# Tapping Sun's Energy **URL:** \ **Category:** Factual Questions\ **Created:** [July 9, 2013, 11:14am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030 "2013-07-09T11:14:48Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [July 10, 2013, 4:30pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/21 "2013-07-10T16:30:49Z")
> [@Crafter\_Man](#): > > Agree. And the fact that such endeavors require massive amounts of public subsidies to stay afloat is also an indication that it is a total waste of money and energy. > > It should be noted, however, that technological advances could one day make PV arrays economically viable for large-scale power production. How? As noted above, the ultimate limiting factor is the amount of energy put out by the sun. Even if we had 100% efficient solar cells (something that is physically impossible), we’d have to damn-near cover the entire planet in solar cells to be able to replace our current power plants. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [July 10, 2013, 4:48pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/22 "2013-07-10T16:48:48Z")
> [@Diceman](#): > > Even if we had 100% efficient solar cells (something that is physically impossible), we’d have to damn-near cover the entire planet in solar cells to be able to replace our current power plants. This is probably an overstatement. According to [this](http://landartgenerator.org/blagi/archives/127), a reasonable estimate, including efficiency and cloudy days, it would require only the area of Spain. 🙂 So it would be a lot bigger than any other project mankind has undertaken, but there certainly is enough wasteland in the Sahara to make it happen (if every other issue involved in doing so was nullified). ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 10, 2013, 5:03pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/23 "2013-07-10T17:03:36Z")
> [@Diceman](#): > > How? As noted above, the ultimate limiting factor is the amount of energy put out by the sun. Even if we had 100% efficient solar cells (something that is physically impossible), we’d have to damn-near cover the entire planet in solar cells to be able to replace our current power plants. Nobody (well, nobody that matters) has ever suggestion that all power generation be replaced by solar. The question is whether or not it makes economic sense to build solar plants at all. ---
**Author:** ![pancakes3](https://avatars.discourse-cdn.com/v4/letter/p/ba9def/32.png) [@pancakes3](https://boards.straightdope.com/u/pancakes3)\ **Post date:** [July 10, 2013, 7:28pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/24 "2013-07-10T19:28:16Z")
- **Cost** - Though KW/$ it’s cheap, the infrastructure isn’t. - **Storage** - If you don’t want your power to go out when the sun goes down, you’ll have to store it - **Transport** - I can choose where to strategically place power plants for the most efficient power grid. I can’t so much with all solar. - \*\*Land use \*\*- No greenhouse emissions doesn’t necessarily mean it’s good for the environment. Having massive tracts of land “sterilized” for the purpose of sun harvesting will still harm the environment. I think solar is a great supplement and they’ve developed new paneling that can roll on like wallpaper, it’s hopelessly naive to think a single power can solve all of our energy problems. It’ll take some hybrid of many different sources to carve out a path of least evil. ---
**Author:** ![BubbaDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bubbadog/32/333_2.png) [@BubbaDog](https://boards.straightdope.com/u/BubbaDog)\ **Post date:** [July 10, 2013, 7:33pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/25 "2013-07-10T19:33:50Z")
> [@friedo](#): > > Nobody (well, nobody that matters) has ever suggestion that all power generation be replaced by solar. … The Op did. Are you insulting one of our newest members? 😃 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 10, 2013, 10:27pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/26 "2013-07-10T22:27:49Z")
> [@](#): > > - Cost - Though KW/$ it’s cheap, the infrastructure isn’t. The price per kilowatt, or other power unit, is high, precisely because that’s a function of the expensive infrastructure. The marginal price per kilowatt-_hour_, or other energy unit, is low, because there’s no need to purchase fuel. ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [July 10, 2013, 11:00pm UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/27 "2013-07-10T23:00:25Z")
So, to make things easy on people, if you want to go solar at home, with staying on the electrical grid so you can still have all the electricity with less bill. These are the parts of a grid-tie system, in order: 1. **Solar Modules** (aka PV Panels) collect energy from the sun and turn it into direct current. 2. **Power Inverter** turns the DC from the panels into AC that your appliances can use. 3. **PV Disconnect** lets you cut off power so that you can work on the system without electrocuting yourself. 4. \*\*Your home’s breaker box \*\*is where the solar energy connects to your house. 5. **Net meter** connects your house to the grid, measuring how much power you take from - or give to - the power grid at large. Start by going and getting a copy of your electrical bill, and find out what the average amount of kW you use on a daily basis. [monthly kW divided by 30] For sake of argument, you use 900kWh per month that comes out to be 30 kWh per day. Find the insolation in your area [here](http://www.nrel.gov/gis/solar.html). [use photovoltaic] So, 30 kWh/day at 5 hours of sunlight, then you need to have PV panels that produce 6kW to be stored in batteries to be run through your inverter to power your home. So, if you check the average solar supplier, you need 25 panels supplying 240W at $300 per panel [the supposed regular price for Canadian Solar brand at solar town, which I googled] and each panel is 64"x38". [roughly 5.3 feet x 3 feet] which needs to be put up in the sun somewhere. This doesn’t count the cost of the construction, electrician or other materials you will be needing. I wouldn’t put it on the roof, can’t easily access it to clean bird crap and detritus off, so it needs to be plunked down in your yard. Can’t be overshaded by trees, so you need to not have a neighbor who is into raising sequoias … and your HOA can’t hate you for cluttering up your yard. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [July 11, 2013, 4:16am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/28 "2013-07-11T04:16:55Z")
> [@Ferret\_Herder](#): > > Germany gets over [20% of its power from solar](http://www.washingtonpost.com/blogs/wonkblog/wp/2013/02/08/germany-has-five-times-as-much-solar-power-as-the-u-s-despite-alaska-levels-of-sun/) even though their sunlight level is similar to Alaska’s. The article notes that solar power equipment is historically expensive, but beginning to drop in price. Where does it say “over 20%” in the article? The article says: > [@](#): > > Yet despite those limitations, Germany has still managed to be the world leader in solar power. At the end of 2012, the country had installed about 30 gigawatts of solar capacity, providing between 3 percent and 10 percent of its electricity. Note that the typical value is about 3% ([German solar power output up 60 pct in 2011 | Reuters](http://www.reuters.com/article/2011/12/29/germany-solar-idAFL6E7NT1WK20111229?sp=true)). The 10% figure is for a single month. ([http://thinkprogress.org/climate/2012/06/12/497984/solar-provides-10-of-germanys-electricity-in-may/](http://thinkprogress.org/climate/2012/06/12/497984/solar-provides-10-of-germanys-electricity-in-may/)) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 12, 2013, 12:17am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/29 "2013-07-12T00:17:56Z")
> [@](#): > > Quoth **aruvqan** : > > Start by going and getting a copy of your electrical bill, and find out what the average amount of kW you use on a daily basis. [monthly kW divided by 30] No, your average power usage is the same no matter what time period you’re looking at, be it day or month. You want your energy usage there (i.e., how many kWh you use), not your power (i.e., how many kW). Your statement here, as written, is equivalent to answering “Farmer John had thirty horses in April. How many horses did he have on each day in April?” with “1 horse”. ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [July 12, 2013, 1:26am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/30 "2013-07-12T01:26:06Z")
> [@Chronos](#): > > No, your average power usage is the same no matter what time period you’re looking at, be it day or month. You want your energy usage there (i.e., how many kWh you use), not your power (i.e., how many kW). > > Your statement here, as written, is equivalent to answering “Farmer John had thirty horses in April. How many horses did he have on each day in April?” with “1 horse”. Sorry, I was going by memory, on this stupid phone it is tricky to surf and get back .. next time I will answer at home on a real computer 🙂 ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [July 12, 2013, 1:32am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/31 "2013-07-12T01:32:12Z")
> [@Una\_Persson](#): > > Where does it say “over 20%” in the article? The article says: > Note that the typical value is about 3% ([German solar power output up 60 pct in 2011 | Reuters](http://www.reuters.com/article/2011/12/29/germany-solar-idAFL6E7NT1WK20111229?sp=true)). The 10% figure is for a single month. ([http://thinkprogress.org/climate/2012/06/12/497984/solar-provides-10-of-germanys-electricity-in-may/](http://thinkprogress.org/climate/2012/06/12/497984/solar-provides-10-of-germanys-electricity-in-may/)) Apologies. Was surfing on a small phone, here’s the sort of numbers I saw in the Google results that confused me: [22% from renewable energy](http://www.motherjones.com/environment/2013/04/germany-solar-power-energy), but about a quarter of that from solar. I remembered the “Germany gets a mess of energy from solar compared to the US and they’re a smaller country with less sunlight than the US” summary and searched to figure out how much. ---
**Author:** ![GameHat](https://avatars.discourse-cdn.com/v4/letter/g/ed655f/32.png) [@GameHat](https://boards.straightdope.com/u/GameHat)\ **Post date:** [July 12, 2013, 1:55am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/32 "2013-07-12T01:55:59Z")
[Dyson rings, nets, bubbles, swarms and/or spheres.](http://en.wikipedia.org/wiki/Dyson_sphere) C’mon, NASA! We should have had these 20 years ago! 😉 I kid, I kid. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [July 12, 2013, 2:17am UTC](https://boards.straightdope.com/t/tapping-suns-energy/663030/33 "2013-07-12T02:17:38Z")
How much energy is used to manufacture a solar panel? How much pollution and toxic waste does this manufacturing process create? [Previous page](https://boards.straightdope.com/t/tapping-suns-energy/663030.md?page=1)