# What are the primary problems that plague alternative energies? (beside economic)

#### budder8819

I know that economics must play a large part in determining why alternative energies aren't as effective as burning oil. Oil is cheaper. I'm an electrical engineering student and I'm curious about some of problems plaguing the alternative energy business. Ie. Solar, Wind, Geothermal, ect...One of my professors mentioned that manufacturing is a large part of it. What do people on this forum think about it? How many MWatts could you get out of a traditional oil run power plant in comparison with a solar run or wind?

Does anyone know what kind of research is going on in alternative energy systems?

Related Electrical Engineering News on Phys.org

#### DaleSwanson

Economics are probably the biggest factor. Just looking around for some estimates it seems a large solar plant cost $100 million for 30 million kWh per year. For nuclear a new plant may be as high as$5 billion, but would provide 10 billion kWh per year. Coal is even cheaper, about $500 million for 4.5 billion kWh per year. This works out to 0.3, 2, and 9 Wh per$ respectively. It doesn't take into account operating costs, which for solar and nuclear are both rather low (and yes solar has operating costs), but even with it factored in I doubt it would change things much. There's a reason coal is the main source of power throughout the world, it's cheap.

As for other factors, reliability is a big one. Solar and wind are probably the main sources people think of when they think alternatives. Both suffer from the fact that at any moment power could go out, this requires backup power from some sort of traditional power plant. Most traditional power plants have a hard time spinning up quickly, and to be always available they must be continually ran, even if the power isn't being used. Natural gas and hydroelectric are the two major types that are able to quickly provide power if needed. Natural gas is expensive, and still a fossil fuel, and hydroelectric isn't suitable for many areas.

They also suffer from the low hanging fruit problem. Certain areas are prime candidates for solar and wind, while others are very poor choices. As the best areas are taken advantage of we can expect less and less suitable areas to be used. This leads to a large portion of the nameplate capacity not being used. In other words even though your solar plant could produce 100 gWh per year you are only seeing 20 gWh because the conditions are just so poor for solar.

I also think there is not a lot of capability to increase production of solar. However, I don't feel this is a real problem. If there were a major increase in demand greater production capability should be created for no other reason than it will be profitable to do it.

If we want to be able to use some sort of intermediate source of power we will need a way to store excess power and use it later. There are a number of ways to do this, but none are very economical, or efficient. Most don't scale up very well either. I think one of the ways utilities do it is to pump water with excess power, and then use it to run turbines during shortages (effectively an dam without a natural water source). Another way to help ease storage issues would be to transmit excess power long distances to where there are shortages. That has it's own problems though, like transmission losses, and what happens during widespread low wind or sun times. The only two sources of power that seem capable of meeting our current demands are coal and nuclear. Coal is dirt cheap, but filthy, and people have a negative association with nuclear. Thus it looks like we will be stuck with coal for the foreseeable future.

The two main areas that need improvement before solar and wind could be realistic options are costs, and storage of excess power. Efficiency isn't very good for either, but it's unlikely to improve much, so I think the main effort should be in reducing the cost of current efficiency levels and improving the storage of excess power.

#### Phrak

One of my professors mentioned that manufacturing is a large part of it.
?? As in, it's hard to manufacture something you want but don't know how to make?

#### Proton Soup

thermodynamic problems. do you have to put in more energy than you get out?

political. why don't we have more nukes? even the french love nukulur.

environmental. how many birds will you kill, or midget sturgeons and purple snail darters will go extinct?

economic. i don't want your windmills off my coast because they obstruct the view and devalue my beachfront property.

technological. there are known knowns, and known unknowns, and unknown unknowns.

#### Phrak

thermodynamic problems. do you have to put in more energy than you get out?

political. why don't we have more nukes? even the french love nukulur.

environmental. how many birds will you kill, or midget sturgeons and purple snail darters will go extinct?

economic. i don't want your windmills off my coast because they obstruct the view and devalue my beachfront property.

technological. there are known knowns, and known unknowns, and unknown unknowns.
Well done.

"Zero Point Energy!! Horrah!"

"What do you mean my Prius--holier than your car--has a carbon, pollution, and a hidden fuel oil footprint?"

"What do you mean I should have a handle on economics, physics, engineering and enviromental religion (and sociological problems like ignorance) or shut up my silly opinion?"

"We can get energy from hydrogen. Water has hydrogen. It's like free energy."

"Wind energy is like, organic, man."

Last edited:

#### skeptic2

Excellent report DaleSwanson. I've often wondered if solar might be practical if installed as part of new houses or other buildings and amortized over the life of the mortgage. This of course would limit the placement of trees near those buildings.

Do you think huge flywheels might be a practical means of storing energy for a short time such as overnight? I can picture a situation where of lots of home owners have installed solar panels producing energy by day but using the most energy at night recharging their electric cars.

#### Phrak

I’m wondering... how many tons of coal per annum does it take to produce a 30 million kWhr/yr solar power plant amortized over it's lifetime?

I.e., does it take more coal to fuel a solar power plant than a coal burning plant?

#### Topher925

Do you think huge flywheels might be a practical means of storing energy for a short time such as overnight?
Yeah, its already being done. http://www.beaconpower.com/products/EnergyStorageSystems/index.htm" [Broken]

Wind:
Wind energy is getting cheaper by the year and has a very small cradle to grave pollution footprint. It's main weakness is it doesn't produce a base load energy supply and its output is dependent on the environment. There are a few start ups attempting to build "high altitude wind generators" that operate in the stratosphere where wind is constant. (I used to work for a HAWG start up and can give you detailed information you want it)

Solar:
Solar has a small output with respect to cost and real estate and its output is also dependent on the environment. There are some research groups that are working on developing solar powered water thermolysis plants that theoretically could produce H2 very efficiently that would then be converted to electricity using fuel cells(my current research area). However, there are large challenges in material technologies to overcome in order to produce a water thermolysis plant.

Tidal/Current/Hydroelectric:
Hydroelectric and Tidal power plants are great with respect to cost and pollution. The problem is there just aren't many places to build them. Tidal/Current power generation is a technology still in its infantsy but has the potential to you yield pollution free (in operation) base load power at a practical cost. A water current type turbine can generate ~833 times more energy than a wind turbine given of the same diameter. I have also read papers about development of water turbines that are subject to Betz's Law.

BioFuel:
Biofuel's are a huge area and I have a really tough time keeping up with it. Bio-based energy sources consist of organisms that can generate energy from sunlight in the form of electricity to plants that we can refine alcohol from. I honestly don't know a whole lot about about bio-fuels except most technologies have very low energy densities, so I won't comment about it.

Geothermal:
I hear a lot from people saying that geothermal is the energy source of the future although I have yet to be convinced. Geothermal plants can only be constructed in selective places around the world and while they are relatively pollution free, I don't believe they can meet the demand that our society currently requires. Technology for individually heating and cooling buildings seems to be maturing and is a promising technology.

Last edited by a moderator:

#### skeptic2

This morning's paper revealed a solar power plant will be built near town producing 200 - 300 Megawatts at a cost of \$900 million. Your figure was right on DaleSwanson.

http://www.chieftain.com/

#### DaleSwanson

Well at the homeowner level the storage issue is lessened. First just using lead acid car batteries is a cheap way to store power. There are still a lot of problems and it certainly isn't good for the environment if that is your goal. At least for now though the best solution is to simply use the grid as an ideal battery. Sell excess power to the grid and buy power when you have a deficit. This will work as long as the number of people with private solar or wind is insignificant. If large percentages of areas start to be powered by their own solar and wind then you run into the same problems as a large plant powering them. Fossil fuel will have to be burnt and the power not even used because they need to be able to supplement the solar and wind at a moments notice.

Flywheels are one of the more interesting methods for power storage. Unfortunately what makes it interesting to read about is that it's quite an engineering challenge. It's certainly possible, but it's another very complex piece being added to the puzzle. Storing the energy mechanically will also lead to a great show the first time it's accidentally released (to watch from a great distance).

Hydroelectric and geothermal are both great. Iceland gets almost all it's heat and electric from geothermal. They both share the same problem though, very limited areas that can use them. Dams also pose a lot of ecological problems so if you are aiming to help the environment it's sort of counter productive. Also as I said above when you store energy mechanically it becomes easier to release all at once. I will say this though, there are a lot of dams which are there for controlling the river, and which currently produce no power. Installing small generators on these dams would be rather cheap and there wouldn't be any additional ecological concerns.

I strongly believe that nuclear is the best available option. I don't oppose private individuals or companies building solar or wind. I just don't think it will be profitable to do so without government subsidies, except is the very best cases. I would support a government ban on new coal plants, as there is simply no way a coal plant can contain all the waste it puts out, and thus it's everyone's problem. This would only work though if the government fully embraced nuclear, and streamlined the approval process. A large portion of the cost of new nuclear plants is the red tape, and the length of time to get approval. A single safe design could be used and built across the country. The use of breeder reactors eliminates a lots of the waste (which isn't as horrible as people seem the think to begin with). France's policy on nuclear is a great example of what every industrialized nation should be doing. Maybe 20 years from now when they have cheap power with little foreign dependence other countries will see what they are missing.

#### Topher925

Keep in mind that the use of breeder reactors is still not a success.

France’s engineers tried harder than those in any other country to build and run breeder reactors reliably at a commercial scale, but ultimately they failed.
http://www.spectrum.ieee.org/feb07/4891/2

I still have yet to be convinced that the nuclear waste problem has been solved and until I am I don't believe that nuclear power is the answer. It may be a temporary solution that could bridge the gap to a better technology but it's not something that we should rely on. Not yet anyway.

#### DaleSwanson

Well I think it comes down to this, nuclear and coal are the only ways we can provide enough power, and nuclear is (much) better than coal. In a sense nothing is a permanent solution, we are always going to come up with better technologies that will solve the problems of current ones. I'm sure one day we will have something which is undeniably better than fission (perhaps the mythical fusion). For today though, nuclear fission is the best we've got.

I should have just said http://en.wikipedia.org/wiki/Nuclear_reprocessing" [Broken] instead of breeder reactors. The fact that the US stopped reprocessing in the 70's was purely political, and didn't make sense. The US has enough actual nuclear weapons to wipe out the entire human race, but it stops reprocessing because of proliferation?

As for waste even without any reprocessing the actual quantity of waste is rather small. As we don't have any permanent waste storage site (Yucca Mountain) reactors just store the waste locally, and they don't have much problem doing it. The great thing about radioactive stuff is that the more dangerous it is the shorter it lasts. The stuff that lasts millions of years isn't very dangerous, and the stuff that is deadly to just be around is gone in years if not days.

Again, nuclear fission certainly isn't the perfect solution, but it is the best we can do today to meet the demands.

Last edited by a moderator:

#### Phrak

I live next door to a putonium accident. About 40 years later and it's still here. This isotope seems to be both very lethal and quite long lasting.

#### budder8819

Topher925 said,

Wind:
Wind energy is getting cheaper by the year and has a very small cradle to grave pollution footprint. It's main weakness is it doesn't produce a base load energy supply and its output is dependent on the environment. There are a few start ups attempting to build "high altitude wind generators" that operate in the stratosphere where wind is constant. (I used to work for a HAWG start up and can give you detailed information you want it)
So did your research on these high altitude "windmills" continue or was the task impractical. Just curious, how exactly did you plan on keeping them up in the air, balloons or something, or would the wind turbines generate their own power to keep them up in the air? What about weather? I think the stratosphere is too high up for weather to really effective the wind turbines but transporting the power to ground would involve running some type of cable or something right?

#### Topher925

Right now I think most HAWG projects are on hiatus as far as I know given the state of the economy. At operating altitudes of 15k+ you don't have to worry about storms or precipitation since they mostly occur closer to the troposphere. Transferring the energy from the generator to the ground is the most difficult task and is the Achilles heal in most HAWG concepts. To answer your questions about how they operate, here's a video of the project I was involved with;

http://ctngreen.com/ecologic/video/
http://www.skywindpower.com/ww/index.htm

There are many others, some with major funding from companies like Google.

http://venturebeat.com/2008/08/23/makani-power-takes-in-5m-for-high-altitude-wind-energy/
http://www.makanipower.com/home.html [Broken]
http://www.magenn.com/technology.php [Broken]
http://peswiki.com/index.php/Directory:High_Altitude_Wind_Power

Last edited by a moderator:

#### Wozerd

Keep in mind that the use of breeder reactors is still not a success.

http://www.spectrum.ieee.org/feb07/4891/2

I still have yet to be convinced that the nuclear waste problem has been solved and until I am I don't believe that nuclear power is the answer. It may be a temporary solution that could bridge the gap to a better technology but it's not something that we should rely on. Not yet anyway.
How far away do you (or anyone) think we are from space elevators. I understand the breakthrough has been made in carbon nano technology (disclaimer-- I am not an educated person-- please forgive me) that will allow the super light, super strong cables that are required. Store the waste until these elevators are proven reliable and in place. Once accomplished, we could start safely packing containers of waste to a point where they could be launched into the sun.
Sincerely-- are we-- never ever? or in 20 years? 50 years?
(Just want to know when I can expect to see "SAVE THE SUN" bumper stickers)

#### Phrak

To paraphrase DaleSwanson, (maybe a lot of para-paraphrasing) there is only one problem with alternate energy; a deficit in stupidity. It's stupid to do things the hard way. It's stupid to do things the way that cost you the most. More stupid = more alternative energy.

Last edited:

#### Wozerd

OR:
When Stupid talks, Stupid listens!
(and believes!)

#### Topher925

To paraphrase DaleSwanson, (maybe a lot of para-paraphrasing) there is only one problem with alternate energy; a deficit in stupidity......More stupid = more alternative energy.
That's a rather arrogant statement. What is so stupid about creating a nearly pollution free energy infrastructure? How do you even know that all alternative energy technologies will cost more than nuclear in the future? Most technologies are still in early stages of development and some are said to be able to compete with coal prices in the future.

What about countries like North Korea and Iran? Should countries that are threatening to destroy the western world have nuclear power plants also?

#### russ_watters

Mentor
What is so stupid about creating a nearly pollution free energy infrastructure?
It is stupid if it isn't possible and right now it isn't.
How do you even know that all alternative energy technologies will cost more than nuclear in the future?
We don't know, but we do know that they are more expensive now and we need more clean energy now.
Most technologies are still in early stages of development and some are said to be able to compete with coal prices in the future.
That's speculation by people who stand to profit from it. In other words: predictions that are probably not reliable.
What about countries like North Korea and Iran? Should countries that are threatening to destroy the western world have nuclear power plants also?
Irrelevant to the question of whether the US should have them.
I still have yet to be convinced that the nuclear waste problem has been solved and until I am I don't believe that nuclear power is the answer. It may be a temporary solution that could bridge the gap to a better technology but it's not something that we should rely on. Not yet anyway.
Define "temporary". We've been using nuclear power with no major problems for about 50 years. And there is currently no evidence that an alternate source of energy is on the horizon, so we'll need to use it for perhaps another 50. Is 100 years "temporary"?

Regardless of how you define "temporary", right now, *half* of the electricity in the US comes from coal. Eliminating that is a "right now" problem, not a temporary or a future problem and there is only one way to do it: with nuclear power.

It does not make sense to push *future* solutions to *right now* problems.

Last edited:

#### raithrovers1

It is difficult to see how wind turbines on a large sclae will ever replace any other power generating scheme due to it relying on the weather and storing large amounts of power.
However if it was done on a small scale ie. homeowners and private business fitting turbines, then once the technology becomes cheap enough and reliable, if enough people used them it could make a large dent in the worlds power usage. Once again you would have to use batteries of some discription to act as a buffer when there is no wind so it is not perfectly enviromentally friendly.

http://www.powerups.co.uk

#### Phrak

Russ watters just covered the "if" arguments selling future pomises. Did you miss it?

"What are the primary problems that plague alternative energies? (beside economic)"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving