The energy efficiency and load management transportation programs offered by Southern California Edison help our customers save energy and money by using electricity more efficiently and shifting use to off-peak periods. These programs are designed to help SCE minimize the electric system impacts of increasing on- and non-road electric-drive use.
At the same time, like SCE's overall energy efficiency and load management strategies, our electric-drive work supports California's energy and economic well-being by reducing electricity demand during high-use periods. In addition, we work closely with the electric-drive industry on infrastructure issues such as the technology to manage electric-drive energy usage, and codes and standards to ensure the safety and efficiency of charging systems and equipment.
Load Management
Load management (also called load shifting) programs move electricity use away from the afternoon peak periods, when energy demand and costs are highest – particularly during the heaviest-use summer months.
One way SCE encourages off-peak charging is through Time-of-Use (TOU) rates. When business customers on our TOU rates charge electric-drive technologies during summer off-peak periods, they pay about a quarter to a half in energy costs of what they would pay for charging during on-peak periods, providing substantial savings.
SCE also supports load shifting by helping business customers design the most cost-effective and energy-efficient duty cycles for their equipment. For example, with energy management systems (EMS), time clocks or existing battery charger onboard timers, customers automatically can shift electricity use from on-peak to off-peak hours for charging forklifts, pallet jacks, sweepers, tugs, golf carts and other electric-drive technologies.
Customers also can use an EMS to expand load management strategies to other energy demands, such as lighting, and heating, ventilation and air conditioning (HVAC), to save even more.
A 2004 study commissioned by SCE of industrial customers' electric forklift battery charging habits indicates that the highest-energy-use customers can save, on average, as much as $5,000 annually by shifting some of their charging from summer on- to off-peak periods, as shown here.
Forklift Load Shifting Benefits
|
Customers With
200 – 500 kW* Demand |
Customers With
500 kW* and Above Demand |
| Average Number of Electric Forklifts |
26
(range of 14 to 35) |
64
(range of 7 to 275) |
| Average Controllable kW/Forklift |
1.21 kW |
1.15 kW |
| Average Projected Total Load Management Savings |
$1,515
(range of $479 to $2,900) |
$4,977
(range of $296 to $18,726) |
*kW = kilowatts
In years to come, advanced energy batteries from the transportation sector could play a role in energy efficiency and load management in stationary (non-mobile) applications. For example, less-expensive off-peak energy stored in advanced batteries could be used to help reduce daytime on-peak demand, enhance electricity grid reliability and quality, and even support and complement clean photovoltaic systems.
See the Garage of the Future.
Energy Efficiency
In this area, SCE's state-of-the-art Electric Vehicle (EV) Technical Center continues to develop methods and procedures to improve the interface between both the electric grid and the charger, and between the charger and the battery, for non-road electric-drive technologies.
Key EV Technical Center energy efficiency projects include:
Energy-Saving Strategy
The EV Technical Center developed and tested a procedure that communicates with the charger and battery to apply a more efficient charging strategy. When used with electric forklifts, this strategy achieved these impressive results in lab tests compared to conventional charging strategies, which normally involve significantly overcharging flooded lead-acid batteries:
- Required 12% less energy to charge batteries.
- Reduced 32% of battery charging time.
- Decreased 50% of the battery watering requirement.
Field tests confirmed the lab results, showing a 12% energy use reduction with no forklift performance degradation. For a typical SCE commercial customer operating three shifts a day on a Time-of-Use rate, this result translates to savings of up to $400 in electricity costs per forklift annually.
Energy Efficiency Standards for Battery Chargers
The EV Technical Center, along with SCE's Energy Efficiency Group and California utilities, has completed draft test procedures for measuring the efficiency of battery chargers for the State of California, with the procedures published in August 2008 as part of the Title 20 Appliance Efficiency Standards. (See http://www.energy.ca.gov/appliances/2008rulemaking/ for details.)
Development of standards for efficient non-road battery charger performance could significantly lower charging costs along with reducing energy use and associated emissions, minimize negative impacts on the electric grid, give manufacturers charger performance design parameters, and offer customers confidence in the efficiency of qualifying products.
For more information about SCE's electric-drive load management and energy efficiency programs, including work conducted by the EV Technical Center, e-mail evtc@sce.com.
Electricity…Sustaining Our Transportation Future.