Electricity will become cheaper thanks to renewable energies (Solar, Wind...) and energy storage improvements (Batteries). But, I think we should point out that those energies represent large investments at first. For instance, building solar electricity plants is very expensive, the same way as Wind power.
Germany is a good example: they stopped nuclear plants to increase their renewable energy production but costs of electricity increased a lot there.
I'd say electricity costs will go up first (because of high investments) and then will decrease.
The cost of solar production is highly dependent on geography, and in some places, like California, Nevada or Arizona deserts cheap land and good weather allows for massive economies of scale https://gigaom.com/2015/01/20/a-special-report-the-rise-of-a...
But there's no turning back - once the newcomer into space gets a massive economic advantage by having access to cheap energy, they attract industries that are relying on cheap energy, and soon those market participants overrun their competitors whose cost structure includes higher energy costs.
