23 replies to this topic

[engware]

To All:

I would like to invite both Forum members and visitors to start a discussion on Renewable Energy (All Forms) -- ask questions of interest, share knowledge and experience related to Renewable Energy (both present and future potential, benefits and commercialization issues can be considered).

Also, everybody is welcome to contribute to the Renewable Energy (All Forms) topic.

Thanks,

Gordan

Below are a few plots related to combustion -- complete combustion of carbon, hydrogen, sulfur, coal, oil and gas with air at standard conditions (298 [K] and 1 [atm]) with no heat loss and stoichiometric conditions.

[Steve McGahey]

Are any of the people in these forums familiar with solar thermal generation?

http://www.azsolarce.../faqs/solar.pdf

"A 10- to 400-megawatt power plant capable of producing clean electricity both night and day from solar energy."

I understand that Bechtel, Boeing and others are now going to build another, further-improved power tower in Spain.

The most interesting thing is that this solar-thermal technology can generate enough heat energy to create a buffer for operation during the night!

Does anyone know of any similar players or projects in this area?

I think this is a very promising technology, especially since it can be built with largely existing technology (normal power generation Rankine cycle) and could be integrated with existing coal-fired pwoer plants where the sunshine is present.

Any thoughts?

[djack77494]

Steve,
I found your linked article to be very interesting and informative. Unfortunately, I had never even heard of a solar power tower before this. Sorry I can't help you out, but thanks for the enlightenment.
Doug

[engware]

Steve:

Thanks for the post.

It is an interesting post and article.

Steve, I have to point out that when I was a first year student, some 25 years ago, I had a chance to see a video on such an experimetal solar power plant located in Arizona -- there was no molten salt involved.

Yes, the idea is OK, but the capital expenses are high and such a plant can be only used for baseload operation.

Today, in my opinion, the push is to use the renewable energy to generate hydrogen and go towards hydrogen economy.

Thanks,

Gordan

[engware]

Steve:

Here is an interesting article that just got posted on MSNBC.com -- http://www.msnbc.msn...60106/from/RS.2

It is about low and/or no carbon economy ...

Thanks,

Gordan

[atg]

What about Geothermal power/

I've seen lots of discussion about various renewable energy sources including solar (both PV & thermal), wind & tide.

The one that seems to get little discussion is geothermal power. It appears to be an established technology with commercial sites operating and a huge potential source of energy meaning we can use it for centuries. refer http://www1.eere.ene...gov/geothermal/

I'm guessing the costs are high at the moment - though this must be questionable if commercial sites are opeating.

Why does this not get more discussion / investigation / research/

ATG

[engware]

Hi ATG:

Geothermal energy has been out there for a number of years.

It can be used for the basload operation.

The capital costs are high and it takes time for the return on investment to come through.

However, the benefits of the geothermal energy can be significantly increased when dealing with global warming issues -- there are no CO2 emissions.

In my opinion, geothermal energy is one of the technologies that can be efficiently and effectively used when dealing with global warming and transitioning towards hydrogen economy.

Thanks,

Gordan

Dear all:

¿some of you are involved in biodiesel production?

Both bioethanol and biodiesel seems to be a key to reduce the oil dependance, and reduce the CO2 to the atmosphera.

Hi superchemist,

there are some issues with fuels derived from crops which propbably mean that they can only be a small (though perhaps important) part of the solution. The amount of carbon which can be converted to plants, bacteria algae etc has a limit.... only so much area and solar radiation is available to power biological activity. There are various different estimates around but all the ones I have seen show that humans vastly more energy than the earth is able to produce biologically. This means that even if we convert our all our farms to growing fuel instead of food and we also convert all our forests and ocean-surfaces to production of bio-fuels we will still not produce enough energy to meet our needs at current usage rates..... we will also get very hungry.... I once saw a back-of envelope calculation (sorry cant find reference or link) which suggested that planting around half of western europe with soy and turning over 2 crops per year would produce enough biodiesel to cover perhaps 1/3 of the US's oil imports... even if this calculation was off by a huge margin this is clearly not sustainable. (I am not an expert in crop yields or the net productivity of the earth so dont believe me..... there's heaps of info available online and elsewhere). The destruction of forests and other issues related to growing these crops are also enourmous issues... I have visited SE Asia (source of the worlds palm-oil) many times over the last 20 years and have observed the growing problems for myself. Some of these issues are discussed in the following article - The Guardian - Most destructive crop......

(note: this article has a fairly high estimate of the difference between what the earth produces and what we consume as energy..... i have seen a range of estimates, some a good order of magnitude lower - but it doesnt make much difference in the end - you could probably estimate it yourself using data from the following NASA website - NASA - Earth Observatory)


Biofuels from wastes are an entirely different matter. As a result of the way we live we produce waste products. It is emperitive that we get the best usage from all resources so it would be just plain stupid to not convert USED oils, tallow etc to biodiesel. Oils are not the only source... existing technology such as pyrolysis is able to convert anything from wheat-stalks to nut-shells to sawdust into diesel like fuels as well as gas products. In fact an Australian company is now even using these techniques to create very high quality fuels from used plastics.

The growing of crops specifically for fuel is not viable in the long term. The practice may form an important part of our transition away from fossil-fuels but the long term solutions must focus on reduction of energy usage and energy sources other than biological activity. This means that the 'key' to solving energy and climate problems is likely to be behavioral change and waste reduction rather than a technological 'silver-bullet'. This is not to say that clever technological solutions will not play a vital role.

I look forward to hearing everyone else's thoughts and discussion...



Nat.

To clarify my mention of 'ocean-surfaces' for growing crops.(see previous post) there has been some interesting work done lately on growing algae for biofuel production..... it seems the yields are great compared to the usual land crops but all the previos arguments still stand and we just cant grow enough 'stuff ' to cover our energy needs.

Nat

[engware]

Hi there:

I would like to thank you for your posts and contribution.

Nice thoughts.

In an ideal case, I do believe that successful and safe hydrogen economy is the answer coupled up with all other kinds of energy generation and production that are environmentally friendly.

Thanks,

Gordan

I am currently doing a project in my engineering degree to design a geothermal powerplant, from a BFD through to a Hysys model and P&ID. It is extremely open ended, but basically the conditions are appropriate such that either a single or double flash unit should be used. (Have been given that located in the central North Island of New Zealand and that the well fluid is saturated liquid at 250oC with a flowrate of 2m^3/s)

Currently, I am at a bit of a loss how to create a Hysys model for it, so does anyone have any information related to this that could help? Anything would be greatly appreaciated.

Cheers,
Jason

Hi ATG:

Geothermal energy has been out there for a number of years.

It can be used for the basload operation.

The capital costs are high and it takes time for the return on investment to come through.

However, the benefits of the geothermal energy can be significantly increased when dealing with global warming issues -- there are no CO2 emissions.

In my opinion, geothermal energy is one of the technologies that can be efficiently and effectively used when dealing with global warming and transitioning towards hydrogen economy.

Thanks,

Gordan

[engware]

Jason:

I would suggest that you go to the Chemical Process Simulation Forum at Cheresources.com, which was created a few weeks ago.

I do believe that this is the right place for you where to get input and help regarding your question.

Thanks,

Gordan

[TroyH]

Have any of your heard of the Enviromission Solar Tower Project?

They were originally going to build a 1km tall one in New South Wales (Aus) but it seems $$ have forced them to scale it down.

Still seems interesting all the same.


http://www.enviromission.com.au/

http://www.enviromis...video/video.htm





I came across a patent document yesterday that outlined a method for producing hydrogen renewably from water, using solar energy. Basically it involved heating ZnO to about 2000 Degrees C to yield oxygen and molten zinc. The zinc was then reacted with water to make hydrogen and zinc oxide. The zinc oxide was then recycled.

I was thinking that the hydrogen and oxygen could be potentially fed into a fuel cell, and that the water could then be recycled also.

Will be interesting if they can make it work economically.

edit: OK, looks like it wasn't a patent document after all. The link I found was actually a US Dept. of Energy site. http://www1.eere.ene..._splitting.html

[TroyH]

The process doesn't use electrolysis to generate the hydrogen and oxygen, the solar energy is used only for heating the ZnO up to a temperature where it decomposes into zinc metal and oxygen. There are no photo voltaic cells used.

So the answer to your question is yes it would be wasteful, but that is irrelevant in regard to this technology as it is completely different .

[engware]

Hi there:

When you use solar energy to generate hydrogen, there is no fuel cost -- it is free.

The idea about generating hydrogen is that you use hydrogen as an energy carrier. Such stored hydrogen, can be used later when there is a need for it.

For example, stored hydrogen can be used to meet the energy on demand needs -- wirless computer applications -- it is possible to sell such stored hydrogen at higher prices ...

Thanks,

Gordan

[Adriaan]

I read somewhere that nuclear energy and wind power are now of about equal cost; wind energy cost having come down thanks to increased wind turbine efficiency AND cost of scale savings, nuclear energy becoming costlier "thanks to" nuclear fuel becoming costlier to obtain.

The article further suggested that the EXTRA cost of nuclear power - measures to prevent terrorism primarily - might well make wind power cheaper than nuclear power in the none too distant future!

Along the canal, across from Spijkenisse here, a row of three bladed wind turbines (a row that stretches for MILES) has been built in recent years and I must say that the view took some getting used to... but against the industrial background (refineries and whatnot behind the highway that is behind those wind turbines) it is not a problem. I would, however, not really like to see those wind turbines erected in more rural areas!

[Adriaan]

There is an installation near(ish) here in which foodstuff waste - from restaurants and shipping companies spoiled cargo, mainly - is used to generate power AND to deal with said waste. Thanks to a "green energy" subsidy the owner / founder was able to set up the installation but after said subsidy was terminated it wasn't possible for him to expand the installation even though there is FAR more source material than his current installation can process.

The result is that Dutch organic material waste is shipped from Rotterdam to Germany for processing, something that might be cost-effective BUT not exactly environmentally sound ....

Good news; the "green energy" subsidy is to be re-started! Here's hoping that really happens and that the installation - and other projects like it - will benefit.

[engware]

Adriaan:

Interesting posts.

The green energy is coming big time ...

Thanks,

Gordan

[gman]

hi all,

I am currently doing a study on developinga model to power the electricity of Australia using renewable energy.
Anyone know of a link which outlines the hourly or daily solar insolation anywhere in Australia or globally?

thanks all.

[engware]

Hi there:

How about if you try to check out the American Solar Energy Society at http://www.ases.org.

Also, do a Google search ...

Thanks,

Gordan

[NeiNastran]

I read through that .pdf - and that's an excellent solution. I have driven by the one in Dagget CA (next to Calico - and on the way to Vegas). I kind of wanted to take a tour - but this .pdf replaces that desire. California could have enough of those plants to significantly contribute to the Southern CA megaoplis. I sure hope this happens.

I am working with a Biofuel company so i can help regarding queries or questions.
I feel like these are future fuels and feedstock may be Wood, grasses, and other agricultural and industrial wastes.
There are enzymatic (Biochemical) route and Gasification (Thermochemical) route for production of biomass and lots of research is going.