Topic7 Flashcards
Battery
the device where potential energy can be stored in various types of chemical bonds , formed into electro-chemical devices known as batteries.
Grid Storage
Grid storage is a stationary electricity storage device that is installed primarily for the purpose of supporting the grid.
Vast majority of grid storage today is pumped hydro, used to meet peak power, instead of larger energy applications.
Chemical battery storage is also developing, but they need to bring down upfront capital cost and cost per megawatt hour.
Pumped Hydro
The method of electricity storage by which fresh or salt water is pumped to a higher elevation and stored in a reservoir for later use. Quite high overall efficiency.
The vast majority of grid connected storage is given by PUMPED HYDRO SYSTEMS. to meet the peak power and ancillary service needs
portable
portable storage devices take energy from the locations where energy is more available to places where energy is less available, but where energy demand happens. example: laptop. portable storage devices solve the where and how certain problem. portable devices are primarily batteries as opposed to mechanical storage.
storing and delivering electric charge on demand; Portable (WHERE AND HOW CERTAIN)
Portable Batteries include primary consumer devices, rechargeable consumer devices, auxiliary power units (APUs), military applications and automotive and transport uses.
Fuel cell
Similar to battery; can keep replenishing; much more quickly - you have a cartridge; hydrogen fuel cells in cars; natural gas fuel cells that produce electricity in the house
FUEL CELLS (hydrogen promise) : combine hydrogen with oxygen to generate electricity, producing heat and water as by products. Fuel cells generate energy from hydrogen far more efficiently than simply burning does, and both of its by products may be used for secondary applications. Fuel cells lack moving parts and are easy to mantain, which has the benefit of increasing their lifespan and reliability while reducing operating costs…
3 problems limit deployment of fuel cells: efficient hydrogen storage, fueling station infrastructure, and costs. hydrogen takes a lot of space.
Energy Density (volumetric energy density)
the amount of energy that can be stored in the storage per unit storage volume.
Space constraints are binding on application or technology choice
STORAGE; innovation component. improving leads to
Specific Energy (gravimetric energy density)
the amount of energy that can be stored in the storage per unit of storage mass.
Improvements in specific energy are crucial for storage.
Value for storage
power density
the amount of power that can be transferred in and out of the storage device per unit time.
response time
how quick the storage can be called on to accept or deliver electricity. if the storage can respond ultrafast, it is called a spinning reserve. response time is very short for frequency regulation applications.
lifetime
how long the storage can be in service. The more frequent the storage is charged and discharged (a cycle) the quicker that it degrades. Storage lifetime is often measured in cycle life, or how many cycles that can be expected before the storage degrades below acceptable performance level.
hazmat issues
Materials used in chemical storage include acids and toxic metals that pose environmental hazards under accidents or end of life disposal. Any uncontrolled discharge of electricity is also a hazard.
cycles
Cycle charge and discharge (related to lifetime of storage)
A Value component
cycle cost
cost per incidence of charging and drawing.
LCOS
Capital Costs.: number of cycles, and usage patterns
O&M:
Fuel Costs: round trip efficiency (heat rate)
STORAGE PROVIDES A STREAM OF BENEFITS (ENERGY POWER, RISK MITIGATION, TIME SHIFTING, ETC.)
important indicator when determining the economics of storage devices.
time shifting
the energy application of grid storage. grid storage can move chunks of energy from the time in which they are generated to another time when they are more valuable. there are several ways to do this: 1) load shifting: which allows for a energy input from a few hours before the peak which can then be delivered at the peak, and being compensated by the differential value for the electricity. Think about a solar generation whose peaking production (2pm) is a few hours ahead of peak demand (6 pm). Store that peak production and deliver it to meet peak demand hours later. 2) load leveling (day-night arbitrage): buy power at the most part of the day (often at night) at the non-peak price of that time, and sell it back at the peak hours of the next day (i.e. in the middle of the day or late afternoon/early evening) at the peaking price.
