The result is a material that has an energy density of about 0.005 watt-hours per kilogram.

ECONOMIST: Carbon-composite batteries

This incessant march of energy density (more energy per unit of raw material) has undeniable logic, deniable only by the illogical or irrational.

FORBES: Looking At Nuclear In A New Light

This incessant march of energy density (more energy per unit of raw material) has undeniable logic extending along the entire length of the arrow of progress.

FORBES: Investing in Biofuels or Biofools?

If a source has low power density, then it will likely require too much real estate, material or space to provide the power that we demand at prices we can afford or in the vast quantities that the world needs.

FORBES: The Real Problem With Renewables

He studies the material properties of tissue and organs from animals and cadavers to assign shape, size, density, mass and ten or more coefficients that describe how each cube of virtual flesh will deform when confronted with a given force from a given direction.

FORBES: Smart Dummies