Ovo je nestanak struje.

Both ovo and to can mean this/that, but they are used a bit differently.

• ovo = this (something close to the speaker, or being presented right here)
• to = that (something a bit more distant, or something already mentioned)

In Ovo je nestanak struje, ovo works like This is a power outage or This is the loss of electricity.

You will often hear this pattern in Croatian:

• Ovo je kuća. = This is a house.
• To je kuća. = That is a house.

So ovo is natural if you are identifying or pointing out something as this.

Je is the 3rd person singular form of the verb biti = to be.

So:

• ovo = this
• je = is
• nestanak struje = power outage / loss of electricity

Together: Ovo je nestanak struje. = This is a power outage.

Some other forms of biti in the present tense are:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is
• mi smo = we are
• vi ste = you are
• oni/one/ona su = they are

Nestanak comes from the verb nestati, which means to disappear or to vanish.

So nestanak is a noun meaning:

• disappearance
• loss
• outage, depending on context

In this sentence, nestanak means something like the loss/disappearance of electricity.

Examples:

• nestanak osobe = disappearance of a person
• nestanak vode = water outage / loss of water supply
• nestanak signala = loss of signal

So the basic idea is: something is no longer there.

Because struje is in the genitive case.

The noun nestanak often takes a noun after it in the genitive, similar to English the disappearance of... or loss of...

• nominative: struja = electricity / current
• genitive: struje

So:

• struja = electricity
• nestanak struje = loss of electricity

This is very common in Croatian. A noun is often followed by another noun in the genitive to show of:

• čaša vode = a glass of water
• kraj filma = the end of the film
• nestanak struje = power outage / loss of electricity

Yes. Struja is the normal everyday Croatian word for electricity or electric current.

In daily speech, Croatians often use struja where English speakers would say electricity or power:

• Nema struje. = There is no electricity / The power is out.
• Došla je struja. = The electricity came back / The power came back on.
• Račun za struju = electricity bill

So in this sentence, struje refers to electrical power.

Yes, it is a very natural and standard expression.

Common ways to talk about a power outage include:

• nestanak struje = power outage
• nema struje = there is no power / the power is out
• došlo je do nestanka struje = there was a power outage
• struja je nestala = the power went out

So Ovo je nestanak struje is grammatically correct and understandable, though in everyday conversation people might more often say something like:

• Nema struje.
• Struja je nestala.

Those can sound more natural in real-life situations.

Croatian does not have articles like English a/an and the.

So nestanak struje can mean:

• a power outage
• the power outage
• just power outage as a general idea

The exact meaning depends on context.

For example:

• Ovo je kuća. can mean This is a house.
• To je problem. can mean That is the problem or That is a problem.

Croatian usually shows definiteness through context, word order, emphasis, or the situation itself, not through articles.

Yes, Croatian word order is more flexible than English word order, although some versions sound more natural than others.

The neutral order here is:

• Ovo je nestanak struje.

You could also hear other orders in special contexts, for emphasis, but they may sound marked or less neutral.

For example:

• Nestanak struje je ovo. — possible, but unusual and strongly emphatic
• Ovo je struje nestanak. — not natural

So for learners, the best version to use is the standard one:

• Ovo je nestanak struje.

A simple approximate pronunciation is:

Ovo yeh NEH-stah-nak STROO-yeh

More carefully:

• Ovo = OH-vo
• je = yeh
• nestanak = NEH-stah-nak
• struje = STROO-yeh

A few useful notes:

• Croatian j is like English y in yes
• je is pronounced roughly ye
• struje has two syllables after str: stru-je
• stress can vary by dialect, but the above approximation is good enough for a learner

It is correct, but it sounds a bit like a definition, label, or explanation rather than the most spontaneous everyday reaction.

It would fit in contexts like:

• explaining a term
• labeling a picture
• identifying a situation
• a textbook example

In ordinary conversation, people are more likely to say:

• Nema struje. = The power is out.
• Nestala je struja. = The power went out.
• Opet je nestala struja. = The power went out again.

So your sentence is good Croatian, but it may sound slightly formal or descriptive depending on the situation.

Nestanak is in the nominative singular here, because it is the predicate noun after je in a sentence like This is X.

Structure:

• Ovo = nominative
• je = is
• nestanak = nominative singular
• struje = genitive singular

So the core pattern is:

• Ovo je + nominative noun

Examples:

• Ovo je problem. = This is a problem.
• Ovo je pitanje. = This is a question.
• Ovo je nestanak struje. = This is a power outage.

Yes. Prekid struje is also a common expression and can mean power outage or interruption of electricity.

There is a slight nuance:

• nestanak struje = the electricity disappeared / loss of power
• prekid struje = interruption of the power supply

In many everyday situations, they overlap a lot.

You may hear:

• Došlo je do prekida struje. = There was a power outage.
• Zbog oluje je došlo do nestanka struje. = Because of the storm, there was a power outage.

Both are useful, but nestanak struje is very common in ordinary speech.