Solar Panels: Cost, Use, and Benefits

In summary: A solar homepower system is not a solar panel system. Solar panels are only the heart of the solar homepower system. The heart of a solar homepower system is its power storage and power conditioning equipment. Solar homepower systems cost about 10 to 20 dollars per peak kilowatt to install. For comparison, a brand new nuclear power plant with AP1000 reactors built today would cost about $1.50 per peak watt to install -- and, unlike your solar homepower system, the nuke plant would produce peak power 95% of the time, 24/7/365. Solar homepower is always a financial loser no matter how it is done
  • #1
Pengwuino
Gold Member
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So what's the deal with solar panels? How much do you end up paying per average watt-hour your house consumes through solar panels to equal your use? As in... if a panel costs $2000 for that generates 200Wh, I am paying $20/Wh for the panel to equalize it. What are some real world figures though? And how many panels do you need relative to your average kwh use in say, California?

Also, is it worth it and what are the tax incentives like?
 
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  • #2
Real costs of solar homepower

Pengwuino said:
So what's the deal with solar panels? How much do you end up paying per average watt-hour your house consumes through solar panels to equal your use?
If I recall correctly, amortized over 20 years, it is roughly 25 to 75 cents per kwh.


if a panel costs $2000 for that generates 200Wh, I am paying $20/Wh
Power is not energy. Watts are units of power and watt-hours are units of energy. Your panel would generate 200 watts (this is assuming dead-on sunlight at an intensity of exactly 1000 watts per square meter; 1000 watts per square meter is only seen on Earth when the sun is directly overhead and skies are perfectly clear; this level of insolation is impossible anywhere within the geographical United States because no part of the geographical United States is in the tropics), not watt-hours (which would be nonsensical). You would be paying $20 per peak watt. Solar panels these days actually retail for about $4 per peak watt.

A solar panel, or a collection of them, is not a solar homepower system and is not even the heart of the system. The heart of a solar homepower system is its power storage and power conditioning equipment. Complete solar homepower installations cost about 10 to 20 dollars per peak kilowatt to install. For comparison, a brand new nuclear power plant with AP1000 reactors built today would cost about $1.50 per peak watt to install -- and, unlike your solar homepower system, the nuke plant would produce peak power 95% of the time, 24/7/365.



And how many panels do you need relative to your average kwh use in say, California?
Typical solar homepower installation include about 3 peak kilowatts of solar panels. This would cost ~$12,000 and is less than you would need for average California household electricity usage. Homepower folks usually resolve this power discrepancy by also making their households ultra energy efficient.



Also, is it worth it
Unless one lives extremely far from the grid, homepower today is always a financial loser no matter how it is done and will continue to be a financial loser into the forseeable future. Generally, wind homepower is cheaper than solar homepower and microhydro homepower is cheapest of all.
 
  • #3
Bah, got that stupid watt/watthour thing confused agian.

What is microhydro homepower?
 
  • #4
Pengwuino said:
Bah, got that stupid watt/watthour thing confused agian.
No problems. I know MIT students who mix those up sometimes.



What is microhydro homepower?
It is hydropower. It is smaller than commercial hydropower, so it is called micro. Homepower folks also call it low-head hydro. If you have a stream on your property and you set up a turbine (and associated components such as a pipe called a penstock which serves to feed the water with minimal friction and turbulance downhill to the turbine) in it (or next to it, which is more often the case) to produce power for your house, you are doing microhydro. Ivan Seeking is into low-head (micro) hydro, so he can probably tell you all about about it. Also, I have found this site useful for learning about it:
http://www.microhydropower.net/intro.html
 
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  • #5
Well i live on a lil normal 1/2 acre house in a neighborhood and all so there's no streams around here :D. Oddly enough though, we have a LOT of canals in our city and i doubt they use the water for power... any reason why they wouldnt?
 
  • #6
Most likely the cost/benefit of setting up the distribution and monitoring of the sites. I would doubt that it would be financially viable once you take into account the number of people to maintain and keep track of those stations. Not to mention the up front costs that are probably pretty steep as well. Are there fluctuations in those canals' flows? That could be another issue as well.
 
  • #7
Pengwuino said:
. . . we have a LOT of canals in our city and i doubt they use the water for power... any reason why they wouldnt?
Not enough flow, most likely. Usually for hydro, one needs a height of water (which implies dam) to generate the potential energy ([itex]\rho[/itex]gh, aka head of water), which is then converted to the rotational kinetic energy of a turbine. Flow could be used directly with a magneto-hydrodynamic system, but that requires a conductive fluid (any salts or soluble minerals in the canal water?) and magnetic field, so too expensive in general. Nevertheless, one needs an appreciable flow.
 
  • #8
This came up somewhere else. There are a couple of engineers who think they have come up with a practical windmill style design for very low head systems, like canals. I don't know if the math adds up or not but they seem to think so. I believe that this story ran on Discoveries This Week, on the science channel - SCI.

For anyone interested, as for low-head home projects, I can't tell you all about it, but I have looked into this quite a bit, [also took a minor in hydraulic engineering] and the Banki Crossflow Turbine is the best solution for most applications. It is relatively cheap and easy to design, make, and install, and it performs well over wide ranges of both flow and head. By chance, one classic paper on this is available at Oregon State University's Mechanical Engineering Dept.
 
  • #9
A copy of the paper Ivan mentioned can be found here:

http://home.carolina.rr.com/unclejoe/banki_scan.pdf


The associated website http://home.carolina.rr.com/unclejoe has some good info as well.
 
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1. How much do solar panels cost?

The cost of solar panels can vary depending on several factors such as the type and size of the panels, installation fees, and any additional equipment needed. On average, the cost of solar panels ranges from $15,000 to $25,000 for a typical residential installation. However, many factors such as government incentives and tax credits can help reduce the cost.

2. How do solar panels work?

Solar panels work by converting sunlight into electricity through the use of photovoltaic (PV) cells. These cells are made up of layers of silicon, which absorb the sun's energy and convert it into direct current (DC) electricity. This electricity is then sent to an inverter, which converts it into alternating current (AC) electricity that can be used to power homes and businesses.

3. What are the benefits of using solar panels?

There are numerous benefits to using solar panels, including reducing your carbon footprint, saving money on energy bills, and increasing the value of your property. Solar energy is also a renewable source of energy, meaning it will never run out, unlike fossil fuels. Additionally, solar panels require very little maintenance and can last for 25-30 years.

4. How much energy can solar panels produce?

The amount of energy that solar panels can produce depends on several factors, including the size and type of panels, location, and weather conditions. On average, a residential solar panel system can produce between 9,000 to 10,000 kilowatt-hours (kWh) of electricity per year. However, this can vary significantly depending on the factors mentioned above.

5. Can solar panels be used in all climates?

While solar panels can still produce electricity on cloudy days, they are most effective in areas with abundant sunlight. However, solar panels can still be used in all climates as long as they are properly installed and maintained. In fact, some countries with colder climates, such as Germany and Canada, are among the top users of solar energy in the world.

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