Selvitämme suuren energiankulutuksen syyn.

Selvitämme is the 1st person plural present tense form of the verb selvittää.

• selvittää = to find out, investigate, clarify, sort out
• selvitämme = we find out / we investigate / we clarify

So the ending -mme tells you the subject is we.

Also, Finnish present tense often covers both present and near-future meaning, so depending on context selvitämme can mean:

• we are investigating
• we investigate
• we will find out

They are ending in -n for different but related reasons.

1. suuren is the genitive singular of suuri (big, large, great).
2. energiankulutuksen is the genitive singular of energiankulutus (energy consumption).
3. syyn is the object form of syy (reason, cause) in this sentence.

Here is the structure:

• suuren energiankulutuksen = of great/high energy consumption
• syyn = the reason/cause as the object

So the first two words form a genitive phrase modifying syyn, and syyn itself is in the form used for a complete object.

Finnish usually does not use a separate word like English of here. Instead, it often uses the genitive case.

So:

• energiankulutuksen syy = the cause of energy consumption
• literally something like energy-consumption's cause

And because suuren modifies energiankulutuksen, it also agrees with it in case:

• suuri energiankulutus = high energy consumption
• suuren energiankulutuksen = of high energy consumption

This is a very common Finnish pattern.

Because Finnish uses compound words very freely.

energiankulutus is made of:

• energia = energy
• kulutus = consumption, use

Together:

• energiankulutus = energy consumption

This is extremely normal in Finnish. English often writes these as two words, but Finnish often combines them into one noun.

Then the genitive form is:

• energiankulutus → energiankulutuksen

Because syyn is the object form here.

The basic form is:

• syy = cause, reason

But in this sentence, the cause is the thing being investigated or found out, so it functions as the object of the verb selvittää.

With a total object in the singular, Finnish usually uses a form that looks like the genitive:

• syy → syyn

So:

• Selvitämme syyn = We will find out the cause

If the meaning were more incomplete or ongoing, Finnish might use a partitive instead:

• selvitämme syytä = we are investigating the cause / looking into the cause

That is an important Finnish object-case distinction.

Because syyn suggests a total object: the cause is treated as something definite and bounded, something that will be fully identified or clarified.

Compare:

• Selvitämme syyn.
  = We will find out the cause / determine the cause.

• Selvitämme syytä.
  = We are investigating the cause / trying to figure out the cause.

The difference is not always easy to translate directly into English, but in Finnish it reflects whether the object is seen as complete/resultative (syyn) or ongoing/partial/open-ended (syytä).

Suuren is the genitive singular of suuri.

Forms:

• suuri = big, large, great
• suuren = of a big/large/great ...

This is not just suuri + n. The word changes its stem:

• suuri → suure- → suuren

This kind of stem change is normal in Finnish adjectives and nouns.

Because suuren modifies energiankulutuksen, it must match it in case and number:

• suuren energiankulutuksen = of high energy consumption

In natural English, it usually means high energy consumption rather than literally big energy consumption.

The adjective suuri often corresponds to:

• big
• large
• great
• and in some contexts more naturally high

So in this sentence, suuren energiankulutuksen syy is best understood as:

• the cause of the high energy consumption

Because Finnish has no articles.

There is no direct equivalent of English a/an or the in most normal sentences. Whether something is indefinite or definite is usually understood from:

• context
• word order
• case marking
• the situation being discussed

So:

• syy can mean a cause or the cause
• energiankulutus can mean energy consumption or the energy consumption

In this sentence, the context makes it natural to translate the phrase as the cause of the high energy consumption.

The word order is quite normal.

• Selvitämme = verb
• suuren energiankulutuksen syyn = object phrase

So the structure is basically:

• We investigate/find out + the cause of the high energy consumption

Finnish word order is more flexible than English because cases show grammatical relationships, but this sentence uses a very straightforward order.

You could move things around in some contexts for emphasis, but this version is the most neutral and natural.

Yes, potentially.

Finnish present tense often covers meanings that English divides between present and future.

So Selvitämme suuren energiankulutuksen syyn can mean, depending on context:

• We are investigating the cause of the high energy consumption
• We will determine the cause of the high energy consumption
• We are going to find out the cause of the high energy consumption

The exact English translation depends on the broader situation, not just the verb form by itself.