Which Renewable Energy Are The Most Promising?

ByAria Parker

Which renewable energy are the most promising?

Renewable energy comes from natural sources that are constantly replenished, such as sunlight, wind, rain, tides, and geothermal heat. The development and use of renewable energy is critical for replacing fossil fuels, which are non-renewable and release greenhouse gases responsible for climate change. Renewable energy sources currently provide about 27% of the world’s electricity. The most promising renewable energy sources for the future are solar, wind, hydropower, geothermal, and bioenergy.

This article will provide an overview of the top five most promising renewable energy sources. For each one, we will explore how the technology works, its current use and capacity, advantages and disadvantages, and future potential. Understanding the benefits and challenges of each renewable can help inform energy strategies and investments for a more sustainable future.

Solar

Solar energy comes in two main forms – solar photovoltaics (PV) which converts sunlight directly into electricity via solar panels, and solar thermal which uses the sun’s heat for heating water or spaces. Solar PV has seen massive growth and cost declines in recent years due to improvements in panel efficiency and manufacturing scale (DOE, 2016). The average cost of solar PV electricity has dropped over 90% in the last decade to around 3-4 cents/kWh today for utility-scale systems (CNET, 2023). Further cost reductions of up to 24% are projected by 2024 as manufacturing scales up further (IEA, 2023).

Global solar PV capacity is projected to grow from over 600 GW in 2020 to over 8,500 GW by 2050 under net zero scenarios, a 14-fold increase (IRENA, 2021). Utilizing existing rooftops alone could provide around 25% of total electricity generation from solar PV in major markets like the U.S., EU, China and India (NREL, 2021). With continuing innovation and scale driving down costs, solar PV is poised to become the number one source of electricity globally in coming decades.

Wind

Wind energy has emerged as one of the most promising renewable energy sources worldwide. Both onshore and offshore wind capacity has expanded rapidly in recent years. According to the U.S. Department of Energy’s Wind Vision report, wind power could supply 20% of U.S. electricity by 2030 and 35% by 2050.

Onshore wind is the most established form of wind energy, while offshore wind is a newer but fast-growing segment. Offshore wind turbines are installed in bodies of water, which means they can access stronger and more consistent winds. However, offshore wind projects are more expensive to construct. The average turbine installed today is around 2-3 megawatts (MW), but new offshore turbines can reach 12 MW or more.

The cost of wind power has declined dramatically in recent years to become cost competitive with conventional sources. The levelized cost of energy for new U.S. onshore wind projects is estimated at $28-$54 per megawatt hour (MWh) and offshore wind at $65-$117/MWh.[1] At the end of 2020, global wind power capacity stood at around 743 gigawatts (GW), with offshore wind accounting for 35 GW of that total.[1]

Hydropower

Hydropower is one of the most established and widely used renewable energy sources globally. It utilizes the energy from flowing water to generate electricity. There are several types of hydropower systems:

Conventional Hydro: Uses dams on rivers to store water in reservoirs. The water is released through turbines to generate electricity. These large-scale hydro plants can generate hundreds of megawatts of power.

Pumped Storage: Stores energy by pumping water uphill into reservoirs when electricity demand is low. The water is released to generate power during peak demand. This allows grid operators to balance electricity supply and demand.

Small Scale Hydro: Generates up to 10 megawatts using small rivers or existing dams and reservoirs. These systems provide localized renewable energy solutions.

Micro Hydro: Produces up to 100 kilowatts of power using small water channels, streams or pressure pipelines. Ideal for remote areas that lack access to the main electric grid.

With flexible deployment options, hydropower provides reliable and cost-effective renewable energy across the world. It also offers grid stability services and helps integrate variable renewables like solar and wind.

Geothermal

Geothermal energy comes from the natural heat within the earth. Traditional geothermal power plants utilize hydrothermal resources where there are underground reservoirs of steam or hot water. Wells are drilled into these reservoirs to bring the steam or hot water to the surface to power turbines that generate electricity. Geothermal energy can also be used directly for heating homes, buildings, hot springs, and agriculture through a process called direct-use heating. Enhanced geothermal systems (EGS), also known as engineered or engineered geothermal systems, are a new technology that holds promise for geothermal development. EGS involves injecting fluid into hot dry rock reservoirs deep underground at high pressures. The fluid flows through the cracks and fractures in the rock, capturing the heat of the rock until it is recovered as very hot water and steam at production wells. The recovered fluid is used to produce electricity in a power plant on the surface. EGS has the potential to greatly expand the use of geothermal energy by accessing geothermal resources that lack natural fluids but have appropriate temperatures and rock properties. However, EGS technology is still in the demonstration and research phase as engineering challenges need to be overcome to make it commercially viable.

Bioenergy

Bioenergy refers to energy derived from biomass, which includes crop-based biofuels like ethanol and biodiesel as well as biomass power from sources like wood pellets and agricultural residues. Biofuels accounted for around 5% of global road transport fuel in 2021, while biomass power provided about 2% of global electricity generation (IEA, 2022).

First generation biofuels like corn ethanol and soy biodiesel have raised concerns about sustainability, as they may compete with food crops for land use. Advanced biofuels from non-food crops like switchgrass or agricultural wastes can help address these concerns. According to the IEA, advanced biofuels could meet around 15% of global transport energy demand in 2030 in a sustainable low emissions scenario (IEA, 2022).

Sustainable certification programs like the Roundtable on Sustainable Biomaterials (RSB) aim to ensure bioenergy feedstocks are produced in ways that protect land, water, and labor rights. RSB certified biomass made up over 25% of global biofuel production in 2020 (RSB, 2021).

Overall, bioenergy from sustainable sources can provide low carbon renewable power and fuels while supporting rural economies. However, appropriate policies and safeguards are needed to maximize these benefits and minimize risks (OECD/FAO, 2021).

OECD/FAO. (2021). Biofuels. OECD-FAO Agricultural Outlook 2021-2030, OECD Publishing, Paris.

IEA. (2022). Biofuels. IEA, Paris.

RSB. (2021). Impacts and Benefits. RSB, Geneva.

Wave & Tidal

Wave and tidal energy represents a significant source of renewable power from the ocean. Tidal power can be harnessed in two main ways: tidal barrage and tidal stream. Tidal barrage involves building a dam-like structure to trap water at high tide which is then released to drive turbines as the tide goes out. Major tidal barrage plants exist in France and South Korea, producing over 90% of current tidal power capacity globally (Stanford).

Tidal stream systems use underwater turbines to capture the kinetic energy of tidal currents. While still a nascent industry, companies are working to deploy and scale up tidal stream farms in areas with consistently strong tidal currents like the UK and Canada. Projections indicate major growth in tidal stream capacity by 2025 as larger multi-megawatt tidal arrays come online (Ocean Energy Europe).

Ocean waves also carry tremendous renewable energy potential. Wave energy converters capture this motion for electricity generation or other applications like desalination. However, Wave power technology has lagged behind tidal, with only a few pilot projects producing single-digit megawatts globally (Statista). Significant challenges around device durability and grid integration must still be overcome.

In total, experts estimate marine energy could provide over 1,000 GW of electricity capacity globally. But costs remain relatively high compared to other renewables. Continued technological innovation and economies of scale can help improve competitiveness as the industry matures.

Hydrogen

Green hydrogen, produced from renewable energy sources like solar and wind, is emerging as a promising clean energy carrier for the future. According to the International Renewable Energy Agency, green hydrogen production costs have fallen quickly and could become cost-competitive with less sustainable forms of hydrogen by 2030. With continued cost reductions, green hydrogen could reach $2/kg or lower within the next decade (International Renewable Energy Agency, 2020).

A key advantage of green hydrogen is its versatility. It can be used as a zero-emission transportation fuel for vehicles like fuel cell electric cars and trucks. When combined with oxygen in a fuel cell, hydrogen releases only water vapor as exhaust. Green hydrogen can also enable long-term energy storage for excess renewable electricity production. This storage capacity will help address intermittency issues with renewables and support grid stability.

Overall, green hydrogen’s falling costs and wide-ranging applications make it one of the most promising renewable energy technologies today. With further development, green hydrogen could play a major role in decarbonizing multiple sectors of the global economy.

Conclusion

Based on the analysis in this article, wind, solar, and hydropower are among the most promising renewable energy technologies. Wind and solar power have seen rapid growth and cost declines in recent years, making them competitive with fossil fuels in many markets. They offer unlimited renewable potential and can be deployed at large scale. Hydropower provides reliable low-cost renewable energy, though suitable sites are limited. Further research is needed to expand energy storage capabilities to accommodate intermittent renewables like wind and solar. Emerging technologies like wave power, enhanced geothermal, and advanced biofuels warrant further study to evaluate their large-scale viability.

In summary, renewables like wind, solar, and hydro are critical technologies to facilitate the global transition to a low-carbon energy system. Continued technological improvements and cost declines will enhance their competitiveness and adoption worldwide. However, increased R&D and investment is required to fully realize their potential and develop the next generation of renewable energy solutions.

References

Several key sources were used in researching the content in this article. Highlights include:

The sources linked above provide statistics, analysis, and projections to showcase the latest landscape for renewable energy. Of course, many other quality publications exist for those interested in diving deeper into any particular renewable energy type.

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