Solar Power
US photovoltaic radiation insolation 2004
Solar power. That great fiery sphere in the daytime sky, provider & facilitator of all life on earth - the sun. Much revered, sometimes feared, adored as a godlike entity, baking us in summer & warming us in winter. A medium sized star in the scheme of the universe but responsible for mankind, flora & fauna flourishing & evolving. For roughly 4.5 billion years the sun has been bathing the earth with solar energy. Modern technology has enabled us to capture solar power more efficiently than ever before.
How is solar power produced? Sunlight, which is essentially electromagnetic radiation emitted by the sun, is made up of particles known as photons. These photons, which are basically units of electromagnetic radiation, are absorbed by solar cells which excite electrons within the semi conductor layers of these cells. This produces what's known as the photovoltaic effect which produces an electric field inside the cell, thus producing direct current electricity. This can now be used by converting the DC power into AC power by way of an inverter or stored in batteries for use on those cloudy days or during the night. Solar panels or photovoltaic panels are made up of single cells wired in series. Solar panels come in many different sizes, shapes, wattage, materials & most importantly, cost. The old adage of 'you get what you pay for' is very evident when shopping for solar powered systems.
Is solar power expensive? It certainly can be. Can you build your own solar powered system yourself? Could you scrounge up enough materials on say eBay, at a junkyard or hardware store? Absolutely. Are you handy enough given the right tools, materials & know-how to build your own solar panels & install the array & infrastructure to produce your very own solar power? Or do you get it done professionally? We all know that going this way could take a sizable chunk out of your wallet if you want to take a sizable chunk out of your power bill. These are all issues that need to be addressed depending on your budget, DIY skills, motivation, time & your ultimate goals. But you’d have to weigh up the pros & cons. Do you live in a particularly sunny area?
The image to the upper left depicts photovoltaic radiation insolation in the USA mid 2004. The light to dark orange ares are obviously particularly sun drenched locations. For the best results regarding capturing the most amount of solar energy possible, solar panels should be tilted to the latitude of your location. For instance, if you lived in Phoenix Arizona, latitude 33º 26’ 53’ N, then ideally you should tilt your solar array at around 33.5º or thereabouts. Obviously this can be impractical. It is much easier to fix a solar array to the existing pitch of your south facing roof area but there are other options. If your roof pitch is too shallow, then solar array systems that employ adjustable pitching are a solution. What if you don’t have a south facing gable? Solar power can be captured even more efficiently with active or passive solar trackers which are mounted on free standing posts. Active solar trackers commonly use small gear driven arrangements & these units can be as basic or extravagant as your budget allows. High end models not only track the sun’s movements during the day, but also self adjust for optimal declination from season to season. They also reset each evening to face the morning sunlight. Two main types of active solar trackers are single axis & dual axis. Single axis trackers are of either horizontal types which are fixed south facing & only move to suit the sun’s path in a given season. Polar type single axis trackers have a fixed inclination but move in a radial path to face the sun over the course of the day. Dual axis trackers move vertically & horizontally therefore maximizing solar power collection. These do consume some power but is offset by their efficiency. Up to 15% more solar power is collected in winter & anywhere from 40% to 60% in summer. Passive solar trackers are a much cheaper alternative consuming no power but aren’t quite as accurate at tracking the sun’s path as active solar trackers but the difference is insignificant. These trackers utilize low boiling point fluids much like refrigerant in cylinders aligned on the eastern & western sides of the solar array. The sun’s heat & gravity creates an imbalance within the cylinders at dawn & so the fluid will equalize the difference across the array thus pointing it squarely at the sun & continues to do so throughout the day. Well built models employ ‘shock absorbers’ at the pivotal points that provide the tower with increased strength & stability in windy conditions.
One final thought to consider. On the other side of the ledger, solar energy is free. The sun will rise tomorrow & the day after that. There’s actually more than enough solar power to provide even the hungriest energy consumers across the globe. Our dependence on fossil fuels could be completely eliminated such is the potential solar power just waiting to be collected. So the question is, do you want to spend thousands of your hard earned cash on a decent size solar array to minimize your power bill? Do you just want to save power or will your system have the capacity to make your meter spin backwards? Power grid feed in tariffs vary widely depending on where you live & are an excellent incentive. Many states & counties offer sales tax & property tax incentives for renewable energy systems as well as rebates, grants & utility loans – the list is large. More details are available on the Wind Power page. One other thing, if you’re lucky enough to have a shed, workshop or barn with a separate electricity meter, then that’s a great opportunity to produce your own solar power purely to make money with feed in tariffs & incentives to help your community as well. I for one would love to be paid by my utility company to help light up my town & produce some green energy of my own.
How is solar power produced? Sunlight, which is essentially electromagnetic radiation emitted by the sun, is made up of particles known as photons. These photons, which are basically units of electromagnetic radiation, are absorbed by solar cells which excite electrons within the semi conductor layers of these cells. This produces what's known as the photovoltaic effect which produces an electric field inside the cell, thus producing direct current electricity. This can now be used by converting the DC power into AC power by way of an inverter or stored in batteries for use on those cloudy days or during the night. Solar panels or photovoltaic panels are made up of single cells wired in series. Solar panels come in many different sizes, shapes, wattage, materials & most importantly, cost. The old adage of 'you get what you pay for' is very evident when shopping for solar powered systems.
Is solar power expensive? It certainly can be. Can you build your own solar powered system yourself? Could you scrounge up enough materials on say eBay, at a junkyard or hardware store? Absolutely. Are you handy enough given the right tools, materials & know-how to build your own solar panels & install the array & infrastructure to produce your very own solar power? Or do you get it done professionally? We all know that going this way could take a sizable chunk out of your wallet if you want to take a sizable chunk out of your power bill. These are all issues that need to be addressed depending on your budget, DIY skills, motivation, time & your ultimate goals. But you’d have to weigh up the pros & cons. Do you live in a particularly sunny area?
The image to the upper left depicts photovoltaic radiation insolation in the USA mid 2004. The light to dark orange ares are obviously particularly sun drenched locations. For the best results regarding capturing the most amount of solar energy possible, solar panels should be tilted to the latitude of your location. For instance, if you lived in Phoenix Arizona, latitude 33º 26’ 53’ N, then ideally you should tilt your solar array at around 33.5º or thereabouts. Obviously this can be impractical. It is much easier to fix a solar array to the existing pitch of your south facing roof area but there are other options. If your roof pitch is too shallow, then solar array systems that employ adjustable pitching are a solution. What if you don’t have a south facing gable? Solar power can be captured even more efficiently with active or passive solar trackers which are mounted on free standing posts. Active solar trackers commonly use small gear driven arrangements & these units can be as basic or extravagant as your budget allows. High end models not only track the sun’s movements during the day, but also self adjust for optimal declination from season to season. They also reset each evening to face the morning sunlight. Two main types of active solar trackers are single axis & dual axis. Single axis trackers are of either horizontal types which are fixed south facing & only move to suit the sun’s path in a given season. Polar type single axis trackers have a fixed inclination but move in a radial path to face the sun over the course of the day. Dual axis trackers move vertically & horizontally therefore maximizing solar power collection. These do consume some power but is offset by their efficiency. Up to 15% more solar power is collected in winter & anywhere from 40% to 60% in summer. Passive solar trackers are a much cheaper alternative consuming no power but aren’t quite as accurate at tracking the sun’s path as active solar trackers but the difference is insignificant. These trackers utilize low boiling point fluids much like refrigerant in cylinders aligned on the eastern & western sides of the solar array. The sun’s heat & gravity creates an imbalance within the cylinders at dawn & so the fluid will equalize the difference across the array thus pointing it squarely at the sun & continues to do so throughout the day. Well built models employ ‘shock absorbers’ at the pivotal points that provide the tower with increased strength & stability in windy conditions.
One final thought to consider. On the other side of the ledger, solar energy is free. The sun will rise tomorrow & the day after that. There’s actually more than enough solar power to provide even the hungriest energy consumers across the globe. Our dependence on fossil fuels could be completely eliminated such is the potential solar power just waiting to be collected. So the question is, do you want to spend thousands of your hard earned cash on a decent size solar array to minimize your power bill? Do you just want to save power or will your system have the capacity to make your meter spin backwards? Power grid feed in tariffs vary widely depending on where you live & are an excellent incentive. Many states & counties offer sales tax & property tax incentives for renewable energy systems as well as rebates, grants & utility loans – the list is large. More details are available on the Wind Power page. One other thing, if you’re lucky enough to have a shed, workshop or barn with a separate electricity meter, then that’s a great opportunity to produce your own solar power purely to make money with feed in tariffs & incentives to help your community as well. I for one would love to be paid by my utility company to help light up my town & produce some green energy of my own.
