Solar Power Can Double Pumped Hydro Output (Nice)

May 29th, 2012 by Zachary Shahan

In Germany, due to cheap afternoon solar power, pumped hydro operators have been running on two cycles a day, not just the normal one at night. Essentially, this means that you’re doubling the potential of existing pumped hydro infrastructure.

Here’s a little more info on this from KMB48:

Solar has driven down the afternoon wholesale price of electricity to approximately the same level as midnight when pumped hydro normally charge up their reservoirs.

Pumped solar relies on price differentials of daily electric markets. At night, when old fashioned coal and nuclear power is abundant and not in demand, power prices are cheap. Pumped hydro operators buy the cheap nighttime power to run pumps to move water to high ground. During daytime peaks, electricity prices are higher, so the pumped storage operator let’s the water run down through turbines to generate instant-on electricity to meet peak demand.

What’s new is that there is now a new low price trough in the afternoon in Germany since so much solar power has been installed. There is one peak price in the morning and another peak price in the late afternoon/early evening. In the mid afternoon on sunny days, wholesale prices are about the same as at midnight. This allows pumped hydro operators to recharge their reservoirs in the afternoon as well as the evening.

Now, Japan, which is putting full blast on renewable energy, has a lot of pumped hydro and is likely to see a similar trend occur. “Cheap solar power during afternoon peaks could double the number of pumped hydro cycles from one to two times per day” in Japan, KMB48 adds.

This is one of those rather hidden but huge benefits of large-scale solar power implementation.

Thank to the reader who passed this one on to me!

Image Credit: Qurren

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Tags: germany pumped hydro, japan pumped hydro, pumped hydro solar, solar pumped hydro

About the Author

Zachary Shahan spends most of his time here on CleanTechnica as the director/chief editor. Otherwise, he's probably enthusiastically fulfilling his duties as the director/editor of Solar Love, EV Obsession, Planetsave, or Bikocity. Zach is recognized globally as a solar energy, electric car, and wind energy expert. If you would like him to speak at a related conference or event, connect with him via social media. You can connect with Zach on any popular social networking site you like. Links to all of his main social media profiles are on ZacharyShahan.com.

http://ronaldbrak.blogspot.com.au/ Ronald Brak

Getting more out of pumped or other energy storage by using the daytime dip is great. Anything that lowers the cost of storage is useful. But it is possible to use a considerable amount of use intermittent capacity without storage. In the March quarter 34.5% of South Australia’s electricity came from wind and solar (31% wind, 3.5% solar) without using any storage. A small portion of the wind energy was exported to Victoria, which is a giant electricity sink, but most of it was used in state.
Bob_Wallace

The same will be true for large scale battery storage.

Revenues will double meaning much faster return on investment. Actually more than double when you add in money earned by grid smoothing in addition to two storage cycles per day.

Operating/maintenance costs will stay roughly flat. (Except for moving parts wearing out sooner.)
Ross

This seems particularly good for pumped storage as unlike with batteries the extra cycle count will not cost too much extra in wear and tear on the generators.
- Bob_Wallace
  
  With double cycling batteries the initial investment is returned in approximately half the time. That’s a huge gain.
  
  What we don’t know, and won’t know for a while, is cost per cycle for pump-up and battery storage.
  
  Battery has a huge location advantage – much easier to find locations and capable of being distributed which cuts transmission/infrastructure costs. Battery is also quicker to bring on line and can be relocated if desired.
  
  Old factory sites should be ideal for large scale battery storage. They won’t object to sitting on brown fields, the land should be relatively inexpensive, and there should already be large power lines to the location.
  
  Current design is to fit the battery bank into stackable shipping container sized packages. Build them in factories, rail/truck them to location, unload and plug in. When they’ve reached their cycle life end, truck/rail them back to the factory for rebuilding.
  - Ross
    
    Good to know.
    
    One other advantage for pumped I’ll hazard to guess is that for the most part the investment in pumped has already been made so for the operators this is like free money.
    - Ross
      
      I don’t mean advantage over battery just plus for pumped.
    - Bob_Wallace
      
      True for existing pump-up.
      
      We’re going to need massive amounts of new storage. The big question is which will give us the least cost/most usable storage.
      
      We’ve got tons of existing dams which can be converted to storage. And some dams currently in use for generation could be upgraded for storage.
      
      I’ve lived near two CA dams which trapped spring runoff and used it for generation. Later in the year water levels dropped (less head) and generation hours were cut in order to stretch generation days.
      
      If we built small holding reservoirs below those dams we could add additional pump/turbines and use them to gen large morning/evening output, replacing water during high wind/solar hours.
      
      Then, during the infrequent periods of little wind/sun we could run them full out to make up for shortfall.
  - Onefinity
    
    There is no comparison between pumped storage and batteries. Pumped storage can easily provide 10 to 15 or more hours of storage within normal cost parameters; batteries only 4 hours unless you want to spend 2x or 3x more. Pumped storage lifetimes are 75 years. Battery lifetimes are a (yet to be proven) 15 years. Pumped storage is first and foremost firm generating capacity with extreme speed and flexibility, with ability to double as load; batteries are best suited for an ancillary services market and are thus more dependent on that as well as on price arbitrage, which is of itself not a viable revenue generator in the U.S. As for location, batteries do have a modularity and location flexibility, but the reality is that there are more than sufficient viable pumped storage projects proposed in the U.S. today to most markets in the U.S. Battery advocates should simply address their particular niche and not even attempt to put themselves in the same class as pumped storage, or even CAES for that matter.
    - Bob_Wallace
      
      Of course there is a comparison between pump-up hydro and batteries.
      
      You can compare them on the basis of cost. Right now pump-up is probably cheaper, but new battery technology looks like that may not hold.
      
      You can compare on life expectancy. But that’s really just a cost comparison. It wouldn’t matter if batteries lasted only a week if they were sufficiently cheaper to replace over the 75+ life of a pump-up project.
      
      You can compare them on difficulty to site. Shipping container sized batteries are easy to plop down on an appropriately zoned piece of land. Obtaining land and getting it approved for pump-up is a major task.
      
      You can compare them in terms of which is easiest to locate near point of generation or point of use. Batteries win this one hands down.
      
      I’m neither a battery nor a pump-up advocate. As well I don’t advocate for CAES, thermal, or any of the other storage solutions being investigated.
      
      I don’t think there will be a ‘one size fits all’ solution. But what I am seeing is that there seems to be a lot more activity and investment surrounding grid battery storage than any of the other technologies.
      - Onefinity
        
        I don’t think any utility executive would choose a battery facility over a good pumped storage facility — if they were looking for the widest functionality and longest-term cost effectiveness at a scale in the hundreds of megawatts. However, you are correct in that the projects will be chosen at least partly on their economic merits, so we shall see what happens.
      - Bob_Wallace
        
        If you look at what is happening utilities are installing large battery packs on their grid. And we’re building very little new pump-up.
        
        How will it play out over time? That’s impossible to predict. But if batteries get to the pump-up price point then they are likely to dominant the grid.
        
        Full disclosure – I’ve been off the grid for over 20 years. I know that batteries work very well for storing electricity, I’m running on mine right now because the Sun has moved far to the west.
        
        Batteries are really low involvement technology. They passively accept power when there is extra and give it back when the grid desires. There’s no dealing with a spinning turbine.
        
        Utility systems, given the right price, can park large batteries around their territory and worry little about them. Use them, replace them when they wear out.
        
        By distributing them around the grid lots of supply issues are minimized. Smaller transmission lines can be utilized and neighborhoods are less likely to go dark when a line goes down.
        
        Utility managers, assuming large scale batteries mature, can simply contact the factory and order more storage. It can be trucked in and plugged in. No years of site location, permitting and construction.
        
        If there is more storage in one area than needed the container can be loaded up and moved.
        
        I think that modular aspect of batteries is going to make them very attractive.
Onefinity

A parallel phenomenon, although not as dramatic in price swings, will be seen for pumped storage projects in the U.S. Southwest (e.g., the proposed Eldorado Pumped Storage project south of Las Vegas or Bison Peak near Tehachapi) if designed to blend the firming of both wind and PV solar into an intermediate-capacity delivery block. Winds in that region peak at night, so wind energy will tend to use the storage facility’s capacity overnight. PV peaks mid-day, but load peak is not until later in the afternoon. So while pumped storage begins to generate in the morning using wind-pumped water, its output can be modulated to firm PV entering the grid during a less valuable period. Then, during the peak load block, pumped storage and PV generation are at full output.