The author's point is that Spain's electricity is very cheap compared to other European countries thanks to its great electricity mix, etc.
The reality is that Spain's electricity is cheap because it is relatively insulated from Europe's core network, because its interconnections with other countries are limited. In financial words, there is a spread with the rest of Europe because the ways to arbitrage that spread are extremely limited. If Spain was located near Germany and well interconnected, their prices would look like Germany's. And while cheap energy is pictured by op as a good thing, Spain understands very well that higher prices are good for its renewables industry, and is pressing for more interconnections[1].
The overall tone of the article feels like the author is here to extoll the virtues of renewables.
[1]: https://www.ft.com/content/8e94079c-585f-11e4-b331-00144feab...
This is an interesting point about energy market balancing but it has causality backwards. Spain simply has a better energy mix than Germany, no matter how big the spread between the countries is as a function of interconnectedness.
Hmm. Everyone should just disconnect Germany, let them freeze, and enjoy cheap electricity?
It is worth mentioning that the linked FT article supporting the claim is from 12 years ago.
This is a lesson in how electricity isn't really a commodity e.g. it's very very difficult to send some electrons from one side of the world to another.
The relative isolation you cite for power being cheap were true a decade ago when power was expensive. The author is correct in extolling the virtues of renewables.
I mean it is hard to argue with the number - I believe everyone will benefit for more interconnections. More energy to Europe, more money to Spain.
And for the numbers it seems obvious that renewables are a fundamental part of the picture.
To add to this, Spain gets it gas from Algeria, the rest of europe gets it from Russia and the middle east. So yeah, It's easy to have better prices when your gas is comparatively free from disruptions.