I am trying to do a project where I determine the reservoir storage capacity for a pure pumped storage hydropower plant to store excess capacity and generate auxiliary power at an existing plant. I need to know how planners generally decide what capacity is required for a given thermal utility.
Pumped storage hydropower plants operate with two reservoirs: a lower and an upper one. A river, a lake or an existing reservoir can serve as either reservoir. In other cases a new reservoir must be created, the characteristics (i.e. size) of which depend on the site’s topographic and hydrological conditions.
Pumped storage power plants are characterized by:
•Installed capacity in pumping mode and in turbining mode (from several MW to more than 1,000 MW); and
•Storage capacity of two reservoirs determining the duration time for operation at full capacity.
Depending on whether either of the reservoirs is part of the natural river system, or whether both reservoirs are human-made storage basins, pumped storage hydropower plants can fall into one of two categories:
•mixed pumped storage hydropower plants; and
•pure pumped storage hydropower plants.
Mixed pumped storage hydropower plants have natural inflow; pure pumped storage hydropower plants have none.
Pumped storage power plants are operated on daily and weekly cycles and are designed to provide peak electricity during periods of high electricity demand. This can be done in a very short time, i.e. within minutes. The water is released from the upper reservoir through the turbines to generate electricity. However, the duration of electricity supply from pumped storage hydropower plants is limited. The upper reservoir normally contains a certain amount of water that can provide full operation during several hours.
Water is typically pumped up from the lower to the higher-level reservoirs during off peak periods (i.e. during the night) using surplus electricity generated by conventional base-load power plants. The market electricity price also has an impact on when the water is pumped up: usually this happens when the electricity price is lowest.
Electricity generation from pumped storage hydropower plants is not considered as renewable, since pumping the water up consumes electricity produced by other power plants in the grid and pumped storage power plants thus become net energy consumers. In fact, more electricity is needed to pump water from the lower to the upper reservoir than is generated when water is released from the upper reservoir into the lower one (overall efficiencies are in the range of 70-75%). However, this drawback is compensated for by the flexibility these plants can provide.
Pumped storage power plants are important to optimize the operation of the conventional thermal generation fleet. As pumped storage power plants cover peak demand situations while consuming electricity in periods of lower demand, they allow thermal power plants to stay connected and generate electricity even when demand is low. Through this optimization effect, pumped storage power plants also contribute to reducing greenhouse gas (GHG) emissions from thermal power plants, as they need not deviate from the most efficient load. Pumped storage facilities work as a huge electricity storage resource by charging or discharging power according to the system’s demand. Compared to conventional reservoir-type hydropower plants, pumped storage power plants use the water stored in the reservoirs repeatedly and do not need natural inflow into the reservoirs.
The role of pumped storage hydropower plants is twofold: balancing the grid for demand driven fluctuations, and balancing generation-driven fluctuations – a new and increasingly important role due to the increase of renewables in the electricity system.
Like conventional reservoir-type hydropower plants, pumped storage power plants can provide the full range of grid-stabilizing services, thanks to their ability to follow demand or generation fluctuations within only a few minutes.
Therefore storage hydropower is a key tool for TSOs to maintain a stable and balanced grid.
The size of the hydropower plant will depend of the amount of energy need to produce in order to stabilize the supply of electricity to the grid.
In any form of storage there are a couple of things one has to look at.
The two most important are 1) Storage (usually MWh) and 2) Power rating (MW)
Other aspects to consider is financial viability per MW- and MWh respectively, transmission line capacity, base load and the peak load to be shaved.
I can recommend you "Integration of Alternative Sources of Energy" (Farret & Simoes, 2006) that treats the basics in a section, or "Energy Storage for Power Systems" (Ter-Garzarian, 1994) that treats the topic in detail, dedicating a whole chapter to it. Hope this helps!
Pumped storage hydropower plants operate with two reservoirs: a lower and an upper one. A river, a lake or an existing reservoir can serve as either reservoir. In other cases a new reservoir must be created, the characteristics (i.e. size) of which depend on the site’s topographic and hydrological conditions.
Pumped storage power plants are characterized by:
•Installed capacity in pumping mode and in turbining mode (from several MW to more than 1,000 MW); and
•Storage capacity of two reservoirs determining the duration time for operation at full capacity.
Depending on whether either of the reservoirs is part of the natural river system, or whether both reservoirs are human-made storage basins, pumped storage hydropower plants can fall into one of two categories:
•mixed pumped storage hydropower plants; and
•pure pumped storage hydropower plants.
Mixed pumped storage hydropower plants have natural inflow; pure pumped storage hydropower plants have none.
Pumped storage power plants are operated on daily and weekly cycles and are designed to provide peak electricity during periods of high electricity demand. This can be done in a very short time, i.e. within minutes. The water is released from the upper reservoir through the turbines to generate electricity. However, the duration of electricity supply from pumped storage hydropower plants is limited. The upper reservoir normally contains a certain amount of water that can provide full operation during several hours.
Water is typically pumped up from the lower to the higher-level reservoirs during off peak periods (i.e. during the night) using surplus electricity generated by conventional base-load power plants. The market electricity price also has an impact on when the water is pumped up: usually this happens when the electricity price is lowest.
Electricity generation from pumped storage hydropower plants is not considered as renewable, since pumping the water up consumes electricity produced by other power plants in the grid and pumped storage power plants thus become net energy consumers. In fact, more electricity is needed to pump water from the lower to the upper reservoir than is generated when water is released from the upper reservoir into the lower one (overall efficiencies are in the range of 70-75%). However, this drawback is compensated for by the flexibility these plants can provide.
Pumped storage power plants are important to optimize the operation of the conventional thermal generation fleet. As pumped storage power plants cover peak demand situations while consuming electricity in periods of lower demand, they allow thermal power plants to stay connected and generate electricity even when demand is low. Through this optimization effect, pumped storage power plants also contribute to reducing greenhouse gas (GHG) emissions from thermal power plants, as they need not deviate from the most efficient load. Pumped storage facilities work as a huge electricity storage resource by charging or discharging power according to the system’s demand. Compared to conventional reservoir-type hydropower plants, pumped storage power plants use the water stored in the reservoirs repeatedly and do not need natural inflow into the reservoirs.
The role of pumped storage hydropower plants is twofold: balancing the grid for demand driven fluctuations, and balancing generation-driven fluctuations – a new and increasingly important role due to the increase of renewables in the electricity system.
Like conventional reservoir-type hydropower plants, pumped storage power plants can provide the full range of grid-stabilizing services, thanks to their ability to follow demand or generation fluctuations within only a few minutes.
Therefore storage hydropower is a key tool for TSOs to maintain a stable and balanced grid.
The size of the hydropower plant will depend of the amount of energy need to produce in order to stabilize the supply of electricity to the grid.
The value of pumped storage comes from the added flexibility of operations, and the value of reservoir storage can be calculated using the value water method, valuing the opportunity of storing extra units of water. Power System Research model NCP can be used to value and dimension pumped storage reservoirs, see "Energy storage optimization with NCP " 2013 at http://www.psr-inc.com.br/app/publicacoes.aspx
Joanna, It all depends on the what do the operation aims/optimise for? Normally the whole operation optimise for lowest cost, although some water reservoir/storage are purely to supplement the operating generation asset, during high power demands. What I mean is, the size of the storage depends on what the system is aimed for.
Wan
For the pump storage to be feasible (deciding the capacity of reservoirs) you should have at least 400m head difference.
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