Místo abych spotřeboval více elektřiny, vypnu spotřebič.

It means instead of me doing... or more naturally in English, instead of doing...

In full, Czech often says:

• Místo toho, abych...

In everyday use, toho is often omitted, so:

• Místo abych spotřeboval více elektřiny...

means the same as:

• Místo toho, abych spotřeboval více elektřiny...

So the structure is basically:

• místo (toho), abych + verb = instead of my doing / instead of doing

Because abych is the 1st person singular form: so that I / for me to

The forms are:

• abych = so that I
• abys = so that you
• aby = so that he/she/it/they
• abychom = so that we
• abyste = so that you plural/formal

So in this sentence, the subject is I, which is why Czech uses abych.

This is a very common learner question.

Spotřeboval does look like a past-tense form, but after abych it is not actually past tense. It is part of a different construction.

Czech uses:

• abych + l-participle

So:

• abych spotřeboval

means something like:

• for me to consume
• that I consume
• instead of consuming

depending on context.

So although spotřeboval by itself can be part of the past tense, here it is being used in a clause with abych, not as a simple past.

Yes, aspect matters here.

• spotřebovat = perfective, to use up / consume
• spotřebovávat = imperfective, to be consuming / consume repeatedly

In your sentence, spotřeboval presents the action as a whole, completed action: consume more electricity.

That works well if the idea is:

• Rather than consume more electricity, I switch the appliance off.

If you wanted to stress an ongoing or habitual process, an imperfective form could be possible in another context, for example:

• Místo abych spotřebovával víc elektřiny...

But your original sentence is grammatical and natural enough.

Because více meaning more is followed by the genitive.

So:

• více elektřiny = more electricity

Here:

• elektřina is the dictionary form
• elektřiny is the genitive singular

This is very common after quantity words and expressions such as:

• hodně vody = a lot of water
• málo času = little time
• více peněz = more money

They both mean more.

• více = a bit more formal or neutral
• víc = more common in everyday speech

So both are possible here:

• více elektřiny
• víc elektřiny

The sentence with více sounds slightly more careful or written; víc sounds more conversational.

Vypnu is from the perfective verb vypnout = to switch off / turn off.

It is formally a present-tense form, but with a perfective verb, Czech present forms usually refer to the future:

• vypnu = I will turn off / I turn off

So in this sentence, it means a single completed action:

• I switch off the appliance
• I will switch off the appliance

depending on context.

This is one of the most important things to remember in Czech:

• imperfective present = real present
• perfective present = future meaning

Because the two verbs give different meanings.

• vypínám = I am switching off / I switch off regularly
  
  • imperfective
  • ongoing or habitual
• vypnu = I will switch off / I switch off
  
  • perfective
  • one complete action

In your sentence, vypnu fits well because the speaker is choosing one concrete action: I turn the appliance off.

If you said vypínám spotřebič, it would sound more like:

• I am turning the appliance off
• I switch the appliance off regularly

So vypnu is the better match here.

Because Czech usually drops subject pronouns when they are not needed.

The verb ending already shows the person:

• abych spotřeboval = I would consume / for me to consume
• vypnu = I will turn off

So já is unnecessary unless you want extra emphasis or contrast.

For example:

• Já vypnu spotřebič, ne ty. = I’ll turn off the appliance, not you.

But in a neutral sentence, leaving out já is normal.

Because Czech has no articles.

So spotřebič can mean:

• an appliance
• the appliance

The exact meaning depends on context.

That is normal in Czech. The language relies on context, word order, and the situation instead of articles.

Because Místo abych spotřeboval více elektřiny is a subordinate clause, and in Czech subordinate clauses are normally separated by a comma.

So the structure is:

• Místo abych spotřeboval více elektřiny, = subordinate clause
• vypnu spotřebič. = main clause

Czech punctuation is usually stricter than English here, so the comma is important.

Yes. Czech word order is flexible.

For example, you could also say:

• Vypnu spotřebič místo toho, abych spotřeboval více elektřiny.

That means essentially the same thing.

Your original version puts the instead of... idea first, which gives it a bit more emphasis:

• Instead of consuming more electricity, I switch off the appliance.

So the original word order is perfectly fine and highlights the contrast well.