Want to grow your portfolio but support a better future for the Earth at the same time? Clean energy investment opportunities may be just what you're looking for. If you invest in clean energy, you're not only helping to fund a greener future but also throwing your hat into the ring with a growing, thriving industry.

Here are three areas of the green energy industry where you can look for investment opportunities.

1. Wind Energy

Setting up wind turbines for private renewable energy isn't as common as a homeowner putting up a solar array, so predictably the retail market may not be the best place to invest in wind energy. Instead, you can find a yieldco that lets you invest in actual currently existing wind farms. These wind farms may pay high dividends, depending on which group you choose.

2. Solar Energy

One obvious way to support the industry and get a good return on your investment is to back companies that develop, produce, and sell solar panels. However, you can also get behind utility companies that provide clean energy (such as solar power) for residential and commercial applications.

Utility companies can be a steady, lower-risk investment, and if you're interested in helping the environment, you can look for a company that allows its customers to choose energy from clean sources. Some utility companies source some of their energy from a solar farm, for example, and allow customers to pay extra for the privilege of using that cleaner electricity.

3. Hydroelectric Power

Hydroelectric may not seem as flashy or cutting-edge as solar power, but in some areas of the country it can be more reliable and predictable. For instance, in the Pacific Northwest, running water may be available day in and day out year-round, while full sun is only available intermittently.

While hydroelectric power only works with a reliable source of water, damming up a river or stream can often help to keep the flow of water more consistent, allowing hydroelectric power to be attainable in many areas of the country. While large plants may be publicly owned, smaller hydroelectric plants may be available for investments.

These are just a few sources of clean energy investment opportunities. Other, less well-known types of clean energy may include biofuels, geothermal energy, and wave energy converters. These could be worth investing in as well if you want to invest in as many clean energy sources as possible, although they could be more difficult to find investment chances for.