Survey Plan - Smart Charging for PEVs

Quantifying the Benefits and Constraints of Plug-In Electric Vehicle Smart Charging Adoption

0. Brief Summary

This article is our survey plan. It consists of Target Population, Conjoint Questions, and Other Survey Contents.

The survey is broken down into 6 parts:

1. Welcome page (including consent info)
2. Education information
3. Critical questions: eligibility questions and charging habit questions
4. Conjoint questions (considering all 5 attributes, with options A, B, and a “No” option)
5. Other questions
6. Ending page

An extra hint from JP: all surveys require the IRB approval prior to publication.

1. Target Population

The desired target population is those who currently own or rent an EV. However, the team is also interested in those who plan to buy an EV in the near future. Those who do not have and do not plan to have EVs can also fill in our survey, but we will consider them as low priority.

In summary, the target population, from most important to least, can be listed as follows:

1. Current EV owner
2. Current EV renter
3. Prospect EV buyer
4. Others

Of course, there are also some basic requirements for the participants:

• They should be at least 18 years old to fill in the survey;
• They should possess a driver’s license.

The eligibility questions are:

1. Do you currently own an EV or lease an EV?
2. Based on the answer of the previous question, there will be 4 versions of this question:
   • Which EV do you own?
   • Which EV do you lease?
   • Which EV do you plan to buy?
   • Which EV is your favorite?
3. What is the max range of the EV that you just picked?

2. Attributes and Levels for Conjoint Questions

This is the core part of our survey. After asking the eligibility questions, we are ready for the conjoint questions. The team plans to have 5 conjoint questions, each of which contains Option A, Option B, and Not Interested.

For both options A and B, all attributes are considered, which means the combination of the attributes for a specific option is fixed. It is desired that the participant will choose a relatively better option based on his/her attribute preferences. If the participant is really not interested in any of them, the “Not Interested” option can be a life saver.

2.1 Conjoint Question Text

If these were your only options, which smart charging plan would you choose?

2.2 Attribute Table

attributes <- read_csv(here('pilot',
                            'data',
                            'attributes.csv'))

attributes %>% 
    kable(format = 'html',
          escape = FALSE,
          align = c('c', 'l', 'l', 'c', 'c', 'l')) %>%
    kable_styling(full_width = FALSE,
                  bootstrap_options = c("striped", "hover")) %>%
    column_spec(column = 2, width = '14em') %>% 
    column_spec(column = 3, width = '10em') %>% 
    column_spec(column = 6, width = '25em')

No.	Attribute	Levels	Unit	Demand	Comments
1	Upfront Incentive	100, 300, 500	USD	+	A study shows a cap of 300
2	Free Level 2 Charger	No, Yes	(Nil)	+	So far we ignore the installation cost
3	Electricity Price Discount	10, 25, 50	%	+	Expected correlation with those who know the electricity prices
4	Override Window	0.5, 1, 2, 4	hrs	+	The length of time for users to manually override smart charging
5	Guaranteed Range if smart charged for 8 hrs	25, 50, 75	%	+	Will require prior selection of max mileage. The % here will be used as a background multiplier. The real question will show mileages.

2.3 Sample Conjoint Question

Below is an arbitrary sample conjoint question. Option A provides a lower upfront incentive, but other relatively better options; Option B gives a much higher upfront incentive, but there are compromises in other options. Those who care more about upfront, and who care more about long-term benefits, will usually make different choices with these given conditions.

However, it is not always true that our conjoint questions will generate the dilemmas in this typical way, since all attribute values will be randomly assigned.

If these were your only options, which smart charging plan would you choose?

sample_question <- read_csv(here('pilot',
                                 'data',
                                 'sample_conjoint_question.csv'))

sample_question %>% 
    kable(format = 'html',
          escape = FALSE,
          align = c('l', 'c', 'c')) %>%
    kable_styling(full_width = FALSE,
                  bootstrap_options = c("striped", "hover")) %>%
    column_spec(column = 1, width = '20em')

Attribute	Option A	Option B
Upfront Incentive	$100	$500
Free Level 2 Charger	Yes	No
Electricity Price Discount	25%	10%
Charging Window	5pm to midnight	24/7
Guaranteed Range if charged for 8 hrs	200 miles	100 miles

3. Non-conjoint Survey Contents

3.1 Welcome page

Welcome to the survey of EV Smart Charging! We are a student team of the George Washington University that studies users’ willingness to adopt EV smart charging, and we appreciate your participation.

This survey will take about 10 minutes to complete. It can be stopped at any time, in which case we won’t keep your answers. Your personal information will be kept private and won’t be shared with anyone else.

If you have any questions, you can reach out to us at emsepevteam@gmail.com. We will respond at our first convenience.

The survey begins upon clicking the “I agree” button. We greatly appreciate your inputs.

3.2 Consent page

The consent contents will appear on the Welcome Page.

To take a part in this survey, you must:

• Be at least 18 years old.
• Authorize us to analyze the data exclusively for research purposes. 

By selecting the “I agree” button below, you confirm that you have reviewed and understood the information provided in this welcome page and agree to participate in the “Smart Charging Survey”.

3.3 Education information

Before the survey begins there is a brief introduction of Smart Charging that you might want to know:

• EV, or Electrical Vehicle, is a type of vehicle that is powered by electricity. For example, a Tesla car is a typical EV.
• Smart Charging, or Controlled Charging, is a technique that controls the charging time window and charging amount of an EV.

Smart charging is beneficial in 3 ways:

• For the grid, it ensures off-peak charging and decreases the grid’s peak load.
• For the users, it helps them charge the cars in a low-cost time window.
• For the environment, it helps utilization of renewable energy rather than fossil fuels.

The figure below shows how smart charging smooths out the peak power output, and how it reduces the power capacity requirement:

Figure 1. Smart charging helps avoid peak load (Bartz/Stockmar 2018)

For additional information, we recommend you to watch this 30 seconds video:

Video 1. Smart Charging Intro (EVBox 2019)

3.4 Critical respondent information

The critical respondent information refers to a group of “must-ask” questions. They consist of eligibility questions (stated in Section 1) and charging habit questions. The questions are placed right in the beginning, so that the participants fill out the most important info when their minds are fresh.

3.4.1 Eligibility Questions

The eligibility questions are (with options):

1. Do you currently own an EV or lease an EV?

• Yes, I own an EV
• Yes, I lease an EV
• No, but I plan to buy an EV in the near future
• No, I don’t have an EV

2. Based on the answer of the previous question, there will be 4 versions of this question:

2.1 Which EV do you own?

2.2 Which EV do you lease?

2.3 Which EV do you plan to buy?

2.4 Which EV is your favorite?

For this question, we prepare to have a list of brands and models. Here is a brief list:

• Tesla: Model S, Model 3, Model X, Model Y, Others
• Nissan: Leaf, Ariya, Others
• Chevrolet: Bolt EV, Bolt EUV, Others
• BMW: i3, i4, i8, iX, iX3, Others
• Audi: e-tron, e-tron Sportback, Q4 e-tron, Q4 Sportback e-tron, Others
• Volkswagen: ID.3, ID.4, D. Buzz, Others
• Hyundai: Ioniq Electric, Kona Electric, Ioniq 5, Others
• Kia: Soul EV, Niro EV, EV6, Others
• Porsche: Taycan, Taycan Cross Turismo, Others
• Ford: Mustang Mach-E, F-150 Lightning, Others
• Volvo: XC40 Recharge, C40 Recharge, Others
• My car is not listed

3. What is the max range (in Mileage) of the EV that you just picked?

• Below 100
• 100~200
• 200~300
• 300~400
• 400~500
• Over 500

3.4.2 Charging Habit Questions

Apart from the eligibility questions, the charging habit questions are also critical:

1. Do you charge at work or at home?

• At work
• At home
• Both

2. (If work is chosen) When do you usually charge your car at work?

• In the morning
• In the afternoon
• Both

3. (If home is chosen) When do you usually plug in your car at home?

• 5~7pm
• 7~9pm
• 9~11pm
• After 11pm

3.5 Other questions

Other questions refer to some trivial questions that may help distinguish some more detailed customer information. However, since they are not as important as critical questions, they are placed after the conjoint part.

1. What is your gender?

• Male
• Female
• Non-Binary
• Prefer Not to say
• Other

2. What is your age?

• Under 18
• 18-24
• 25-34
• 35-44
• 45-54
• 55-64
• 65 and over

3. What is your annual household income?

• Less than $25,000
• $25,000-$49,999
• $50,000-$74,999
• $75,000-$99,999
• $100,000-$149,999
• $150,000 and above
• Prefer not to say

4. Attribution

The team worked together in Wednesday’s class to generate the first draft, and had further discussions and edits based on professor Helveston’s instructions. Below is the breakdown of each member’s works:

• Pingfan was responsible for the 0. Brief Summary and the section of 2. Attributes and Levels for Conjoint Questions. He embedded links to the image and video, and he was also responsible for reviewing and rephrasing the texts and formats on the other sections based on other members’ works, especially the rephrasing of 3.4 Critical respondent information.

• Vedanth was responsible for the section of 1. Target Population. His part is essential to the latter parts of 3.4.1 Eligibility Questions and 3.5 Other questions.

• Bharath and Sampada were both responsible for the section of 3. Non-conjoint Survey Contents. Bharath did 3.1 Welcome page and 3.3 Education information, and Sampada worked on 3.2 Consent page and 3.4.2 Charging Habit Questions.

References

Bartz/Stockmar. 2018. “The Case of Smart Charging.” May 2018. https://energytransition.org/2018/04/europe-must-choose-a-green-future/.

EVBox. 2019. “How Does EV Smart Charging Work?” December. https://www.youtube.com/watch?v=nibU1Iq6g3Y.