Vianden Pumped Storage Hydro-Electric Plant (Pumpspeicherkraftswerk)

     A friend from one of my classes invited me on a field trip the Energiespeichern class was making to Luxembourg.  The system in Luxembourg is similar to systems in the US (such as Raccoon Mountain); excess power during low demand times is used to pump water up to a reservoir built on a mountain, which is later on sent through turbines to generate power.

      Energiespeichern covers any system that saves energy for future use, and is very useful for balancing out the demand on a grid.  Germany (and the world) is doing a lot of research on energy storage because it is one of the major drawbacks with renewable energy, and is also the cause of a lot of energy waste within traditional energy production systems.  "Batteries" allow you to instantly fluctuate power supply and avoid over-producing or running plants in inefficient conditions.

     We visited the Vianden Pumped Storage facility, which is just outside of Luxembourg city:

The plant has existed in some form or another since the 1930's.  Here is one of the original turbines from one of the power systems built from the dammed river.  You can see that cavitation (extreme low pressure on blades causing water to "boil/implode") is a very powerful mechanism for wearing blades.

When we got to the facility we sat in the sites visitor center movie theater and watched to histories of the facility.  The site has seen major renovations is both capacity and efficiency throughout its past.  Here is a picture of area (from a scale model!), the pump station is the void in the mountain:

The videos were very cool, although Luxembourgian is complete gibberish.  It was a truly colossal engineering feat to build the reservoir and install the systems underneath the mountain.

After the video we got to go on a tour inside the pump/house, which is underneath the mountain.  The visitors path is lined with interesting exhibits on area history, carbon and emissions politics, energy sources, etc.

 Helping visualize what emissions really are:

Here they showed how much a kWh of energy was in different resources, including oil, compressed air, batteries, petrol, etc:

 This showed major countries and the emissions per capita. The US isn't the worst in the world but is definitely being beaten by a lot of other countries.  Step it up America!!!!  Also, this is not the only time generic Americans have been portrayed as cowboys- I'm always entertained by the stereotype.

A decent picture of the reservoir on the mountain:

A scale model of one of the older models of the pump/turbine/generator combination:

There are 9 of these 100MW generators in the main cavity of the site. Elsewhere there is a 200 MW tubine hiding.

 Escape route. Or Maintenance route. But when you're standing next to a shaking, 100MW turbine operating at 430 psi, the exit looks like a necessary escape. It was loud and awesome:

Each turbine has a throughput of 300 cubic meters per second.  Repeat: 300 cubic meters of water per second (20'x20'x26'); with all 9 turbines, they can drain the 500,000,000 cubic meter lake in just 3.5 hrs.

Afterwards we went to the reservoir to see the view (it was pitch black). Luckily they had a visual guide so we could pretend:

 Overall, the plant can operate at 80% + efficiency (Energy Out/ Energy In).  Although this energy efficiency doesn't sound that great, it is obviously good enough to be economically viable and save the state lots of money.  Coal and Nuclear power plants are not that flexible, and when they are asked to change energy output, it can put a lot of strain on the equipment, as well as effect the conversion of heat to energy.  Gas power plants are much better, but still not perfect.  Luxembourg coordinates with their Coal, Nuclear, and Gas plants to make sure they operate within near-constant parameters, and then uses renewable energy and the pumped water to meet the rest of the fluctuating demand.

I'm glad I got to visit and it was cool learning more about systems we have in the US.

Fun fact: a town in Germany pumps air into an abandoned mine to store energy created during the day or during low demand periods.  The cavern acts like a giant pressurized oxygen tank, and they can release the air pressure across turbines to generate electricity when they need it.  The future will be creative!