The world is going green, from recycling and power generation to organic groceries and sustainable fisheries. Everyone, it seemsincluding climate change scientists, businesses, consumers and politiciansis interested in easing the burden humanity places on the environment.

If you are looking for ways to put a little green in your wallet by putting some green in your portfolio, you might be surprised at the wide range of available offerings. Here is a look at 11 top green investment areas.

Editor's Note: Please note that the companies mentioned in this article are examples to help you begin your research, not investment recommendations.

Green Power Investments

Green energy is a hot topic in a world concerned about climate change. Power generation that doesn’t rely on the burning of fossil fuels to generate electricity for our homes or industries is creating a growing number of investment opportunities. Water, wind and solar are among the top sources of renewable energy.

Water Stocks

One of the most important natural resources we have is water. There is considerable fear the world will run out of fresh water due to climate change. Cape Town, South Africa, was months away from running dry in 2018, until swift conservation measures helped to replenish supplies.

The European Environment Agency notes that some 20 European countries depend on other countries for more than 10% of their water resources. Five (the Netherlands, Hungary, Moldova, Romania, and Luxembourg) rely on rivers that flow in from other countries to provide more than 75% of their water. In the United States, cities from Los Angeles to Miami are concerned about water scarcity as climate change takes a toll on water resources.

A portfolio of water investments might include companies that collect, purify and distribute water. The largest water utility company in the U.S. is American Water (AWK), which supplies drinking water to 14 million people. Essential Utilities (WTRG) supplies water to nearly 3 million people. And, sticking with our water theme, these utilities are just the tip of the proverbial iceberg.

If picking individual stocks is too much hassle, mutual funds provide additional ways to invest. The Calvert Global Water Fund and the AllianzGI Water Fund tap into water-based opportunities across the globe.

Exchange-traded fund offerings include:

  • Invesco Water Resources Portfolio ETF (PHO)
  • Invesco Global Water Portfolio ETF (PIO)
  • First Trust Water ETF (FIW)
  • iShares U.S. Utilities Index ETF (IDU)
  • Zacks Global Water Index
  • Invesco S&P Global Water Index ETF (CGW)

Water has also been the go-to resource for renewable energy for centuries. The ancient Greeks ran grain mills on water power. Today, projects such as China's massive Three Gorges Dam can supply electricity to between 70 million and 80 million households. According to the International Renewable Energy Agency (IRENA), hydropower is the most cost-efficient means of generating electricity.

There are few pure-play stocks in the hydro business. However, there are three energy producers with notable amounts of hydropower in their portfolios. PG&E (PCG) has one of the largest hydro operations. Idacorp (IDA) has 17 hydro projects. Meanwhile, Brookfield Renewable Partners (BEP) derives 74% of its portfolio from hydropower.

Wind Power

Wind is one of the fastest-growing sources of renewable energy, having increased 75-fold over the past two decades. China leads the world with 217 gigawatts of installed capacity in 2018, followed by the U.S. with 96 gigawatts and Germany with 59 gigawatts.

If this renewable interests you, look for wind farms that sell wind-generated energy, or consider companies that manufacture wind turbines. Here again, there are few pure-play stocks, but a few of the interesting wind stocks include:

  • General Electric (GE)
  • NextEra Energy Partners (NEP)
  • Siemens Gamesa Renewable Energy (GCTAY)
  • Vestas Wind Systems (VWDRY).

Furthermore, the First Trust Global Wind Energy ETF (FAN) provides a passive way to invest in wind energy.

Solar Energy 

Energy from the sun powers homes, buildings and a variety of other items from lights to radios. If you think the sun is just starting to rise in this industry, focus your attention on companies that make solar panels, which will benefit as homeowners and businesses increasingly adopt solar power. First Solar (FSLR) is a leading producer of solar modules and systems. JinkoSolar Holding (JKS) also makes solar modules and claims to have delivered 52 gigawatts of production capacity. Sunpower (SPWR) makes solar modules and storage solutions for homes and businesses.

Of course, there’s more to solar than panels. From components to installation, a wide variety of businesses present investment opportunities, including:

  • Enphase Energy (ENPH)
  • Sunrun (RUN)
  • Vivint Solar (VSLR)
  • Invesco Solar ETF (TAN)

Pollution Controls

The reduction is the key term here. From reducing greenhouse gas emissions on industrial power plants to minimizing the emissions that come out of the tailpipe of your car, the pollution control industry is on the rise. This is the industry that responds every time legislation mandates an improvement in the amount of some harmful chemical that can be released into the environment. Companies and ETFs that focus on pollution control technologies include:

  • Fuel-Tech (FTEK)
  • VanEck Vectors Environmental Services ETF (EVX)
  • Invesco Cleantech ETF (PZD)

Green Transportation

When it comes to transportation, Tesla (TSLA) is the first name on many people’s lists. While an attention-grabbing leader and exciting technology have kept this company in the news, it’s not the only game in town.

On a smaller scale, researchers are working with fuel-cell technology to develop an alternative method of powering automobiles. If this technology works, there are millions of carsand millions of consumerswaiting for it.

Companies that operate in the space include Ballard Power Systems (BLDP), which produces cells that can be used in vehicles and back-up power systems. Meanwhile, FuelCell Energy (FCEL) focuses on providing power options to commercial and industrial facilities.

Waste Reduction

Recycling has become a standard practice. Most people are aware that paper, metal and glass can be reprocessed and reused, but the things you didn't know you can recycle continues to grow. Waste oil, vegetable oil, batteries, cell phones, computers and even car parts can have a second life. Recycling these items involves a business enterprise humming along in the background.

In terms of your portfolio, waste management companies with a large base of recycling facilities may be of interest, including companies such as Republic Services (RSG) and Waste Management (WM). Covanta (CVA) takes a different approach, generating power by incinerating waste.

Organics

Organic farms eschew the use of pesticides, engage in sustainable farming practices and sell products that are often healthier to eat than the stuff composed of three-syllable words that you can't pronounce and a shelf-life measured in decades. They also engage in animal management practices that avoid the use of hormones and antibiotics, keeping those chemicals out of the food chain and out of the ground and water surrounding the farms. One of the biggest organic food companies is United Natural Foods (UNFI), a wholesale distributor of healthy food options.

Aquaculture

Sustainable fishing is another food-related investment opportunity that is generating attention as the plight of the world’s overfished oceans impacts the human food chain. Mowi ASA (MNHVF), a Norwegian firm with global operations, is an interesting play in this space.

Geothermal

Geothermal energy uses heat from the earth to produce clean energy. Ormat Technologies (ORA) builds, owns and operates geothermal plants, with operations in the U.S., Guatemala, Guadeloupe, Honduras, Indonesia and Kenya.

Top Environmental Policies

For many companies, the urge to go green is a relatively recent phenomenon. As with change everywhere, some firms adapt and some don't. Investment managers in the green space have begun to categorize firms by the place they hold along the green spectrum.

Take oil companies, for example. One would be hard-pressed to think of these firms as green, and for the most part, they aren't. But if you take a closer look at their business models, it is easy to see that some are greener than others. In fact, several large oil companies are among the global leaders in promoting a tax on greenhouse gases and investing in energy sources that will help the world transition away from oil. Choosing the firms with the best environmental records and practices is another way of looking at green investments.

Green Up Your Portfolio

If a green investment catches your eye, there are plenty of ways to find a place for it in your portfolio. You don't have to choose individual companies to get into the area. Mutual funds, exchange-traded funds, stocks, bonds and even money market funds that focus on the environment are all available.