One often overlooked idea for a renewable energy source is fusion. Fusion could, in theory, provide almost unlimited energy without carbon emissions and, unlike fission reactors, little radioactive waste. Over the past decade fusion has advanced by leaps and bounds, and two up-coming projects are ITER, or the International Thermonuclear Experimental Reactor, and the Wendelstein 7-X are the paragons of those advancements. ITER, under construction in Cadarache, France, is the result of a collaboration of 35 nations (2) and plans to first fuse its deuterium and tritium fuel mix around 2025 (2). Commercial fusion is still many decades away, as all currently operating reactors consume more energy than they release, and all are prohibitively expensive (3). The ITER however, would be an ideal research platform to study more efficient fusion processes and nuclear reactions. The Wendelstein 7-X, or W7X, is a reactor that finished construction in 2014 and is the largest stellarator in the world (4). Stellarators are one of the most promising ideas in the field of nuclear fusion, a s they can sustain fusion for a projected time of 30 minutes (5). For comparison, the longest plasma fusion record was 6 minutes and 30 seconds (4). This means that stellarators could have huge potential as commercial power sources. But fusion has its downsides. Tritium, a primary fuel of current fusion reactors, is in short supply. ITER will ultimately need one kilogram of tritium annually, and the total amount of tritium in the world right now is... 25 kilograms (3). This is obviously not sustainable. You might be thinking, 'well, why not just use a 100% deuterium fuel, deuterium occurs natural in most water sources and is relatively easy to extract' and the reason this is rarely used is that the fusion of deuterium produces 1/100 of the amount of energy tritium does (3). This is not necessarily a roadblock though, as one of the goals of ITER is to create tritium inside of the tokamak by the bombardment of deuterium (2). Another problem for the ITER and W7X is that they were incredibly expensive to create, so there won't be any large-scale adoption of their designs any time soon. Other companies however, are setting their sights on smaller fusion reactors, such as Lockheed Martin's Compact Fusion Reactor project (1). This, in my mind, is a great example of where fusion is going as a sustainable energy source: it is an idea with solid research and funding behind it, so companies and labs and countries will push, sometimes slowly, to advance the field until it becomes a viable energy source.
So what do you all think? Do you think that it is too expensive, too far of a leap to take, and too much time that could be spent doing other things or do you think that it is a good idea that we should put money and time into?

Links
1: http://www.world-nuclear.org/informatio … power.aspx

2: https://www.iter.org/proj/inafewlines

3: https://thebulletin.org/iter-showcase-d … nergy11512

4: https://www.businessinsider.com.au/germ … or-2015-10

5: https://www.euro-fusion.org/news/detail … ge-again/?