Synchronizing generators is not a good idea for a novice. Just buy one 80 kwatts generator.

Get just one, then you don't need to worry about syncing multiple generators to get all the phases to match, balancing load currents between generators, etc.

Commercially available generators go up to about 2MVA so one that will do around 80kW shouldn't be a problem.

One generator operating at around 75-80% load is fine.

Around 100kVA would work.

This is a simplistic answer of course. You may have some special operating conditions that need to be considered.....

Is this for prime or standby duty? If it is prime what redundancy do you need?

What is the service application? How do you know that your loading is 80kW?

As Wal indicated there is other information required here in order to give a more suitable answer to your query. There is also the type of load, what voltage do you wish to operate (80kw - possibly 400V), does it need to synchronise with the mains, what payback period do you want? If you are unsure what you require, you would be better asking a company that specialises in generator supplies to investigate and offer a solution that is specific to your site.

Normally generators are rated in kVA not kW. Assuming a reasonable power factor go for at least 100kVA. Computer loads are very bad loads so take care. Likewise you must consider the largest drive you have on the plant. A DOL motor has a large start up current and should be no more than 25% the rating of the generator to ensure a start.

If you are connecting to existing plant you will need to consider the Zs of the generator which might be too high to clear your protection.

One. You can rent (buy) gen sets of 1/2 mega watt. Aggreco, GE. Do a web search.i