Why Solar & Wind won't be viable anytime soon?

[Midpack]

I've seen, and asked here myself, this question several times in discussions about wind & solar. Those who seem to argue as if expanding wind and/or PV solar is a no-brainer, never seem to address the intermittent question (much less the horrible economics in the case of solar at least). I have seem some veiled references to batteries, but that seemed improbable with what I know about commercial and residential UPS's (battery backup systems). So here's a credible source statement. The TED video is worth the half hour to view it IMO, but the first link is a condensed text.

Quote:

"All the batteries we make now could store less than 10 minutes of all the energy [in the world]," he said. "So, in fact, we need a big breakthrough here. Something that's going to be of a factor of 100 better than what we have now." Bill Gates

Bill Gates: We need global 'energy miracles' - CNN

Bill Gates on energy: Innovating to zero! | Video on TED.com

[chinaco]

Watched. Thanks.

I found this interesting:

TerraPower Home

[HFWR]

I am reminded of an environmental piece I saw on TV some time ago. The subject was a small town in WVa, dealing with the health problems of surface mining, specifically the water pollution caused by "holding ponds" leaching into the water table. Without arguing that one way or another, one of the ironies of the program was when a group of local activists visited NYC, to attend some sort of protest/conference/I forget. But this group was standing in Times Square, amid the glow of a brazillion watts worth of flashing neon/video screens/etc. I'm thinking about all the coal/oil/nucular-generated power it took to run all those lights...

[GregLee]

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Originally Posted by Midpack I've seen, and asked here myself, this question several times in discussions about wind & solar. Those who seem to argue as if expanding wind and/or PV solar is a no-brainer, never seem to address the intermittent question (much less the horrible economics in the case of solar at least).

If we increase our pumped storage capacity from its current 2.5% level, it seems we could just feed the power back into the grid:

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In 2009 the United States had 21.5 GW of pumped storage generating capacity, accounting for 2.5% of baseload generating capacity.[3] PHS generated (net) -6288 GWh of energy in 2008[4] because more energy is consumed in pumping than is generated; losses occur due to water evaporation, electric turbine/pump efficiency, and friction. In 2007 the EU had 38.3 GW net capacity of pumped storage out of a total of 140 GW of hydropower and representing 5% of total net electrical capacity in the EU (Eurostat, consulted August 2009). Pumped-storage hydroelectricity - Wikipedia, the free encyclopedia

The Andasol solar plant in Spain (not PV) stores 7.5 hours worth of power in a molten salt reservoir:

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Andasol has a thermal storage system which absorbs part of the heat produced in the solar field during the day. This heat is then stored in a molten salt mixture of 60% sodium nitrate and 40% potassium nitrate. A turbine produces electricity using this heat during the evening, or when the sky is overcast. This process almost doubles the number of operational hours at the solar thermal power plant per year.[2] A full thermal reservoir holds 1,010 MW·h of heat, enough to run the turbine for about 7.5 hours at full-load, in case it rains or after sunset. Andasol Solar Power Station - Wikipedia, the free encyclopedia

[ERD50]

Thanks, I'll check these links out later, and revisit that "without the hot air" pdf on the subject.

David MacKay FRS: Sustainable Energy - without the hot air: Contents

Let's think about storing a GW of heat to carry a solar plant for a mere 7.5 hours (the Sun is often gone/diminished for far longer than that!), or bringing our 21.5GW of pumped storage up to something that could reliably support a high % of intermittent renewables. That is a whole heck of a lot of energy stored up. It would require massive structures, distributed all across the world, including places that get earthquakes, tornadoes, hurricanes, or could be terror attack targets. So now imagine a poster coming along, and describing the worst case scenarios for all this storage, a combination of events that we just couldn't plan for. They would want to stop it in its tracks! Too dangerous!

-ERD50

[chinaco]

I have not looked into it... but one would think that geothermal would be a viable source of energy.

Not sure if it is cost effective.

[GregLee]

Quote:

Originally Posted by ERD50 Thanks, I'll check these links out later, and revisit that "without the hot air" pdf on the subject. David MacKay FRS: Sustainable Energy - without the hot air: Contents

MacKay discusses the feasibility of pumped storage in Britain starting on p. 190. His conclusion:

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By building more pumped storage systems, it looks as if we could increase our maximum energy store from 30 GWh to 100 GWh or perhaps 400 GWh. Achieving the full 1200 GWh that we were hoping for looks tough, however.

[ERD50]

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Originally Posted by chinaco I have not looked into it... but one would think that geothermal would be a viable source of energy. Not sure if it is cost effective.

A few issues, according to McKay (bolds mine):

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As I said before, geothermal energy comes from two sources: from radioactive decay in the crust of the earth, and from heat trickling through the mantle from the earth’s core. In a typical continent, the heat flow from the centre coming through the mantle is about 10 mW/m2. The heat flow at the surface is 50 mW/m2. So the radioactive decay has added an extra 40 mW/m2 to the heat flow from the centre.

The anti-nukes aren't going to like that. It has scary words in it!



Ch 16 Page 98: Sustainable Energy - without the hot air | David MacKay

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For the temperature profile shown in figure 16.4, I calculated that the optimal depth is about 15 km. Under these conditions, an ideal heat engine would deliver 17 mW/m2. At the world population density of 43 people per square km, that’s 10 kWh per person per day, if all land area were used. In the UK, the population density is 5 times greater, so wide-scale geothermal power of this sustainable-forever variety could offer at most 2 kWh per person per day. This is the sustainable-forever figure, ignoring hot spots, assuming per- fect power stations, assuming every square metre of continent is exploited, and assuming that drilling is free. And that it is possible to drill 15-km deep holes.

That's a lot of assumptions. To put the 2kWh per person per day in perspective, if we look at just electricity production, and assume a family of four has a $100 monthly bill @ ~ $0.10/kWh, they are using ~ 1,000kWh/month, or 33.3kWr/day or 8.33 kWr/day/person. So perfect engines, no losses, and every square meter used only provides a quarter of what we use (this is before we start plugging in our EVs).

It's much more practical in places like Iceland with 'hot spots', but those places are fairly rare. And I wonder what affect pulling all that heat out would have on the earth's crust? Would it cause it to shrink and trigger earthquakes?

-ERD50

[GregLee]

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Originally Posted by GregLee ... it seems we could just feed the power back into the grid:...

But can we get the power from the wind or solar plants to the grid? This just in (4/11):

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The BritNed interconnector, the first power line linking UK and the Netherlands has successfully gone live, according to National Grid. ... Chris Huhne, Secretary of State for Energy and Climate Change said: "Renewables win as it means surplus wind power can be easily shared. Consumers win as a single European market puts pressure on prices. And more new cables are planned so by 2020 we could have over 10 GW of additional electricity flowing under the North Sea.” BritNed interconnector goes live - Cogeneration & On-Site Power Production

[rockyj]

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Originally Posted by Midpack ...Those who seem to argue as if expanding wind and/or PV solar is a no-brainer, never seem to address the intermittent question (much less the horrible economics in the case of solar at least).

Emphasis added - expanding use *is* a no-brainer - it's already happening.

I also find the the title of this thread curious; solar and wind both are "viable" now, in that each is already providing a non-trivial and growing portion of the total energy portfolio in a number of developed and developing countries (no not the majority, but significant and growing nevertheless). For more centralized power generation models, a US example would be Florida Power and Light, which operates from a diverse portfolio of sources, including wind and solar. A look across Europe will show a number of countries with significant wind and solar contributions to their overall energy mix. China is making huge investments in wind and solar, for domestic use and as an export industry. Yes, it's still pales in comparison to their use of coal, but it is indeed expanding.

With smaller scale, household or other individual sources and net metering in the mix, the potential for overall contribution to reduced demand for home and building related power requirements is enormous, with at least some peak period excess generation put back into the system.

Households putting peak-period over-generation back into the system gets to the problem of intermitttency that OP alludes to. The more pragmatic shorter term solutions that I see proposed in that regard (on both regional and larger scales) include 1) a diversified portfolio of energy sources and generation points (sort of like our retirement portfolios, eh?) to include wind, solar and other renewables, in addition to nuclear, coal (clean coal being the goal), gas and others. 2) smarter generation and transmission gird with variable capacity among the more persistent sources.

There are indeed challenges here, but as Bill Gates seemed to be saying toward the beginning of the TED talk linked in OP above. "All" of the solutions have challenges (in reaching the goal of providing economically viable energy, in sufficient quantities, delivered when and where it's needed, while minimizing CO2 emissions). The likely solution will involve multiple technologies/sources. Solar and wind are a part of that solution now, and every indication is that they will increased their contribution going forward.

An interesting project related to this discussion is the DOE Solar Decathlon (U.S. Department of Energy Solar Decathlon Home Page). About twenty student teams from different universities design/build solar houses and set them up in DC for judging and a week-long performance competition. The houses are great and I highly recommend that anyone who has the opportunity to go to DC during the week they are there do so. Talk to the students. Most of the homes achieve net-zero metering or greater (i.e. they generate more power then they use). They still are comparatively pricey, but many of the subsystems are off-the-shelf commercial components, so this isn't pie-in-the-sky futurism. The students typically are very sharp, very motivated and believe in the future of what they're doing.

[samclem]

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Originally Posted by rockyj I also find the the title of this thread curious; solar and wind both are "viable" now

Viable = Contributing net energy without subsidies. Until then it is "economically noncompetitive but still worthwhile thanks to transfer payments from other ratepayers/taxpayers"

[rockyj]

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Originally Posted by samclem Viable = Contributing net energy without subsidies. Until then it is "economically noncompetitive but still worthwhile thanks to transfer payments from other ratepayers/taxpayers"

And which major energy producer in the US does not receive ferderal, state or local subsidies or incentives?

[samclem]

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Originally Posted by rockyj And which major energy producer in the US does not receive ferderal, state or local subsidies or incentives?

They all get some, which is too bad. The level of these subsidies is notoriously difficult to price out (e.g. to the degree that nuclear fuel is a by-product of US nuclear weapons production, and the weapon production will occur anyway, how do we calculate the subsidy?)
But I'm very sure that wind and solar subsidies are significantly higher on a per kWh basis than those for coal, natural gas, and nuclear power, especially if computed on a net basis (that is, after including taxes paid by the suppliers on their profits).

[Zathras]

Quote:

Originally Posted by samclem They all get some, which is too bad. The level of these subsidies is notoriously difficult to price out (e.g. to the degree that nuclear fuel is a by-product of US nuclear weapons production, and the weapon production will occur anyway, how do we calculate the subsidy?) But I'm very sure that wind and solar subsidies are significantly higher on a per kWh basis than those for coal, natural gas, and nuclear power, especially if computed on a net basis (that is, after including taxes paid by the suppliers on their profits).

You may find this paper from the DOE interesting. I solar and wind are right up there near the top. However, any new technology generally will be untill it expands and is producing more power (at which point the subsidies/Mw will go down).
http://www.eia.doe.gov/oiaf/servicer...df/execsum.pdf
Scroll down to table ES5 for the table in question, although much of it is interesting.

I agree with you as far as subsidies go. I would like to see them all disappear.
But since we are talking about a perfect world, I would also like to see all forms of energy include the full cost of mining/refining/distributing the power. Including health costs to those that live near refineries, storage, waste and the power generating devices themselves (wind turbines for example).

[Disappointed]

Has anybody ever looked into Bloom Energy?

Alternative Energy: The Bloom Box - 60 Minutes - CBS News

Not sure if it is all ture.

[GregLee]

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Originally Posted by Disappointed Has anybody ever looked into Bloom Energy? Alternative Energy: The Bloom Box - 60 Minutes - CBS News Not sure if it is all ture.

I didn't know about it -- thanks for the link. I suppose that what is said in the 60 Minutes piece is true, but the report doesn't say it will succeed, of course. Just that it's persuasive enough to sink $400M into development costs.

[kumquat]

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Originally Posted by ERD50 And I wonder what affect pulling all that heat out would have on the earth's crust? Would it cause it to shrink and trigger earthquakes? -ERD50

Global cooling (as opposed to global warming climate change)?

[samclem]

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Originally Posted by Zathras You may find this paper from the DOE interesting. I solar and wind are right up there near the top. However, any new technology generally will be untill it expands and is producing more power (at which point the subsidies/Mw will go down). http://www.eia.doe.gov/oiaf/servicer...df/execsum.pdf Scroll down to table ES5 for the table in question, although much of it is interesting.

Thanks. That ES5 chart was exactly what I was looking for.
It would be good if we could assure all the costs of each type of production were reflected in the energy prices (especially if we could enforce it worldwide, so we weren't harming ourselves for no reason), but this kind of computation is so subjective that I'm just not sure it is possible. What would be the price per kW for these bird kills in the Altamont Pass wind farm (link)

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A 1992 study commissioned by the CEC "conservatively" estimated that 39 golden eagles were being killed at AltamontPass each year, a significant figure given a total population of 500 br eeding pairs. [88] On a percentage basis, the mortality rate per year at Altamont Pass under the estimate is eight times greater than the bald eagle kill from the Valdez oil spill in Prince William Sound in 1989, and it recurs every year. [89]

Surely solar power is better for birds. Maybe not--depends on how it is done.

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Thermal solar installations have had a disappointing past. Solar One, a 10 MW solar thermal project operated by Southern California Edison for high-demand periods, closed in 1988 after six years of operation. The facility, 80 percent of which was funded by the DOE, was so experimental and expensive that no cost per kWh was publicly revealed. [171] In addition to heavy land requirements, bird deaths ("the birds died primarily from collisions with the picture-like surface of the heliostats") [172] were as much as 10 times the kill at Altamont Pass per megawatt, although endangered species and other high-profile birds were not at risk. [173]

So, I'm not sure how we price in dead birds compared to dead fish compared to dead miners or people killed installing wind turbines. Then we'd have the task of computing the cost of keeping the oil accessible.

Extra Credit Quiz: Which country has the world's greatest proved fossil fuel energy reserves?

Answer: The United States of America. (CRS Report, table 5) (And, they didn't count US oil shale or methane hydrates--we've got lots of energy there, too, once we can economically extract it)

[Gone4Good]

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Originally Posted by chinaco I have not looked into it... but one would think that geothermal would be a viable source of energy. Not sure if it is cost effective.

Geothermal requires appropriate geological thermal reserves and the U.S. doesn't have that many.

[Nords]

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Originally Posted by samclem Viable = Contributing net energy without subsidies. Until then it is "economically noncompetitive but still worthwhile thanks to transfer payments from other ratepayers/taxpayers"

I'd like to think that my state/federal tax credits are just giving me temporary custody of the eventual extraction I'm going to have to supply when our island's demand requires the construction of another electrical-generating plant.

In the meantime our array has paid for its subsidized self, and the rest of the subsidies will be paid off in a few more years. Thanks to my sacrifice, HECO should be able to avoid building a new utility plant for at least a few months...