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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
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
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Signing UpStep 1Power 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.
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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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.