Hybrid renewable energy systems are becoming popular as stand-alone power systems for providing electricity in remote areas due to advances in renewable energy technologies.

Power plants where a combination of energy sources to make a process more efficient or and less damaging to the environment.

Hybrid nuclear fusion–fission is a proposed means of generating power by use of a combination of nuclear fusion and fission processes.

A two fluid reactor that has thorium in the fuel salt is sometimes called a "one and a half fluid" reactor, or 1.5 fluid reactor.

A specialised type of substation which forms the terminal equipment for a high-voltage direct current (HVDC) transmission line. It converts direct current to alternating currentor the reverse, They are land based facilities and offshore structures for offshore wind farms.

Converts electric power from high voltage alternating current (AC) to high-voltage direct current (HVDC), or vice versa

Heating, ventilation, and air conditioning

High voltage direct current.

High voltage alternating current.

The concentration of water vapor present in the air.

A humid subtropical climate is a zone of climate characterized by hot and humid summers, and cold to mild winters.

A humid continental climate is a climatic region typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold in the northern areas) winters.

Environmental changes caused directly or indirectly by humans.

Hub height is the height of the rotor axis above the ground.

The rotating component of the wind turbine to which the rotor blades are fixed.

Hot working process metals are plastically deformed above their recrystallization temperature.

Hot Wet Rock (HWR) hydrothermal technology makes use of hot fluids found naturally in basement rock.

A hot stick is an insulated pole, usually made of fiberglass, used by electric utility workers when engaged on live-line working on energized high-voltage electric power lines, to protect them from electric shock.

A hot spring is a spring produced by the emergence of geothermally heated groundwater that rises from the Earth's crust.

Hot spots in subatomic physics are regions of high energy density or temperature in hadronic or nuclear matter.