The electricity a wind farm uses itself
A wind farm can become an electricity customer when the wind drops. Its own meters reveal the motors, controls and heaters behind that change of direction.
A place for slower thoughts
Stored Sunlight
Energy storage and the material limits behind useful power.
Words by Amara Finch
The archive
5 storiesFrom the notebook
Pumped storage starts with two reservoirs
Pumped storage lifts water when electricity is available and sends it downhill when the grid needs it. The reservoirs hold the energy; the head, machinery and landscape set the limits.
What a solar panel rating leaves to the weather
The wattage on a solar module is a measurement at agreed test conditions. Sun angle, cloud, cell temperature, shade, wiring and the inverter determine what reaches a meter over time.
The useful heat left in a hot-water tank
A tank's litres and average temperature can hide the hot layer that actually serves the next draw. Stratification preserves useful delivery temperature; mixing, flow and standby losses change what remains available.
Why a battery has more than one measure of health
A full charge, remaining capacity, power delivery and future life are different battery questions. Good measurements name the task, test conditions and limits of each result.