Energy storage in urban multi-energy systems | Marco Carlo Masoero
1. Energy storage in urban
multi-energy systems
Prof. Marco Carlo Masoero
ICARB Workshop: Energy Storage for the Built Environment
Edinburgh, 21st October 2014
2. Outline of the presentation
Electrical Energy Storage (EES)
The role of EES
The technical parameters
Electric Energy Storage systems typology
Thermal Energy Storage (TES)
Purpose of TES in Energy Plants
Technologies
Short-term (daily) vs Long-term (seasonal) storage
Applications: District Heating and Cooling
Power-to-Fuels
Conclusions
209/01/2015
Energystorageinurbanmulti-energysystems
3. The role of Electric Energy Storage I
3
Distributed generation
development by renewables
More efficient use of HV and MV
power grids
Smart Grid in support to Local
Energy Communities
Higher flexibility to rapidly respond
to variable load demand
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Generation Transmission Distribution End User
ElectricEnergyStorage
4. 09/01/2015
Ancillary services:
Primary regulation f/P
Secondary regulation
Tertiary regulation
Reactive power regulation
Black-start
Load rejection
Remote disconnection service
Load interruption
4
The role of Electric Energy Storage II
Generation Transmission Distribution End User
ElectricEnergyStorage
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EES could represent a feasible solution to dealing
with several aspects:
Secondary and tertiary regulation
Over voltage
Reverse power flows
Resolution of congestions storage of energy in
excess at peak-hours
The role of Electric Energy Storage III
ElectricEnergyStorage
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EES could represent a feasible solution to dealing
with several aspects:
Line capacity investment deferral: EES discharges at
peak times and charges at off-peak times
Peak shaving long discharge/charge times
Power quality short discharge/charge times
Reduction of the resistive line losses
Provision of ancillary services:
balancing energy
Rotary reserve
Substitutive reserve
frequency regulation
• in normal power grid condition
• in islanding working mode
The role of Electric Energy Storage IV
ElectricEnergyStorage
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EES could represent a feasible solution to dealing
with several aspects:
control system and power quality improvement
• Dip voltage and over/under-voltage
• Frequency variations
• Low power factor
• Harmonic distortion
support service to voltage control
• instead of capacitor banks, EES can compensate for
voltage drop
provision of black-start services
• overall blackout
The role of Electric Energy Storage V
ElectricEnergyStorage
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Source: Eurelectric, Decentralised storage: impact on future distribution grids, 2012
The role of Electric Energy Storage VI
ElectricEnergyStorage
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EES systems are defined by the following technical
parameters:
• Specific energy (kWh/kg) or energy density (kWh/m3)
• Specific power (kW/kg) or power density (kW/m3)
• Efficiency
• Number of cycles
• Useful life
• Charge/discharge times (h)
• Ramp rate (s)
• Specific costs (€/kWh or €/kW)
• Maturity
The technical parameters I
ElectricEnergyStorage
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Mainly the electrochemical EES are also defined by
the following parameters:
• Memory effect
• Charge/discharge velocity
• Depth of discharge
• Self discharge
The technical parameters II
ElectricEnergyStorage
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Energy intensive: Availability to store large amounts of energy
Power Intensive: Ability to deliver / absorb great amount of
power in short time
Source: EPRI, Electric Energy Storage Technology Options: A White
Paper Primer on Applications, Costs, and Benefits, 2012
Energy and Power Intensity
ElectricEnergyStorage
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• Mechanical energy:
• Pumped Hydroelectric Storage (PHS)
• Compressed Air Energy Storage (CAES)
• Flywheels
• Electromagnetic and electrostatic energy:
• Electric Double Layer Capacitors - EDLC
• Superconducting Magnetic Energy Storage – SMES
• Chemical energy (hydrogen vector):
• Compression
• Liquefaction
• Chemi-sorption
• Physi-sorption
• Thermal energy:
• Molten salt
• Liquefied Air Energy Storage (LAES)
• Phase Change Materials
Electric Energy Storage systems typology
ElectricEnergyStorage
14. Storage in potential energy
convenience:
𝑃 𝑔𝑒𝑛
𝑃 𝑝𝑢𝑚𝑝
≥ 1.4
More than 99% of EES
Difficulty of installation
Storage in compressed air
Integration with thermal power
plants
Difficulty of installation
14
PHS
CAES
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Mechanical energy EES I
ElectricEnergyStorage
15. Storage in kinetic energy
Angular speed 60.000-100.000 rpm
High energy density
Rapid ramp rate
High efficiency (90-95%)
High self-discharge
15
Flywheels
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Mechanical energy EES II
Chemical energy (H2 storage)
Compressed gas: 200-700 bar
Liquid H2: -253 °C
Chemi-sorption: Metal hydrides
Physi-sorption
Power to Gas: EC + H2 + FC
ElectricEnergyStorage
16. Storage in electric field
Specific energy: 1 ÷ 5 Wh/kg
Specific power: 100 ÷ 2.000 W/kg
High number of charge/discharge
cycles
Storage in magnetic field
Superconductors between 4÷100 K
Rapid ramp rate (20 ms)
High specific power
High efficiency (>97%)
16
EDLC
SMES
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Electric energy EES I
ElectricEnergyStorage
17. Li-ions: high specific power and
efficiency
Lead Acid: high specific power, low
energy density. Mature
Ni-Cd: high number of cycles.
Environmental risk
ZEBRA: high specific power and
efficiency. High temperature
Na/S: high number of cycles
Ni-MH: high specific power, low
energy density
Flux: Vanadium RedOx, Zn-Br
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Electrochemical batteries
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Electrochemical energy EES I
ElectricEnergyStorage
18. Purpose of Thermal Energy Storage in
Energy Plants
The use of thermal storage systems in energy plants can have multiple
purposes:
1. Increase the stability in short term operation of the plants (e.g. load
variation in heat pump systems)
2. Reduce the use auxiliary boilers (e.g. in district heating)
3. Shift the heat production through CHP to periods where the electricity
production is more convenient (in the case of backpressure plants or
internal combustion engines) or less convenient (in the case of
extraction plants)
4. Increase the use of renewable primary resources (e.g. solar thermal
systems)
All these have in common the decoupling between heat generation and
utilization.
ThermalEnergyStorage
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Technologies: Embedded Systems
In Thermally Activated Building Systems (TABS) the
thermal capacity of the building is enhanced by the
installation of water pipes within the slabs.
ThermalEnergyStorage
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Technologies: Embedded Systems
Phase Change Materials (PCM) can be installed within
structural elements of buildings (typically walls).
Their fusion temperature being around 25°C, their phase
(liquid/solid) changes in a temperature range that is practical
for normal building uses and allows to store/release thermal
energy
ThermalEnergyStorage
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District Heating (DH) Networks
Total Heat Load results from the aggregation of
multiple users
Need of adapting the heat demand side with the
heat supply side along the day
Need of operation optimization for different
generation units (e.g. CHP, boilers, heat pumps,
solar collectors)
ThermalEnergyStorage
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The role of Thermal Storage:
Decoupling Supply and Demand
Supply Side Demand Side
DH systems have to match the user demand, as a result it is
difficult to optimize CHP size and operation
ThermalEnergyStorage
26. Current District Heating Network in Turin
As of 31-12-2012:
• largest DH system in Italy
• 53,4 Mm3 supplied buildings
(88 Mm3 in future planning)
• 1.89 TWh heat supplied
• 467 km grid length
• 1.77 GW peak heat
generation
• 1.14 GW of power (CHP)
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ThermalEnergyStorage
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The role of Thermal Storage:
Turin DH daily profiles
January
April
July
Daily peaks
ThermalEnergyStorage
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The role of Thermal Storage:
Decoupling Supply and Demand
Turin Politecnico:
Re-Heating and Pumping
Plant with 2.500 m3 storage
North Turin:
Combined Cycle
Cogeneration Plant
with 5000 m3 storage
ThermalEnergyStorage
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Heat storage systems behaviour
Storage
Unload
Storage
Load
Heat storage systems
CHP units
Boilers
DH system of Turin
ThermalEnergyStorage
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Heat storage systems behaviour
Heat Storage SystemsCHP UnitsBoilers
The heat storage
allows to increase
the utilization factor
of CHP units
DH system of Turin
ThermalEnergyStorage
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Biomass DH System Configurations
CHPBoilers +Boilers only
Heat storage
systems
+
CHP
Boilers
+
Hours
HeatLoad
Hours
HeatLoad
Hours
HeatLoad
ThermalEnergyStorage
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Biomass DH System Simulation
The heat storage helps to increase the overall efficiency of the system
ThermalEnergyStorage
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Biomass DH System Simulation
• The heat storage systems move and lower the optimum pay back time.
• The incentives change the convenience of installing heat storage systems.
Best PBT
ThermalEnergyStorage
37. District cooling- Paris Centre
ThermalEnergyStorage
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Water cooled Air cooled Total energy storage: 140 MWh
38. Outine: Power-to-Fuels
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ENERGY CONTEXT: THE NEEDS:
1. Large size storage of RES: storage in forms of chemicals
2. Chemicals that can have interest for the energy sector: existing distribution
and utilization infrastructure; several final users (e.g. stationary systems,
automotive, etc.)
3. Chemicals as CO2 sink
A POSSIBLE SOLUTION: GREEN FUELS
One option for fast and sustainable storage is the production of gaseous fuels to
be fed in the distribution grid: those fuels could be produced by means of
electrolysis processes and thus converted into synthetic methane to be fed into
the existing distribution infrastructure.
PROS
1. conversion of relevant amount of renewable sources from “flow” to “stock”
2. chemical fixing of carbon recycled from CO2
3. easy utilization of synthetic methane into existing energy infrastructure
(distribution and final uses)
Power-to-Fuels
40. GAS DISTRIBUTION GRID
ELECTRIC GRID
Electrolysis
Low-priced
surplus electricity
H2
Methanation
CH4
CO2
Biomass, biogas, industry,
CCS
Up to 5% in CNG
Mobility (road
transportation)
Gas-to-power
Power-to-gas
H2
Wind, solar,
nuclear
H2/syngas
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Power-to-Fuels
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Conclusions
Energy storage is a key issue in any multi-energy
system applied at the urban scale
Integration of distributed generation should
compete with quality standard warranty
The role played by EES will be fundamental to shift
towards a smart grid concept
TES is essential for an efficient integration of
thermal energy production and distribution, using
both fossil and renewable sources
The choice to install a certain typology of storage
system depends on the application desired
Conclusions