Is the energy rally tapped out? Energy shares, as represented by the Select Sector Energy SPDR ( XLE) exchange-traded index fund, are down more than 5% since early September as the price of oil has skidded from more than $70 a barrel to less that $56. As a result, many market-watchers are proclaiming that the bull market in oil-pproducing companies is over. Don't top off that tank just yet, says Tim Guinness, manager of the ( GAGEX) Guinness Atkinson Global Energy fund. Guinness believes that oil prices are only taking a breather down here and are headed up to $85 a barrel in the next three years due to an increase in demand and a slowing of supply. And, of course, he expects the big oil producers to follow especially diversified companies like BP ( BP) and ConocoPhillips ( COP). And if you want to talk about run-ups, Guinness' fund is up 55% year to date compared with 32% for the average energy mutual fund, according to fund tracker Morningstar. Guinness stopped by TheStreet.com to drill down on the future of oil prices. To view Gregg Greenberg's StreetWatch interview with Guinness, click here .