Part of the reason the US, and Europe, for that matter, still rely on fossil fuel is the expense of changing over. A new renewable plant costs far more than a fossil fuel plant whose cost was amortized years ago. And renewable plants aren't zero operating costs... they require substantial maintenance. With governments already running deficits, where will that money come from?
Part of the reason is that neither the US or European economy could function on renewables alone, with current technology. The most promising renewables: solar and wind, don't deliver power when it is needed. Wind farms shut down during storms or when the wind dies down, and solar quits when the sun goes down.
What is missing is a cost effective way to store large amounts of electric power, so that it can be generated in optimal renewable conditions, yet be available when it is needed to run a nation's economy. That solution is in progress. Nations could help by cutting funding on climate research, and boosting funding for the solution to climate change, which we already know: use less fossil fuel. Duh just doesn't say it.
As for alternate fuel autos, a lone US company has done far more than any country in that regard.
Until the first part of this decade, the available all electric vehicles were fairly pitiful (g-wiz), accepting the idea that one had to suffer to be green.
Enter Elon Musk and the Tesla Model S - the first all electric car that people actually want to own, and not just because it's electric... it's a terrific (albeit pricey) car. And the price is about the same as, say, a BMW 5 series, which the Model S competes with.
So the powerful auto lobby and the powerful oil lobby couldn't stop one person who nearly went broke getting Tesla off the ground.
Since Tesla rose to fame, some auto makers have gone back to the drawing board and have begun to come up with viable, practical, decent electric cars. This wasn't a conspiracy, it was more dull auto executives and entrenched thinking. Nothing like losing sales to get them moving.
The upcoming Tesla model 3, at USD$35k with a 200 mile range, is definitely a positive step, as is the half million pre orders for it... with a $1k deposit. The interest is there. When someone can develop an all electric car, with a 500 mile range, priced at under $25k, people will buy it. Not to be green, but because it's a better deal. In the US, if 1/4 of the cars on the road were all electric, we could shut off foreign oil purchases completely, from the ME and elsewhere.
In the end, that is what it will take to get us off of fossil fuel. The replacement not only has to be green, it has to be less expensive than fossil fuel, or enough short sighted people will go to the polls and vote in legislators to restore their lower power bills.