Natural Environment Blog

Blogging for the Natural Environment

Month: July 2010

More Efficient Solar Power for Batteries

University of southern California experts show us a more powerful use of graphene solar panels.

Is it possible to imagine people powering their cellular phone or music/video device while jogging on a sunny day?

A University of Southern California team has produced flexible transparent carbon atom films that may have great potential for a new breed of solar cells.

In a paper recently published in the journal ACS Nano, researchers stated that organic photovoltaic (OPV) cells have been proposed as a way to create low cost energy due to their ease of manufacture, light weight, and compatibility with flexible substrates.

This work shows that graphene, an extremely conductive and highly transparent form of carbon consisting of atoms-thick sheets of carbon atoms, has high possibility to fill this role.

While graphene’s existence has been known for many years, it has only been studied extensively since 2004 because of the impossibility of manufacturing it in high quality and quantity.

The Study

The University of southern California team has produced graphene/polymer sheets ranging in sizes approximately 150 square centimeters that in turn can be used to create dense arrays of flexible organic photovoltaic (OPV) cells.

These organic photovoltaic (OPV) devices convert solar radiation to electricity, although not as efficiently as silicon cells.

The power provided by sunlight on a sunny day is approximately 1,000 watts per meter square, for every 1,000 watts of sunlight that hits a square meter area of the standard silicon solar cell, 14 watts of electricity will be generated, Organic solar cells are less efficient; their conversion rate for that same 1,000 watts of sunlight in the graphene-based solar cell could be only 1.3 watts.

Benefits of OPV

But what graphene organic photovoltaic (OPV) lack in efficiency, can potentially be compensated by its lower price and, greater physical flexibility.

Researchers think that it may eventually be possible to cover with inexpensive solar cell layers extensive areas like newspapers, magazines or power generating clothing.

In the meanwhile Prof. Ruoff and his colleagues of the mechanical engineering department at the University of Texas at Austin, are studying the basic science in the development of graphene-based ultracapacitors for usage in electronics and other fields.

Batteries vs Ultracapacitors

Prof. Ruoff says batteries are relatively slow, they can store energy but require sometime to charge up, and then they distribute energy slowly, over time.

Ultracapacitors can be charged quickly, within seconds, and discharge in a short time, but, right now, they’re not able to store very much electrical energy.

The introduction of stable and less expensive ultracapacitors could be a key step in using wind or solar-generated power, specially if researchers can discover methods to enable capacitors to store energy longer, that is not yet possible.

Current Potential Usage

Even with their current storage capacity, the graphene devices could provide quick energy when needed in certain situations on the ecological way.

They could be used, as an example, to absorb the heat generated in braking an automobile or train, and store it for a short time, and use it for the electrical needs of the vehicle (i.e. starting the car or acceleration).

About the writer – Sophia H. Walker writes for the solar panel battery charger blog, her personal hobby site focused on tips to help individuals save energy using solar power for small devices.

Statistics Behind World Carbon Dioxide Emissions

Chris over at recently informed me of an infographic on their website. The infographic shows some interesting statistics on world carbon dioxide emissions.

For example, according to the infographic, in 2009, China produced 6,200 million tonnes of CO2 compared to 5,800 for the United States. One only needs to look at the population of these two countries to see that something appears to be out of whack.

China has over 4 times the population of the US and yet, the US emits almost as much CO2 as China. Unfortunately, this gap is bound to widen as China becomes more and more prosperous.

As one would expect, the infographic has an airline/transport spin (no doubt due to the fact that its on a flight website), so there are some interesting statistics in that area.

A copy of the infographic is below. Due to its size, I’ve resized it to fit on this blog.

You can view the full-sized infographic here.

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