O fornecimento de energia voltou agora.

Fornecimento means supply or provision.
So fornecimento de energia literally means supply of energy/electricity.

In this sentence, it refers to the electric power supply, so in natural English it often corresponds to things like:

• the power supply
• the electricity supply
• the power

In everyday Brazilian Portuguese, people often say simply a energia voltou to mean the power came back.

Because fornecimento is a masculine noun in Portuguese, so it takes o:

• o fornecimento = the supply

This is something learners usually just have to memorize with the noun. A useful pattern is that many nouns ending in -mento are masculine:

• o pagamento
• o documento
• o fornecimento

Here de means of.

So:

• fornecimento de energia = supply of energy

This is a very common Portuguese structure:

• fornecimento de água = water supply
• fornecimento de gás = gas supply
• produção de energia = energy production

Portuguese often uses noun + de + noun where English may use either of or a compound noun.

Both can work, but they are not used in exactly the same way.

• energia is very common in Brazil when talking about household electrical power.
• eletricidade is also correct, but it can sound a bit more technical or formal in some contexts.

So these are possible:

• A energia voltou. = The power came back.
• O fornecimento de energia voltou. = The power supply returned.
• O fornecimento de eletricidade voltou. = The electricity supply returned.

In everyday speech, energia is usually the more natural choice.

Voltou is the third person singular of voltar in the pretérito perfeito (the simple past).

Here:

• voltar = to return / to come back
• voltou = returned / came back

Because the subject is singular:

• O fornecimento ... voltou

This tense is used for a completed event: the power was out, and then it came back.

Because the subject is singular: o fornecimento.

Even though energia appears in the phrase, it is not the main subject. The full subject is:

• O fornecimento de energia = the supply of energy

The head noun is fornecimento, which is singular, so the verb is singular too:

• O fornecimento ... voltou

If the subject were plural, the verb would also be plural:

• Os fornecimentos voltaram = The supplies returned

It can correspond to several English translations depending on context.

In this sentence, natural English could be:

• The power came back just now.
• The electricity supply has returned now.
• The power is back now.

Literally, voltou means returned/came back.
When talking about electricity, English often prefers more idiomatic translations like:

• The power is back
• The power came back

So the Portuguese verb is straightforward, but the best English wording depends on context.

Yes, agora means now, but in this sentence it often has the sense of just now or a moment ago.

So:

• voltou agora = came back now / just came back

In context, this usually means the power returned very recently.

Depending on the situation, agora can also mean things like:

• now
• right now
• at this moment
• just now

Putting agora at the end is very natural in Portuguese.

• O fornecimento de energia voltou agora.

This sounds like: The power came back just now.

Portuguese is often flexible with adverb placement, so you may also see:

• Agora o fornecimento de energia voltou.
• O fornecimento de energia agora voltou.

But these can feel slightly different in emphasis.

• ... voltou agora emphasizes when it came back
• Agora ... can emphasize now, sometimes contrasting with an earlier situation

In ordinary speech, the original sentence is very natural.

A Brazilian would understand it perfectly, but in everyday conversation many people would use a simpler sentence, such as:

• A energia voltou agora.
• A luz voltou agora.

These are more common in casual speech.

A few notes:

• A energia voltou = The power came back
• A luz voltou literally means the light came back, but in Brazil it commonly means the electricity came back

So O fornecimento de energia voltou agora sounds a bit more formal or official, while A energia voltou agora sounds more everyday.

Both can refer to something that happened very recently, but they are structured differently.

• voltou agora = came back now / just now
• acabou de voltar = has just come back

So you could say:

• O fornecimento de energia voltou agora.
• O fornecimento de energia acabou de voltar.

Both are natural, but acabou de + infinitive is a very common Portuguese way to express has just ....

Yes, retornou is grammatically correct, but it usually sounds more formal or less common in everyday speech than voltou.

Compare:

• A energia voltou agora. — very natural, everyday
• A energia retornou agora. — correct, but more formal/stiff

So learners should know retornar exists, but voltar is usually the better everyday choice here.

You absolutely can, and in many cases that is the most natural option.

Compare:

• A energia voltou. = The power came back.
• O fornecimento de energia voltou. = The power supply returned.

The longer version is more explicit and more formal. You might see it in:

• official announcements
• utility company messages
• news reports
• formal writing

The shorter version is what people often say in daily life.

Yes. In Brazilian Portuguese, energia very often means electrical power/electricity, especially in everyday contexts.

For example:

• A energia caiu. = The power went out.
• A energia voltou. = The power came back.
• Conta de energia = electricity bill

So even though energia can mean energy in a broad sense, in this kind of sentence it is normally understood as electricity.

In natural English, The power has just come back is often the best translation.

Portuguese voltou agora uses the simple past plus agora, but English often prefers the present perfect with just for very recent events.

So possible translations are:

• The power has just come back.
• The power came back just now.
• The electricity supply has just returned.

All of these can match the Portuguese sentence, depending on style and context.