5 renewable energy resources leading the world to net zero


The landscape of renewable energy resources is constantly evolving as the world moves towa...

NES Fircroft

By NES Fircroft

The landscape of renewable energy resources is constantly evolving as the world moves towards net zero. Renewable energy has a crucial role in the clean energy transition as we move away from using fossil fuels to produce electricity. In recent years, technologies have become more advanced, cheaper, and more reliable in renewable energy. But which renewable energy resources are bringing us ever closer to carbon neutrality? In this article, we will answer this question by exploring the 5 renewable energy resources leading the world to net zero.

​The 5 different types of renewable energy resources

The International Renewable Energy Agency (IRENA) estimates that 90% of the world’s electricity could come from renewable energy resources by 2050. According to the International Energy Association (IEA), global electricity generation from renewables climbed from 27% in 2019 to 29% in 2020. They also added that,

 ‘Renewable capacity additions are set to grow faster than ever in the next five years.’

Additionally, according to the Energy Saving Trust,

 ‘In 2010, just 7% of electricity in the UK came from renewable sources. A decade later, the figure was 42%, as renewable electricity in 2020 overtook electricity generated from gas and coal plants for the first time.’

With all this in mind, let’s delve into the 5 different types of renewable energy resources leading the world to net zero.

1 .Biomass – A versatile source of energy

Biomass is renewable organic matter that comes from plants or animals. Within the energy sector, it refers to any organic matter that is used to generate energy. Traditional biomass was the primary source of energy worldwide until the early 20th century, when coal, and then oil and gas, took over.

However, consumption of traditional biomass energy has remained relatively stable over the past two centuries, and today, of all the sources of renewable energy, bioenergy - energy generated from biomass - is the most used worldwide and accounts for 55% of all renewable energy and around one-tenth of the global energy supply. According to the IEA,

‘The Net Zero Emissions by 2050 Scenario sees a rapid increase in the use of bioenergy to displace fossil fuels by 2030. Use of modern bioenergy has increased on average by about 7% per year between 2010 and 2021, and is on an upward trend.’

Whilst some use the terms biofuel and biomass interchangeably, biomass is generally referred to as the biological material used to produce the fuel, whilst biofuel generally refers to a gaseous or liquid fuel most often used for transportation.

Biomass can encompass matter such as:

  • Wood and wood processing wastes
  • Waste materials and agricultural crops
  • Biogenic materials found in municipal solid waste
  • Animal manure and human sewage

One of the main benefits of biomass is its versatility. In addition, its carbon footprint is far lower than traditional carbon-intensive energy sources. It can be converted into liquid fuels that can replace traditional fossil-based fuels and produce heat, electricity, and bioproducts.

2.  Hydropower – The most reliable renewable energy

Hydropower is one of the oldest sources of energy. Farmers in Ancient Greece were already using the power of flowing water to spin wheels and grind their grain. Fast-forward to today, hydropower has become one of the most reliable, low-cost, and efficient sources of responsible waste management and clean electricity.

IRENA reported in 2022 that hydropower generated 40% of the global energy capacity - 1,230 GW out of 3,064 GW - more than any other renewable resource.

Hydroelectricity also presents the benefit of having the highest electricity yield of all renewable energy sources. Modern hydro-turbines can convert up to 90 per cent of the available energy into electricity. Not only that, but hydropower also provides solutions when it comes to flood control, clean drinking water, and irrigation support.

Hydropower technology generates energy by using the elevation difference, created by a diversion structure or a dam, of water flowing in on one side and out, much lower, on the other.

There are many benefits to hydropower. Firstly, it only relies on the energy of moving water. Furthermore, it has relatively low costs throughout a full project lifetime, with the low operation, maintenance, and fuelling costs. The lifespan of hydropower projects is also longer than most other renewable energy types, meaning upfront project costs are spread out over a longer period.

Hydropower facilities can instantaneously provide electricity to the grid, making it a reliable and flexible backup energy source during disruptions and major electricity outages.

3. Wind – 830GW of capacity bringing the world closer to net-zero

Wind power is produced by converting the wind’s kinetic energy into clean electricity. Wind power, or wind energy, is created using a wind turbine - a machine that channels the wind’s power to produce electricity. In 2021, the global wind capacity reached 830 GW, a 55% increase in the electricity generated in 2020.

A wind turbine works when the wind blows on the turbine’s blades, which are attached to a rotor, which spins to create electricity. Wind turbines can be found onshore and offshore, with 115 countries utilising onshore and 19 countries having offshore wind farms - the latter still in its early stages of development. As the IEA states,

‘Onshore technology continues to dominate wind capacity growth, but offshore is expected to increase its share in the coming years.’

China was responsible for nearly 70% of the total 830 GW generated in 2021, with the US coming in second with 14% and Brazil following them with 7%. 

There are two types of wind turbines:

  • vertical-axis wind turbines (VAWTs)
  • horizontal-axis wind turbines (HAWTs)

HAWTs are the most common and generally have two or three blades positioned to face directly into the wind. VAWTs have shorter, wider curved blades.

Wind turbines can come in a whole range of sizes, from smaller 100 kilowatts turbines that can power a single home to 16 GW turbines that can power thousands of homes that measure hundreds of meters tall.

The electricity generated by the turbines will either be used directly, connected to an electrical grid, or stored for future use.

Currently, there is 743 GW of wind energy capacity worldwide from a combination of offshore and onshore wind farms and turbines.

The largest wind farm in the world is the Gansu Wind Farm in China, with a planned capacity of 20 GW. Once completed, the farm will consist of 7,000 turbines and will generate enough electricity to power a small country.

Ultimately, to meet the net zero targets of around 7,000 GWh by 2030, the expansion of wind energy capacity must increase at an average rate of 18% annually between 2022 and 2030. With investments in wind energy rising to $147 billion, an increase of the $75 billion invested ten years prior, there is hope that wind energy can go a long way to reaching net zero.

4. Solar – An abundant source of renewable energy

Solar Energy refers to the radiation from the sun which produces heat, causes chemical reactions, or generates electricity. The sunlight that reaches us consists of about 50% visible sunlight, and 45% infrared radiation, with the rest amounting to ultraviolet and other forms of electromagnetic radiation.

According to the Encyclopædia Britannica,

‘The potential for solar energy is enormous, since about 200,000 times the world’s total daily electric-generating capacity is received by Earth every day in the form of solar energy.’

And as stated by the US Office of Energy Efficiency and Renewable Energy,

‘The amount of sunlight that strikes the earth's surface in an hour and a half is enough to handle the entire world's energy consumption for a full year.’

Solar energy can turn into electricity when light hits a photovoltaic (PV) panel, which reacts with the silicon crystals in the panel, producing an electric current. This electricity is then fed into a grid or used directly. Electricity can also be produced using mirrors that concentrate solar radiation into a single spot. This is called Concentrated Solar Power (CSP).

Additionally, radiation emitted from the sun can be converted into thermal or electrical energy. Here, the most common thermal energy sources are flat-plate collectors - generally a blackened sheet of metal covered by a sheet of glass heated by the sun - used for solar heating purposes. The heat collected is then transferred to water or air found behind the plate and can be used directly or stored. Most often, this technology will be used for house or water heating.

Solar energy has become much more affordable in recent years and is expected to be 35% cheaper by 2024, with solar panels being 94% cheaper today than in 1989. Due to the fall in prices, global solar installations could hit 350.6 GW in 2023, according to TrendForce:

Below is a list of the top 10 countries that produce the most solar power in MW. (source)

  1. China - 306,973

  2. United States - 95,209

  3. Japan - 74,191

  4. Germany - 58,461

  5. India - 49,684

  6. Italy - 22,698

  7. Australia - 19,076

  8. South Korea - 18,161

  9. Vietnam - 16,660

  10. Spain - 15,952

To support net zero targets, the demand for solar is set to grow between 20-30% in 2023, with Bloomberg Intelligence solar theme basket expected to exceed $220 billion in the same year. BI has also reported that demand for solar increased by 40% in 2022, and industry revenues rose to 50% because of solar. Additionally, IEA expects solar power to surpass coal energy by 2027, and the clean energy transition continues to make significant strides.

5.  Geothermal – Energy coming from deep down under our feet

Geothermal energy was first used in Italy in 1904, and its use has steadily increased. According to IRENA, installed global geothermal energy capacity has grown at an annual rate of 3.5% to reach 15.96 GW in 2021.

Geothermal energy is the eat that comes from the earth's subsurface, most often contained within fluids or rocks beneath the earth’s crust and can go as far down to the earth’s magma (molten or semi-molten natural material from which all igneous rocks are formed).

To produce power from geothermal energy, a well is dug deep down into the ground – about a mile deep – to reach underground reservoirs which contain hot water or steam, which can then be used to drive turbines connected to electricity generators.

There are three types of geothermal energy facilities:

Dry steam

This is the oldest type, which uses steam from underground to directly drive a turbine.

Flash steam

Flash plants pull high-pressure hot water from underground and mix it with cooler low-pressure water. This creates steam that is used to drive a turbine.

Binary cycle

Binary plants use hot water passed through a secondary fluid with a lower boiling point than water. The secondary fluid is turned into vapour which drives a turbine.

Currently, geothermal energy is used in about 26 countries, with the US as its biggest producer. The country also has the largest geothermal field in the world, named “The Geysers” in California, which spans 117 square kilometres and feeds 22 power plants, totalling 1.2 GW in capacity.

As more investment is poured into geothermal energy to support the efforts toward net zero, the global market is forecasted to grow from $59 billion in 2021 to $62 billion in 2022. If projections are correct, the global geothermal market could be valued at $95 billion by 2029 - a CAGR of 6.3%.

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