The reason for that "true cost" line is because you can input all sorts of variables into Plugwiz – the plug-in vehicle make and model, what kind of charger you have at home, when you plan to charge, your gas car's mpg and more. Once you feed all the details in, Plugwiz will tell you how much you can save per month.
As cool as it is, Plugwiz would like some of your personal information (your email, but it doesn't require it), and it doesn't automatically draw down data on local average gas prices – which would be a nice feature – but there's still a lot of real usefulness here, especially since it can talk to your utility about price rates. You just input how much you pay a month for the calculator to make a comparison. A short statement from Plugwiz is available below.
Plugwiz is available on the California PEV Collaborative website. How much do/would you save?
As an example, rate information was taken from California's two largest utilities, Pacific Gas & Electric and Southern California Edison, which have prices in the $0.12 per kWh range for some users and over $0.34 per kWh for others using data found on their websites in early February. This means costs and benefits for customers in these areas can vary by almost 300%. In Texas, if some users do not use a certain amount of electricity, they are subject to added surcharges, which the tool accounts for. Some utilities offer money saving rate options or rebates and some do not, which our tool helps to determine e.g. LA Water & Power's $2,000 EV charger rebate, which could help with a potential buyer's decision.
To demonstrate value we are working with some of the largest and most progressive utilities in the US to communicate value to individual customers. As an example PlugWiz creates over $1,000,000 in annual value to PG&E ratepayers if just 1,000 EV owners learn about and switch to a PG&E EV rate from their normal tiered rate. These numbers vary by utility, $800k+ in Southern CA Edison territory and $200k per year in Hawaii.