Pumped Hydro Storage

ByCatherine Mayida

OutlineIntroductionMain Goal of Pumped Hydro StorageTypes of PHS Power PlantsHow PHS Power Plants WorkPHS Power Plant Infrastructure

Outline

The 5 Largest Operational PHS Plants

Disadvantages of PHS Plant

Environmental Impact of Power Plant

Resources

IntroductionElectrical energy can be stored during times that electrical generation from power plants exceeds the consumption by customers and the stored energy can then be utilized at times when consumption of electricity exceeds generation of electricity.

Main Goal of Pumped Hydro Storage

Bulk energy storage helps avoiding the sharp spikes in power generation thus making the power plant operation more efficient.

Reduces fuel consumption and greenhouse gas emissions[2].

Peak shaving by pumping during low fuel-cost periods and generating during high fuel-cost periods.

Provides reliable spinning and non-spinning reserve capacity.

Types of PHS Power Plants

There are two main types of PHS facilities; Pure or off-stream PHS: which relies entirely on water that was previously pumped into an upper reservoir as the source of energy

Combined or pump-back PHS: uses both pumped water and natural stream flow water to generate power

How PHS Power Plants Work

How PHS Power Plants Work

The relatively low energy density of pumped storage systems

{requires either a very large body of water or a large variation in height. For example, 1000 kg of water (1cubic meter) at the top of a 100m tower has a potential energy of about 0.272 kWh, enough to its raise temp. by 0.42 deg. Fahrenheit}

How PHS Power Plants Work

Pumped Hydro Storage Plant(PHSP) consists of:

Two water reservoirs at different heights

Hydroelectric power generator at the level of the lower reservoir.

Process:

Water can be pumped from the lower to the upper reservoir

Plant operator has to buy electricity.

The PSHP generates electricity by discharging the water and driving the generator.

PHS Plant Technologies

A full-storage strategy, or load shifting, shifts the entire on-peak heating or cooling load to off-peak hours.

Operates at full capacity during all non-peak hours to charge storage on design days.

Strategy best where on-peak demand costs are high or short on-peak period.

PHS Plant Technologies

Partial-storage approach, the peak period cooling load is met by both:

Mechanical equipment

Pumped storage

The equipment size is smaller capacity than the design load.

Partial storage systems may be run as load-leveling or demand-limiting operations.

PHS Plant Technologies

In a load-leveling system, equipment is sized to run at its full capacity for 24 hrs. A load-leveling approach minimizes the required equipment and storage capacities. This strategy is most effective where the peak load >> average load.When the load < equipment output, the surplus energy is stored. When the load > capacity, the additional requirement is discharged from storage.

PHS Plant Technologies

PHS Power Plant Infrastructure

PHS Power Plant Infrastructure

A dam is built on a large river that has a large drop in elevation (there are not many hydroelectric plants in Kansas or Florida!).

The dam stores lots of water behind it in the reservoir.

Near the bottom of the dam wall there is the water intake.

Gravity causes it to fall through the penstock inside the dam.

PHS Power Plant Infrastructure

At the end of the penstock there is a turbine propeller, which is turned by the moving water.

The shaft from the turbine goes up into the generator, which produces the power.

Power lines are connected to the generator that carry electricity to your home and mine.

PHS Infrastructure vs other storage

The 5 Largest Operational PHS Plants

(Source [7])

1. Bath County Pumped Station USA 3003 MW

2. Guangdong Pumped Storage Power Station CHINA 2400 MW

3. Huizhou Pumped Storage Power Station CHINA 2400 MW

4. Okutataragi Pumped Storage Power Station JAPAN 1932 MW5. Ludington Pumped Storage Power Plant USA 1872 MW

PHS Plants in the USA

Disadvantages of PHS Plant

The construction of a PHS station typically takes many years, sometimes over a decade[5].

High upfront capital investment[5].

Salt water plants require special technologies to deal with the following barriers:

Leakage of salt water into the surrounding environment.

Corrosion of the equipment caused by salt water is also a concern.

Environmental Impact of PHS

PlantDisruption of the aquatic ecosystem may destroy terrestrial wildlife habitats[5]

Severely alter the landscape[5]

Pumping may also increase the water temperature and stir up sediments at the bottom of the reservoirs and deteriorate water quality.

Environmental Impact of PHS Plant

PHS operation may also trap and kill fish.

However, There are technologies to mitigate the ecological impacts.

A rubber lining is placed on upper reservoir, seawater detectors, pressure gauges used to detect salt leakage.

Fibreglass Reinforces Plastic (FRP) used for Penstock

Austenite Stainless Steel

Environmental Impact of PHS

PlantFish deterrent systems(breakwater of concrete blocks) minimize fish entrapment.

The water intake and outlet could be designed to minimize the turbulence.

An oxygen injection system can compensate for the potential oxygen loss due to warming of the water after pumping.

In some cases, the PHS system may serve to stabilize water level and maintain water quality[5].

Resources[1] http://www.pumpedhydrostorage.com [2]http://www.bulkenergystorage.com [3] http://www.agrion.org [4]http://en.wikipedia.org/wiki/Pumped-Storage hydroelectricity [5]http://people.duke.edu/~cy42/PHS.pdf [6]How can pumped-storage hydroelectric generators optimise plant operation in liberalised electricity markets  with growing wind power integration?,  David Wilde (Dundee University). [7]http://ga.water.usgs.gov/edu/graphics/hydro-pumped-storage.gif [8]http://2.bp.blogspot.com/_b5hcKABPlGI/TAxth2CMceI/AAAAAAAAgIA/2er5EF2L6f0/s400/6-710a

[9]http://wastedenergy.files.wordpress.com/2010/05/okinawa_ps.jpg[10]http://blogs.worldwatch.org/revolt/pump-up-that-seawater-a-remix-to-pumped-storage-hydro/

[11]http://2.bp.blogspot.com/-O9qqU-9BoW0/UOpxE_lo7MI/AAAAAAAABJY/kTps04faZ2c/s640/2.jpg

Resources[12] http://ixeee.com/storage.html

[13] http://www.fhc.co.uk/images/pics/pumped_storage.jpg

[14] http://en.wikipedia.org/wikiFile:Grid_storage_energy_flow.png

[15]http://www.hydroworld.com/content/dam/etc/medialib/new-lib/hydroreview/print-articles/volume-30/issue-2/48198.res/_jcr_content/renditions/pennwell.web.450.311.gif

[16] http://www.unendlich-viel-energie.de/uploads/media/AEE_Storage_capacity_of_different_systems-01.jpg