Not all energy companies spill oil and spew pollution, but separating truly progressive companies from the pack can be difficult. With a new slew of environmental awards to choose from, here are three dividend stocks worth a second sustainable look.

1. Sempra Energy
Sempra Energy (SRE -0.08%) scored in September, snagging a spot on the 2013 Dow Jones Sustainability Index for the third straight year. Mr. Jones also added Sempra to his World Index for the first time ever, where the company's $22.9 billion market cap made it one of the 10 largest additions to the list. 

The company has spent $20 billion on capital investments over the last eight years, with much of the money headed to cleaner-burning natural gas and renewables projects. Sempra's greenhouse gas emissions rate is currently 40% lower than the industry average, and new natural-gas opportunities should shrink its carbon footprint even more in the years to come.

2. Spectra Energy
Spectra Energy (SE) hit the green spotlight this week when it became the only energy company to claim a spot on the 2013 S&P 500 Climate Performance Leadership Indexes. Spectra also holds spots on the Dow Jones Sustainability Indices, but this latest index addition highlights the company's climate change awareness .

In responses to a Carbon Disclosure Project questionnaire, Spectra had to take a long, hard look at how climate change affects its business and what, if anything, the company is doing about it. With 71 pages of public responses, Spectra's disclosure is an excellent starting point for considering climate change. 

3. National Grid
Going green is a global initiative, and National Grid (NGG -0.09%) is doing its part from across the pond. The U.S.-U.K. utility won a spot as one of the 10 largest additions by market cap to Europe's Dow Jones Sustainability Index.

Like Sempra, National Grid's carbon reduction notions stem primarily from natural gas production. In a news release outlining its plan for a low carbon energy market, the company notes that "security of supply and climate change can be tackled together" via reduced demand, support for low carbon energy sources, and smart infrastructure investments.

The company isn't just talk, either. Last week, the utility's U.S. President Tom King reiterated his support for the EPA's greenhouse gas emissions standards for new power plants. With a progressive energy portfolio already in place, National Grid wants to make sure its going green will keep it increasingly competitive in the years to come. 

Can green awards guarantee greenbacks?
Environmental honors are full of pomp and circumstance, and no investment thesis should be based on these awards alone. But going green can serve as a signal of long-term thinking and foresighted management, two qualities any Foolish investor should learn to love. From massive capital investments to embracing new energy opportunities, giving these companies a go could grow your own green portfolio in the years to come.