5 Feasible Renewable Energy Sources

May 08, 2009 by Miranda Marquit weblog
Wind power is one of the more feasible renewable energy sources. Image credit: Kichigai Mentat

(PhysOrg.com) -- President Barack Obama has made no secret of his desire to develop a "green economy" that includes renewable energy projects meant to benefit the environment. He has said that part of the economic recovery in the U.S. will come from money for, and jobs created by, renewable energy projects. Around the world, politicians, businesses and scientists are developing the technology that could improve the cost-efficiency of renewable energy.

One would expect that -- over time -- the costs associated with renewable energy would go down. With fossil fuels, costs can only go up as the un-renewable sources dwindle and become more scarce even as demand rises. Here are 5 feasible renewable energy sources that could be developed to help meet world energy needs:

1. Solar: This is perhaps the most recognized renewable source. Energy from the sun is captured using cells made from special materials (silicon is quite popular right now) and then converted into electricity. The biggest factor in solar cell production is cost. However, with technological advancements solar is becoming more cost efficient, and high efficiency solar cells are being developed. This is important, since high efficiency cells are hard to come by. New materials are providing solar cells that are easier to transport and install. Flexible can be used for residential use, and building is becoming popular. One of the main factors in efficiency is the fact that solar panels only generate electricity during daylight hours, and can be hampered by cloudy conditions or pollution. Some sort of storage is needed in order to make full use of solar power.

However, there are environmental impacts associated with building arrays, since they take up a great deal of room (which is why deserts are being considered -- but still ecological impacts are a reality). In some areas, power companies are toying with the idea of renting rooftops and installing solar panels. This way companies could generate renewable energy that would be theirs, customers could see their costs decrease, and homeowners would not have to pay for installation. Warehouses would be targeted in larger areas. These types of projects could help overcoming the cost-efficiency hurdle, while reducing the environmental impact of large solar installations.

2. Wind: Wind power is growing rapidly, and is becoming a well-recognized renewable energy resource. Using wind power to turn turbines that generate electricity can provide a cheap source of energy. Building and maintaining equipment could provide thousands of jobs and cost-efficient and clean electricity. Wind farms, however, are not particularly popular. They can impact local environment and wildlife, and even provide noise pollution. Additionally, many people feel that the equipment used obstructs scenic views.

It is possible, however, to construct wind turbines in various sizes. They can be made for single residential use, and they can be constructed on a large scale as well. Wind power could be used in areas where there is a great deal of wind, and a lot of open spaces. Technology is making this mode of renewable energy more efficient and less intrusive, but many still feel that there is a long way to go with wind power.

3. Geothermal: Geothermal energy is extracted from the natural processes of the earth. A great deal of heat is created below Earth's surface, and efforts are being made to extract and use this power. While the ancient Romans knew about and used geothermal heating, now Earth's processes are being used to generate electricity -- going beyond space heating. Geothermal power does not put off greenhouse gases (although some harmful gases from deep in the earth would be released -- and need to be contained), and it is reliable. However, it can only be used in areas where there is tectonic activity.

Unfortunately, drilling is involved with geothermal extraction. Additionally, exploration is rather expensive. The costs of starting a geothermal plant are quite high at the outset, including the piping that would need to be laid and all the other costs, although a geothermal operation takes up less surface space than a power plant that uses coal or oil. Fuel is not necessary for a geothermal plant at all. However, once a successful geothermal plant is established, the long-term cost-efficiency usually makes up for the initial cost outlay.

4. Water: We have been studying water-based renewable energy for quite some time. Hydroelectricity has been a source of energy for years. However, even though the energy production process does not put off pollution, there are other environmental concerns associated with the damming of rivers and ecological impacts stemming from this practice. But hydroelectric power remains one of the more cost-efficient means of generating renewable energy.

Other water sources are being considered as well. Tidal power is being developed right now as an energy alternative. Tidal generators placed underwater work in a similar fashion to wind turbines, only they are turned by currents. While considered environmentally friendly, tidal power will be difficult and expensive to develop, since it involves placing generators at the bottom of the ocean. These "underwater wind farms" are also likely to have impacts on sea life.

5. Nuclear: Perhaps the most controversial form of renewable energy is nuclear energy. Electricity is produced from the energy released by nuclear reactions. While fission (splitting) is the main source used today, interest continues in developing cold fusion. Currently, though, power plants generating power using nuclear fission are among the safest plants. They also generate power without emitting pollution. In Europe, France benefits greatly as its nuclear energy produces the cheapest electricity (according to 60 Minutes).

The biggest drawback that many see with nuclear energy is the waste. Radioactive waste is a concern, since it is a health hazard and if stored improperly can leach into soil and groundwater. However, with the right kind of processes, it is possible to recover the waste from the reactions, reclaiming it for further power generation. With technological advancements, it could be theoretically possible to reclaim up to 95% of the waste from initial reactions. Right now, though, France leads in nuclear waste recycling with only 28%. Another issue is fear of sabotage that could result in large-scale contamination. However, nuclear energy is the probably the fastest method that could be put into practice for energy independence from fossil fuels.

Implementing Renewable Energy

All of these processes would require expense up front. Research and technological developments to advance the efficiency of renewable energy is expense. Producing the equipment would require a large initial capital outlay. Additionally, there are some environmental concerns beyond air pollution and global warming with any of these processes. However, it is thought that the environmental impacts long-term would still be less than those of continuing to use fossil fuels. Additionally, cost-efficiency would increase, and overall energy costs would be expected to fall long-term

No one of these sources could effect a change, however. It would require coordinated implementation of a variety of alternative strategies to replace the energy we get from fossil fuels. Assessments of which types of energy would work best in different locales would be required, and a great deal of planning would be needed for a successful implementation.

© 2009 PhysOrg.com

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User comments : 24

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CWFlink
3.7 / 5 (6) May 08, 2009
Two points overlooked:



1) Wind and solar array farms require an extensive new electric grid to move the power from the midwest to the east and west coasts. Besides the cost, there will be environmental impacts from this alone. Many, many environmental waivers will be necessary to span the country with these lines. Further, the grid presents multiple points of failure whereby large expanses of the nation could be thrust into darkness by natural disaster, accident or terrorist action local to a tower. This will require the grid to be redundant, requiring even more towers, lines and territory.



2) Check out ThoriumPower.com for a nuclear solution that cannot be subverted to produce nuclear bombs AND produces much less waste products that the conventional Uranium fuel reactors. See the "thorium 101" section.

Also search the web for info on micro nuclear reactors... inherently safe, cheap and small enough to distribute close to where the power is needed. This will be big in the 3rd world just like cell-phone towers... no extensive wiring needed, relatively cheap and portable, amenable to mass production economies, inherently fail-safe and distributed... i.e. no massive grid, no single points of failure, massive redundancy.

See: http://smallnuclearpower.com/
E_L_Earnhardt
3.6 / 5 (5) May 08, 2009
Micro-nuclear is the most interesting! Transport of energy is always inherant waste! On the THERMAL SIDE - COOLING is also promising! It is the FLOW of energy that is useful! We live in a CHARGED ENVIRONMENT!
Fazer
2.6 / 5 (5) May 08, 2009
What about the power of the mind?

Right now, I am sending each of you 10 kilojoules of warm fuzzies...and a cup of hot chocolate.

Let me know when they arrive.
JedRothwell
2.4 / 5 (5) May 08, 2009
Interest in cold fusion is indeed growing. This is closer to being made practical than most people realize. It has been replicated thousands of times, and it has produced thousands of times more energy per gram of fuel than any chemical reaction, and it can probably generate millions of times more. In some experiments, it has reached temperatures and power density comparable to the core of a conventional fission reactor.

This method is still not sufficiently understood to be scaled up or controlled, but the potential is great.

I have a collection of 1,200 peer-reviewed cold fusion papers from the library at Los Alamos. I have uploaded a bibliography and hundreds of papers here:

http://lenr-canr.org
Bob_Kob
2 / 5 (4) May 08, 2009
What about the power of the mind?

Right now, I am sending each of you 10 kilojoules of warm fuzzies...and a cup of hot chocolate.

Let me know when they arrive.


aka matrix
vanderMerwe
3.3 / 5 (7) May 09, 2009
I spent twenty years doing alternative energy research and I just hate it when people mislead you about what it can do. Clearing up a few things that this joke of a journalist missed either through ignorance or design.

1) Solar and wind... neither are constant and can't be used for base load. You need to couple them with a energy storage technology like batteries or pumped hydroelectric storage. Pumped hydro is great stuff but the number of places amenable to this technology are very small.

2) Geothermal... yes, there is much expense for finding and setting up a thermal field. Even more important, however, is the fact that a) the steam you tend to get out of such a development tends to have a lot of corrosive mineral salts in it which plays havoc with your piping and heat exchangers. b) the delta T for geothermal plants is typically a small fraction of what you get in a fossil fuel plant. What this means is that your generating station needs a lot more cooling capacity, either water or much more expensive air cooling. Water is a scarce resource even for fossil fuel plants. The impact of geothermal plants will be huge on water resources compared with alternatives.
holoman
1.5 / 5 (4) May 09, 2009
Space microwave power satellites a good possibility.
david_42
4 / 5 (4) May 09, 2009
Odd how people routinely leave out solar-thermal, a technology that is over twice as efficient as photo-voltaic and relatively easy to provide for energy storage. Also, a power-tower doesn't require complex and expensive DC-to-AC converters or kilometers of interconnecting wires.
rajen
1.8 / 5 (5) May 09, 2009
Where does Black light power fit in?
3432682
3.6 / 5 (8) May 09, 2009
When technologies are feasible, they will take market share naturally. Solar is far from feasible now, but will get better. Trouble is, government will waste money implementing high cost, low-availability solar, far before it is competitive.

Government is the biggest cause of problems. They have driven up food prices 10% with ethanol; they ruined the housing market by having government agencies write 40% of subprime loans, and through regulations encouraged mortgage companies to write many more; they are running up medical costs; they are taking over the auto industry and will finish off GM and Chrysler, yet subsidize them with your money; and these energy policies will cause these costs to "skyrocket" in Obama's words.

Food, housing, energy, medicine all ruined by government. That's 70% of household expenses taking a shelling from our heroes - the government.

If it were not for government, empowered by greenies, we'd have 80% nuclear-powered electricity, like France. We'd be producing half the dreaded CO2. Government will continue to block the only real solution to cleaner power, nuclear. They will continue to push their insane agenda of adding 2% of "renewable" power every year, creating much higher costs.

Big Government = big problems.
CWFlink
4.3 / 5 (6) May 09, 2009
Arn't we a happy lot today!

Well to add to the misery: you can well see many environmentalists don't care about the WORLD's environment because they object to drilling off our coasts when they know the alternative is to import oil from 3rd world countries where there ARE NO environmental regulations and where DICTATORS only care about exploiting their resources for personal gain.

If they cared, they would want to bring all the production close to US where they could assure regulations and oversight would protect the world from the side effects of the production.

Instead, the powers that be are exporting our polution AND our recession while importing the capital and brains of the 3rd world to help our so-called "enviromentalists" make themselves rich on "green technology".

It is the "robber barons" all over again, this time cornering the market on "green" instead of "coal and steel".
earls
2.6 / 5 (5) May 10, 2009
Energy generation is not the problem. Storage is. Storage. Storage. Storage.
CWFlink
4 / 5 (5) May 10, 2009
Earls is correct that effective, cheap storage changes the analysis. Day-night cycles, weather impacts on solar/wind, and even the daily variation in load upon coal or nuclear plants would be addressed by efficient storage of MAJOR amount of energy.... But of course:

Coal, petrolium, nuclear, and geothermal are ALL examples of STORAGE of energy.... all fossile fuels are simply releasing stored solar energy; all nuclear plants are releasing energy stored from natural stellar processes dating back to when the elements were formed.

What earls is addressing most directly is how to deal with the variations in wind and solar energy. But beyond wind and solar, if we had efficient energy storage, we could even design fossile fuel engines that are very efficient and non-poluting.... and even could do carbon sequestration more efficiently.

Growing plants and producing dthanol can be viewed as a solar energy storage system AND a CO2 sequestration process! We simply need to balance these processes with the needs of the consumers, and better energy storage techniques can help.
Damon_Hastings
4.7 / 5 (3) May 10, 2009
When technologies are feasible, they will take market share naturally.

Technology takes market share when it is *profitable*, not when it is feasible.

Now, I know what you mean here, and you're right that quite often, individual profit motives will result in good behaviors which benefit society as a whole (aka "the invisible hand" of capitalism.)

However, it is not always so. Look up "the tragedy of the commons" in the context of game theory. This will show you a concrete mathematical description of situations in which the invisible hand fails. That is, it describes a situation where individual entities acting in their own self-interest (i.e. capitalism) do *not* bring about a common good.

Capitalism as a system is pretty good, but it's not perfect. In game theoretical terms, capitalism is bad at avoiding global minima (i.e. global catastrophes) which occur along the gradients of local maxima (i.e. short-sighted profits.) In other words, a system based on individual self-interest does not always lead to the greatest common good.

A lot of people consider this obvious.

In terms of global warming, it is in each individual's self interest to maximize his own profit regardless of what it does to the environment. This individual recognizes that he alone cannot stop global warming. Therefore it is not in his interest to forgo profit in order to try and stop global warming (since he and his family will need those profits the most if global warming *is* real and *does* cause a global catastrophe.) So, to take action against global warming requires something more than individual self-interest. It requires global interest, i.e. altruism.
COCO
1.5 / 5 (2) May 11, 2009
I want to make money from containing my farts.
earls
1 / 5 (2) May 11, 2009
No, apparently I was wrong. Energy storage is irrelevant. Lord_jag, Rick69 and Modernmystic apparently have some insider knowledge that alleviates our energy storage problems.
jstack6
2.3 / 5 (4) May 11, 2009
a few points. Nuclear is NOT RENEWABLE. It uses imported uranium, makes waste that last for thosuands of years and uses a lot of water.

We have storage. All the new plug-in vehicles will have lots of storage. V2G Vehicle to Grid saves it from excess energy at night and can seel it back during the day.

Solar on your home doesn't need any tramission lines or transformers. I run my home for my wife and I on a 2K array,. We made excess most days and months.

The best Renewable energy is more efficiency , Nega watts. We don't have to produce and waste so much energy. A friend in our area is building zero energy ,highly insulated homes for the same prices as watefull homes.

earls
2.7 / 5 (3) May 12, 2009
Care to explain where all this magical storage is? Particularly, at an energy density/cost/size ratio?

Solar is swell, yes sir. But you're still hooked into the grid. Why? Because if something goes wrong you don't have the stored energy to last through it. Just how long will your batteries last?

You're right about NegaWatts. Good name, better trademark it before Neil does. And how do we achieve NegaWatts? The same way we solve our energy storage problems - superconductors. Can you imagine? Electronics that don't put off heat? Exceptionally strong micromotors. Everything we need is right there so why are we squabbling over this nonsense?

Even if we had a direct energy link to the sun, what good is it if a majority of that energy is lost in transmission?
Roach
5 / 5 (2) May 13, 2009
I agree with you earls, except that we do have a direct energy link to the sun, and the majority of it is lost in transmission.
holoman
1.5 / 5 (2) May 13, 2009
Space based solar energy with 24x7 beamed microwaves
to Earth would be another alternative.
chukB
2 / 5 (1) May 13, 2009
How does "cold" fusion beat out hot fusion of tokamaks, stellarators, and laser fusion?
Jmaximus
3 / 5 (3) May 14, 2009
Your statements about Geothermal are outdated and inaccurate.

First, geothermal could replace vast amounts off natural gas and reduce electricity consumption in heating and cooling buildings. This does not require 5 km deep wells and can be done in all 50 states. On average it is 70% more efficient than conventional HVAC.

Second, geothermal electricity production can also be done anywhere in all 50 states, but some regions do have resources closer to the surface. However the entire mantle and the inner cores of the planet are molten and which at the most are about 30 km down. In most cases it would only be necessary to drill perhaps 5 to 7 km for a energy supply that could never be depleted in a million lifetimes and works 24/7 [unlike wind and solar].

MIT did a excellent study of geothermal and its potential...

http://geothermal...ergy.pdf
jerryd
1 / 5 (1) Jun 06, 2009

What a bunch of idiots here. There is no energy shortage, just a shortage of equipment to catch, make it.
A 1kw windgen can be made for $300 in retail parts.
A solar thermal engine making electricity and heat costs less that a coal plant does and can be run when the sun doesn't shine one any fuel like wood pellets.
Oil, coal and all energy is going up with a bullet. Oil went above $70bbl yesterday in the middle of a deep recession. So get a clue and secure inexpensive supply or conserve a lot or you will get screwed. Obama, Dems are trying to get you ready but you all don't have a clue.
Most RE is now the low cost energy source and will only get better. If you build your own RE then you are much better off.
You've been warned.
Geothermal except rare places is not economical. H2 is a Joke as is Fusion and nuke is 2x's as expensive as most RE and we really are running out of oil plus the other 95% of the world wants their share.
Cheap storage is already here in the form of sodium batteries. Check out Zebra Battery.
Solar happen at peal power load times mostly sop no storage needed.
earls
5 / 5 (1) Jun 08, 2009
So let me guess jerryd, you're living off the grid with your $300 wind generator and Sodium batteries?

Or maybe you're just talking down to and insulting everyone with no real respect to what is realistic.

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