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> they just transform it from food via a roundabout process that produces lots of waste. You mean like any other machine that generates power? A human on a bic
by the_gastropod 9y ago
> they just transform it from food via a roundabout process that produces lots of waste.
You mean like any other machine that generates power? A human on a bicycle, assuming a ~20% efficiency of converting food calories to muscle output, gets a gasoline equivalent 600-1000mpge (https://en.wikipedia.org/wiki/Bicycle_performance https://en.wikipedia.org/wiki/Bicycle_performance). And unlike a car, using a bicycle has health benefits.
- jdietrich 9y agoHumans are a pathetically inefficient motor; Gasoline engines are around 30% efficient and battery-electric drivetrains are more than 90% efficient. A bicycle looks efficient because that inefficient motor is also pathetically low in power - a typical recreational cyclist can only sustain about 120 watts of output. The leading vehicles in the Shell Eco-marathon routinely exceed 10,000 MPGe. PAC-Car II is the current world record holder, achieving 12,600 MPGe on hydrogen fuel. Photovoltaic cells are also astonishingly more efficient than photosynthesis. The theoretical maximum efficiency of photosynthesis is ~11%, but most plants only achieve 3-6% efficiency. The leading commercially-available PV panels achieve ~22% efficiency and prototype concentrator PV cells have achieved over 46% efficiency.
- dom0 9y ago> 10,000 MPGe ... 12,600 MPGe (0.024 l/100 km, 0.019 l/100 km)
- the_gastropod 9y agoComparing these completely not road legal cars to technology from the 19th century is a stretch. I can legally ride my ~600MPGe bike on the streets TODAY. If PAC-CAR II equivalent cars are available to the mass market within our lifetimes, it will be impressive.
- jdietrich 9y agoElectrically-assisted velomobiles are road-legal in most jurisdictions. http://www.go-one.us/ http://www.go-one.us/
- dom0 9y ago> 600-1000mpge (0.24 - 0.4 l/100 km)