Fuel
We call these autotrophs.
Chlorophyll
they produce the source of chemical energy for themselves and for other organisms. -Biology
What we normally call heat or thermal energy.
The energy stored in fuel is called chemical energy. This energy is released through chemical reactions, such as combustion, to produce heat and other forms of energy.
A wave
We call that ionizing radiation.
Chemists call the energy needed to get a reaction started the activation energy. This energy is required to break the bonds of the reactant molecules before they can form new bonds and produce products.
Fried Rice
A space that contains no matter is called a vacuum. It is a region devoid of particles and energy, creating a near-perfect empty space.
Usable energy is typically referred to as energy that can be easily converted and applied to perform work, such as electrical energy from batteries or kinetic energy from moving objects. It is energy in a form that can readily be harnessed to do useful work or produce heat.
That sounds like the description of "dark matter".