The International Journal of Engineering and Science (The IJES)
Utor Navitas
1. Utor Navitas
BP Ultimate Field Trip
Oil prices are rising and by 2030 humanity will demand fifty
percent more energy than today, due to this the cost of travel is
also increasing. Therefore a solution to considerably reduce the
cost of passenger kilometre travelled per capita needs to be
found.
When any energy transfer occurs not all of the energy is converted
to a useful output, some is wasted. There are two ways to reduce
energy loss, the first being to improve the efficiency of the
system, and the second being to recycle wasted energy and
harness it.
We have decided to focus on recycling wasted energy because we
believe that it is more plausible for a small team with a small
budget to achieve the most effective gains. The amount of time,
money and manpower that would have to be applied to improve
the efficiency of a system to a comparable level would be greater.
2. Piezoelectric Energy
Harvesting Utilising Trains
The idea that we have come up with is to install piezoelectric energy harvesting devices
in the tracks sleepers to take the kinetic energy from passing trains and convert this into
useful electrical energy. Such as powering level crossings, signals and lights.
A prototype system installed last year by Technion University in Israel has shown that a
railway track with a traffic of 10 to 20 ten-car trains per hour across 16 sleepers can
harvest as much as 120 kWh.
Using this data we can say that, assuming 1kWh costs 5p, in one hour over a 100 metre
stretch, we will produce the equivalent of £67.40 worth of electrical energy.
Extrapolating this to 12 hours usage per day for a year, the equivalent of £283100 of
electrical energy is produced.
The harvesters are manufactured by replacing the standard supporting pads in railway
sleepers with piezoelectric energy harvesters, this means that the development and
manufacturing costs are kept low due to the sleeper design remaining unchanged.
Train passes over
piezoelectric generator
placed in sleeper
Piezoelectric generator
converts kinetic energy
into electric power
Electric power converted
and fed back into track
side infrastructure
3. Piezoelectric Energy
Harvesting
Piezoelectric energy harvesting has been researched since the late 1990’s,
but has not yet been implemented for large scale power generation.
However due to advancements in technology it is now possible for efficient
harvesting of energy using piezoelectric systems.
The piezoelectric effect converts kinetic energy into electrical power. The
kinetic energy can come from many sources, low frequency vibrations and
pressure are amongst the most common. Energy output form a
piezoelectric harvesting device is output in alternating current, this means
that it is very easy to interface into most power systems.
Piezoelectric devices have no moving parts therefore require very little
maintenance and have very long lifespans. Due to having no moving parts
and having a similar density to the support pads they replace, no extra
energy is wasted.
Producing piezoelectric energy harvesters can be produced in large
numbers easily and relatively cheaply. Before 2030 it is expected that
nanofibre piezoelectric energy harvesters which will harvest an amount of
electrical energy orders of magnitude above today technology, this could
feasibly assist in powering the trains themselves.
4. Location
China
We based our choice of location on a number of different factors, the most
important of these being the size and growth rate of the railway system.
China is expanding its rail infrastructure faster than any other country. The
secondary reason we have chosen China is that by 2014 they will have
become the largest research body on the planet.
The government in China are also driving rapid expansion of all pubic
services and infrastructure this is the ideal environment to implement our
solution because we can install it along side new rail developments. This will
significantly reduce the costs because a retrofit of an older train line is not
required.
Last year the Chinese government funded approximately 9000km of high
speed rail line. If this rate of infrastructure development continues and
piezoelectric energy harvesting was added to the sleepers this would
represent an approximate saving of £2.5 million per year, assuming operation
schedules similar to those used previously.
The population in China is also expanding and by 2030 it is calculated that
the population of China will reach 1.465 Billion, this will create a very high
demand for energy and also put strain on the pubic transport networks. The
transport networks will have to be upgraded before they fail due to such high
demand. Thus creating even more opportunities to install the piezoelectric
energy harvesting devices.
