Hoher Energieverbrauch erhöht die Nachzahlung.

Because Energieverbrauch is a masculine noun: der Energieverbrauch.

In this sentence, it is the subject, so it is in the nominative case. Since there is no article before it, the adjective hoch takes the strong nominative masculine ending -er:

• hoher Energieverbrauch

So the pattern is:

• der hohe Energieverbrauch = with article
• hoher Energieverbrauch = without article

That is why hoher is correct.

German often leaves out the article when speaking about something in a general or abstract way.

Here, hoher Energieverbrauch means something like high energy consumption in general, not necessarily one specifically identified instance.

So:

• Hoher Energieverbrauch erhöht die Nachzahlung.
  = a general statement

You could also say:

• Ein hoher Energieverbrauch erhöht die Nachzahlung.

That is also correct, but it sounds a bit more like a high level of energy consumption as one example or instance. Without the article, the sentence sounds more general and headline-like.

It is in the nominative case because it is the subject of the sentence — the thing doing the action of the verb.

In:

• Hoher Energieverbrauch erhöht die Nachzahlung.

the subject is hoher Energieverbrauch, and the verb is erhöht.

A useful question is: What increases the payment due?
Answer: Hoher Energieverbrauch.

That tells you it is the subject, so it is nominative.

That is a very common question. Erhöht can indeed also be a past participle or an adjective in other contexts, but here it is the present-tense verb form of erhöhen.

The verb erhöhen means to increase. Its present-tense forms include:

• ich erhöhe
• du erhöhst
• er/sie/es erhöht

Since the subject hoher Energieverbrauch is third person singular, the verb is:

• erhöht

You can tell it is the finite verb here because it is in the normal German second position:

• Hoher Energieverbrauch | erhöht | die Nachzahlung.

It is in the accusative case because it is the direct object — the thing being affected by the verb.

The verb is erhöhen = to increase.
So the sentence answers:

• What is increased?
  die Nachzahlung

That makes die Nachzahlung the direct object, so it is accusative.

Also, Nachzahlung is a feminine noun:

• nominative: die Nachzahlung
• accusative: die Nachzahlung

For feminine nouns, nominative and accusative often look the same, which is why the article does not change here.

Nachzahlung usually means an additional payment due later, especially after earlier payments were too low.

A common context is utilities or rent:

• You paid estimated monthly amounts.
• Later, the real total was higher.
• So you must make a Nachzahlung.

It does not usually mean a late fee or penalty.

A good English idea is:

• balance due
• additional payment
• payment owed afterward
• in utility contexts, often top-up payment

German often combines nouns into one word.

Energieverbrauch =

• Energie = energy
• Verbrauch = consumption / usage

So the whole word means:

• energy consumption
• energy usage

The last part of a German compound tells you the main noun and also its gender. Since Verbrauch is masculine (der Verbrauch), the whole compound is masculine:

• der Energieverbrauch

This is another compound:

• nach- = after / afterward
• Zahlung = payment

So Nachzahlung is literally something like after-payment, meaning a payment that has to be made later because the original amount was not enough.

The gender comes from the last part:

• die Zahlung is feminine
• so die Nachzahlung is also feminine

Yes. In German, hoch can describe not only physical height but also large amounts, levels, or intensity.

So:

• hoher Energieverbrauch = high energy consumption
• hohe Kosten = high costs
• hoher Preis = high price

This is very natural German.

Yes. This is standard main-clause word order:

• Subject: Hoher Energieverbrauch
• Verb: erhöht
• Object: die Nachzahlung

So it follows the common German pattern:

• Subject – Verb – Object

The key rule is that in a main clause, the finite verb usually comes in second position. That is exactly what happens here.

Yes, absolutely.

• Hoher Energieverbrauch erhöht die Nachzahlung.
• Der hohe Energieverbrauch erhöht die Nachzahlung.

Both are grammatical.

The version without the article sounds more general, compact, and sometimes a bit like a headline or formal statement.

The version with der sounds more like you are referring to a specific high energy consumption already known in the context.

So the difference is mainly one of style and specificity, not basic grammar.

Because in German, all nouns are capitalized.

So:

• Energieverbrauch is a noun
• Nachzahlung is a noun

But adjectives and verbs are normally not capitalized in the middle of a sentence:

• Hoher = adjective here
• erhöht = verb here

This is one of the most visible spelling rules in German.

A rough pronunciation guide is:

• Hoher ≈ HOH-er
• Energieverbrauch ≈ en-er-GEE fer-BROWKH
• erhöht ≈ er-HUYT or air-HUYT depending on accent
• die Nachzahlung ≈ dee NAKH-tsah-loong

A few important points:

• h in hoher is pronounced.
• äu in erhöht sounds roughly like oy.
• ch in Nachzahlung is the throaty German sound, not like English ch in chair.
• German compounds like Energieverbrauch are usually stressed on the main parts, especially -brauch at the end.

This sentence is useful because it shows several important patterns at once:

1. Strong adjective ending without an article

   • hoher Energieverbrauch

2. A masculine noun as the subject

   • der Energieverbrauch

3. A third-person singular present-tense verb

   • erhöht

4. A feminine direct object

   • die Nachzahlung

5. German compound nouns

   • Energieverbrauch
   • Nachzahlung

So it is a very compact example of adjective endings, gender, cases, verb position, and compound nouns all in one sentence.