According to interviews given to German publication Manager Magazine (Google translate) this week, sources from Porsche, Mercedes, and Audi said that they are all readying electric cars to respond “to the success of the Californian newcomer Tesla with its Model S.”

Porsche’s chairman Matthias Müller reportedly said that the company is working on an all-electric car that will be based on the company’s Modular Standard Platform (Modularer Standardantrieb-Baukasten in German, or MSB for short) and look similar to the company’s Panamera (which has already been introduced with a hybrid electric engine).

The car will be "an advanced battery-powered variant [that] is tasked with challenging the Model S on both performance and range,” Autocar UK says. The publication added that Porsche is aiming for a curb weight lower than the 4,647 lbs of Tesla’s Model S in its forthcoming car, and that it will come with a synchronous electric motor with horsepower comparable to the Model S.

Although details about the car are slim, Manager says that the car won’t be released until 2018 at the earliest.

Mercedes sources also told the publication that the company had a Tesla competitor in the works, but the projected timeline for such a car is further out; an all-electric sedan won’t be ready until 2021, sources say. According to the blog Gas2, Mercedes’ battery is currently too big to fit in the car maker’s current models, so some redesigning will reportedly be necessary.

And its well-known that Audi is further along in building an electric car aimed at potential Tesla buyers. The recently announced Audi Q8 e-tron, for example, is anticipating a release in 2017. But the Q8 won’t compete with Tesla’s current Model S, industry watchers say; instead, with that car, Audi has its sights on the Model X SUV that Tesla intends to ship in March 2015.

Autocar suggests that Porsche’s coming electric car battery could be produced in partnership with Audi, which is also finalizing its R8 e-tron electric car.