聚变能(又称核融合能源)指利用核聚变产生能量。 聚变反应是一种结合两个较轻核子产生较重核子的高能反应。合并时，部分质量丧失转换为能量_(根据)。融合能研究主要关注于驾驭这个反应并作为大规模可持续能源的来源。

几乎所有针对大规模商业应用提出的方案，热量都由受控核聚变产生的中子散射提供，并如同现今核能、火力发电厂一般，提供给蒸汽涡轮发动机发电。

许多不同的融合能概念曾被提出，截至January 2016年 (January 2016-Missing required parameter 1=month!)，主要的设计为托卡马克以及惯性约束聚变。这些技术还无法用于商业运转，目前启动以及维持反应所需的能源大于产出。

Fusion power is the generation of energy by nuclear fusion. Fusion reactions are high energy reactions in which two lighter atomic nuclei fuse to form a heavier nucleus. When they combine a release of energy is expected in accordance with Einstein's formula . This major area of plasma physics research is concerned with harnessing this reaction as a source of large scale sustainable energy. There is no question of fusion's scientific feasibility, since stellar nucleosynthesis is the process in which stars transmute matter into energy emitted as radiation.