alternative fuel or what?

[Gerben42]

Link fixed: http://www.ier.uni-stuttgart.de/publikatio..._Aalen_2008.pdf

 

Don't know why it produced the dots.

 

However, the fact that solar cells are manufactured in China is surely not a reason to not use solar cells? A "simple" solution to that would be to just make them in France. Or not buy solar cells from China unless they are made the same way as they are made in France.

 

The point is that currently to produce electricity from solar cells, you need a huge amount of electricity to produce the solar cells in the first place. If this is done in China, the electricity comes from coal, if it's done in France, the electricity comes from nuclear and hydro energy.

 

In 2003. my heat-pump system (new house) cost about 10K and saved me about 20% of a straight electric heating system ($500 per year for heating and AC)

 

An extra 5K would have produced the trench system for the heat sink. Yes, 10 yr payback but only 1/2 a generation, worth it for my grandkid's sake....

 

I think that was a good investment. I mean, you expect to live there for a while, right? And even if not, it probably raises the value of the house by more than 10K because you have to take into account the savings the future owner will make on heating.

[Trinidad]

Wind has the problem that you cannot decide when the energy is produced, it depends on weather. There is no rule that there is wind exactly when the electricity is most needed. For this reason, having more than 10% wind energy is not useful.

As you may know, about 20 years ago, a Dutch engineer with the name of Lievense proposed that excess wind energy would be used to pump water into a basin. When there is a lack of wind, the basin would provide energy through hydro power. He had very concrete ideas of where to put the basin (for the Dutch: In the Markerwaard or alternatively build a new one in the North Sea).

 

The Netherlands never did anything with this idea, I don't know why.

 

Belgium on the other hand, did use the idea. Belgium has (compared to The Netherlands) a lot of nuclear power. Nuclear power plants are not very flexible. They need to deliver a constant amount of power, also when the demand for energy is low (essentially at night). Earlier on, Belgium used the excess power at night to light every square centimeter of freeway. Nowadays, the excess power is used to pump water into a basin to store the energy. During day time, this hydropower is used to supplement the nuclear power.

 

I have alway thought that this was a smart and viable idea, certainly for a country like The Netherlands (with their expertise in building dams, dikes and pumping water). As long as the stored energy doesn't need to be 'portable' this hydropower storage scenario seems to beat the hydrogen economy scenario's easily.

 

Rik

[hrothgar]

I have alway thought that this was a smart and viable idea, certainly for a country like The Netherlands (with their expertise in building dams, dikes and pumping water). As long as the stored energy doesn't need to be 'portable' this hydropower storage scenario seems to beat the hydrogen economy scenario's easily.

 

Rik

So-called pump storage systems are great, so long as you have the right sorts of geography...

 

These systems work best if you can design them such that the water falls a decent amount before hitting the turbines. In the US, most of the pump storage systems involve mountains (or at least hills). You pump the water into a man made lake on top of the hill at night and draw it back down for power during the day time.

 

There are some intriguing suggestions that we should decommission some aged numclear power plants by turning them into pump storage systems. (Basically, you dig a giant pit where the power plant used to be and use the existing turbine infrastructure. Hydro plants are (conveniently) located next to rivers for cooling, so there is even a conveninet source of water)

[Wackojack]

Pumped storage schemes are excellent for "peak lopping" and are designed to respond within a few seconds. As an aside, if after say a big football match, everbody decides to switch on their electric kettles, the "TV pick-up" has to be met very quickly otherwise many will be blacked out completely. The reason pumped storage hydro power is normally in mountainous areas is that power output is directly proportional to the "fall". Basins in a flat landscape wont give you many Megawatts for your money. Of course the net energy from a pumped storage power station is negative. The power that you use to pump the water up a level exceeds what you get back because of the efficiency losses. What you get out of pumped storage is fast response to sudden changes in demand and you flatten out the demand curve. As pointed out by Rik, nuclear power operates most economically and conveniently on a continuous basis. This is called "base load". Thus nuclear power at off-peak times can advantageously be used to pump water up a level for hydo-electric generation at peak times.

 

In theory wind turbines could be used in exactly the same fashion. However, using them for pumped storage hydo power is a "heavy" solution. It would need extensive and environmentally damaging civil engineering, whereas using them to produce hydrogen would not have such an impact.

 

Quote hrothgar Posted on Nov 26 2008, 08:39 AM

There are some intriguing suggestions that we should decommission some aged numclear power plants by turning them into pump storage systems. (Basically, you dig a giant pit where the power plant used to be and use the existing turbine infrastructure. Hydro plants are (conveniently) located next to rivers for cooling, so there is even a conveninet source of water) Unquote

 

 

No way. Hydro and steam (nuclear power is run by steam) turbines are entirely different in design and orientation. Also the fact that nuclear power stations are on low lying sites on river estuaries or the coast is a wrong for pumped storage. Moreover if you de-commision a nuclear station without replacing it with another base load station you wont have the power available to pump the water. Sites that already have nuclear power stations that have come to the end of their life should be replaced with new nuclear power stations. Where else are you going to put them?