Mass storage technologies Flashcards
From what capacity is large scale storage?
More than 100 MWh
What types of storage can handle 100 MWh capacity?
- CAES: Compressed Air Energy Storage
- H2: Hydrogen storage
- SNG: Synthetic Natural Gas
- PHS: Pumped hydro storage
What technology foresees the bigger part of the installed capacity of storage?
Pumped hydro storage, but battery storage made the biggest evolution since 2010 (X24)
How does PHS works?
The PHS consists of two reservoirs connected by an underground shaft and a powerhouse containing a turbine-generator. Energy is stored by pumping water in the highest reservoir. When the water is released, it goes through the turbine which turns the generator to produce electric power. The amount of stored energy is proportional to the product of the total mass of water and the altitude difference between the reservoir (m_water and H (m)),
What are the main advantages of PHS?
- Energy and power scalable independently
- 70-80% round trip efficiency
- Reversible pump-turbine and variable speed
- Low self discharge
- A great lifetime (>50 years)
- Avoid conversion losses, provides directly AC power
- Fast response time (less than 2 minutes from 0 to 100% power)
What are the main disadvantages of PHS?
- Geographical and societal constraints (permits, legal proceedings)
- Costly, long ROI
- High power => connection to transmission grid; only large utilities are economical
- Methane emissions
What is the installed power and capacity of Coo-Trois-Ponts?
1080 MW, 5h long = 5400 MWh
What are alternative ways of PHS?
- Using wind turbine mast as storage and coupled with PHS (TRL 3)
- Underground PHS (TRL 3)
- Gravity power (piston) (TRL 5-6)
- Ocean Renewable Energy Storage (Spheres, can be coupled to FWTs) (TRL 6)
What is the efficiency of CAES?
50-60%
How does CAES works?
In the charging mode, air is compressed, cooled and injected into a reservoir (can be natural). For discharging, the air is withdrawn from the reservoir and heated up by burning gas or fuel. Then the air will expand within a turbine.
What are the main advantages of CAES?
- Energy and power scalable independently
- No or few geographical constraints, environmentally friendly
- Great lifetime (> 30 years)
- Long term energy storage and seasonal storage
- Biogas and biomethane can be used as fuel
- Can be used as gas turbine
What are the main disadvantages of CAES?
- High CAPEX and ROI
- Long responsive time (3-10 min)
- Long time deployment
What is PHCA?
Pumped Hydro Compressed Air: Pumped hydro compressed air is a combination between Compressed Air Energy Storage (CAES) and Pumped Hydroelectric Storage (PHS). Pumping of the liquid compresses the gas/air. TRL 5-6
What are drawbacks of PHCA?
- Low efficiency
- Design to address high pressure
- High cost
- Thermal management
What are advantages of PHCA?
- No geographical limit
- Trigeneration storage expected
- Limited water consumption
- Non-critical materials needed (low risk compared to Li-ion battery)
