Energy explained simply

Energy is messy. These explainers make it a little less ridiculous — for readers, professionals, and companies alike.

Featured image showing renewable electricity being turned into an e-fuel droplet at a clean fuel plant, with wind, solar, an airplane, and a cargo ship nearby.

What are e-fuels? Turning electricity back into something you can burn

E-fuels do something wonderfully inefficient—and potentially very useful. They take renewable electricity, use it to make hydrogen, combine that hydrogen with captured carbon, and rebuild familiar fuels such as kerosene, methanol, or synthetic diesel. Why bother turning electricity into fuel instead of simply using the electricity? Because some machines are much easier to decarbonize with molecules than electrons.

Illustration of Earth resting beside a geothermal power plant with wells carrying hot and cool water through underground heat.

What is geothermal energy? The renewable power plant hiding under your feet

The Earth is hot beneath our feet—hot enough in the right places to heat cities and generate electricity around the clock. Geothermal energy taps that underground heat, but the real story is more interesting than “find a volcano and drill.” New drilling technologies may be turning one of renewable energy’s most geographically limited resources into something much bigger.

Illustrated Combined-Cycle Gas Turbine plant with glowing hot exhaust moving from a gas turbine through heat recovery equipment to a steam turbine producing electricity.

What is a Combined-Cycle Gas Turbine? Two turbines, one flame

A combined-cycle gas turbine burns natural gas once but extracts electricity in two stages: first from a gas turbine, then from a steam turbine powered by the hot exhaust the first turbine was about to throw away. That simple act of refusing to waste heat is why CCGTs can reach efficiencies around 60%—and why they still matter in a power system filling up with wind, solar, and batteries.

Illustrated winter scene showing a heat pump outside in the snow sending warm glowing heat into a cozy home where a family sits indoors.

What is a heat pump? The heater that refuses to make heat

A heat pump can deliver three or four units of heat while using roughly one unit of electricity. No, it is not breaking physics. The trick is that it does not create most of the heat—it moves heat that was already there. Here is why your refrigerator, air conditioner, and one of the biggest technologies in building decarbonization are basically members of the same family.