Can we use Ember.js to build a static website?

Yes building a static site is how the emberjs.com website it build.

Prember is the tool to build static sites with ember.

The simple answer is yes! Ember is a fantastic technology to build static sites in as @kiwiupover mentioned Prember is the main way to turn an Ember app into a "static site", and if you already have your website built as an Ember App it is very straightforward to add Prember and deploy it on a static site hosting (like AWS S3 or Netlify). If you want the simplest possible way to get started I would recommend deploying to Netlify.

The Ember Website is a great example of a site that is built using Ember and gets great Lighthouse scores because it's also a static site. You can see the code in the public github repo

All that is if you want to build something from scratch, but if you're looking for a super quick way to build a static blog then you could check out empress-blog and you can get a blog up and running in less than 5 minutes if you follow the "super quick start" in the readme on empress-blog.

I have a bunch of other recommendations for building static sites with Ember but you can reach out to me on the Ember Discord (you can find a link on the Community Page)