These days you don’t have to wedge yourself into a Prius or a hybrid Honda Civic to get environmental kudos. Car makers are going greener by adding more efficient cars to their line ups—a welcome sign, no doubt, to drivers in cities like San Francisco, where fuel prices now top $4 a gallon. But green and cars have never gone hand in hand, and not all “green” cars are created equal, despite what Detroit or those Autobahn loving Germans tell you. Here’s a look at three luxury sedan models in three shades of green and how they measure up when it comes to MPG.

Green: BMW 528i

How can a gas-only, non-hybrid car be on this list? While we’re reticent to label it green, BMW has used their considerable engineering prowess to create a lightweight and efficient engine for this model. In today’s world of heavier cars and bigger engines, the BMW 5-series lineup is a good choice if you want to reduce fuel consumption without sacrificing BMW’s cache of sport and luxury. Pros: The ultimate driving machine without the ultimate thirst. Cons: It’s the slowest 5-series available, and its 18/27 miles per gallon still isn’t great. Unfortunately the European-only 5-series diesels that get over 40 MPG aren’t available stateside.

Greener: Lexus GS450h

Toyota, Lexus’ parent company, has been at the forefront of hybrid technology since the inception of the Prius. Now applying their technology to their Lexus brand, they claim the power of a top of the line, V-8 midsize luxury sedan, with the efficiency of a smaller engine. Why sacrifice speed and luxury in your efforts to make less of an impact on the environment? Pros: Luxury, speed and sportiness in a hybrid package. Cons: The 3.5-liter V-6 is still large, and even with an electric motor it only returns low- to mid-20s MPG, hardly an award winner in the hybrid world.

Greenest: Mercedes-Benz E300 Bluetec

Mercedes has hybrids in the works, but until then, they have gone the European route and focused on clean diesels. Using an additive in the exhaust, Mercedes diesels pollute much less than the clunkers of yore. Quick, quiet and clean, these diesels provide admirable performance with eco-car efficiency. Pros: Luxurious and fast while returning 30 to 40 mpg, plus this ain’t your grandfather’s diesel—modern diesels are clean and quiet. Cons: It still operates on a fossil fuel, and diesel is now more expensive than gasoline.