LARGE
SCALE
STORAGES
~ Naif Alibrahim
POWER SYSTEMS IN THE FUTURE
CAN NOT BE POSSIBLE WITHOUT
STORAGE, Agree?
Electrochemistry
Chemical ⇆ Electrical
PARTS:
2 HALF CELLS:
AN salt solution (znso4/cuso4)
Respective electrodes
Salt bridge – balances charges –ve so42imbalances.
Oil Rig
Cu2+ (aq) + 2e- → cu(s)
Zn(S) → zn2+ + 2ezn(s) | zn2+ (aq) || cu(2+) (aq) | cu(s)
Electrochemical cells
Electrochemical cells
Galvanic:
ELECTRON FLOW FROM AN TO CATH.
SPONTANOUS REDOX.
ELECTROLYTIC:
ELECTRON FLOW FROM CATH TO AN.
NON-SPONTANOUS REDOX.
BATTERIES
NAMES DEPEND ON
ELECTRODES AND
ELECTROLYTE USED.
Primary vs Secondary Cells
PRIMARY VS SECONDARY
PRIMARY
High specific energy.
Non - rechargeable.
Applications designed to
consume low amount of power.
SECONDARY
Applications involve high
draining.
Rechargeable.
Expensive investment
Cheaper long term.
Grid usage
Peak shaving
Load leveling
Power reserve
Integration of res
PEAK SHAVING
Low demand = low prices = store in batteries
High demand = high prices, do we have to use the
Grid’s electricity though?
Instead use already stored electricity, that was
Extracted from the cheaper part of day.
Reduce dependency on electricity market during
peak periods.
Level peak load profile = save $$$
Load leveling
Level entire load profile during entire day, not
just peak periods.
Use low energy price to cover high priced peak
energy demand.
Like with peak shaving, saves $$ by your
dependency on energy market during peak
periods
Power reserve
Sometimes:
Predicted load (DAY AHEAD) > actual load
Predicted load (DAY AHEAD) > actual load
SOLUTION:
BATTERY STORAGE TO STORE
EXCESS WHEN ACTUAL LOAD
DEMAND IS < PREDICTED. Store the
surplus.
Battery storage systems are ideal due to
their fast response times.
More reserve capacity = ↑system
reliability.
Expensive, so need to find optimal
Res integration
Intermittency and variability of res can be
compensated for with battery storage systems.
ALLOWS INTEGERATION OF HIGHER
AMOUNTS OF DISTRIBUTED GENERATION
↑IN RES IN THE GRID = NEED AN ↑ IN
BATTERY STORAGE.
A few examples of batteries
Lead acid (PB|ACID)
LITHIUM ION (LI ION)
NICKEL CADIUM (NI|CD)
Growth in grid storage
Li - ion
battery
Generally,
high energy densities
Little or no memory effect
Low self discharge relatively.
Best performance-weight ratio in
the market
Long lifetimes.
No memory effect.
Expensive for larger scales.
Poor performance @ higher
temperatures.
Need for protective circuits.
Li - ion
battery
Li - ion
battery
ZenergiZe Energy
Storage Systems
Lead acid
Lead acid
Lead acid
Lead acid
Low cost, reliable power
workhouse.
Used in heavy-duty applications.
Oldest type of rechargeable
batteries, still very relevant today.
Performance depends on
temperature a lot.
Limited energy density.
Lower number of cycles relative to
others.
Ni-cd
Long lifetime.
Survives in harsh environments,
resist great electrical and physical
stress.
Can be charged quickly with high
charge rates. [current higher than
nominal]
Low maintenance.
Bad memory effect.
High cost compared to lead acid.
Limited energy density.
Toxic elements in batteries
comparison
Note: The darker shades
shows the best
characteristics.
+ Can't conclude one is better than other,
application dependent.
+ Some can withstand harsher climates.
+ Lead acid most mature, cheap, lowest cycles
though.
+ Li-ion is now the most advanced and utilized
in the grid.
+ Ni-cd good because it withstands greater
conditions.
+ Future:
+ Improve storage efficiencies.
+ Decrease investment costs, finding
better material sources.
+ High performance and low-priced
systems is our goal.