חברת החשמל השתמשה בהערכת צריכה.

Because חברת is the construct form (called סמיכות) of חברה.

Hebrew often expresses X of Y by putting two nouns together:

• חברה = company
• חברת החשמל = the electricity company / the electric company

For many feminine nouns ending in ־ה, the ending changes to ־ת in the construct form:

• חברה → חברת
• הערכה → הערכת

So חברת החשמל literally works like company of the electricity.

For the same reason: it is also in the construct form.

• הערכה = an estimate / an evaluation
• הערכת צריכה = consumption estimate or literally estimate of consumption

Again, feminine nouns ending in ־ה often become ־ת in construct:

• הערכה → הערכת

So הערכת צריכה is a noun phrase made of two nouns, not an adjective + noun combination.

In a construct chain, the definiteness is usually shown on the last noun, not the first one.

So:

• חברת החשמל = the electric company
• not החברת החשמל

The first word חברת is in construct, so it normally does not take ה־. The second word, החשמל, makes the whole phrase definite.

This is very common in Hebrew:

• בית הספר = the school
• דלת הבית = the door of the house / the house’s door

Because here the phrase is indefinite: a consumption estimate, not the consumption estimate.

• הערכת צריכה = a consumption estimate
• הערכת הצריכה = the consumption estimate / the estimate of the consumption

So the sentence is talking about using an estimate of consumption, not necessarily one specific known estimate.

Because the verb להשתמש means to use, but in Hebrew it takes the preposition ב־.

So Hebrew says, literally:

• להשתמש ב... = to use ...

Examples:

• השתמשתי בעט = I used a pen
• הם השתמשו במחשב = they used a computer

So:

• השתמשה בהערכת צריכה = she/it used a consumption estimate

This is one of those verb + preposition combinations that you simply have to learn.

Because the subject, חברת החשמל, is grammatically feminine singular.

The base noun is:

• חברה = company

Since חברה is feminine, the verb agrees with it:

• השתמשה = she/it used

Even though English uses it for a company, Hebrew still treats company as a feminine noun, so the verb is feminine.

The dictionary form is להשתמש = to use.

In this sentence:

• השתמשה = she/it used

This is the past tense, third person feminine singular form of להשתמש.

A few related forms:

• השתמשתי = I used
• השתמש = he used
• השתמשה = she used
• השתמשו = they used

It can be understood both ways depending on context, but very often חברת החשמל refers to the specific Israeli electric utility, basically the Israel Electric Corporation.

Literally, though, it is just:

• חברת = company of
• החשמל = the electricity

So grammatically it means the electricity company.

No. Here צריכה means consumption.

That can confuse learners because צריכה can also look like the feminine form of צריך in sentences such as:

• אני צריכה = I need / I am in need of ... (said by a woman)

But in your sentence, צריכה is a noun, not a verb/adjective form. In the phrase הערכת צריכה, it clearly means consumption, especially in an electricity-related context.

In theory, you could sometimes rephrase noun relationships with של, but here the construct form is much more natural.

Natural:

• חברת החשמל
• הערכת צריכה

Less natural here:

• החברה של החשמל
• הערכה של צריכה

Hebrew often prefers the construct form for compact noun phrases like these, especially in formal or written language.

A simple pronunciation guide is:

Khevrat ha-khashmal hishtamsha beha'arakhat tsrikha.

A more natural English-style transliteration might be:

Khevrat ha-chashmal hishtamsha be-ha'arakhat tzrikha.

A few notes:

• ח is a throaty sound, like German Bach
• כ/ח in חשמל is also that throaty sound
• חברת is usually pronounced khevrat
• השתמשה is hishtamsha
• בהערכת begins with be-

The structure is:

Subject + verb + prepositional phrase

• חברת החשמל = subject
• השתמשה = verb
• בהערכת צריכה = prepositional phrase, completing the idea of what was used

So it is a normal, straightforward Hebrew sentence pattern. English speakers often expect a direct object after used, but in Hebrew the verb להשתמש takes ב־, so the complement comes as a prepositional phrase instead.