Assessment of Gridbased Energy Storage

Assessment of Gridbased Energy Storage Technologies Jeremy P. Meyers Assistant Professor, Mechanical Engineering The University of Texas at Austin

what is the current state of the electric grid?

what is the current state of the electric grid? We re looking at the connection between where electricity is made and where electricity connects to your house. That is the largest supply chain in the world with absolutely no warehousing capacity.

Batteries have typically been used for spatial decoupling instead of temporal decoupling from primary power source

Storage Potential, California from Sandia National Laboratory

Hours Pumped hydro Minutes Lithium batteries 1 kw Compressed air (CAES) Long-duration flywheels Seconds Discharge time at rated power Types of grid storage High power flywheels High-power supercapacitors 10 kw 100 kw 1 MW 10 MW 100 MW 1 GW

Hours Pumped hydro Compressed air (CAES) Minutes Long-duration flywheels Lithium batteries Seconds Discharge time at rated power Types of grid storage 1 kw High power flywheels High-power supercapacitors 10 kw 100 kw 1 MW 10 MW System power ratings 100 MW 1 GW

Hours Pumped hydro Compressed air (CAES) Minutes Long-duration flywheels Lithium batteries Seconds Discharge time at rated power Types of grid storage 1 kw Po we UP rq ua S High power flywheels lity / High-power supercapacitors 10 kw 100 kw 1 MW 10 MW System power ratings 100 MW 1 GW

Hours Pumped hydro Compressed air (CAES) Minutes Long-duration flywheels Lithium batteries Seconds Discharge time at rated power Types of grid storage 1 kw Bri dg in gp ow Po High power flywheels we e r UP rq ual S i t y/ High-power supercapacitors 10 kw 100 kw 1 MW 10 MW System power ratings 100 MW 1 GW

Hours Pumped hydro En er Minutes Long-duration flywheels 1 kw gy m Bri ent dg in gp ow Po High power flywheels we e r UP rq ual S i t y/ High-power supercapacitors 10 kw 100 kw 1 MW 10 MW System power ratings Compressed air (CAES) ana gem Lithium batteries Seconds Discharge time at rated power Types of grid storage 100 MW 1 GW

Pumped hydro Hours Flow batteries NaS battery Minutes Long-duration flywheels En er 1 kw gy m Compressed air (CAES) ana gem Lithium batteries Seconds Discharge time at rated power Types of grid storage Bri ent dg in gp ow Po High power flywheels we e r UP rq ual S i t y/ High-power supercapacitors 10 kw 100 kw 1 MW 10 MW 100 MW System power ratings A. Price, Electrical energy storage a review of technology options, Proceedings of ICE Civil Engineering 158 November 2005 Pages 52 58 Paper 14175 1 GW

Storage technologies

Storage technologies Pb-Acid Batteries

Storage technologies Pb-Acid Batteries Flooded, valve-regulated

Storage technologies Pb-Acid Batteries Flooded, valve-regulated Limited cycle life = challenge for utility application

Storage technologies Pb-Acid Batteries Flooded, valve-regulated Limited cycle life = challenge for utility application Lead-carbon batteries to improve cyclability

Storage technologies Pb-Acid Batteries Flooded, valve-regulated Limited cycle life = challenge for utility application Lead-carbon batteries to improve cyclability Nickel batteries

Storage technologies Pb-Acid Batteries Flooded, valve-regulated Limited cycle life = challenge for utility application Lead-carbon batteries to improve cyclability Nickel batteries Vented & Sealed

Storage technologies Pb-Acid Batteries Flooded, valve-regulated Limited cycle life = challenge for utility application Lead-carbon batteries to improve cyclability Nickel batteries Vented & Sealed Good high rate capability, energy density Poor cost match Sodium Sulfur batteries

Storage opportunities

Storage opportunities Model specific energy storage technologies with variable efficiency inputs.

Storage opportunities Model specific energy storage technologies with variable efficiency inputs. Can determine key $/kw, $/kwh capacity figures, as well as differential advantage of further price reductions to move into other storage functions.

Batteries have been used primarily for portable/automotive transportation source: http://berc.lbl.gov

Battery research

Battery research Scaling up

Battery research Scaling up understanding potential distributions in larger systems

Battery research Scaling up understanding potential distributions in larger systems new materials

Battery research Scaling up understanding potential distributions in larger systems new materials more stable electrolytes to expand voltage window

Battery research Scaling up understanding potential distributions in larger systems new materials more stable electrolytes to expand voltage window faster charging electrode materials

Battery research Scaling up understanding potential distributions in larger systems new materials more stable electrolytes to expand voltage window faster charging electrode materials Manufacturing for cost and safety

cost reduction in conventional batteries continues source: http://berc.lbl.gov

cost reduction in conventional batteries continues DOE cost target for grid storage source: http://berc.lbl.gov

battery chemistries

battery chemistries aqueous stability window

Cell potentials: spontaneous processes Φsolution Φelectrode Φsolution Φelectrode

Cell potentials: spontaneous processes Φsolution U Φelectrode Φsolution Φelectrode

Cell potentials: spontaneous processes Φsolution U V Φelectrode Φsolution Φelectrode

Cell potentials: charging Φsolution Φelectrode Φsolution Φelectrode

electrolyte stability source: http://berc.lbl.gov

Often, surface is limiting: increase performance by increasing access to electrode surface Enhance surface area in single plane Enhance surface area by 3rd dimension

Porous electrodes in practical systems

How can we effectively increase energy storage per unit cost?

How can we effectively increase energy storage per unit cost? i1 = σ Φ1 i2 = κ Φ2

How can we effectively increase energy storage per unit cost? i1 = σ Φ1 interfacial charge-transfer resistance i2 = κ Φ2

How can we effectively increase energy storage per unit cost? i1 = σ Φ1 i2 = κ Φ2

Limiting cases: finite solution-phase conductivity, simplified kinetics i2 = s = 2 ai0 exp ai0 exp cf RT cf RT s s 2 1 High values of ionic conductivity can yield more effective utilization of electrode materials but generally requires lower cell potentials

Flow batteries

Flow batteries allow for de-coupling of power and duration of storage

Flow batteries allow for de-coupling of power and duration of storage select two different redox couples with sufficiently different reversible potentials

Flow batteries allow for de-coupling of power and duration of storage

Flow batteries allow for de-coupling of power and duration of storage select two different redox couples with sufficiently different reversible potentials

Selection for redox systems

Lessons learned from fuel cell development

what happens when you rely on technology push instead of market pull

cost reduction Cost ($/kw) 3M 1000 2M 500 1M Years in production Number of units sold per year 4M 1500 5M

problem with only one ultimate cost goal

What is needed

What is needed Optimize over different variables: capital cost, lifetime, efficiency(?)

What is needed Optimize over different variables: capital cost, lifetime, efficiency(?) Identify best ways to provide value for different functions

What is needed Optimize over different variables: capital cost, lifetime, efficiency(?) Identify best ways to provide value for different functions Manufacturers need lots of practice and lots of design turns