord or power cable is available for that job, so the best source of energy for spacecraft is sunlight. Engineers have developed technologies to convert solar energy to electrical power efficiently.

Solar arrays that convert energy to electricity on the space station are made of thousands of solar cells. The solar cells are made from purified chunks of the element silicon. These cells directly convert light to electricity using a process called photovoltaics....

Solar arrays. The light in space is enviably abundant and free.