La discriminación horaria distingue horas punta de horas valle.

Because horaria is an adjective agreeing with discriminación, which is a feminine singular noun.

• discriminación → feminine singular
• so the adjective must also be feminine singular: horaria

This adjective comes from hora, so discriminación horaria means something like a time-based or hourly distinction/classification.

Because the subject is La discriminación horaria, which is singular.

Breakdown:

• La discriminación horaria = subject
• distingue = 3rd person singular of distinguir
• horas punta de horas valle = what is being distinguished

So the verb is singular because the thing doing the action is singular.

Because distinguir is commonly used in the pattern:

distinguir X de Y = to distinguish X from Y

So here:

• horas punta = X
• horas valle = Y

The sentence literally follows the normal Spanish structure for saying that one category is distinguished from another.

A very similar alternative is:

• distinguir entre X e Y

But in your sentence, the pattern used is distinguir X de Y, which is very common.

Because Spanish often leaves out articles when talking about categories in a general way, especially after verbs like distinguir.

So:

• distingue horas punta de horas valle sounds general and classification-like
• distingue las horas punta de las horas valle is also possible, but it sounds a bit heavier and more specific

In other words, the version without articles is natural when describing a system or concept.

Because punta and valle are acting like fixed noun modifiers here, not normal adjectives.

In these compound expressions:

• hora punta / horas punta
• hora valle / horas valle

the second word usually stays unchanged.

So even when hora becomes plural:

• hora punta → horas punta
• hora valle → horas valle

This is common in Spanish compound expressions where one noun modifies another.

The difference is just singular vs plural.

• hora punta = peak hour
• horas punta = peak hours

In your sentence, the plural is used because it refers to a category of times, not just one single hour.

The same applies to:

• hora valle = off-peak hour
• horas valle = off-peak hours

Not always. In everyday language, discriminación often has the negative meaning of discrimination against people. But in technical or economic contexts, it can simply mean differentiation or classification.

In Spain, discriminación horaria is a set expression used especially for electricity tariffs and time-based pricing. So in this context it is technical, not social or moral.

That said, some modern usage prefers terms like:

• tarifa por periodos
• facturación por franjas horarias

because they may sound clearer or less awkward to learners.

Yes. The present tense here expresses a general fact or definition.

distingue does not mean it is happening only right now. It means:

• this system/classification generally distinguishes
• this is how it works

Spanish uses the present tense this way very often for definitions, descriptions, and general truths.

Yes, in many contexts you could use diferencia.

For example:

• La discriminación horaria diferencia las horas punta de las horas valle.

That said, distingue works very well here because it suggests separating or telling one category from another. It sounds slightly more formal and classification-based, which fits the sentence nicely.

The structure is:

Subject + verb + object/complement

More specifically:

• La discriminación horaria = subject
• distingue = verb
• horas punta de horas valle = the two categories being contrasted

So the sentence is structurally quite straightforward. The main thing learners usually need to notice is the pattern:

distinguir X de Y