# Solar power...how much and how much? **URL:** \ **Category:** Great Debates\ **Created:** [March 3, 2009, 6:08pm UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170 "2009-03-03T18:08:16Z")\ **Posts on this page:** 14\ **Page:** 3
**Author:** ![R.P.McMurphy](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@R.P.McMurphy](https://boards.straightdope.com/u/R.P.McMurphy)\ **Post date:** [March 6, 2009, 1:58am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/41 "2009-03-06T01:58:02Z")
There’s always an excuse to do nothing. Watch Modern Marvels occasionally. For instance, the Mackinac Bridge cost about $100 million dollars when it was built around 1957. It was such a gamble that the State of Michigan wouldn’t guarantee the bonds. They ended up being sold privately. It was a Modern Marvel. If you tried to build it today it would cost billions. The economic payoff has been incalculable aside from the fact that the bonds got paid off in full. Sometimes you have to have enough foresight to make an investment in the future. Solar power is clean and available. I skirts a lot of political issues. Why not pursue it? ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [March 6, 2009, 2:46am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/42 "2009-03-06T02:46:56Z")
Because sometimes the technology just isn’t ready to deploy…and sometimes it never will be. A similar question might be…why not build a space elevator today, or a fusion plant? The pay off (if we could do it) would be immense. So, why not just start doing it and rely on the technology to simply catch up to meet our needs? Or, perhaps a better example…why not just switch over to battery powered vehicles? Why not just build them now? The technology certainly exists after all…so, why not just do it? The answer of course is that though the technology certainly exists it’s too expensive today…and the manufacturing simply isn’t there to produce what would be needed on the scales we are talking about. The article I put in the OP gives a rough idea of the kinds of money we are talking about…$450 billion a year for 20+ years to get solar deployed on a sufficient scale as to make it a major player. Sure, the pay off would be huge if you could do it…and I’m sure the technology and manufacturing would also be there if you devoted that kind of capital to the project. However, politically, there is no way we are going to invest that kind of money over that kind of time frame in order to do it. -XT ---
**Author:** ![Snowboarder\_Bo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowboarder_bo/32/229_2.png) [@Snowboarder\_Bo](https://boards.straightdope.com/u/Snowboarder_Bo)\ **Post date:** [March 6, 2009, 2:58am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/43 "2009-03-06T02:58:37Z")
> [@xtisme](#): > > The article I put in the OP gives a rough idea of the kinds of money we are talking about…$450 billion a year for 20+ years to get solar deployed on a sufficient scale as to make it a major player. I don’t think you’re reading that correctly. It’s not $450B per year, it’s $450B total (or $400B, depending on the sentence). From the OP: > [@](#): > > The federal government would have to invest more than $400 billion over the next 40 years to complete the 2050 plan. > [@](#): > > But $420 billion in subsidies from 2011 to 2050 would be required to fund the infrastructure and make it cost-competitive. $400B to $450B total over 40 years, not $450B/year for 40 years. And, ramping up industrial capacity is easy. We did it in WW2, we saw the computer industry do it in less than 10 years, cell phones, all kinds of things. If the demand is there, the money is there. And once people see both of those things waiting, production can and will quickly scale up to meet demand. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [March 6, 2009, 3:05am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/44 "2009-03-06T03:05:25Z")
I must be reading it wrong then…I thought it was saying $400+ billion a year. If they are saying $400+ billion spread out over 39 years then I don’t see the problem…that’s only a bit more than $10 billion a year. Of course, if we are talking about 39 years then I’m not sure what the impact would be on the whole global warming thingy in that case. -XT ---
**Author:** ![gethsemenerose](https://avatars.discourse-cdn.com/v4/letter/g/a587f6/32.png) [@gethsemenerose](https://boards.straightdope.com/u/gethsemenerose)\ **Post date:** [March 6, 2009, 5:11am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/45 "2009-03-06T05:11:22Z")
What about all that UNTAPPED solar power stored as GEOTHERMAL heat in our oceans. Does anyone remember [The Millennial Project: Colonizing the Galaxy in 8 easy Steps](http://everything2.com/e2node/The%2520Millennial%2520Project) it talks about simple Geothermal Ocean Generator (OTECS) that could be used to power LOTS of things including the “Gravity Rail” needed to launch the Solar Power generators into orbit. At significantly Reduced costs Signed [The Gnome](http://www.gethsemenerose.com) ---
**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:** [March 6, 2009, 6:15am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/46 "2009-03-06T06:15:57Z")
> [@](#): > > What about all that UNTAPPED solar power stored as GEOTHERMAL heat in our oceans. I’m not sure what you’re talking about, here… Geothermal heat is neither solar nor in the oceans. And heat energy is only usable if there’s some reservoir available of material at a different temperature… What are you proposing to use as the cold reservoir to get useful energy out of ocean heat? ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [March 6, 2009, 6:46am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/47 "2009-03-06T06:46:31Z")
> [@Napier](#): > > There’s an analysis demonstrating that photovoltaic solar power can’t make a net contribution to our total power generation for at least 30 years, because it takes power to manufacture the cells. > > The cells produce more power within their lifetime than it took to make them, but it takes something like 3 years to hit the break even point. If you want to have photoelectric contribute more to our total power generation, you have to keep increasing the production of them. Going faster invests more power in them at first, and going slower takes longer to have a big contribution. The briefest period to reach net contribution was 30 years. > > At least, this is what I remember of it. I did read that Scientific American article, but I don’t think that’s where this tidbit was - I think it was in the Economist a couple years ago. I don’t think you’re remembering quite right. Let’s take the 3 years break-even point. If that’s true, any year we expand our solar capacity by \> 33%, we consume more energy (\*) than solar produced that year. If we expand by \< 33%, solar is a net producer. Of course, we should have some allowance for solar panel production that replaces worn-out panels instead of increasing productivity, so we’ll adjust that number downward a bit to 30%. So how much solar power would we have after 30 years of expanding at that break-even rate? It would be C \* 1.3 ^ 30, where C is current production. So that comes to 2620\*C. 2620 times our current rate of production! I’ve heard bandied around here that current solar production is about 0.1% of current electricity production. I think it’s a little higher, but let’s use the lower number. In 30 years, we’ll have 2.62 times more than 2009’s total electricity production from solar alone. Of course, in 2039, we’re likely to be using more electricity, but even if you assume 3% growth, it’s still only 2.42 times more. So we’d be producing more than 100% of our electricity from solar. In 30 years! Does this sound realistic? Probably not, so what’s more likely is that the growth rate of solar will slow down at some point before 30 years in the futures, fall below 30%, and at that point we’ll have net positive electricity production from solar. (\*) I’ll go ahead and assume that all of the energy used in solar panel production is electricity. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [March 6, 2009, 7:13am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/48 "2009-03-06T07:13:23Z")
> [@Chronos](#): > > I’m not sure what you’re talking about, here… Geothermal heat is neither solar nor in the oceans. And heat energy is only usable if there’s some reservoir available of material at a different temperature… What are you proposing to use as the cold reservoir to get useful energy out of ocean heat? I believe he’s referring to this: [Ocean Thermal Energy Conversion](http://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion). [QUOTE=Wikipedia] Ocean thermal energy conversion (OTEC) is a method for generating electricity which uses the temperature difference that exists between deep and shallow waters to run a heat engine. [/QUOTE] It’s not really solar, except in the sense that wind power is solar, so this is probably a hijack.. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 6, 2009, 7:34am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/49 "2009-03-06T07:34:24Z")
> [@Chronos](#): > > I’m not sure what you’re talking about, here… Geothermal heat is neither solar nor in the oceans. And heat energy is only usable if there’s some reservoir available of material at a different temperature… What are you proposing to use as the cold reservoir to get useful energy out of ocean heat? I believe he’s talking about ocean thermal power, which exploits the temperature difference between the surface layer and the deep ocean. The problem is making it cost-effective. The ocean is a very difficult environment for engineering, and that drives up costs. There is no shortage of mechanisms to extract energy from various natural processes. Wave power, geothermal, solar, wind… I’ve seen proposals that extract power from static tension on huge kite lines. Others that use snake-like floating tubes that twist around in the surf and generate power. It all can be done - in theory. But the devil is always in the details. Once you get away from highly concentrated sources of energy, the feasibility of extracting useful power in an economic way gets more and more unlikely. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [March 6, 2009, 11:29am UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/50 "2009-03-06T11:29:32Z")
> [@Do\_Not\_Taunt](#): > > I don’t think you’re remembering quite right. Let’s take the 3 years break-even point […] Yes, I think you are correct. I now think it is obvious that if solar cell only happened tomorrow, then three years from tomorrow you’d break even and from that point on there is net contribution. Beats me what I was thinking. Now, it could still take a long time to have a net contribution of so many percent of the total - I wonder if that was the point of what I read? Oops - sorry. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [March 6, 2009, 2:47pm UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/51 "2009-03-06T14:47:31Z")
And actual return on energy invested may be earlier than that. [This UN Chronicle report](http://www.un.org/Pubs/chronicle/2007/issue2/0207p63.htm) states that > [@](#): > > A September 2006 joint paper by scientists from Brookhaven National Laboratory, Utrecht University and the Energy Research Center of the Netherlands demonstrates that crystalline silicon PV systems have energy payback times of 1.5 to 2 years for South European locations and 2.7 to 3.5 years for middle-European, while thin film technologies have energy payback times in the range of 1 to 1.5 years in South Europe. > > Accordingly, life-cycle carbon dioxide (CO2) emissions for PV are now in the range of 25 to 32 g/kWh. In comparison, a combined cycle gas-fired power plant emits some 400 g/kWh, while a coal-fired power plant with carbon capture and storage, about 200 g/kWh. Nuclear power emits 25 g/kWh on average in the United States; only wind power is better with a mere 11 g/kWh. For silicon technology, clear prospects for a reduction of energy input exist, and an energy payback of one year may be possible within a few years as silicon growth processes become more efficient. As a result, this could decrease the life-cycle CO2 emissions to 15 g/kWh.[80] Moreover, that article goes on, Concentrating Solar (CSP) may be much better yet. > [@](#): > > The energy payback time of CSP systems is approximately five months, which compares very favourably with their lifespan of 25 to 30 years … CSP offers a rapidly scalable means of low-carbon electricity generation. A September 2005 report by the European Solar Thermal Industry Federation (ESTIF), Greenpeace and the IEA SolarPACES found that “there are no technical, economic or resource barriers to supplying 5 per cent of the world’s projected electricity needs from solar thermal power by 2040”. The authors calculated that CSP could produce 95.8 TWh/year by 2025, avoiding 57.5 millions tons of CO2 annually for a cumulative 362 million tons in the next 20 years. By 2040, they found that CSP could produce as much as 16,000 TWh per year. (Although I doubt those figures included the energy costs of improving the transmission infrastructure, which would also be required to make that work.) ---
**Author:** ![gethsemenerose](https://avatars.discourse-cdn.com/v4/letter/g/a587f6/32.png) [@gethsemenerose](https://boards.straightdope.com/u/gethsemenerose)\ **Post date:** [March 6, 2009, 3:27pm UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/52 "2009-03-06T15:27:09Z")
Yes I was talking about OTECs and I do believe it is “Solar” the same way that earlier it was talked about using Solar power to “STORE” energy as compressed air in caverns and then get that energy back later. The Energy “stored” in the ocean due to the difference in temperature caused by the sun HEATING the upper layer but that heat not reaching lower layers is to all practical purposes LIMITLESS This energy is a lot cheaper to get than many think OTEC tubes can be very cheaply built (Practically GROWN FREE) and the generators are already in existance. Signed [The PhilosoRaptor](http://www.cafepress.com/philosoraptor) ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [March 6, 2009, 5:09pm UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/53 "2009-03-06T17:09:57Z")
> [@gethsemenerose](#): > > Yes I was talking about OTECs and I do believe it is “Solar” the same way that earlier it was talked about using Solar power to “STORE” energy as compressed air in caverns and then get that energy back later. The Energy “stored” in the ocean due to the difference in temperature caused by the sun HEATING the upper layer but that heat not reaching lower layers is to all practical purposes LIMITLESS > This energy is a lot cheaper to get than many think > OTEC tubes can be very cheaply built (Practically GROWN FREE) and the generators are already in existance. > > Signed > > [The PhilosoRaptor](http://www.cafepress.com/philosoraptor) How much does it cost? Please provide cites. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [March 6, 2009, 6:42pm UTC](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170/54 "2009-03-06T18:42:06Z")
FWIW, [here’s](http://www.nrel.gov/otec/markets.html) not any real numbers quoted, but at least some reasoned analysis about where it may be cost-effective: > [@](#): > > An economic analysis indicates that, over the next 5 to 10 years, ocean thermal energy conversion (OTEC) plants may be competitive in four markets. The first market is the small island nations in the South Pacific and the island of Molokai in Hawaii. In these islands, the relatively high cost of diesel-generated electricity and desalinated water may make a small [1 megawatt (electric) (MWe)], land-based, open-cycle OTEC plant coupled with a second-stage desalinated water production system cost effective. A second market can be found in American territories such as Guam and American Samoa, where land-based, open-cycle OTEC plants rated at 10 MWe with a second-stage water production system would be cost effective. A third market is Hawaii, where a larger, land-based, closed-cycle OTEC plant could produce electricity with a second-stage desalinated water production system. OTEC should quickly become cost effective in this market, when the cost of diesel fuel doubles, for plants rated at 50 MWe or larger. The fourth market is for floating, closed-cycle plants rated at 40 MWe or larger that house a factory or transmit electricity to shore via a submarine power cable. These plants could be built in Puerto Rico, the Gulf of Mexico, and the Pacific, Atlantic, and Indian Oceans. … OTEC’s greatest potential is to supply a significant fraction of the fuel the world needs by using large, grazing plantships to produce hydrogen, ammonia, and methanol… —the Pacific Islands are expected to be the initial market for open-cycle OTEC plants. This prediction is based on the cost of oil-fired power, the demand for desalinated water, and the social benefits of this clean energy technology And this [one](http://www.otecnews.org/articles/ro_vs_otec.html) sees its cost-effectiveness also based on its desal capacity. Its cost seems high and its utility limited to very particular areas. [Previous page](https://boards.straightdope.com/t/solar-power-how-much-and-how-much/488170.md?page=2)