Exchange-traded funds involving solar energy have been stellar over the past two months. A rising stock market and higher oil tends to help. Many companies are raising guidance or are calming fears that margin compression is escalating and that orders are dropping.

We have taken a look at some of the solar ETF products on the market that offer the best alternatives on investing, although there are also some broader ETF products via alternative energy and clean energy ETFs, which of course include heavy weightings in solar stocks. Guggenheim Solar ETF (TAN) and the Market Vectors Solar Energy ETF (KWT) are key solar ETFs in the mix. We have also loosely covered solar via broader alternative energy ETFs of PowerShares WilderHill Clean Energy (PBW), Market Vectors Global Alternative Energy ETF (GEX), and the iShares S&P Global Clean Energy Index (ICLN). As First Solar Inc. (FSLR) is the largest solar stock out there, we have tried to show how it relates into each because the weighting and balancing of each fund differs.

"Renewable fuels and clean energy, a sector beaten down hard since last fall, are now primed for a major comeback," says Eric Roseman, editor of The Commodity Trend Alert. Here's his ETF play on the sector.

"With every passing day the price of crude oil rises, the secular trend to alternative energy becomes even more powerful. Consumers, companies and governments are now sick and tired of soaring energy prices.

"The long-term solution is to obviously reduce our dependence on oil and increase our consumption of renewable fuels like wind, solar, and nuclear energy.

"The bull market in alternative energy began in 2005 when a host of companies in this thriving sector went public, supported by government subsidies, especially in Germany and Spain. Interestingly, Germany and Spain have just reduced solar energy subsidies this spring.

"In my view, those subsidy cuts don't matter at this stage. When companies in the solar sector are making money, why should governments continue subsidizing them?