Nearly 10 million people worldwide were employed in the renewable energy sector last year, according to a recent report from the International Renewable Energy Agency (IRENA).

CNBC breaks down IRENA's research and takes a look at 10 renewable technologies and the amount of people they employ worldwide.

Concentrated solar power, or CSP, employed 23,000 in 2016, according to IRENA.

IRENA's report states that 5,200 people in the U.S. were employed in CSP last year.

Geothermal energy, which makes use of heat from below the surface of the earth, employed more than 180,000 people in 2016.

In its report, IRENA noted that estimating small hydropower employment is "challenging", in part because many of the jobs associated with it are informal. This year's estimate, of 211,000 jobs, was 4 percent higher than in 2015.

Worldwide, biogas employed more than 330,000 people last year.

In Bangladesh, jobs in biogas increased by over 60 percent, according to IRENA.

The National Renewable Energy Laboratory describes biogas as the product of anaerobic digestion, "a biological process in which microorganisms break down biodegradable material in the absence of oxygen." It's mostly made up of methane and carbon dioxide.

As the U.S. Energy Information Administration puts it, biomass is organic material from animals or plants, and is a renewable source of energy.

With just over 720,000 people working in solid biomass, IRENA describes it – along with liquid biofuels and biogas – as being a "major" employer.

According to IRENA, jobs in the solar heating and cooling sector fell by 12 percent in 2016 compared to 2015.

This drop took place "amid an installation slowdown in major markets such as China, Brazil and the European Union."

Almost 1.2 million people worked in the wind industry in 2016, according to IRENA, an increase of 7 percent compared to 2015.

In the U.S. alone, the American Wind Energy Association says that there were more than 100,000 "wind-related" jobs at the end of 2016.

"Large" hydropower was responsible for over 1.5 million jobs last year, according to IRENA.

The operation and maintenance segment of the value chain is responsible for the majority of jobs in large hydropower.

IRENA says that the estimated number of people working in biofuels reached over 1.7 million last year, representing a 2 percent increase.

IRENA also states that, excluding the European Union, "bioethanol output increased among all leading producers." Production of biodiesel also increased in 2016.

According to IRENA, employment in the solar photovoltaic (PV) sector rose by 12 percent to hit 3.1 million jobs last year.

The Chinese market was responsible for over half of solar PV jobs, and was the world's "largest installer and manufacturer of solar PV panels."

Solar photovoltaic, also known as solar PV, refers to a way of directly converting sunlight into electricity.