Awareness around climate change is shaping the future of the global economy in several ways. Governments are planning how to reduce emissions, investors are scrutinizing companies’ environmental performance, and consumers are becoming conscious of their carbon footprints. But no matter the stakeholder, energy generation and consumption from fossil fuels is one of the biggest contributors to emissions. Therefore, renewable energy sources have never been more top-of-mind than they are today.
The Five Types of Renewable Energy
Renewable energy technologies harness the power of the sun, wind, and heat from the Earth’s core, and then transforms it into usable forms of energy like heat, electricity, and fuel. The above infographic uses data from Lazard, Ember, and other sources to outline everything you need to know about the five key types of renewable energy: Editor’s note: We have excluded nuclear from the mix here, because although it is often defined as a sustainable energy source, it is not technically renewable (i.e. there are finite amounts of uranium). Though often out of the limelight, hydro is the largest renewable electricity source, followed by wind and then solar. Together, the five main sources combined for roughly 28% of global electricity generation in 2021, with wind and solar collectively breaking the 10% share barrier for the first time. The levelized cost of energy (LCOE) measures the lifetime costs of a new utility-scale plant divided by total electricity generation. The LCOE of solar and wind is almost one-fifth that of coal ($167/MWh), meaning that new solar and wind plants are now much cheaper to build and operate than new coal plants over a longer time horizon. With this in mind, here’s a closer look at the five types of renewable energy and how they work.
1. Wind
Wind turbines use large rotor blades, mounted at tall heights on both land and sea, to capture the kinetic energy created by wind. When wind flows across the blade, the air pressure on one side of the blade decreases, pulling it down with a force described as the lift. The difference in air pressure across the two sides causes the blades to rotate, spinning the rotor. The rotor is connected to a turbine generator, which spins to convert the wind’s kinetic energy into electricity.
2. Solar (Photovoltaic)
Solar technologies capture light or electromagnetic radiation from the sun and convert it into electricity. Photovoltaic (PV) solar cells contain a semiconductor wafer, positive on one side and negative on the other, forming an electric field. When light hits the cell, the semiconductor absorbs the sunlight and transfers the energy in the form of electrons. These electrons are captured by the electric field in the form of an electric current. A solar system’s ability to generate electricity depends on the semiconductor material, along with environmental conditions like heat, dirt, and shade.
3. Geothermal
Geothermal energy originates straight from the Earth’s core—heat from the core boils underground reservoirs of water, known as geothermal resources. Geothermal plants typically use wells to pump hot water from geothermal resources and convert it into steam for a turbine generator. The extracted water and steam can then be reinjected, making it a renewable energy source.
4. Hydropower
Similar to wind turbines, hydropower plants channel the kinetic energy from flowing water into electricity by using a turbine generator. Hydro plants are typically situated near bodies of water and use diversion structures like dams to change the flow of water. Power generation depends on the volume and change in elevation or head of the flowing water. Greater water volumes and higher heads produce more energy and electricity, and vice versa.
5. Biomass
Humans have likely used energy from biomass or bioenergy for heat ever since our ancestors learned how to build fires. Biomass—organic material like wood, dry leaves, and agricultural waste—is typically burned but considered renewable because it can be regrown or replenished. Burning biomass in a boiler produces high-pressure steam, which rotates a turbine generator to produce electricity. Biomass is also converted into liquid or gaseous fuels for transportation. However, emissions from biomass vary with the material combusted and are often higher than other clean sources.
When Will Renewable Energy Take Over?
Despite the recent growth of renewables, fossil fuels still dominate the global energy mix. Most countries are in the early stages of the energy transition, and only a handful get significant portions of their electricity from clean sources. However, the ongoing decade might see even more growth than recent record-breaking years. The IEA forecasts that, by 2026, global renewable electricity capacity is set to grow by 60% from 2020 levels to over 4,800 gigawatts—equal to the current power output of fossil fuels and nuclear combined. So, regardless of when renewables will take over, it’s clear that the global energy economy will continue changing. on
#1: High Reliability
Nuclear power plants run 24/7 and are the most reliable source of sustainable energy. Nuclear electricity generation remains steady around the clock throughout the day, week, and year. Meanwhile, daily solar generation peaks in the afternoon when electricity demand is usually lower, and wind generation depends on wind speeds.As the use of variable solar and wind power increases globally, nuclear offers a stable and reliable backbone for a clean electricity grid.
#2: Clean Electricity
Nuclear reactors use fission to generate electricity without any greenhouse gas (GHG) emissions.Consequently, nuclear power is the cleanest energy source on a lifecycle basis, measured in CO2-equivalent emissions per gigawatt-hour (GWh) of electricity produced by a power plant over its lifetime. The lifecycle emissions from a typical nuclear power plant are 273 times lower than coal and 163 times lower than natural gas. Furthermore, nuclear is relatively less resource-intensive, allowing for lower supply chain emissions than wind and solar plants.
#3: Stable Affordability
Although nuclear plants can be expensive to build, they are cost-competitive in the long run. Most nuclear plants have an initial lifetime of around 40 years, after which they can continue operating with approved lifetime extensions. Nuclear plants with lifetime extensions are the cheapest sources of electricity in the United States, and 88 of the country’s 92 reactors have received approvals for 20-year extensions. Additionally, according to the World Nuclear Association, nuclear plants are relatively less susceptible to fuel price volatility than natural gas plants, allowing for stable costs of electricity generation.
#4: Energy Efficiency
Nuclear’s high energy return on investment (EROI) exemplifies its exceptional efficiency. EROI measures how many units of energy are returned for every unit invested in building and running a power plant, over its lifetime. According to a 2018 study by Weissbach et al., nuclear’s EROI is 75 units, making it the most efficient energy source by some distance, with hydropower ranking second at 35 units.
#5: Sustainable Innovation
New, advanced reactor designs are bypassing many of the difficulties faced by traditional nuclear plants, making nuclear power more accessible.
Small Modular Reactors (SMRs) are much smaller than conventional reactors and are modular—meaning that their components can be transported and assembled in different locations. Microreactors are smaller than SMRs and are designed to provide electricity in remote and small market areas. They can also serve as backup power sources during emergencies.
These reactor designs offer several advantages, including lower initial capital costs, portability, and increased scalability.
A Nuclear-Powered Future
Nuclear power is making a remarkable comeback as countries work to achieve climate goals and ultimately, a state of energy utopia. Besides the 423 reactors in operation worldwide, another 56 reactors are under construction, and at least 69 more are planned for construction. Some nations, like Japan, have also reversed their attitudes toward nuclear power, embracing it as a clean and reliable energy source for the future. CanAlaska is a leading exploration company in the Athabasca Basin, the Earth’s richest uranium depository. Click here to learn more now. In part 3 of the Road to Energy Utopia series, we explore the unique properties of uranium, the fuel that powers nuclear reactors.
