You can make a coherent, logical argument for cars that don't burn gasoline without once mentioning global petroleum supply. You can talk about international relations and the power of gasoline exporters (just read the first three paragraphs of this for a bit of history). You can talk about climate change. You can talk about the health effects of CO2 in the air. But the fact remains that gasoline (or diesel) remains the go-to fuel for almost every passenger vehicle on the planet, so the question of how much black gold is out there is an important one. The answer, though is not so clear.
Despite some claims that peak out has already happened, a new study (PDF) by the International Energy Agency (IEA) predicts that increased energy production in North America means that, between now and 2018, global oil production capacity will increase by 8.4 million barrels a day. Since this is "significantly faster than demand," Time says peak oil is dead, with perilous consequences. As the chart above shows, the IEA's predictions are that OPEC will have spare capacity for years to come.
On top of North American production, crazy new energy sources are being investigated (like methane hydrate, or crystalline natural gas. See video below). These require incredibly expensive research and exploration efforts, but the end result could be, as The Atlantic so provocatively puts it, "infinite fossil fuel?" The magazine has a detailed debate on the subject between Charles Mann and Amory Lovins here, here and here. Well worth reading.