European shares higher, helped by Wall Street

* FTSEurofirst 300 index up 0.73 percent

* German energy companies fall sharply

* Autos gain after strong car sales data

By Atul Prakash and Danilo Masoni

LONDON/MILAN, Sept 15 (Reuters) - European shares were slightly higher in late trading on Tuesday, helped by a positive start at Wall Street, but with German energy firms RWE (Amsterdam: RW6.AS - news) and E.ON lower after a report they needed to set aside more money to shut down nuclear power plants.

Volumes remained thin as investors were reluctant to make big bets before the Federal Reserve decides on Thursday whether to raise U.S (Other OTC: UBGXF - news) . interest rates for the first time since 2006.

Shares (Berlin: DI6.BE - news) in RWE (Xetra: 703712 - news) and E.ON both fell more than 4 percent after Spiegel Online said they were short as much as 30 billion euros ($34 billion) of the money they need to set aside to build a safe disposal site for nuclear waste as part of Germany's exit from nuclear power.

E.ON said that nuclear provisions were adequate.

"Uncertainty about the Fed's likely decision continues. If there is no rate hike on Thursday, it could also give a signal that the Fed has some concerns about the health of the economy," said Christian Stocker, strategist at UniCredit (EUREX: DE000A163206.EX - news) in Munich.

Traders raised their bets the Fed would raise interest rates this week as an in-line report on August U.S. retail sales signaled steady U.S. economic growth in the third quarter.

By 1431 GMT, the pan-European FTSEurofirst 300 index was up 0.73 percent at 1,403.90 points.

Although the benchmark index is up more than 5 percent from a low it hit late last month, it is down about 14 percent from its peak two months ago, mainly on concerns about the pace of economic growth in China and the prospects of a U.S. rate hike.

The mood among investors in Germany, Europe's biggest economy, slumped in September to its lowest level in 10 months, hit by fears about slower exports to emerging markets, a survey by the ZEW think tank showed on Tuesday.

The auto sector was up 1.4 percent after figures showed European car registrations surged 11.5 percent last month as a regional market recovery gathered pace.

The STOXX Europe 600 Basic Resources index turned slightly positive, after being the top sectoral decliner in Europe.

Miner and commodity trader Glencore (Xetra: A1JAGV - news) was down 0.7 percent in late trading after falling as much as 7.7 percent as a slowdown in demand sent coal prices below levels last seen in the global financial crisis of 2008-2009.

Europe bourses in 2015: http://link.reuters.com/pap87v

Asset performance in 2015: http://link.reuters.com/gap87v

Today's European research round-up

(Editing by Jeremy Gaunt.)