An dieser Tankstelle gibt es Diesel und Benzin, aber unser Auto braucht nur Benzin.

An dieser Tankstelle means at this gas station.

Here, an is being used in a location sense, so it takes the dative case.

• die Tankstelle = the gas station
• dieser Tankstelle = this gas station / at this gas station

Why dieser?

• Tankstelle is feminine
• after an with a stationary location, German uses dative
• feminine dative singular of dieser is dieser

So:

• an dieser Tankstelle = at this gas station

German often uses an with places like stations, counters, coasts, borders, and similar points or locations.

So an dieser Tankstelle is the natural way to say at this gas station.

If you said in dieser Tankstelle, it would sound more like inside this gas station/building, which is usually not what is meant here.

Es gibt is a very common German expression meaning there is or there are.

So:

• An dieser Tankstelle gibt es Diesel und Benzin
  = At this gas station, there is/are diesel and gasoline

Even though English uses both there is and there are, German usually just uses es gibt for both singular and plural ideas.

Examples:

• Es gibt ein Problem. = There is a problem.
• Es gibt viele Autos. = There are many cars.

In a normal German main clause, the finite verb must be in second position.

The first position can be filled by different elements, not just the subject.

Here the first position is:

• An dieser Tankstelle

So the verb comes next:

• gibt

Then the subject-like element of the expression appears:

• es

Structure:

• An dieser Tankstelle | gibt | es | Diesel und Benzin

This is a basic example of the German verb-second rule.

In es gibt, the es is part of the fixed expression meaning there is/there are.

It does not mean it in the normal sense here. You usually learn es gibt as a set phrase.

So in this sentence, it is best understood as:

• es gibt = there is / there are

Because they are being used as uncountable substances or fuel types in a general sense.

Just like English often says:

• We need gasoline
• They sell diesel

German often says:

• Diesel
• Benzin

without an article when talking about the substance in general.

You can use articles in other contexts, but here article omission is normal and natural.

Their dictionary genders are usually:

• der Diesel
• das Benzin

But in this sentence, you do not see the articles because the words are being used as mass nouns:

• gibt es Diesel und Benzin
• braucht nur Benzin

So even though they have grammatical gender, the article is simply not needed here.

The word nur usually goes directly before the word or idea it limits.

Here:

• nur Benzin = only gasoline

So the sentence means:

• our car needs only gasoline

If you moved nur, the emphasis could change or the sentence could sound unnatural.

For example:

• Unser Auto braucht nur Benzin = natural, standard
• Unser Auto nur braucht Benzin = incorrect
• Unser Auto braucht Benzin nur = unusual in this context

Because Auto is the subject of the clause, so it is in the nominative case.

• das Auto = the car
• unser Auto = our car

For neuter nouns like Auto, unser in the nominative singular does not add an ending.

Compare:

• unser Mann = our man / our husband
• unsere Frau = our woman / our wife
• unser Auto = our car

It is in the accusative case, because brauchen normally takes a direct object.

So in:

• unser Auto braucht nur Benzin

Benzin is the thing needed, so it is the direct object.

You do not see any visible change here because Benzin has no article in this sentence. If there were an article, you might see the case more clearly.

Yes. Brauchen means to need.

So:

• unser Auto braucht nur Benzin = our car only needs gasoline

This is a very normal everyday use of brauchen.

Because aber is a coordinating conjunction. It connects two main clauses and does not send the verb to the end.

So the structure is:

• An dieser Tankstelle gibt es Diesel und Benzin
• aber unser Auto braucht nur Benzin

After aber, the second clause behaves like a normal main clause:

• subject: unser Auto
• verb: braucht
• rest: nur Benzin

This is different from conjunctions like weil or dass, which push the verb to the end.

Because in German, all nouns are capitalized.

So in this sentence:

• Tankstelle
• Diesel
• Benzin
• Auto

are all capitalized because they are nouns.

This is a basic spelling rule in German.

Yes. Tankstelle is the general German word for the place where vehicles get fuel.

Depending on your variety of English, it can be translated as:

• gas station (American English)
• petrol station (British English)

Both are correct translations.

Yes, it sounds natural.

There is no strict grammar rule requiring this exact order, but Diesel und Benzin is a very normal pairing. Reversing it would still be grammatically possible:

• Benzin und Diesel

But the original order sounds completely fine and idiomatic.

Yes, that is possible, but it is a little different in tone.

• An dieser Tankstelle gibt es Diesel und Benzin = At this gas station, there is diesel and gasoline / they have diesel and gasoline available.
• Diese Tankstelle hat Diesel und Benzin = This gas station has diesel and gasoline.

Both are understandable, but es gibt is especially common when talking about what is available somewhere.