There is a current raging debate about the merits of government support for Big Oil compared with support for clean-energy technologies such as wind and solar power. The clean-energy crowd is adjusting to a world of fewer government subsidies, but these “green” advocates insist that wind, solar and other technologies could be quite competitive with fossil fuels if government policy makers stopped backing the oil and gas industry as well. This idea is starting to have some resonance on both ends of the political spectrum.

If oil prices stay at or above $100 a barrel, then the hands-off approach could really gain some traction. Profits for oil companies would be so large that they’d likely be more willing to loosen their stance on government subsidies for alternatives. In contrast, green technologies would become much more cost-competitive with oil at high price levels, opening the door for new large-scale renewable energy projects.

With this in mind, here are three clean-energy companies that may double their revenue in the next three years if oil prices remain steep.

1. JinkoSolar (NYSE: JKS)
This solar-wafer maker is well on the way to doubling sales from 2010 by 2013. This is because sales are already expected to nearly double this year alone to about $1.4 billion. The strong growth comes from past moves to rapidly build new manufacturing capacity.

When these moves were announced, investors fretted that the company would overshoot the mark and be saddled with too much capacity. But JinkoSolar has done an impressive job of lining up demand with its rising output.

The debate around the company’s supply and demand dynamic has made for a volatile stock. JinkoSolar went public in May 2010 at $11 a share, zoomed to $40 later in the year on the heels of impressive quarterly results, but now sits back at $21 a share, as investors remain concerned about the near-term outlook for solar-power demand, especially after Germany and Italy throttled back subsidies. Notably, signs have emerged that Italian subsides for the solar-power industry  will not fall to the extent many had expected, which recently led the company to issue second-quarter guidance above the consensus forecast. (Analysts continue to underestimate the company’s quarterly momentum: per-share profits have topped the consensus by at least 37% in each of the last four quarters.)

Management’s decision to sharply ramp-up output was simply intended to secure scale economies. The company has been able to reduce its production costs for almost all items: from $0.89 kilowatts per hour in 2009, to $0.75 kwh in 2010, to a projected $0.67 kwh by the end of 2011. These kinds of gains are enabling JinkoSolar and its peers to inch ever closer to price parity with gas and coal-fired power plants.

JinkoSolar’s momentum is nonetheless offset by a broader pause in solar spending. As a result, per-share profits are likely to stay in the $6-$7 range in 2011 and 2012, as was the case in 2010. Still, shares trade for about three times the profit run rate. Such a low multiple is far too bearish for an industry that is doing “good, not great.” Analysts at Brean Murray figure shares are likely to trade for about 4.5 times projected 2012 profits, or about $35. That’s more than 40% upside from current levels.

2. A123 Systems (Nasdaq: AONE)
This advanced battery maker for electric vehicles has been a real disappointment for investors, falling more than 75% since surging from its $17 September 2009 initial public offering  to $25  by Oct. 2 of that year. Investors had been expecting imminent torrid growth, but instead saw year-over-year sales rise just 7% in 2010 to $97 million — most of it being  from customer-funded research and development. Yet it increasingly appears as if the revenue ramp will finally emerge this year and next year, as new orders roll in. If this really happens, then sales could double in 2011 and again in 2012.

Goldman Sachs raised its rating on A123 from “neutral” to “buy” in April (with a $9-a-share price target, representing 50% upside), noting the market was discounting the current chapter of the story while “business momentum is starting to accelerate.”

The real test for the company will come in the next 18 months, as automakers roll out more electric vehicles. If demand is strong for these vehicles (and $4/gallon gasoline will help), then A123 Systems could finally meet those lofty sales expectations.

3. Broadwind Energy (Nasdaq: BWEN)
This company has a shot at doubling revenue within three years simply because sales have slumped badly recently. Broadwind generated $207 million in sales in 2008, when wind farms were being built at a fast pace (thanks to surging energy prices), but sales slumped 34% to just $137 million in 2010. Yet as I noted in May sales have begun to rebound and backlog is growing at a nice clip.

As is the case with solar power, wind power costs are steadily dropping, moving ever closer to parity with fossil fuels. To boost sales by 100% in three years, Broadwind will need to deliver on current growth forecasts and increase sales another 25% in 2013.

Right now, shares are trading on the rising and falling prospects that the company will be acquired. Shares have fallen about 15% since late May, as hopes for a deal have ebbed once again. In coming quarters, it’s the fundamentals that should finally serve as the catalyst for the stock, as Broadwind is expected to post sequentially rising sales throughout 2011.

Action to Take –> If oil prices remain high, then demand for clean power is likely to pick up again. When this happens, these stocks may finally reverse their recent negative trend and start to show solid improvement in sales. This makes for potential 40% to 50% upside with each of these stocks in the next two years or perhaps more, granted they deliver on growth forecasts.

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