There has been many an attempt made to produce the so called renewable energy. The machines required for this need to have certain characteristics–namely, the ability to work without wear and tear for a long time. An automobile or a lawn mower engine, with its limited duty cycle will simply not do. A modern car is designed to work for about 4000 hours between major overhauls.
Eco-Friendly Vehicles?
Another trend in hyping of these new fangled machines is the undue importance given to the most “eco-friendly” component of the system.
Hybrids
A hybrid is considered more environmentally benign choice compared to the standard gasoline engine. However, consider this–the hybrid is really two machines in one, and instead of driving a single car, you are now simultaneously driving two! The environmental impact of manufacturing a single car would be enormous. In fact, several sources give the amount of money that you might spend on gas in the couple of years you own a car–considering a reasonable distance of 30,000 miles, you would spend less than $5k even at the highest prices. This means that the cost of the vehicle, which is mostly manufacturing cost, would be about an order of magnitude larger than the fuel cost. Since the energy cost is significant factor in determining the manufacturing cost, this is definitely something to be considered during purchase.
Regenerative Braking
Another much touted feature in such cars is regenerative braking. Whereas you need energy to accelerate your car, you can theoretically get it back when braking. These cars claim to have brakes that will feed the energy into batteries while braking improving fuel efficiency. However, this needs some qualification—it is only available if you brake gently. In that case you might
Historical Energy Sources
A common sight in the middle ages was the truly renewable energy source of a dog wheel. A small dog would be made to run inside a giant hamster wheel. Now, we make jokes about things powered by hamsters, but the few watts produced by a small canine was very useful in those days. Farmers used small animals like sheep to run small machines, the ones that did not require “horse power”. Here the animal walks on an inclined tread mill, which drives a small machine.
The earliest machines were powered by water, and it was used to power fountains and carry water from a lower level to a higher level. Hopefully, the source of water was a stable one, like the palaces of Louis XIV in Versailles. Some of the kingdoms in south east Asia were not so fortunate, the river having shifted course, rendering their elaborate constructions useless.
Inherent Inefficiencies of Local Power Generation
Small machines inherently have greater frictional resistance when operated in a piston cylinder arrangement. Large machines have their own problems, mainly the manufacture of such large cylinders and fitting pistons. However, since the surface area per unit volume for the smaller machines were much larger, the frictional losses were larger too.
Tags: animal power, hybrid, Renewable energy
