An Energy Storage System which reduces costs and generates revenue for the Transit Authority by Jacques Poulin, ABB www.polisnetwork.eu/2014conference #polis14
Urban Rail Transportation Energy and Power Challenges Increasing energy consumption Rail amongst the largest electricity loads Demand charges grow faster than energy costs Starting power of new trains require infrastructure overbuilt Sustainability and renewable energy credit targets Courtesy of Metro Trains Melbourne Orange = train capacity / Blue = power limitation
Electric Utilities Industry challenges Phase out fossil-based generation Increase the penetration of renewables Address Transmission and Distribution (T&D) congestion Improve asset efficiency (gas-based spinning reserve and base load generation)
Future Grid Ecosystem Network of distributed assets to meet the constantly changing generation and demand Spinning reserve Capacity firming Frequency regulation Load levelling Peak shaving Power quality
SEPTA Energy Optimization Project Serving Urban Transportation and Utilities together Project Facts Energy Savings - 2 MWh per day - 70 kw demand reduction - $80K per year Energy Market Revenues - > $200k per year Environmental Benefits - CO2: > 1,000 tons - SO2: > 5 tons - Nox: > 1 ton - Mercury: > 50 pounds
The Braking Energy Opportunity Energy which today is dissipated as heat DC Power Stored and returned for acceleration Braking Acceleration Constant speed Coasting Station stop Acceleration Constant speed Coasting Back to AC Only a few kilowatt hours, each time, but thousands of times every day
ENVILINE TM Energy Recovery Solutions
ENVILINE TM ESS with super capacitors Captures braking energy, sustains acceleration MV/HV Network AC ~ ESS Legend TDR energy rectification - acceleration ESS energy storage - breaking TDR DC + DC -
kwh / hr Percent recovery Braking energy recovery ~5-20% recovery depending on headways 1000 Daily profile of consumption & recovery 20% Headway (minutes) 800 16% 10-15 600 12% 5-10 400 8% 200 4% 2-5 0 1 3 5 7 9 11 13 15 17 19 21 23 Time (hours) Traction (kwh/hr) Recovery (kwh/hr) Recovery % 0%
Beyond braking energy recovery Warsaw metro line 2, 3.0MW Captures the braking and gravitational energy Provides emergency backup under the river
Starting Power and Demand Charge A major technical, and costly challenge 43% of the cost Car analogy Odometer indicates the amount of energy, or Energy Consumption, Speedometer indicates the power level, or Demand Charge, Customers pay for consumption ( mileage ), but also significantly for demand ( maximum speed )
kwh / hr # of trains in service Utility Metered Demand Charge Power peaks well beyond the measured demand 2500 Daily consumption profile 20 8000 Actual Demand 2000 15 7000 6000 1500 5000 1000 10 4000 3000 500 0 1 3 5 7 9 11 13 15 17 19 21 23 5 0 2000 1000 0 7:10 7:20 7:30 2500 2000 1500 1000 500 Today s Demand Charge 15-min average consumption Today s demand charge is based on (kwh) consumption during a 15-minute window The real peak power is much higher, imposing even more strain on the grid 0 7:10 7:20 7:30
Current (Amp) ENVILINE ESS power assistance Lowers the starting power and demand charge 5500 4500 Train power 3500 Utility supply 2500 1500 ESS supply 500-500 Time ESS recovery -1500 0 10 20 30 40 50 60 (Seconds)
ENVILINE ESS avoids infrastructure cost Capacity for starting is costly and inefficient AC line drop Energy Storage System AC Switchgear Transformers Traction Rectifiers Voltage Limiting Device DC Switchgear
Storage, the Holy Grail of the Energy Industry Balancing generation with demand Complete utilization flexibility Responds rapidly Efficient at partial load Simple to grow with demand Deployed where needed Well suited for coincident needs (Demand response and power quality, regulation and peak shaving,.) No need for major infrastructure upgrade of T&D or generation
Power (kw) SEPTA Energy Optimization Project Turns the substation into a Smart Grid asset Saves energy by recovering the braking energy ~ 1.5-2.0 MWh / day Lowers the demand charge ~70 kw Generates revenue from sale of regulation service to local Grid 1000 800 Load regulation 600 400 200 0-200 Behind the meter train load modulation -400-600 -800-1000 PJM Reg ESS Response Braking energy recovery
In Summary Energy storage allows a positive business case Reduces electricity bills by 10-20% from energy savings and reduced demand charge Makes the substation smart and revenue generating, >$200K / year at SEPTA Cuts peak starting power to avoid infrastructure CAPEX and inefficiencies Installs easily with no adverse effect on the existing network Makes Rail Operation more sustainable and aligned with CO 2 emission reduction targets