Different Types of Renewable Energy

Different Types of Renewable Energy

Our Atmosphere now contains the highest levels of C02 ever. We know the threat of climate change is very real. Burning fossil fuels contributes around 90% of the CO2 emissions attributed to climate change. As such, the switch to cleaner types of renewable energy is critical to prevent the worst impacts of climate change.

Technology is improving fast. As a result, renewable energy is more reliable and affordable. And it’s getting better all the time. Meanwhile, demand for renewables is growing.

We can now see forward-thinking governments legislating in favor of renewable energy. In turn, the transition to renewable energy is gathering momentum. This progress is positive. And encouraging as shown below:

What is Renewable Energy?

Renewable energy is energy sourced from natural resources that are in abundance, for example, the sun and the wind.

Traditionally we’ve relied on fossil fuels to generate electricity. We’ve drilled and extracted these energy resources from the earth and burnt them to produce our electricity. Unlike renewable energy, fossil fuels are finite. Researchers forecast that we’ll have depleted our fossil fuel energy sources by 2060. Whereas this may seem a long way off, while we continue to burn fossil fuels, we continue to emit vast amounts of CO2, the lead contributor to climate change.

However, renewable energy is on the rise, now accounting for 26% of global electricity generation.

Types of Renewable Energy

1. Hydroelectric Power

Hydroelectric power uses energy from the flow of water stored in dams and rivers. When released, the flow spins turbines. Turbines, in turn, generate electricity.

The history of hydropower dates back to 1771. Historians record the first use as an English mill. The mill used the energy from a nearby flowing river to spin cotton.

Hydroelectric power is the most popular renewable energy source in the world. It accounts for 71% of all renewable energy globally. This popularity is down to the fact that rivers almost always flow. Of course, the weather impacts the availability of the sun or wind. However, Hydropower generates electricity day and night, regardless of the season.

“Pump Storage” aids Hydropower’s generation capacity. Pumps pump water back into storage reservoirs. When there is less natural flow stored water is released back through the turbines. A regular flow, in turn, levels out electricity generation. Pumps mean Hydropower can always generate electricity. Even when there is less water flow through rivers or dams.

HydroPower worldwide

Asia leads the pack in Hydropower generation with over 511GW of installed capacity. As a result, the continent boasts nearly double the amount of Hydropower than in Europe.

The world’s largest Hydropower plant is the Three Gorges Dam, situated on the Yangtze river in China. Three Gorges was fully commissioned in 2010 and can generate 22,500MW of electricity. That’s 20 times more than the world-famous Hoover Dam in the United States.

When the dam was flooded this behemoth displaced 1.3 million people - a staggering number. All lived on or near the flooded land behind the dam.  Worldwide controversy followed. Should it have been built at all given the human cost?

Environmental Impact

Picture: Holyoke Dam on the Connecticut River, Massachusetts U.S. Flowing water spins turbines and generates hydropower. Holyoke famously first used the Hercules water turbine. As a result, the efficiency of its turbines increased by 80%. Photo Credit: American Public Power Association on Unsplash.

Building big Hydro has broader impacts. A 2016 research paper looks at the growth of Hydropower in the developing world6. Their study notes:

“disrupting river ecology, deforestation, losing aquatic and terrestrial biodiversity, releasing substantial greenhouse gases, displacing thousands of people, and altering people’s livelihoods plus affecting the food systems, water quality, and agriculture near them.”

Human invention continues to seek better answers. A great deal of work is ongoing. Much of this looks at how we can reduce the environmental impact of large-scale Hydropower dams.

Improvements available with “small Hydro” are gaining ground. Engineers are working to increase the efficiency of turbine blades and finding ways to generate power with less water flow.

2. Solar Energy

The history of solar energy dates back to several decades. Today, we can benefit from electricity produced by solar panels or photovoltaics PV. Technology is aiding the rapid evolution of solar power, in turn, positioning solar as a lead renewable energy source.

This type of renewable energy relies on the sun's energy. Here, it uses solar cells that then rely on the photovoltaic effect to absorb photons. We can generate electricity by converting photons into electricity.

In its infancy, photovoltaics, or PV systems, existed only on a small scale. Initially, small solar panels powered calculators. Now large-scale solar energy installations generate vast amounts of electricity.

Solar energy also comes in several other forms. Solar thermal collects the heat from the sun in tubes of liquid. We can then use the stored solar energy to heat our homes.

Solar energy worldwide

Noor Solar Complex Morocco
The Noor Solar Complex Morocco. Noor is the largest in the world. In concentrated solar huge mirrors reflect light towards a central point. At this central point, the concentrated heat from the sun creates steam from water. In turn, steam is then used to generate electricity. Photo Credit: International Renewable Energy Agency on Flickr. License CC BY-NC-ND 2.0)

The largest solar plant is the Noor Complex, found in the Sahara Desert in Morocco. This monster plant has a 580MW capacity. Incredibly, that’s enough to generate electricity for a million people. The sun shines 70% of the time in the Sahara, aiding Noor’s colossal capacity.

Toda,y solar energy is one of the most reliable renewable energy sources. Especially in areas where the sun is hot and reliably present.

Solar energy underpins many government climate change policies. The International Energy Agency estimates that solar power will provide 25% of energy to the world by 2050. Meeting this target will play a key role in reducing carbon dioxide emissions globally. And contribute significantly to the increased use of renewable energy.

Many other countries have also installed vast amounts of solar power capacity. China is leading the way. In 2018 China had a total PV capacity of 176,100MW. Japan, Germany, and India are following closely behind. All are looking to take advantage of the clean energy source solar offers.

3. Wind Power

Walney Offshore Windfarm
Walney Offshore Windfarm. Built off the coast of Cumbria, England. Constructed in two phases, together Walney generates 659MW. Walney is the world's largest offshore wind farm. Photo Credit: David Dixon. Wiki Commons. License: CC BY-SA 2.0.

For centuries, we have benefitted from the wind as an energy source, from sailing ships to windmills and more.

However, it wasn’t until the 20th century when the wind became a significant source of renewable energy. Initially, small wind turbines generated power in remote and rural areas.

As demand grew so did the popularity of wind power with a sustained period of research and development, resulting in improved efficiency. More recently, engineers have improved rotor speeds, placements, and electrical output. The result? Wind farms are now a familiar sight on the landscape.

Experts now consider wind one of the cleanest types of renewable energy. Primarily as a result of the wind blowing reliably and steadily. The wind usually is constant throughout the year. As such, it meets the high demands of electricity usage.

However, wind farms can get a bad wrap as unsightly. Partly as a result, a growing trend is to move wind power offshore where the wind is often stronger.  We can produce electricity without blighting our landscapes. As a result, offshore wind energy has a higher capacity.

Becoming more cost-effective

In its infancy, wind energy was one of the more expensive renewable energy sources. Today, technology improvements and increased demand have brought the cost down.

By 2050, as much as 35% of electricity generated in the US could come from wind power3. Worldwide wind power could contribute as much as 25-30% of global electricity by 20507.

Wind energy is now more cost-effective than certain fossil fuels, costing around $30-$60 per megawatt-hour. This is less than natural gas, which can cost between $43-$78 per megawatt-hour.

Growing wind energy capacity will also impact jobs. The growth in this type of renewable energy, therefore, requires large-scale employment with many people employed to build wind farms. As a result, supporting infrastructure requirements will also create jobs to meet renewable energies targets.

4. Biomass

Biomass was once the most popular renewable energy source. We can convert organic materials into energy for Biomass. Of course, it’s not a new concept. We have been burning wood to create energy for centuries.

Biological processes create raw biomass materials. The raw materials are essentially grown. On the other hand, geological processes form the raw materials for fossil fuel energy. This process can take thousands of years. Therefore, unlike fossil fuels, biomass benefits from a quicker cleaner source of raw material.

Biomass  - a fossil fuels replacement?

Crucially, we can use biomass to offset climate-polluting fossil fuels. In the US, it accounted for 5% of primary energy needs in 2017.

Today, biomass fuels not only provide a renewable source to generate electricity. We can also use it to provide energy for our cars and transport.

Biomass provides as much as 38% of renewable energy in the UK and contributes around 11% of overall energy production.

Cleaner, but not perfect

It is, however, not without knock-on environmental problems. Today, large-scale agricultural processes grow the raw organic material used for biofuel. However, producers often clear forest-rich areas for biomass crops5. Thus, drastically reducing the ecological benefits.

Besides, we still burn biomass to produce electricity. The raw materials are certainly cleaner. However, burning biofuel still emits pollutants into the environment. There is some debate. Whereas many consider biomass clean energy, the evidence suggests otherwise. The Partnership for Policy Integrity, an America think tank and lobbyist for clean energy, says:

“Despite the frequent depiction of biomass as “clean” energy, data from air permit applications and real smokestack tests demonstrate quite clearly that biomass is a heavily polluting technology.”

5. Tidal Power

For similar reasons to wind power, tidal power has a lot of future potential. The tides are reliable and predictable.

Tidal energy also has a long history. For example, dams contained water from rising tides as early as 900AD. And the released stored water-powered water wheels. The resulting energy was used to grind flour for bread.

France constructed the world's first tidal power plant in Brittany in 1966, the Rance Tidal Power Station. It was also the world’s largest until 2011. Rance has a capacity of 240MW. It was recently surpassed by Sihwa Lake in South Korea, with a capacity of 254MW.

However, tidal power can come at a high cost. Reliance on high tidal ranges and flow velocities make it challenging. Despite these potential restrictions, improvements in design have helped to increase the availability of tidal power1.

Swansea

The UK is lacking in pushing forward with this type of renewable energy8. We’re fortunate in the UK to have some of the highest tidal ranges in the world. The Bristol Channel is one.

Tidal lagoon plans recently submitted look to take advantage of the tidal ranges in Swansea. The tidal lagoon in Swansea will cost around £1.3bn. A significant amount of money for a single scheme. The UK government recently rejected proposals to subsidize its development, leaving its future uncertain.

6. Geothermal

Geothermal energy comes from the earth. Drawn from the earth's natural energy geothermal heat, used to produce electricity, is both natural and sustainable. Geothermal uses natural energy like hot springs with other sources, including magma and hydrothermal circulation.

While Geothermal energy technology is improving4, geothermal energy itself is diffuse. We can only find it in specific locations. For example, in Iceland, they have been heating water using geothermal energy for centuries. Today, Costa Rica, Kenya, and El Salvador all generate over 15% of their electricity from geothermal energy.

7. Hydrogen

We can find hydrogen in many organic compounds, including water. In fact, it's the most commonly found element on earth. However, it doesn't exist naturally on its own, for example when combined with oxygen it makes water. When we separate hydrogen we can burn it to produce renewable energy. However, whereas clean-burning, hydrogen requires energy to separate it. All the same, improvements in this process point to hydrogen playing a larger role in our renewable energy future.

At home generation and storage

Tesla powerwall. Photo Credit: Tesla

We’re experiencing a growing trend towards home energy generation. Couple at home renewable sources and energy storage and homes can become energy independent. Government subsidies can often help homes to afford to install different types of renewable energy sources such as small-scale solar and wind generation.

In the U.S. subsidies can take many forms. Examples include tax credits and loan guarantees2. Meanwhile, in the UK, the government has stopped accepting “feed-in” tariff applications. Commentators widely regard this controversial move as contradicting the recently announced climate emergency.

Regardless, many homes can generate a renewable energy source of their own. The choice to go “off-grid” is growing in popularity. In 2018 6107MW of feed-in capacity was recorded in the UK9. Renewable energy homes generated most of this via small-scale wind turbine sources of energy supply or rooftop energy-efficient solar panels.

Home energy storage

A related trend, home energy storage helps to ensure effective home energy generation. Home energy storage allows the storage of excess energy from renewable energy sources when the wind is blowing. Or when the sun is shining. What’s more, home energy storage reduced energy costs and can mean no more energy bills entirely.

Improvements in battery technology contribute to its growing popularity. As a result, the efficiency of home storage has risen and costs reduced.

Home use stored energy later when generation is insufficient, replacing the need to draw power from the grid. Recently, Tesla launched its powerwall 2 product to address this need. At TRVST, we’re watching keenly to see how this technology develops.

Summary

We need to do more to reduce our reliance on fossil fuels. The different renewable energies are continually improving, and in line with demand, they become more efficient and cost-effective.

Today, choosing renewable energy sources is now more critical than ever before. It’s also cleaner and often cheaper. As consumers, we must support clean green energy at home. Do your bit by making a simple switch to use renewable energy providers.

1S. E. B. Elghali, M. E. H. Benbouzid and J. F. Charpentier, "Marine Tidal Current Electric Power Generation Technology: State of the Art and Current Status," 2007 IEEE International Electric Machines & Drives Conference, Antalya, 2007, pp. 1407-1412. doi: 10.1109/IEMDC.2007.383635
2Richard G. Newell, William A. Pizer, Daniel Raimi, U.S. federal government subsidies for clean energy: Design choices and implications, Energy Economics, Volume 80, 2019, Pages 831-841, ISSN 0140-9883, https://doi.org/10.1016/j.eneco.2019.02.018.
3Ryan Wiser, Eric Lantz, Trieu Mai, Jose Zayas, Edgar DeMeo, Ed Eugeni, Jessica Lin-Powers, Richard Tusing, Wind Vision: A New Era for Wind Power in the United States, The Electricity Journal, Volume 28, Issue 9, 2015, Pages 120-132, ISSN 1040-6190, https://doi.org/10.1016/j.tej.2015.09.016.
4Enrico Barbier, Geothermal energy technology and current status: an overview, Renewable and Sustainable Energy Reviews, Volume 6, Issues 1–2, 2002, Pages 3-65, ISSN 1364-0321, https://doi.org/10.1016/S1364-0321(02)00002-3.
5Christopher B. Field, J. Elliott Campbell, David B. Lobell, Biomass energy: the scale of the potential resource, Trends in Ecology & Evolution, Volume 23, Issue 2, 2008, Pages 65-72, ISSN 0169-5347, https://doi.org/10.1016/j.tree.2007.12.001.
6Sustainable hydropower in the 21st century. Emilio F. Moran, Maria Claudia Lopez, Nathan Moore, Norbert Müller, David W. Hyndman. Proceedings of the National Academy of Sciences Nov 2018, 115 (47) 11891-11898; DOI: 10.1073/pnas.1809426115
7Sawyer, Steve & Teske, Sven & Fried, Lauha & Shukla, Shruti. (2016). Global Wind Energy Outlook 2016.
8Burrows, Ruain & Yates, Nick & Chen, Daoyi & Hedges, Terry & Holt, J & Walkington, I & Zhou, J & Proctor, Roger & Li, M & Wolf, Judith. (2009). Tidal energy potential in UK waters. Proceedings of The Institution of Civil Engineers-maritime Engineering - PROC INST CIVIL ENG-MARIT ENG. 162. 155-164. 10.1680/maen.2009.162.4.155.
9UK ENERGY IN BRIEF, Department for Business, Energy & Industrial Strategy. July 2018.
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