Residential Energy Use by Time-of-Day and the Duration of Charging Sessions. (Note: Time is active charging time only.)
The US Department of Energy (DOE) published a new report on electric car charging presenting customer behaviors and impact on the grid.
Data comes from different projects made by six utilities:
- Burbank Water and Power (BWP)
- Duke Energy (Duke)
- Indianapolis Power & Light Company (IPL)
- Madison Gas and Electric (MGE)
- Progress Energy (now part of Duke Energy as a result of a merger in 2012)
- Sacramento Municipal Utility District (SMUD)
According to the report, the electric power industry expects a 400% growth in annual sales of plug-in electric vehicles by 2023, so not strange that utilities are interested to learn something onhow to take advantage of electric cars and not end up with a black out.
For now, the impact of electric car charging on the electric grid is negligible due to the low number of plug-in vehicles, however typical load curves already can be determined, as well as finding that only a few percent of charging sessions are longer than 4 hours (and 12 kWh). It should be easy then to encourage EV owners to charge off-peak during the night.
"There are relatively few plug-in electric vehicles on the road today; as a result the six SGIG projects focused on establishing the charging infrastructure with a relatively low number of stations and evaluated a small number of participating vehicles. As expected, project results showed negligible grid impacts from small-scale electric vehicle charging today, but gave utilities important insights into the demand growth and peak-period charging habits they can anticipate if electric vehicle adoption rises as expected over the next decade. Utilities face a challenge in determining when their customers purchase electric vehicles, and where and when they will plug-in to satisfy charging needs."
"Given the current rate of customer electric vehicle adoption, utilities are considering plans for electric vehicle charging programs. For example, BWP analysis showed that with a 25% per year growth in usage at public charging stations, utility investments could have a seven-year payback, which would be a financially attractive business case for some utilities. Table 1 provides a summary of the key project experiences from the six projects."
Table 1. Summary of Key Project Experiences