If your assumptions and math are correct (and I have no reason to think otherwise, based on a first reading), then how does the 5X greater land requirement of renewables vs. nuclear power prove that "Renewable energy can generate all the world's energy needs" is a "myth"?Lou had a point, but a point which I believed could be answered. I responded:
Lou, there are several issues here. First, in order build an energy gathering array over a large area, large materials and labor inputs are required. These inputs are expensive, and the massive deployment required will create a materials inflation. Peter Lang and Barry Brook have documented the materials input of renewables, and some of that documentation has appeared on the Energy Collective. There estimates show that nuclear power requires significantly less materials input per unit of generation capacity, and far less materials input per unit of electrical output. You have not disagreed with their estimation of materials input, or of overall expenses, as I recall.
Secondly, the land use requirements of renewables conflicts with other "green" values. Windmills kill birds and bats, soil disturbances required to build solar and wind arrays lead to soil erosion, and at least solar thermal requires large amounts of water, the equivalent amount of water required by a nuclear generating plant, in water scarce areas. In addition to the effect of windmills on flying animals, both solar and wind have other intrusions into wildlife habitat. Solar thermal has an especially egregious effect on both soil and habitat, because it requires scraping soil bare of all vegetation. In addition, renewables arrays are visually intrusive, and deface the landscape, Windmills also create noise pollution. The manufacture of PV modules is both energy intensive and creates large amounts of toxic waste. Since much of that manufacture has moved or is moving to China, the management of that waste is not under effective control.
Thirdly, the materials, labor and capital costs of a renewables solution are would all be extremely high, and many renewables advocates have expressed doubts that the massive deployment of renewables energy sources is possible by 2050. In fact, many renewables advocates see an energy gap that would require bridging by fossil fuel use to 2050 and quite probably beyond. Most hide the implication of this by limiting the fossil fuel use to natural gas, which is, of course, not green at all.
Fourth, renewables advocates acknowledge that renewables cannot fulfill current energy demands, but argue that demand can be dramatically lowered through investments in efficiency. Although current efficiency efforts are proving successful, there are potential structural impediments that may impede efficiency efforts down the road. In addition, successful efficiency efforts would also lower the cost of a nuclear substitute for fossil fuel generation.
Fifth, in order to be successful, an all renewable grid would require a huge and costly expansion of its electrical gathering and distribution system, and a large investment in energy storage systems. Nuclear would require far fewer modifications to the present grid, and energy storage with nuclear would be limited to cases in which it was clearly cost effective.
Sixthly nuclear has the potential for producing industrial process heat and cogeneration, while renewables do not. Waste heat and electricity from sea side nuclear plants can be used to desalinate sea water. Renewables are far more limited in their capacity to produce fresh water.
Lastly, and this is a very important point. The potential exists to dramatically increase the land use and materials input efficiency of nuclear power, by switching to a more advanced type of reactor. Labor costs can be dramatically lowered by changing nuclear manufacturing techniques. The means that nuclear capital costs can be dramatically lowered in a way that is not possible with renewables.
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When anti nuclear fanatics have their way and the Earth surface get all covered with solar PV panels, solar concentrators and ugly wind farms there will be no more room, natural beauty, materials or money for human habitat. At that time we will need to think where to house humans.
I have already a proposition going with my friend Dave to solve the coming problem. We want to purchase a horizontal boring machine and start boring underground caves for human housing.
The new enterprise will be called Dave's Cozy Caves LLC
Of course, I am just joking in here, however, the alternate energy solutions will occupy far more than 5x the land surface than nuclear plants would. When power transmission lines and roads to service all that dispersed hardware are added it will be more like 1000x, most likely many times more, hence the idea with Dave’s Cozy Caves does not sound too bad after all.
The idea is to compare existing technologies.
By that standard a thinfilm solar cell/modern wind turbine is about 3-10 times energy efficient than a nuclear plant.
Your reasoning on process heat is also faulty. Where is nuclear process heat used for desalination? Thats not common practice for obviouse reasons.
A Biomass plant in comparison can reach energy conversion efficiency of 90% and higher and can even be operated in combination with industrial plants like wood industry.
There are also areas where it is impossible to operate nuclear plants. Rooftop nuclear? Desert nucelar? Offshore nuclear? (well...some luciouse dreams where already abandonded in that area).
Bird kill? House cats kill more birds than windturbines. We should stop driving for the same reason.
If you try to gain on bashing renewable energys on false reasons you will never succeed.
Why not try to develope the MSR without fighting other good technology?
It just looks too obviouse that you have little to no idea about renewable energy production.
Keep fighting fossile fuels...
anonymous, how do you measure efficiency. If you measure efficiency by capacity factor, nuclear winds. If you measure efficiency by output units per dollar spent, nuclear winds. If you measure efficiency by dollar spent per unit of carbon mitigation, nuclear wins, and if you measure efficiency by the smallest space occupied per init of carbon mitigation, nucleare wins. Process heat from a nuclear plant has been used to desalinate water in the Soviet Union. Using process heat for desalinization is dependent on siting, and since no new reactor sites have been established since the 1970s in the United States, is because there was no demand then, and sites were not picked accordingly. Oh and the
indians are building a couple of reactors that will use residual heat for desalinization. Blame all those birds killed by windmills on cats, will you.
The only false reasoning around here is yours.
Efficiency is also how much (fossile) energy you have to put in and what you get out.
So how much energy do you get in return on building a nuclear plant? how much energy is returned by a solar cell/wind mill.
The other use of efficiency is how much energy you can turn into useable power. Lost thermal energy is of no use beyond killing fish and destroying eco systems.
For birdkill just look up the facts.
Lets talk about the indian nuke program when we know to which degree it fails.
Again...stop bashing things you don`t have a clue about.
@Anonymous - You are clearly out of your league here. If you want to engage in a meaningful discussion, read the copious previous posts by Charles where he has given both historical and factual presentations to all of your accusations.
We'll see you in a couple of weeks.
Anonymous, At present it clearly would costs more to build a post-carbon grid with renewables than with nuclear. Nuclear uses less steel concrete per kWh of output than wind and ST, and less cooper than all renewables. Energy storage will greatly increase the demand for materials needed to make an all renewables grid work. In addition, an all renewables grid will require an expensive and materials intense expansion of the grid. You cannot rely on a diffuse energy source and not end up spending a lot of money on gathering and transmission, and you cannot use intermittent energy sources with out creating a great deal of redundancy, and still needing to spend a lot on storage as well.
"Efficiency is also how much (fossile) energy you have to put in and what you get out."
No, it isn't. But if that's what you care about then nuclear still wins because it doesn't have to be backed up by natural gas turbines.
Here's the EDP for the Forsmark NPP: http://www.environdec.com/reg/021/
Click EPD content-> 3.4 Environmental Information - Results from LCA
"So how much energy do you get in return on building a nuclear plant?"
I don't really see why this measure is more useful than the amount of CO2 emitted per kWh, cost per kWh, cost per kg of CO2 avoided etc; but if you insist.
First, it's ambiguously defined(if you include all energy, all forms of energy are always net losers. E.g. it takes more energy emboddied in sunlight than you get out as electricity of a solar panel).
The energy contained in the uranium is "free" in the same sense as sunlight; humans performed none of the work done by the super nova that created that uranium, they just performed the work to dig it out of the ground.
There's still at least two gotchas left.
Nuclear power plants consume some of the electricity they produce internally to run pumps. At Forsmark this is ~4%. I'm not going to include this since it's completely internalized to the operation of the nuclear plant and the only cost is a slightly lower efficiency in converting of uranium to electricity. Counting this into EROI is like counting internal resistance losses in a solar panel into its EROI.
The other gotcha(that I can see) is whether you count primary energy as equivalent to electrical energy. Is 1 kWh of electricity worth no more than 1 kWh of heat generated by burning some coal? Evidently people convert coal into electricity at a mere 40% efficiency, so this is not the case, but it's hard to quantify. More on this below.
The EPD says Forsmark consumes per kWh net electricity at the busbar:
0.33 g coal,
0.45 g crude oil,
0.24 g lignite,
0.22 g natural gas,
0.042 g wood
1.1*10^-4 g peat
1.4*10^-4 kWh hydroelectric power.
2.1*10^-6 kWh solar electricity.
3.0*10^-5 kWh wind electricity.
The primary energy(amount of heat you get when you burn them) in those fuels is:
3.1*10^-3 kWh of coal(assuming anthracite)
5.6*10^-3 kWh of crude oil.
1.0*10^-3 kWh of lignite.
2.3*10^-3 kWh of NG.
1.8*10^-4 kWh of wood.
4.7*10^-7 kWh of peat(assuming dry)
Simply summing the heat provided by these fuels to the electricity provided by hydro etc. gives 0.012 kWh per kWh of nuclear electricity produced, that's an EROI of 83.
If you try to be a little bit more realistic and compare secondary energies(the amount of electricity you would have got if you put the oil and gas through a combined cycle gas turbine, the coal, lignite and peat through a coal plant) produced it directly from that oil, coal, gas etc.) you get an EROI of ~150-200.
This is at the busbar, grid infrastructure consumes quite a bit more energy for all the aluminium conductors, transformers etc. But all these energy costs are higher for intermittent generators that have to be sited where the wind and solar resource is rather than near the consumer and near the existing infrastructure, and only uses the powerlines some of the time.
Continued:
"how much energy is returned by a solar cell/wind mill."
This is even less welldefined.
Wind and solar by themselves do not produce dispatchable(i.e. useable for normal purposes) electricity. You MUST either provide electricty from hydro or natural gas to fill in the gaps or use massive redundancy and back-up storage. What you properly should consider is the combined EROI of these systems.
Since I can't find the relevant numbers, I'm going to consider the EROI of unusable kilowatthours from wind and solar PV. Even this is not easy to find, and it is a guaranteed overestimate of EROI.
http://www.nrel.gov/docs/fy05osti/37322.pdf
Payback for solar is 3-3.7 years under some kind of unspecified set of conditions(most likely ideal, think California); with an indication that thinfilm is anticipated to drop to a payback time of 1 year at some unspecified point in the future.
The panels have an economic life of ~30 years, so that's an EROI of 10 or so and expected to grow to 30.
http://www.awea.org/pubs/documents/faq2002%20-%20web.pdf
I'd rather have a better source than the american wind energy association, but it will do. They figure payback takes 3-8 months; that's an EROI of 40-100.
Now, again, why does EROI matter when wind and solar energy necessitate the the production of much more CO2 through burning natural gas than nuclear does? When they cost much more? When they're far more difficult to integrate into the grid?
I think another good reason for debunking Myth #1 is the concept of energy density. Dilute sources of energy require large collection apparatuses and lots of them to do the same job that a thermal power plant can do. A friend of mine said after I was explaining to him about the Jevons effect, "since the sun and the wind are the 'fuel' for renewables, wouldn't that make this Jevons effect a moot point?". I thought about this for awhile as I could see where he was going, the it occurred to me the Jevons effect works a little differently with renewables. The maximum efficiency of a wind generator or PV panel tops out at around 30-40%, there is no way to add more wind or sun to make them perform better, thus you add more machines if you want more energy. This is true of thermal plants as well, but to a far less degree. In this sense the fuel is the wind generator or the PV panel and this is why renewables will always have a difficult time scaling. Of course a substantial amount of fossil fuels is used in the industrial process to create and deploy wind generators and PV panels, to do it without it would be virtually impossible.
The concepts of energy density and the Jevon's effect are rarely discussed in the circles of renewable advocates. Moreover, they fail to understand the micro and macro variances of these concepts. For example, I saw one article discussing the Jevon's effect and how it applies to high-mileage vehicles, noting that people didn't seem to drive them anymore than their previous lower mileage cars. Driving is a chore and personal travel habits are affected more by fuel price and income. However, total miles driven by the whole USA definitely reflects the economic dynamic described by Jevons.
We can discuss details for the many reasons why renewables are not suitable for powering modern civilization until we are blue in the face, but until renewable advocates start to grasp the intimate system dynamics of energy and the economy they will continue to believe in the impossible.
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