There is an observational limit to the universe. Due to expansion, there is a certain distance where the rate of expansion exceeds the speed of light. That point is at about 14 billion light years. That means, if expansion continues, that we will never see any light emitted from beyond that point. Our observable universe is larger, but that's another topic. Anyway, there is an observable limit to what we can see in the universe. Since we will never see anything beyond that limit, it is impossible to say one way or another if there is an infinite or finite amount of energy in the universe. The only thing we could do is measure the amount of energy in the observable universe, but the observable universe is an open system so our measurement would be ever-changing. The entire universe that exists outside the observable universe, well we just don't know if it's open or closed nor will we ever know until the expansion of space ceases.

When trying to reach a conclusion, I like to use Occam's razor. While it doesn't always hold true, the theory with the least amount of assumptions is typically correct. I reason that that is there is an infinite amount of energy and space in the universe based on Occam's razor. You only have to make one assumption, that it's infinite. If you assume it is finite, then you have to make assumptions about the size of the universe that exists outside our observable universe, its shape, its boundaries, if anything does or does not exist beyond its boundaries, how much of everything it contains, and probably many other assumptions I can't think of.

So I would assume an infinite amount.

I am not a Physicist per say but very close anyway. "Do we know is there a finite amount of energy in the universe?". No, we don't. To say yes it will imply it has been properly measured and accounted for (we cannot even agree on dark matter). However, a much more important concept to grasp here is that we keep learning more every day and we won't stop...hope this helps

Thanks Guys. Here is my thinking, bearing in mind I an no physicist by many light years, and this is probably standard thinking anyway. If the the universe we exist in is finite, and there is an expansion, it must eventually either reach a critical mass point and collapse, or keep expanding until it runs out of energy and becomes entropic. If one of these models is the case, and bear in mind that I am a bear of little brain in this area, which is the prevailing model and if not, is there any consensus as to what is?

That's not an easy question to answer. We have an estimate of how much mass and energy our universe contains, although "contains" is also confusing. Our universe IS its mass and energy. Also, keep in mind that mass and energy are equivalent according to Einstein's E=mc^2 relationship. In addition, according to our current understanding of cosmology, about 95% of the mass and energy is not visible or measurable. But the simple answer to your question is that the energy in our universe is not infinite.

I was under the impression it was finite i think it has something to do with thermodynamics ( i may be wrong)

The deeper into space you go, the more energy you will discover - so my answer is infinite.