The idea is to use several motorized mirrors that point the Sun energy to a unique spot, creating temperature in the hundreds of degrees to some kind of battery made from common molten salt. Then, the thermal energy is transduced to energy even by night, allowing a production of 24 continuous hours.
A tower puts the target high, hundreds of mirrors with several meters each focus to it, creating an enormous quantity of energy.
This is an example of how the limitations are only in terms of international planning, there's ready technology and locations where this interesting plants could be constructed. The problem is the consideration of what cheap and expensive is, possible or impossible.
Projects like this started in the Mojave Desert and after in Spain, demonstrating with is possible to conceive systems to maintain a continuous flow of energy at night or in cloudy days. Store heat when it's possible and after use it at the desired rhythm.