Der Stromanbieter schreibt das Guthaben gut.

Because the verb here is gutschreiben, which is a separable verb.

In a normal main clause, separable prefixes move to the end:

• Der Stromanbieter schreibt das Guthaben gut.

Compare:

• Infinitive: gutschreiben
• Main clause: schreibt ... gut
• Past participle: gutgeschrieben

So gut is not just an adverb here; it is part of the verb.

The full verb is gutschreiben.

In this sentence, it means something like to credit an amount, to apply a credit, or to enter something as a credit to an account.

This is a useful business and billing verb. You will often see it in contexts like:

• banks
• utility bills
• refunds
• customer accounts

So the structure is not schreiben in the everyday sense of to write. It is the fixed verb gutschreiben.

Because it is the direct object of the verb.

German main-clause word order usually works like this:

1. one element in first position
2. the conjugated verb in second position
3. other sentence elements
4. the separable prefix at the end

So:

• Der Stromanbieter = subject
• schreibt = finite verb
• das Guthaben = direct object
• gut = separable prefix

That gives:

• Der Stromanbieter schreibt das Guthaben gut.

It is in the accusative case, because it is the thing being credited.

A small detail that can confuse learners: das looks the same in nominative and accusative for neuter nouns.

So from the form alone, das Guthaben could be nominative or accusative, but here the sentence structure shows it is the object, so it is accusative.

Guthaben is neuter, which is why it takes das in the singular.

Here it is singular.

In many contexts, Guthaben behaves a bit like an uncountable noun in English, such as credit or balance. It often refers to the amount available on an account rather than to one separate item.

Yes, German often leaves that unstated if the context is obvious.

This sentence does not explicitly say to whom or to which account the credit is applied. In a fuller sentence, you might see:

• Der Stromanbieter schreibt dem Kunden das Guthaben gut.
  • The utility provider credits the customer with the balance.

or

• Der Stromanbieter schreibt das Guthaben auf das Konto gut.
  • The utility provider credits the amount to the account.

So the shorter version is perfectly normal when the recipient or account is already understood from context.

Not as a normal main clause.

In a main clause, the separable verb splits:

• Der Stromanbieter schreibt das Guthaben gut.

But in other structures, the verb appears as one word:

• infinitive: gutschreiben
• subordinate clause: ..., weil der Stromanbieter das Guthaben gutschreibt.
• past participle: gutgeschrieben

So a very common learner mistake is trying to keep the verb together in a main clause. Standard German does not do that with separable verbs.

It is fairly formal and very typical of billing, banking, and administrative language.

You are especially likely to see it in writing, for example on invoices, account statements, or customer-service messages.

In more casual speech, people might choose other wording depending on the situation, but gutschreiben is absolutely standard and common in official or commercial contexts.

Yes. German main clauses follow the verb-second rule, which means the conjugated verb stays in second position, but the first position can be filled by different elements.

So these are also possible:

• Das Guthaben schreibt der Stromanbieter gut.
• Heute schreibt der Stromanbieter das Guthaben gut.

The meaning stays broadly the same, but the emphasis changes.

In your original sentence, Der Stromanbieter is first because it is the topic or starting point of the sentence.

Not really by itself.

Historically, yes, it comes from the word gut, but in this sentence you should treat gutschreiben as a single vocabulary item. The meaning is not simply write well or write good.

So it is best learned as:

• jdm. etw. gutschreiben = to credit something to someone / to someone’s account

That is much more useful than trying to interpret gut separately in this sentence.