Energy Converter

A kettle is 95% efficient and a power station is 45%. That's not engineering quality — it's the second law of thermodynamics, and it explains heat pumps too.

Hydrogen fuel cell vehicles require 3× more renewable electricity per kilometre than battery EVs — not because the vehicles are worse, but because electrolysis → compression → fuel cell conversion chain loses efficiency at each step. Here's the full well-to-wheel efficiency comparison, why hydrogen's 120 MJ/kg energy density is undercut by its terrible volumetric density at 700 bar, and the BTU-to-kW conversion that makes US and European appliance ratings incomparable without conversion.

A horsepower is not a horse's actual sustained output — James Watt's 1780s definition was deliberately set high (about 745 watts) to make steam engines look better in comparison to the horses they replaced. Here's why three different definitions of "horsepower" (mechanical, metric/PS, electrical) produce different watt values, why old American muscle car horsepower figures were inflated by the SAE gross testing methodology, and how torque and power are related (and why each matters differently for real driving).

A "5 kW" solar system doesn't produce 5 kWh every hour — kW measures the rate of production (power), kWh measures the total amount produced (energy), and conflating these is the most common error in solar estimates. Here's how "peak sun hours" translates rated kW into estimated daily kWh, why capacity factor explains why solar's "rated power" and "actual output" differ so much, and how to compare a system's estimated production against your electricity bill's kWh usage.

Food calorie labels use Atwater values from the 1890s and don't account for the thermic effect of food, the difference between raw and cooked, or gut microbiome variation. Here's what food calories actually measure, why protein delivers fewer net calories than the label suggests, and why individual calorie extraction varies.