Strømmen er fornybar.

Because Norwegian usually adds definiteness to the end of the noun.

• en strøm = a current / an electricity supply
• strømmen = the current / the electricity

So -en is the definite ending for many masculine/common-gender nouns.

In context, strømmen often means the electricity or the power supply. If you said strøm instead, it would sound more indefinite or more like the substance/concept in general.

Strøm is an en-word in Bokmål, often called common gender.

So its forms are:

• en strøm = a current / an electricity supply
• strømmen = the current / the electricity

That is why the definite form ends in -en.

In Norwegian, the is often attached to the noun instead of being a separate word.

So:

• strømmen literally contains the idea of the electricity
• you do not normally say the strømmen

This is one of the biggest differences from English. Norwegian often marks definiteness with a suffix:

• en bil = a car
• bilen = the car

The same pattern is used in strømmen.

Er is the present tense of å være (to be).

So:

• å være = to be
• er = is / are

In Strømmen er fornybar, er simply links the subject and the adjective, just like English is in The electricity is renewable.

Fornybar is an adjective. It describes the noun.

Here it means renewable.

It is built from the idea of to renew:

• å fornye = to renew
• fornybar = renewable

So grammatically, the sentence is:

• Strømmen = subject
• er = verb
• fornybar = adjective describing the subject

Because the adjective agrees with the noun.

Here, strømmen is singular and common gender, so the adjective takes the basic form:

• strømmen er fornybar

Compare:

• et system er fornybart = a system is renewable
  because system is neuter
• løsningene er fornybare = the solutions are renewable
  because løsningene is plural

So fornybar is the correct form for a singular common-gender noun like strømmen.

Yes. In a sentence like this, the adjective is predicative—it comes after er and describes the subject.

Predicative adjectives agree mainly with:

• gender
• number

They do not take the same definite ending pattern that adjectives do before nouns.

So:

• den fornybare strømmen = the renewable electricity
  here the adjective comes before the noun
• strømmen er fornybar = the electricity is renewable
  here the adjective comes after the verb

That is why you get fornybar, not fornybare, in this sentence.

Sometimes yes, depending on what you mean.

• Strøm er fornybar can sound more like a general statement about electricity as a concept.
• Strømmen er fornybar more naturally refers to the electricity in a specific context, such as the electricity from a certain supplier, area, or source.

In real usage, Norwegian can be flexible with mass nouns like strøm, but the definite form often feels more concrete or context-based.

Not always. Strøm can mean different kinds of current or flow, depending on context.

For example, it can refer to:

• electric current / electricity
• a current in water
• a stream or flow

In everyday modern Norwegian, though, strømmen very often means the electricity or the power.

A rough guide is:

• strømmen ≈ STRUHM-men, but with the Norwegian vowel ø
• fornybar ≈ for-NY-bahr

A few notes:

• ø does not exist in standard English; it is somewhat similar to the vowel in some pronunciations of bird, but with rounded lips.
• mm in strømmen is clearly pronounced.
• The stress in fornybar is on ny.

If you are learning pronunciation, the vowel ø is probably the trickiest part of this sentence.

This is standard Norwegian main-clause word order:

• Strømmen = subject
• er = verb
• fornybar = complement

So the pattern is:

Subject + verb + adjective

This is the normal order in a simple statement.

If you changed the order, it would usually become a question or require a different structure. For example:

• Er strømmen fornybar? = Is the electricity renewable?

This sentence is perfectly normal Bokmål.

In Nynorsk, you would typically say:

• Straumen er fornybar.

So the main difference is the noun:

• Bokmål: strømmen
• Nynorsk: straumen

The adjective fornybar is the same in both.