Instructables
Picture of Solar Power (Article)
Every project requires energy. It must power the tools and the batteries and the outlets that items are plugged into. With all of the problems that are tied to fossil fuels and so much solar energy out there, why aren’t solar panels everywhere, powering everything? Why can’t we make the switch into the most renewable source of energy? It would be nice, but the clean energy future is still a ways away.

This article is one in a series of Instructables articles about DIY technology. The full list can be seen here.

Photo by Rob Patto from D.I.Y. Solar Setup

Step 1: Power Overwhelming

Picture of Power Overwhelming
A tremendous amount of energy comes from the sun. It lights up our days, helps our plants grow, and generally ensures that life continues on our planet. Add it all up and there is 162 petawatts (162 x 1015 watts) worth of energy coming in all the time. At the same time, our global capacity is only 16 gigawatts (16 x 109 watts). And those solar panels provide the world with less than .1% of its current energy needs. A jump would be nice, but it’s not likely to have an effect any time soon.

Solar panels collect their energy as the light hits the photovoltaic (PV) cells. The PV cells are semiconductors and when the light hits them electrons inside get knocked loose. If this happens enough times it can create a current of electrons moving in one direction. Combine that with the voltage of the PV cell and we get power. Not all of the light gets converted into power, however. Most solar panels are only 12% to 18% efficient.

The light that hits the PV cells is made up of different photons with different amounts of energy. To knock the electrons loose, the photon has to have the right amount of energy. Photons with too little or too much pass right on by. That’s 70% of the energy just moving right along while some other problems taking out a little bit more.

A disadvantage with the solar panels is the cost of production. Prices have been coming down, but are still an investment. In the United States, prices are around $4 per watt. Installing a 100-watt system, enough to power one 100-watt incandescent light bulb, would cost $400. At current electricity prices in California it would take well over a decade for the solar panel to start paying for itself.

Another problem with solar is where to put all of the panels. Energy is lost in transmission, which is why it’s great to put the panels on top of homes. It barely has anywhere to go, it’s the best commute ever. After that, solar installations take up a lot of space that then can’t be used for homes, parks, or anything else. And of course it needs to be installed somewhere where it will get a good amount of sunshine. All of this drastically limits the number of options.

 
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londobali2 years ago
There's a few steps for any alternative energy (or better: all at once) development to be able to replace fossil fuel. But most importantly, energy consumption must be reduced!
I don't mean we should stop using convenient appliances and move back in to caves, we just have to use energy more wisely.
There are so many energy-monster appliances that was (is) inherited from the "cheap" fossil fuel era, that are still being used. They should start to go to the recycle factories to be made into newer more efficient appliances..

Solar panels are expensive, so dont waste it on inefficient appliances!!

There are plenty of articles even books (such as: www.withouthotair.com) that compares the current usage of energy vs the current capabilities of alternative energy.
They compare the energy usage of highly inefficient combustion engine in cars, and calculate how many solar panels needed to get at the same level..
They forget that if we convert to alternative energy, we dont use combustion engines anymore! We'll be using electric cars that are at least three times more efficient (and getting better), as they dont convert the energy to heat and noise as combustion engine does..

Reduce the use (going more efficient), increase the alternative generators!!
The future is in hybrid systems. linking together solar photo voltaic with solar Thermal, advancements in tech still need to be made but we re getting there:)
rimar20003 years ago
Very interesting instructable.

Harnessing solar energy does not go only by the photovoltaic panels. Moreover, I would say that that aspect is secondary.

I built years ago a rudimentary solar cooker using 1 m2 of glass mirrors, and I was surprised by its power, in winter, a windy and cold day. You can see this here and here.

Photovoltaic panels are certainly very useful, because they provide for storing electrical energy, that as heat would soon be lost, but I think it is necessary always to bear in mind the possibility of direct use of solar heat through the different types of solar cookers.
howitgoes (author)  rimar20003 years ago
Yes, solar panels are secondary. The amount of solar energy that gets converted into plant material is far, far greater.