HyperSizer is computer-aided engineering (CAE) software used for stress analysis and sizing optimization of metallic and composite structures. The wind turbine design industry uses the program to design 100-meter long blades that are light and manufacturable.

Hyperboloid cooling tower, where the hyperboloid geometry's structural strength is used to support an object high above the ground.

A hydrothermal vent is a fissure on the seafloor from which geothermally heated water discharges.

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

Hydrothermal explosions occur when superheated water trapped below the surface of the earth rapidly converts from liquid to steam, violently disrupting the confining rock.

Hydrothermal circulation is the circulation of hot water.

Fluid statics or hydrostatics is the branch of fluid mechanics that studies "fluids at hydrostatic equilibrium and the pressure in a fluid or exerted by a fluid on an immersed body".

The pressure at any given point of a non-moving (static) fluid.

In fluid mechanics, hydrostatic equilibrium is the condition of a fluid or plastic solid at rest.

Hydronics (hydro- meaning "water") is the use of liquid water or gaseous water (steam) or a water solution (usually glycol with water) as heat-transfer medium in heating and cooling systems.

Harnessing of water to produce energy.

Hydrology is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability.

A unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors.

Wind turbines that stand atop a a tower with the blades upstream of the tower and must be pointed into the wind.

Is the worlds largest wind farm by capacity with 1,218 megawatts (MW) of capacity.

Horizontal wind shear is a change in wind speed with a change in lateral position for a given altitude.

Heat exchangers of shallow buried corrugated pipe in small areas.

Deep Horizontal drillhole disposal is the concept of disposing high-level radioactive waste from nuclear reactor in deep horizontal boreholes instead of in more traditional deep geological repositories that are excavated like mines.

A homopolar generator is a DC electrical generator comprising an electrically conductive disc or cylinder rotating in a plane perpendicular to a uniform static magnetic field.

The density at all points of a homogeneous object equals its total mass divided by its total volume.