How Does Renewable Energy Work, & What Is It Used For? (Solar, Wind, Hydro, Geothermal & More)

How Does Renewable Energy Work, & What Is It Used For? (Solar, Wind, Hydro, Geothermal & More)

Renewable energy is used for a number of things in society.

Different types of renewable energy also work in different ways.

In the guide below, we outline each renewable energy source, what renewable energy is used for, and how each renewable energy source works.


Firstly, What Is Renewable Energy, & What Are The Different Types Of Renewable Energy?

Although bioenergy is classified as a renewable energy by some, other argue how sustainable and renewable some forms of bioenergy are compared to other forms of renewable energy like solar and wind energy for various reasons.


What Is Renewable Energy Used For?

Renewable energy is mainly used for electrical energy (hydro power is currently the leading renewable energy source for electricity generation, but solar and wind are expanding).

But, some renewable energy sources like solar thermal can also use renewable energy sources for thermal energy (to heat water for example). 


How Does Solar Renewable Energy Work?

You can read about how both Solar PV (Photovoltaic), and Solar Thermal work in this guide:


How Does Wind Renewable Energy Work?

You can read about how both Onshore Wind and Offshore Wind work in this guide:


How Does Hydro Renewable Energy Work?

You can read about how Hydro Dams, Run Of River, & Pumped Storage Hydro Energy work in this guide:


How Does Geothermal Renewable Energy Work?

You can read about how geothermal renewable energy works in this guide.


How Does Bioenergy & Biomass Renewable Energy Work?

Bio energy is energy made from organic matter (it can be solid, and even sewage biomass).

The energy in solid organic matter is ‘stored sunlight in the form of chemical energy’ ( This chemical energy usually comes from photosynthesis.

Traditional biomass has been used since the beginning of human time – using organic matter like wood to provide heat energy.

But, there are many forms of bioenergy and biomass in modern times that are used and converted for electrical energy, heat energy, and as biofuels for vehicles.

There are many ways to create bioenergy from biomass:

  • Electrical and Heat Energy – [some of the methods used to create heat and electrical energy from biomass are conventional combustion, gasification, pyrolysis, and anaerobic digestion] (
  • Biofuels – First generation biofuels are produced from sugar and vegetable oil. Algae biofuels are most advanced form of biofuels that produced from algae as its source of energy-rich oils ( Algae production for transport fuels, requires a controlled growing environment using specific microalgae species. The algae are then processed to separate the oils which are refined into biofuels (


How Does Wave Renewable Energy Work?

You can read about how wave renewable energy works in this guide.


How Does Tidal Renewable Energy Work?

You can read about how tidal renewable energy works in this guide.












‘Which Renewable Energy Source …’ (FAQ Guide)

'Which Renewable Energy Source ...' (FAQ Guide)

This is an FAQ guide answering some of the most common questions that start with ‘Which Renewable Energy Source’.

*Note – this guide mostly refers to modern renewables solar, wind, hydropower, geothermal, and tidal/wave energy. Bioenergy may have been omitted in some of the stats and figures below.


Which Renewable Energy Source Produces The Most Energy, & Electricity?

There are global, but also country or city specific renewable energy stats for energy and electricity production, and these stats can differ.

It should also be noted that total energy production is different to electricity production (as energy involves other sectors like transport, heating etc., whilst electricity is just the power sector). But, hydropower tends to be the prominent renewable energy source in terms of production and consumption

  • Globally, hydropower was responsible for 7% of total primary energy consumption in 2015 (
  • Globally, hydropower was responsible for 15.8% of total electricity produced in 2018 (

You can read about the energy mixes of some of the major countries in the world in this guide.


Which Renewable Energy Source Is The Most Used Worldwide?

As mentioned above, hydropower has the highest installed capacity, production and consumption totals and shares worldwide. But, the most used renewable energy source can vary country to country, and city to city.


Which Renewable Energy Source Is The Most Efficient?

According to some sources, wind, geothermal and hydropower are the most efficient renewable energy sources.

But, efficiency can sometimes be dependent on the technology available, and also the specific type of renewable energy source e.g. offshore vs onshore wind, large hydro dams vs run of river vs pumped storage hydro, and so on.


Which Renewable Energy Source Is The Cheapest?

‘Cheapest’ can refer to a few different things:

Overall though …

  • Historically, hydropower has been the cheapest way to source renewable electricity. But that’s changing. Wind and solar (also called photovoltaic solar, or PV) have become the most economic forms of electricity. They are the renewables of tomorrow. (


Which Renewable Energy Source Has The Greatest Environmental Footprint?

Solar and wind can have a large land footprint for the utility sized wind and solar farms.

But, large hydroelectric dams, geothermal energy, and tidal/wave energy might have some of the most negative environmental side effects. Bioenergy with the use of resource intensive bio crops can also be environmentally damaging. 

Despite the environmental side effects of renewable energy, it’s often mentioned that these environmental side effects are nowhere near as bad as fossil fuels like coal, oil, and natural gas.


Which Renewable Energy Source Is The Worst?

There are a number of ways you can measure the worst renewable energy source:

  • Which source is the most expensive
  • Which source is the most unreliable
  • Which source provides the least energy and electricity
  • Which source has the least long term potential
  • Which source is the most environmentally damaging
  • Which source is the most socially damaging
  • Or, you could combine all factors

Out of wind, solar, hydropower, geothermal, and tidal/wave energy … tidal and wave energy are probably the ‘worst’ at this point in time because they are costly, speculative and produce almost no electricity as a share of total renewable electricity (but, both might have much better long term potential than what they produce right now).

Bioenergy can be good in some applications and not so much in others. Bioenergy that requires the growth of biocrops can be resource intensive and environmentally damaging/unsustainable in some aspects.


Which Renewable Energy Source Is The Most Plentiful?

This can be country or city specific. 

Based on global stats, you might say that hydropower in most plentiful because it has the highest installed capacity and generation.

But, in reality, each country or location with populations of people has different natural resources available.

Just as one example, Iceland gets most of it’s electricity from hydropower (about 87%), with a smaller amount from geothermal (about 13%) (

On the other hand, different States in Australia have different renewable energy mixes, and Australia overall, because of it’s masses of available land, is seen as having tremendous potential for solar and wind energy (because solar and wind farms use up a lot of land).


Which Renewable Energy Source Is The Most Reliable?

In this instance, we define reliable as the consistency of the power supply.

Solar and wind can be reliable when part of a flexible and diverse energy system. But, right now, on their own or when used solely/primarily together, they are seen as variable and intermittent sources of energy. They usually need other complementary sources of energy to help meet energy demand at certain points (when sun and wind conditions are poor or when energy demand is high), or they need expensive battery energy storage, or both. This of course could change in the future with technological breakthroughs.

Hydropower is probably the most reliable renewable energy source right now along with geothermal (neither are seen as intermittent sources).


Which Renewable Energy Source Is The Best?

There is no clear objective way to classify the ‘best’.

But, if we had to pick, we would say that solar, wind and hydropower are the best renewable energy sources because:

  • Hydropower already has proven energy and electricity generation capability in the present day, and pumped storage hydro has the capability to store energy
  • Solar and wind have been expanding rapidly the last decade or two, receive most of the investment money, are getting cheaper, are performing better, and are overall seeing the most development and real life results of the modern renewable energy sources. Specifically, solar PV and onshore wind.
  • Most of the studies and reports about a 100% renewable energy future specify solar, wind and hydro as key parts of that future

If you are interested in reading about other considerations such as cost, efficiency, power density etc., we have put together a guide discussing some of these things, and comparing renewable energy to fossil fuels and nuclear energy in some of the same areas.











Non Renewable Energy Definition (With Examples)

Non Renewable Energy Definition (With Examples)

This is a very short guide that outlines the definition of non renewable energy, along with some clarifications of what it is in comparison to other types of energy, and also includes some examples of different types of non renewable energy.


Definition Of Non Renewable Energy

There’s many slightly different definitions of non renewable energy. 

Most definitions include the following components … non-renewable energy:

  • Comes from non natural sources, or non natural processes (for example, oil has to be refined by man made processes)
  • Comes from a source, that when used, will deplete, or takes a long time to regenerate (more than the length of a human lifetime – usually hundreds, thousands or millions of years)

It’s called non renewable, because if you compare it to energy sources like wind and solar, these energy sources are natural and are available almost immediately for an infinite amount of time (as long as the wind is blowing and the sun is shining). Non renewable energy sources in comparison may face scarcity and depletion issues over time.

Fossil fuels for examples take hundreds of thousands or million of years to form from the heat and pressure under the Earth’s surface, whilst uranium ‘has been thought to be produced in one or more supernovae over 6 billion years ago. More recent research suggests some uranium is formed in the merger of neutron stars. Uranium later became enriched in the continental crust’ (


Types & Examples Of Non Renewable Energy

They mainly consist of fossil fuels (coal, oil, gas), and nuclear energy (from uranium):



  • Crude oil and other liquids produced from fossil fuels are refined into petroleum products [via human processes] that people use for many different purposes. We use petroleum products to propel vehicles (such as gasoline and diesel), to heat buildings, and to produce electricity (

Natural Gas

  • Natural gas is a hydrocarbon fossil energy source that formed deep beneath the earth’s surface. Once raw natural gas is processed, and the natural gas liquids are separated, various natural gas products can be created and used for many energy applications, such as heating and cooking, transport, and electricity generation.
  • If we take gas powered cars for example – A natural gas vehicle (NGV) is an alternative fuel vehicle that uses compressed natural gas (CNG) or liquefied natural gas (LNG). Natural gas vehicles should not be confused with vehicles powered by LPG (mainly propane), which is a fuel with a fundamentally different composition (


  • Uranium ore is mined from the ground, which is then processed and refined, before we can use it as a nuclear reactor fuel. We use nuclear reactors for electricity generation (when uranium atoms are split).


An Asterisk With Nuclear & Uranium

Although uranium and nuclear are looked at as non renewable, there are potential technological breakthroughs that could significantly extend the supplies of uranium we have left. 

These breakthroughs might include new types of reactors, and extracting uranium from seawater


Other Resources On Non Renewable Energy Sources










Renewable Energy Definition (With Examples)

Renewable Energy Definition (With Examples)

This is a very short guide that outlines the definition of renewable energy, along with some clarifications of what it is in comparison to other types of energy, and also includes some examples of different types of renewable energy.


Definition Of Renewable Energy

There’s many slightly different definitions of renewable energy.

Most definitions include the following components … renewable energy:

  • Comes from a natural source or natural processes
  • Comes from a source, that when used, doesn’t deplete, or can regenerate very quickly (either immediately, or within the course of a human life time)

It is called renewable because, if you compare it to an energy source like fossil fuels, fossil fuels take hundreds or even millions of years to form from the buried remains of decayed plants and animals, that are exposed to heat and pressure over that time. Once mined and used, these sources aren’t renewed quickly. They can eventually present scarcity issues, and issues with depletion of resources.


Modern vs Traditional Renewable Energy

Traditional biomass, such as the burning of wood for heat and energy, is considered a traditional form of renewable energy.

Modern renewable energy is generally all other forms of renewable energy (including modern bio fuel and modern forms of waste-to-biomass conversion).


Different Types Of Renewable Energy (With Examples)

The different types of renewable energy are:

Read more about the different types of renewable energy in this guide.


Renewable vs Clean/Green vs Alternative Energy

There is a difference between renewable, and green or alternative forms of energy. 

Nuclear is an example of an energy source that isn’t renewable (yet), because uranium has be mined to use it. But, nuclear is far cleaner in it’s operation stage (in terms of emissions and pollution) than energy sources like coal and natural gas.

Bioenergy is another example of an energy source that may be renewable in some ways, but, where crops, trees, and other organic matter has to be planted and grown, there are questions over the use of other resources (land, water, fertilizer, pesticide etc.), pollution/emissions, waste produced, and overall how sustainable some methods of bioenergy prodution are.

Read more in this guide about what green energy is.

Alternative energy is usually just an energy form that is different from the conventional energy that is used in a particular sector. For example, an alternative energy car might use renewable energy to power a hydrogen fuel cell car (as compared to a combustion engine car using petroleum or diesel).








The Importance Of Renewable Energy, & The Benefits & Advantages (Economic, Environmental, Social & Health)

The Importance Of Renewable Energy, & The Benefits & Advantages (Economic, Environmental, Social & Health)

This guide outlines why renewable energy is important to our future.

It also outlines the benefits and advantages of renewable energy economically, environmentally, and socially (including health benefits).


Summary – Importance Of, & Benefits & Advantages Of Renewable Energy

  • The importance of renewable energy for the future is significant. One of the main reasons is the fact that these energy sources won’t face the same depletion and scarcity issues that non renewable energy sources might
  • But, this is only one of many reasons. Renewable energy has different economic, social (and health), and environmental benefits and advantages, as well as other types of benefits and advantages
  • Perhaps two of the biggest issues (apart from depletion of resources) that renewable energy has the potential to help us address are climate change via reduced greenhouse gas emissions, and air pollution/air quality via reduced air contaminant pollution
  • Something that should be noted is that individual types of renewable energy all provide their own set of benefits, and pros and cons. For example, wind and solar may provide different benefits to hydropower and geothermal. Furthermore, there can be different types of bioenergy (which is considered a renewable source of energy), and the different types of bioenergy may provide different pros and cons to each other. So, the different types or energy production methods of an individual renewable energy source need to be considered too. This guide looks at renewable energy as a whole.
  • For the purposes of this guide, renewable energy sources are solar, wind, hydropower, geothermal, and wave and tidal energy. Bioenergy can also be classified as a renewable energy, but not all bioenergy processes can be classified as sustainable. Nuclear isn’t a renewable energy source, but it does have a relatively clean operational stage with little or zero emissions and air pollution.
  • Non renewable energy sources generally include fossil fuels like coal, natural gas, and oil. 


Why Is Renewable Energy Important?

Renewable energy is important for a number of key reasons. 

What makes renewable energy different from non renewable energy is that it generally comes from natural sources and processes, and it won’t deplete after use.

Compare this to non renewable energy like fossil fuels which often need refining processes, and take hundreds of thousands, and even millions of years to regenerate after being mined.

Immediately, we can see that renewable energy sources don’t face the same depletion or scarcity issues that fossil fuels might. So, they have the ability to provide us with sustainable energy sources going into the future.

But, there’s additional factors that make renewable energy important – the potential economic, environmental, and social benefits they provide.


Economic Benefits & Advantages Of Renewable Energy

Some of the economic benefits of renewable energy are:

  • Job creation (increase the total number of jobs)
  • Higher quality and safer jobs
  • A good ROI on investment in renewables
  • A trickle effect on other areas of the economy
  • Economic stimulus
  • Can reverse the poverty cycle in poorer regions
  • Trade, import and export benefits
  • More independence and control over energy, which leads to more independence and control over the economy for individual countries
  • More competition creating lower electricity prices
  • Creates additional and different sources of income for individuals
  • Increase locally sourced services
  • Saves costs having to address other issues caused by fossil fuel energy (environmental, health, etc)
  • Save on costs with increased energy efficiency and reduced consumption
  • Other indirect economic benefits


We’ve already written several guides on the economic impact of renewable energy:


Environmental Benefits & Advantages Of Renewable Energy

How environmentally friendly an energy source can be looked at:

  • Across the entire lifecycle of the energy source (from extraction, all the way through to use and any waste products)
  • Or, at a particular stage of the energy process e.g. during operation/during energy production.


Renewable energy in general tends to be more environmentally friendly than non renewable energy, especially fossil fuels, because:

  • The energy source doesn’t need to be mined (like coal, oil, and natural gas do for example … compare that to sunshine which we get directly from the sun for solar energy)
  • The energy source doesn’t need to undergo processing or human refinement (like for example refinement of crude oil into gasoline or diesel products)
  • Greenhouse gas emissions during operation are generally far lower, or zero
  • Air pollution and air contaminant emissions are generally far lower, or zero
  • There’s reduced, or zero waste products from energy generation (compare that to coal for example which produces coal ash, which contains heavy metals, just as one example)


Some of the main environmental benefits of renewable energy are:

  • Addressing Climate Change – fossil fuels tend to emit carbon dioxide and greenhouse gases during energy generation, and GHGs are thought to be the main cause of climate change and global warming. Renewable energy sources are clean in their operation with little to no greenhouse gases emitted.
  • Addressing Air Pollution – fossil fuels emit an array of air contaminants, which degrade air quality (the air that humans breathe in – especially around cities and heavily populated areas). Renewable energy does not pollute the air during operation.

Other environmental benefits of renewable energy can include:

  • Addressing Water Pollution – both mining of fossil fuels, and the discharge from power plants (including heavy metals and other toxic chemicals) can pollute the water. Renewable energy can severely reduce water pollution in these regards.
  • Addressing Land Degradation – mining of fossil fuels can cause land degradation, and other land issues.
  • Address Waste Pollution – wastes from fossil fuels like coal ash can compose a large and toxic % of a country’s waste stream. Renewables have little to no waste
  • Provide Better Ecosystems For Our Wildlife – water and air pollution, as well as the clearing of land for mining, are not good for the ecosystems that wildlife live in. 
  • Address Ocean Acidification and Warming – side effects of carbon emissions.
  • Reduce Acid Rain – a side effect of air pollution.
  • Other Environmental Benefits – there are sure to be other indirect environmental benefits of using renewable energy not mentioned above.


The above is not to say renewable energy has no environmental issues at all – every energy source has at least some environmental considerations. In addition to these environmental issues, the mining of precious metals (and their scarcity/depletion), and recycling energy storage batteries (from electric cars and for electricity energy storage) in the future may become bigger environmental issues.


Social (& Health) Benefits & Advantages Of Renewable Energy

Renewable energy sources:

  • Are some of the least dangerous and most safe forms of energy generation for humans. Outdoor air pollution is one of the biggest causes of health problems and increased mortality rates in some cities and countries. Using renewable energy sources can not only improve our health, but also decrease the number of energy workplace accidents
  • Can put less strain on our health systems
  • Can provide better and higher quality jobs compared to fossil fuels
  • Can reduce the political and power based wars that are fought over oil and fossil fuels
  • Can give energy sovereignty to less powerful States and countries
  • Can reach remote and rural areas, and help lift the quality of life in societies and countries worldwide


Other (Miscellaneous) Benefits & Advantages Of Renewable Energy

  • Save water (which is a precious resource) in energy generation – fossil fuel plants like coal plants use a lot of water in cooling towers and for other applications. Renewables tend to be far more water efficient.
  • Renewable energy seems to have a lot more potential left to increase performance and energy capabilities (to provide more benefits to society) with further technological breakthroughs compared to fossil fuels 
  • Renewable energy can be portable
  • Renewable energy can be used on an individual, domestic and large scale commercial/utility level – can be used as part of, or away from the grid. Lots of flexibility


Further Resources On Renewable Energy










Transitioning Towards Renewable Energy – Solutions, Strategies & Considerations

Transitioning Towards Renewable Energy - Solutions, Strategies & Considerations

Renewable energy is becoming more prominent in the electricity (and eventually overall energy) supply of more cities and countries worldwide.

There are challenges and problems with transitioning to renewable energy.

But, there are also solutions and strategies involved in that transition, and that is what we have outlined in this guide.


Summary – Solutions & Strategies For Transitioning Towards Renewable Energy

  • Ultimately, every city, State and country’s energy mix and energy system is different. So each will have it’s own individual solutions and strategies (short and long term) when trying to integrate and transition to a higher share of renewables. These solutions and strategies should be based around the factors and variables that make up that place’s energy situation/scenario 
  • Some cities and countries already have a majority renewable energy mix for their electricity supply – so, these cities and countries show what is possible
  • Ultimately, a transition towards an increased use of renewable energy worldwide will require a balancing of various social, economic, environmental, and other types of priorities and factors. It will involve possible breakthroughs in aspects like energy storage and back up dispatchable energy sources. And, while it’s clear there are problems like variability/intermittency of renewable energy, and inadequacies of existing grids and infrastructure, it’s also clear that it’s likely solutions to the current problems of renewable energy can be developed in the future. In any transition, a hybrid flexible energy system that composes of different types of energy (fossil fuels, nuclear, conventional renewables, and modern renewables) might be required as a bridging system. It’s possible short terms costs and drawbacks might need to be tolerated, in order to receive the big picture, and mid to long term benefits that cleaner energy forms will deliver


Have Diversified, Flexible Energy Systems 

One of the big criticisms of renewable energy sources like wind and solar is that they can be variable and intermittent (creating numerous problems for power grids and meeting demand consistently). 

In cities, States or countries where the variability of renewable energy has lead to problems, sometimes the fact that the energy system isn’t diversified or flexible enough is one of the major causes.

A diversified and flexible energy system might have:

  • A range of renewable energy sources in the mix (wind, solar, hydro, geothermal etc.)
  • Dispatchable energy sources (that can ramp up and down quickly)
  • Energy storage (in the form of batteries, or pump storage hydro)

Although not ideal, a diversified and flexible energy system may also have coal, natural gas, nuclear, and conventional (as opposed to modern) renewables like bioenergy providing energy in small amounts, to provide complimentary power where required in the short term.

Less desirable energy sources can be phased out as required over the mid to long term as renewables and clean energy become cheaper, more competitive and more reliable to run by themselves.

If we use South Australia as one example, when they had their power black out, the State was using primarily wind, solar and combined cycle gas energy sources. They did not have large scale energy storage in place (to store energy from solar and wind sources), but have recently had a large scale battery built to store energy. Latest reports indicate it has prevented further blackouts. optimistically reports that energy storage installations will increase exponentially up to 2040 for stationary storage and electric vehicles – and, this will come mainly as a result of sharp declines in the cost of lithium-ion batteries.


Upgrade Existing Power Grids & Infrastructure, & Build New Support Infrastructure

Existing power grids and energy infrastructure are generally designed and built for fossil fuels and existing energy sources. 

Power grids can be upgraded to handle fluctuating and increased loads, along with the ability to handle different types of energy requirements.

Existing infrastructure can be upgraded, as well as new infrastructure built, to cater to renewable energy.

Transmission lines, interconnectors, convertors, and other infrastructure can be built new for renewables.

For example, transmission lines are needed to get power from solar and wind farms to where it is required – these farms can be far from where the energy is required.

Interconnectors (used as a transmission link) can be used between States and countries if a particular place is exporting excess/surplus power to another. Germany has done this with Poland and the Czech Republic, and Australia does it between some of it’s States, just as two examples.


Consumer/Customer Demand 

Government support for renewables helps, but ultimately, renewable energy needs to be something that is in demand by the market, and supported by customers.

Demand drives investment and development, economies of scale, and long term cheaper prices and better products and services.

If the public wants more renewable energy in their energy mix, they should be willing to purchase electricity from renewable energy suppliers (over fossil fuels and other energy sources).


Government Action & Support

Over the long run, renewable energy is expected to continue to become cheaper, and competitive enough to be equal with, and even out compete fossil fuels from a price perspective (renewably sourced electricity is already contributing to lower electricity prices in some places).

Because renewable energy is still establishing itself in many markets, it needs short to mid term support from governments.

There’s a few ways this can happen:


  • Like Portfolios that specify the minimum amount of each renewable energy source that must be used for a State’s electricity
  • Like licenses for power plants that stipulate emission and pollution standards


  • Subsidies, tax breaks, concessions, credits, and other incentives for the development or use of renewables


  • Carbon taxes, polluters taxes, and other penalties that discourage dirty forms of energy production (coal and gas plants have traditionally never paid a price for their negative environmental and social impact – but, this is slowly changing with how expensive new coal and gas plant technology is becoming which minimises pollution and emissions)

Something that has to be noted is that government action and support has the potential to destroy a competitive market and specific parts of the energy sector if not used properly. There needs be be a balance between supporting new clean energy technology, whilst still supporting competitive, reliable energy sources that meet a natural need and demand.


Provide More Certainty For Lenders & Investors

Risk of technology or projects, uncertainty in the future, and questionable profits and returns can all lead to less lending and investing in renewables.

Government support in the form of direct investment for research and development, loan assistance, and Portfolio Standards (guaranteeing a minimum amount of supply from renewables) can be a start.

But, there can be more done to provide certainty and favorable conditions for investors and lenders.


Consider The Makeup Of Existing Energy Markets, & Market Entry For New Clean Energy Competitors

In some countries and States, the energy market has been established for a long time now to cater to fossil fuel energy.

There can be many powerful fossil fuel related companies and organisations (mining companies, utilities and power plants, etc.) that can have an immense amount of control and success in the energy sector.

These things can make it hard for renewables in general, and new clean energy competitors to gain market entry and compete, without the necessary support. 

Greater understanding of how the market functions, and changing it to allow better communication between energy providers, and between suppliers and the end user (as well as the power grid and transmission operators), can help. 

Additionally, support for those trying to enter and compete in the market with certain types of clean technology, in the form of subsidies, grants and concessions, may help. 

What most people don’t realise is that fossil fuels have historically been subsidised, and continue to be subsidised heavily to this day (so, it’s not like fossil fuels are always cost competitive) in many countries.

Consider this from “fossil fuels have received government subsidies for 100 or so years. These days, fossil fuel subsidies reportedly total approximately $5 trillion globally each year. Despite tremendous health costs, climate costs, and countless premature deaths caused by pollution … . Renewable energy also receives subsidies, but not to the same degree.”


Continued Technological Research & Development

Renewable technology, especially hydropower, solar and wind, has progressed rapidly over the last few decades.

But, continued technological research and development can lead to even better performance, better capacity, new capabilities, cheaper prices, and more.

This may not be limited to just renewables either. Cleaner energy in general, such as nuclear, may benefit us in the future with further technological breakthroughs.

Public and private investment can play a big role in research and development, as well as consumer demand.


Electric Cars, & Electrifying Fossil Fuel Dominated Industries & Sectors

Renewable energy has penetrated the power sector (electricity generation) far more than any other sector.

But, other industries like transport, and heating and cooling, are still very energy reliant on fossil fuels.

A continued switching to electric and hybrid cars could help in the transport sector.

In heating and cooling, district heating or electrification of heat might help (


Greater Awareness & Education For The Public & Government With Transparent, Independent & Non Partisan Data

It’s argued that the barriers to transitioning to renewable energy aren’t economic or technological, but social/cultural, political and institutional (with major points being that government officials don’t understand how important renewables are in addressing environmental and social issues, and the general public doesn’t know how reliable and beneficial they can be in the right energy systems). 

Data and information that is independent, objective and non partisan being spread to government representatives and the general public can provide an accurate view of renewable energy to these groups.



Digitalisation is the use of digital technologies to make things better.

The energy sector lags behind other industries in terms of digitalisation. 

Digitalisation in the energy sector:

  • … will go beyond the installation of “smart” electricity meters connected to the internet, or being able to remote-control household heaters with a mobile phone
  • … [it will include things like the] exchange of surplus power generation among neighbours and the activation of flexibility on smaller scales
  • Creating demand flexibility can only work via communication. This is where digitalisation can show its strengths
  • [Digitalisation can be vital in allowing renewable energy to penetrate the transport and heating sectors]



Other Resources On Transitioning Towards Renewable Energy












Challenges & Problems With Transitioning To Renewable Energy

Challenges & Problems With Transitioning To Renewable Energy (Arguments Against Renewables)

Cities and countries around the world are transitioning the energy sources for electricity towards renewable energy sources at different rates.

Inevitably, there are potential challenges and problems with this transition that can occur.

In this guide, we list and explain those different challenges and problems. 

Some of these problems and challenges are often used as arguments against renewables by those who support the use of other energy sources (fossil fuels, nuclear, and so on)


Summary – Challenges & Problems With Transitioning To Renewables


Capital Costs

The cost of renewable energy capital (i.e. – to build solar farms, wind farms, mega hydro dams etc.) can be expensive compared to some fossil fuel capital (

What tends to happen though, is that these upfront costs average out over time with the low running costs of solar and wind farms, and over the long term, renewables can be as cost effective as fossil fuels. This provides some certainty for investors over a 20 or 30 year period for example.

In addition to this, many sources quote the old prices of coal, natural gas and other fossil fuel plants. New fossil fuel plants with devices and systems for minimising carbon emissions and air pollutants can be far more expensive. Clean coal and CCS technology can also be expensive.

Add to this that renewable energy technology and equipment is becoming cheaper as demand increases and economies of scale kick in, and capital costs are becoming less of a challenge.

An asterisk to cost, is of course, that developed/wealthy countries and cities are going to have far more of a budget to finance renewable energy technology and systems than developing/poorer countries and cities. So, level of financing is an issue here too.


Supporting Infrastructure

Existing energy grids and infrastructure like power lines are largely set up for fossil fuel energy.

It can be both time and money intensive to to build new infrastructure, upgrade power grid, build new transmission lines and interconnectors, build new convertors, and so on – all to support renewable energy or a changed energy mix.

However, some of these costs are more of a one time cost that benefits the energy system over the long term (the same way existing infrastructure and energy systems were originally paid for and built for fossil fuels)


Reliance On Government Support

At least in the short to mid term, some argue that renewable energy needs to support of governments to get into and compete in the market via subsidies, tax breaks, carbon tax (on other energy sources that pollute), schemes and concessions, credits, and so on. 

How much a government supports renewable energy can heavily influence it’s expansion and use. This support can’t waver from year to year – it really needs to be a long term commitment to help the technology get set up, develop and stabilise. 

We see different governments around the world supporting renewable energy, and even individual renewable energy sources, to different extents.

For example, even though the US isn’t a country that has majority of it’s electricity supplied by renewable energy sources yet, parts of the US like California, and the MidWest, have governments that support renewable energy in different ways.


Decentralization, Siting & Transmission 

Fossil fuel plants tend to be centralized in one place, where as renewables like solar and wind can be decentralized and spread out.

This presents two issues – siting, and transmission:

  • Siting – for every piece of land wind and solar occupy, there can be ensuing negotiations, contracts, permits, and community relations, all of which can increase costs and delay or kill projects. (
  • Transmission – power needs to get from where it’s produced, to where it’s needed. Transmission lines are needed, which take time to build and are costly, and they also need to be sites ( The further away solar and wind farms are from where the energy they produce is needed, the more complications that can arise.

Solar is often classed as utility (solar farms) and distributed (solar panels on buildings and in residential areas). A decentralized system like this can also provide benefits, such as stabilising the power grid in the event there is an issue with the main energy system, but, also providing multiple points of energy generation in the event of a natural disaster or extreme weather events.


Intermittency & Variability

Renewable energy sources solar and wind are often called intermittent and variable sources of energy.

This is because the consistency of their energy supply is often determined by how much the sun is shining and how much the wind is blowing i.e. the quality of sun and wind conditions.

This can be a problem as there can be very little, intermediate amounts, or too much energy coming through at any one time or over a certain period.

In comparison, fossil fuel energy sources like natural gas and coal tend to be consistent because they rely on coal and gas resources supplies, which are always abundant and available.

Variability and intermittence can lead to a number of issues like:

  • the mismatch of energy supply with demand (electricity needs to be timed to be used at the time it is required, unless energy is stored in a battery),
  • blackouts,
  • uncertainty for other energy sources and operating at smaller scale (this means operators of these plants lose money and profits)
  • the phasing out of other energy sources (and shutting down of these power plants),
  • the requirement for back-up energy sources,
  • decreased investment in certain energy sources,

It really can be a domino effect with variability.

(In fairness though, there are things that can be done to address variability and intermittence, such as introducing market controls for a more stable energy market, introducing energy storage, introducing backup dispatchable energy sources, and so on)



Over capacity is when there is an over supply/surplus of energy to the power grid.

This is usually caused by conditions with too much sun and wind providing too much solar and wind energy.

The impact of this can be a power grid that becomes unstable, and electricity prices that drop.

Germany is one example of a country that has experienced overcapacity as a result of variable solar and wind energy supply (


Grid Stability

When the power grid is unstable, it can be due to a variety of reasons.

Specifically with renewable energy, it can refer to a surplus or lack of power supply that can impact availability of energy, but, can also refer to the ability of the grid to withstand load fluctuations from variable energy sources.

Countries like Poland and the Czech Republic have suffered grid stability issues from the transmission of surplus energy from the German power grid (


Volatility Of Electricity Prices

Germany has experienced volatility of electricity prices when there has been a surplus of solar and wind power. Surplus electricity has forced prices negative in the past, forcing power plants to pay commercial customers to receive the surplus (

Having said that, Germany has addressed this problem: ‘[volatile electricity prices] can be somewhat addressed by replacing the feed-in tariff subsidy with a market-responsive auction system based on pre-set RES capacity growth caps (

Furthermore, wind and solar energy in South Australia has actually made the market for wholesale electricity prices more competitive with natural gas – leading to cheaper prices (


Interference With A Competitive Market

There’s several ways the introduction of renewables, or the support of renewables by regulations and government tool, can interfere with the market.

Some of these ways includes:

  • If renewable energy portfolios require a minimum amount of renewable energy to be used, and for renewables to be used first, then other energy sources are capped at the scale they can operate (especially if they have to ramp up and down when there is a lack, or a surplus of energy)
  • There can be the closure of other energy sources if they aren’t supported or they can’t run at full capacity
  • Subsidies for renewable energy capital costs can be passed onto customers
  • Other more energy or cost efficient forms of energy can be forced out of the market even if they are more competitive (because renewables might be heavily supprted by non market support like regulations and government tools)

But, some people point to the support and subsidies fossil fuels have been receiving for years, and say that all the issues renewables might cause n interfering with a cost and economically competitive market could be said about fossil fuels too (especially when you take into account the environmental and social costs fo fossil fuels that aren’t priced).


Availability Of Back Up Dispatchable Energy Sources

A definition of dispatchable energy is: ‘Dispatchable generation refers to sources of electricity that can be used on demand and dispatched at the request of power grid operators, according to market needs. Dispatchable generators can be turned on or off, or can adjust their power output according to an order’ (

Because of the variable nature of renewable energy like solar and wind, when sunshine and wind conditions change, and energy supply of these sources are low or high, some energy systems require back up dispatchable sources of energy that can ramp up and down quickly to address baseload, low and peak demand.

Due to several factors, these back-up sources are usually natural gas or coal (nuclear less so). In Germany, having fossil fuel back up energy sources has actually lead to an increase in greenhouse gas emissions over the short term (


Requirement For Energy Storage

Again, due to the variable nature of renewable energy sources like solar and wind in some places, dispatchable energy sources and/or energy storage may be used separately or in combination to provide energy when primary renewable energy sources are not providing enough power.

Energy storage can take several forms, with two of the more notable forms being battery storage, and pumped storage hydro energy.

Energy storage technology with batteries has technological and economic limitations with large batteries right now – the bigger they are and the more hours of energy they store, the more costly they are … they can be very expensive. They usually only have enough stored energy to last a few hours or for shorter bursts at the moment on the commercial scale. South Australia recently got a very large energy storage battery built to address recent blackout problems they had.

Pumped storage hydro energy involves storing energy in the form of water, pumping it up to a higher reservoir, and releasing that water downhill through turbines when energy is needed to generate electricity.


Political, Social, Cultural & Institutional Problems

Some sources indicate the problems with a transition to renewables aren’t technological or economic in some countries and cities, but political (politicians being supported by or being misinformed by fossil fuel companies), social (social misconceptions with the use of fossil fuel and renewable energies and what each can provide), cultural (biased cultural support for fossil fuels because of jobs, economic benefits and so on) and institutional (the energy industry is set up for fossil fuels and not renewables in many ways).


Penetration Into Transport, Heating & Cooling, & Sectors Other Than The Power Sector

Right now, most of the installed capacity, production of renewable energy, and consumption of renewable energy, penetrates into the power/electricity sector. Hydropower currently leads the charge in this regard of all the renewable energy sources.

Transport, and heating and cooling, though, are primarily fossil fuel powered right now. Transport, through the use of petrol and diesel-fuelled cars; and for heating, through the use of oil and natural gas boilers in buildings (

It will be a challenge to electrify these sectors and penetrate them with renewable energy sources in the future.


Market Entry

The existing energy market in countries like the US is set up for fossil fuels and existing established energy sources, and these energy sources benefit from existing infrastructure, expertise, and policy (

Because of the market power of existing energy suppliers, it can be hard for renewables and individual clean energy competitors to enter the market and survive.


Unequal Playing Field

Renewables may not be entering a level energy market playing field in some countries.

Some argue in countries like the US, fossil fuels benefit from political influence, and receive direct subsidies (through subsidies, tax breaks, and other incentives and loopholes, and indirect subsidies (through not being punished for polluting for example) ( 


Reliability Misconceptions

Because of the variability of wind and solar, some people think that they are unreliable.

But this may not be true:

  • Solar and wind are highly predictable, and when spread across a large enough geographic area—and paired with complementary generation sources—become highly reliable. Modern grid technologies like advanced batteries, real-time pricing, and smart appliances can also help solar and wind be essential elements of a well-performing grid. (

In addition to that, wind might be used more in the winter, and solar in the summer, and, there are new technologies being developed that might allow solar to generate energy at night time too.


Environmental Problems

Renewable energy is not without it’s own environmental issues (although, many argue that the environmental problems caused by renewables are minimal compared to those caused by fossil fuels). Just as a few examples might be:

  • Solar – solar farms use up a large land area (are land inefficient compared to fossil fuel power plants)
  • Wind – can be in the flight path of migratory birds and other flying animal species. Can also use up a large land area
  • Hydroelectric – the construction of dams, and the discharge of water can have a negative impact on water sources, the aquatic environment, aquatic wildlife, and downstream water users
  • Geothermal – can release waste steam and gas, can cause hydraulic fracturing, and can cause air and water pollution, amongst other issues
  • Wave & Tidal – can dislodge and have a negative impact on seabeds, and marine life
  • Bioenergy – uses land, can use fertilizer and pesticides (to grow crops for biofuel), uses water, and creates waste

–, and


Other Problems & Challenges 

  • Questions over whether renewable energy systems can scale up fast enough to a certain scale, by a certain target year
  • Adding turbines to some existing hydropower dams (for increased capacity) may be physically impossible
  • A potential shortage of precious metals int he future for renewable energy equipment and batteries (like nickel, cobalt, copper, lithium etc.)
  • The need for frequency control and the provision of inertia, price signaling and communication between distributors and the wholesale electricity market (
  • Older power engineers are attached to the concepts of base load, intermediate and peak load power stations … and cannot envisage a system that contains a large fraction of variable RElec and where demand can be modified almost instantaneously (
  •  The natural renewable resources each country or city has, and how much potential they have to expand e.g. Australia might have far more land and sunshine than other countries to expand their solar and wind equipment
  • Large hydro power projects like mega dams can be highly unpredictable in the design and approval stage, and can have feasibility issues
  • Renewable energy investment can be variable from year to year


Other Resources On The Challenges & Problems With Transitioning To Renewable Energy

There are many more challenges and problems than the ones we have listed above.

Some of the guides that list further challenges and problems are:




















A Guide On 100% Renewable Energy (What It Is, Whether It’s Possible, Countries, Cities, By 2030, By 2050 + More)

A Guide On 100% Renewable Energy (What It Is, Whether It's Possible, Countries, Cities, By 2030, By 2050 + More)

You may have heard of the term 100% renewable energy.

In this guide, we discuss what is it, whether it’s possible, how different countries and cities are going with it, and how we might progress towards it by 2030 and 2050.


Summary – 100% Renewable Energy

  • 100% renewable energy is supplying 100% of energy by renewable energy sources, specifically by modern renewable energy sources like solar and wind. 
  • Some cities and countries already have a majority or full renewable energy mix in their electricity supply, so, 100% renewable energy is possible
  • Countries and cities that aren’t 100% renewable energy supplied in their electricity sector may have different plans for achieving 100% renewable energy by 2030 or 2050 (or another year that they have identified as their target year). 
  • Plans for 100% renewable energy differs by each country and city, and can depend on many variables and factors. The support of the government and government policy is a huge variable
  • There are models and studies that have been put together that can forecast the feasibility of different energy mixes for different cities and countries. There’s also websites that provide updates on the cities worldwide that are taking action on different sustainability measures in real time
  • It should be noted that some cities and countries may determine that 100% renewable energy isn’t ideal for them individually. A hybrid mix including fossil fuels and nuclear power may be ideal for different reasons


What Is 100% Renewable Energy?

100% renewable energy is supplying 100% of energy by renewable energy sources, specifically by modern renewable energy sources like solar and wind (but can also include other renewable energy sources like hydropower, geothermal, tidal and wave energy, and so on).

Right now, it primarily refers to 100% renewable energy supply in the electricity sector. 

But, in the future, it could also refer to 100% renewable energy supply in other sectors that are currently fossil fuel dominated, like transport, and heating and cooling.


Is 100% Renewable Energy Actually Possible?

Yes, some cities and countries already run on 100% renewable energy.

But, each country and city faces different challenges and problems with transitioning to a majority or full renewable energy supplied mix.


100% Renewable Energy Countries & Cities


  • According to, the number of countries getting at least 90% of their electricity from renewable energy sources was 12 countries

The countries currently getting 100% of their electricity from renewable energy sources are:

  • Albania – 100%
  • Democratic Republic Of The Congo – 100%
  • Iceland – 100%
  • Paraguay – 100%



  • As of January 2018, 42 cities were getting at least 100% of their electricity from renewable energy sources, 59 cities were at at least 70%, and 22 cities at at least 50% (according to’s interactive map)


100% Renewable Energy By 2030, & 2050

Studies & Reports Of The Future

Some studies and reports analyse factors like the year a city or country can reach 100% renewable energy, the challenges in getting there, what the energy mix might look like, and more.


Real Time Progress

Some websites provide information on the real time progress of some cities worldwide meeting certain sustainability measures. 

Examples are:



Plans For 100% Renewable Energy

Each city and country has different plans for transitioning to an increased renewable energy mix. 

Government support is a big variable.

Some national and State governments are more pro renewable energy than others, for different reasons.








Hydroelectric Dam vs Run Of River vs Pumped Storage Hydro Energy Comparison: What They Are, Differences & Examples

Hydroelectric Dam vs Run Of River vs Pumped Storage Hydro Energy Comparison: What They Are, Differences & Examples

There are several different types of hydro energy set ups used to generate electricity globally.

In this guide, we compare hydroelectric dams vs run of river vs pumped storage hydro energy projects and power plants.

We look at what each is, their differences, and examples of each being used in the world.


Summary – Hydroelectric Dam vs Run Of River vs Pumped Storage Hydro Energy

  • Hydro energy is the use of running water to create electricity
  • Hydropower as a whole produces the most electricity of any renewable energy source – roughly around 50% of all electricity produced by renewable energy sources globally
  • There’s several different types of hydro energy – hydroelectric dams (built on rivers with an impoundment facility, dam and reservoir), run of river (may or may not have a dam – but can simply use flowing water without a dam or reservoir), and pumped storage hydro (using two reservoirs or water – one on a higher level and one on a lower level)
  • Essentially, they can be divided into hydro energy power set ups that use dams and reservoirs, and those that don’t
  • They can also be divided into large, medium and small sized hydro power plants, depending on the amount of electricity capacity they have (dam hydro power usually produces the most electricity)
  • Hydropower is expected to expand into the future, particularly in developing economies, but growth isn’t expected to be as strong as the last 5 years to one decade (investment and expansion will mostly be in solar, wind, and bioenergy)
  • Large and mega sized hydro projects can have some uncertainty regarding their funding, planning and construction – so growth and added capacity of hydro energy can be dependent on this
  • According to recent studies, there is potential for many new pumped storage hydro sites worldwide – pending on-site feasibility checks. Pumped storage hydro can be a good source of stored renewable energy in the future (especially as a backup to intermittent energy like solar and wind) 


What Is Hydro Energy?

  • Hydro energy is the use of running water to create electricity


The Different Types Of Hydro Energy, & How Each Works

Hydro energy can be broadly categorised into two types:

  • Hydro energy with dams and reservoirs,
  • and, hydro energy without dams and reservoirs


Utility scale and large hydro (hydro energy produced for electricity and energy utilities) usually involves dams and reservoirs, and small or local community/village, and run of river hydro usually doesn’t.


Beyond the above broad categorisation, utility scale hydro power plants can be divided into:

  • Impoundment/Dam (using an impoundment facility) – a dam stores water in a reservoir. Water is released from the reservoir through turbines, which activate a generator, and produces electricity. Dams can also serve other purposes other than just producing electricity, such as preventing flooding.
  • Diversion/Run Of River – part of a river is channeled through a canal or penstock. May or may not use a dam. [It helps if a river is chosen that has a consistent flow, otherwise, without a storage reservoir, energy will be variable and not consistent]
  • Pumped Storage – there is an upper and lower water reservoir. Water is stored in the lower reservoir, and when needed, is pumped up to the upper reservoir, and then released back down to the lower reservoir through turbines, which activate a generator, and produces electricity. [Pumped storage can actually store energy in the form of water, so, it can be a good backup to wind and solar energy for example]



Diversion and run of river hydro generally has less negative environmental and social impact compared to large hydroelectric dams.


Something else to note is that renewable hydro energy might be becoming a type of hydro energy in the future. Currently, pumped storage hydro uses fossil fuels to pump water up to it’s top reservoir. In the future, renewable energies like wind and solar might provide the electricity to pump and power hydro power stations.


Large vs Small Hydro (& Medium Hydro As Well)

Globally, there’s no official definition of small, medium and large hydro, but each country has a guide of what they call the different sizes of hydro plants and projects.

Size usually refers to the energy/electricity capacity or generation of the hydro plant.

All of the largest hydro projects tend to be dams as they tend to produce the most electricity (this is true when you look up the largest hydro plants in the world, like the Three Gorges Dam that produces up to 22,500 MW for example).

To give a broad idea of how hydro plants and projects might be categorised by size:

  • Large – 10 GW (10,000 MW) and over
  • Small – 10-30 megawatts (MW)
  • Micro and Pico – in the kW range
  • Pumped Storage – some of the biggest pumped storage plants have a capacity of 1000 to 3000MW. New potential pumped storage sites discovered in recent studies have potential capacity to hold 2-150 GWh of energy ( [and, 2 GWh converts to roughly 2000 MWh]



Differences In The Different Types Of Hydro Energy – Cost, Efficiency, Capacity Etc.

  • Overall, hydroelectricity has been one of the cheapest forms of renewable energy (although solar and wind are challenging it)
  • Large Hydroelectric dams tend to be the most expensive to construct, but tend to have the greatest capacity for production (so, costs and returns can average out over the long term)
  • Large hydroelectric dams tend to have the highest social and environmental impact, whereas run of river and small scale hydro that doesn’t need dams and reservoirs tends not to be as intrusive or destructive on the natural landscape
  • Pumped hydro storage sites require land clearing, and once in use, may use fossil fuels to pump water up to the higher reservoir.
  • Dam and reservoir hydro plants offer energy storage and can ramp up quickly in terms of energy generation in times of peak demand – this is in opposition to run of river hydro energy that requires water be flowing (depends on a river that runs year round) in order to produce electricity


Global Installed Capacity, Production & Consumption Of Hydro Energy

Worldwide, hydro energy installed capacity, production and consumption stats are:

  • At the end of 2018, made up 50% of installed capacity for renewables
  • At the end of 2018, made up 15.8% of total global electricity production
  • At the end of 2016, was the most consumed renewable energy source for electricity


  • Between 2012 to 2018, solar PV led all renewables in annual additional installed capacity by a wide margin, followed by wind energy, hydropower, and all other renewables as a group behind that (including solar CSP/thermal)



  • At the end of 2015, the leading hydropower generating countries were China, the US, Brazil, Canada, India and Russia.



Mixed Plant vs Renewable Hydropower Electricity Generation

In 2016, electricity generation from hydro power was:

  • Mixed Plant – 4,048,420
  • Renewable Hydropower – 0



Investment In Hydro Energy

In 2016, investment in small hydro lagged behind solar, wind and biomass globally.

Major hydro project investment can vary by year and can be unpredictable.


Future Of Hydro Energy

  • Hydropower capacity is expected to increase 125 GW [heading up to 2023] – 40% less than [the increase] in 2012‑17
  • One-fifth of overall growth (26 GW) is from pumped storage hydropower (PSH) projects



  • [it is thought there could be a lot of potential in pumped storage hydro in the future as new scans and studies of the globe have found hundreds of thousands of new potentially usable sites for pumped storage hydro]
  • [pumped storage hydro has the advantage of providing energy storage and baseload power as a complement to solar and wind energy]



Examples Of Hydro Energy Power Plants Globally (By Type, Capacity/Size, Country Etc.)

  • Conventional Hydro Power Plants –

Range from 1000 all the way up to 22,500 MW of capacity. 

China features heavily, having some of the biggest hydroelectric dams in the world, including the biggest – Three Gorges Dam, which is on the Yangtze River.


  • Run Of River Hydro Power Plants –

Highly variance in capacity of the major examples of run of river hydro plants globally.

Range from 16MW of capacity at a station in British Columbia, Canada, all the way up to 11,233 megawatts of capacity at Belo Monte Dam in Brazil.


  • Pumped Storage Hydro Plants –

Range between 1000 to 3000MW of capacity.

China, the US, Japan, Australia, Spain and France has some of the plants with the largest capacity.






















Solar PV vs Solar Thermal/CSP Comparison: What They Are, Differences, & Examples

Solar PV vs Solar Thermal/CSP Comparison: What They Are, Differences, & Examples

This is a comparison guide on Solar PV (photovoltaic) vs Solar Thermal (CSP – Concentrating Solar Power) Energy.

We look at what each of these types of solar technology are, their differences, and examples of each in terms of solar projects and operational solar farms worldwide.


Summary – Solar PV vs Solar Thermal/CSP

  • Solar PV (used for electricity) and Solar CSP (used for electricity, or heating water) are different solar technologies
  • Each can be used on a large utility scale (big solar farms with hundreds or thousands of panels that produce electricity for utilities), or on a distributed residential scale (for individual households, buildings and locations)
  • Solar PV (photovoltaic) currently leads Solar Thermal/CSP by a very wide margin in terms of annual investment of money, annual and total installed capacity, electricity generation, and electricity consumption
  • This trend (of PV outpacing CSP) is only expected to continue into the future with continued investment in and expansion of Solar PV projects
  • Despite Solar PV’s popularity, Solar CSP has a few small advantages (dispatchability, and generating electricity while the sun is down) over Solar PV


What Is Solar PV

  • A solar panel made up of solar cells that converts sun light energy into electricity



Solar PV can be utility scale (solar farms), or distributed (usually rooftop installations and other standalone solar cells that help stabilise or support a power system in the event of power disruptions, blackouts etc.).


How Solar PV Works

  • Sunlight (light photons) hits the solar cells on a solar panel
  • The solar cells convert sunlight into DC electricity
  • DC electricity is fed to the inverter (might be a string inverter or a microinverter) that turns DC energy into AC electricity
  • This AC electricity can be used directly or stored in a battery for later use



What Is Solar Thermal/CSP

  • The use of the Sun’s thermal energy to generate electricity or heat water
  • There’s several different types of Solar Thermal plants such as Linear Fresnel, Tower, Dish and Trough (


How Solar Thermal/CSP Works

  • Solar CSP uses mirrors (lenses and reflectors) to capture the Sun’s thermal energy (infrared radiation) to heat a (thermodynamic) liquid or an oil, create steam, drive a heat engine/generator, and generate electricity
  • Solar CSP can also be used for heating and desalinating water

–,, and


Global Installed Capacity, Production & Consumption Of Solar Energy

Worldwide, solar energy installed capacity, production and consumption stats are:

  • At the end of 2018, solar as a whole made up 20% of installed capacity for renewables
  • At the end of 2018, solar PV made up 2.4% of total global electricity production
  • At the end of 2016, solar was the third most consumed renewable energy source for electricity



  • Between 2012 to 2018, solar PV led all renewables in annual additional installed capacity by a wide margin (55% alone in 2018), followed by wind energy, hydropower, and all other renewables as a group behind that (including solar CSP/thermal)
  • Solar thermal/CSP made up 0.4% of total global electricity production in 2018 along with other renewables like geothermal and ocean power



  • In 2017, solar PV and solar thermal were both responsible for 4% each of renewable energy consumption worldwide



Solar PV vs Solar CSP Installed Capacity

  • In 2018, global Solar PV installed capacity was 480,357 MW, and Solar CSP was 5,469 MW



Solar PV vs Solar CSP Electricity Generation

  • In 2016, Solar PV electricity generation was 317,613 GWh, and Solar CSP was 11,037 GWh



Solar PV vs Solar Thermal – Differences, Cost, Efficiency & More

Solar PV and Solar Thermal are both used on the large utility scale, and on the smaller distributed/individual scale. Cost, efficiency, and other variables can differ depending on the scale they are used.


Apart from the obvious differences of investment, installed capacity, electricity generation and electricity consumption, and how they actually work (light energy vs heat energy), some of the key differences at the utility/large scale are:


  • [solar CSP] provides a dispatchable energy supply – that is, their power output can be adjusted based on grid demand. This makes them more flexible than traditional solar PV plants.



  • One of the main advantages of a CSP power plant over a solar PV power plant is that it can be equipped with molten salts in which heat can be stored, allowing electricity to be generated after the sun has set.



Overall, CSP on the utility scale probably faces more barriers and challenges than Solar PV which is far more widely used.


On a household and individual level, mentions some of the cost, efficiency, flexibility and other differences between the two technologies at

For example, solar thermal is usually used for heating water on homes, whereas panels might be used for electricity.


Investment In Solar Energy

In 2016, solar and wind energy by far had the most investment money on a global level compared to other renewable energy sources.


Future Of Solar Energy (Solar PV & Solar CSP)

  • By 2023, solar PV is expected to grow to 8% of renewable energy consumption worldwide, whilst solar thermal is expected to stay the same at 4%



  • [there is expected to be] a 46% growth over the period 2018 to 2023 in renewable energy as a whole … with solar PV accounting for more than half of this expansion [and, supportive government policies and market improvements are some of the main causes]
  • Utility-scale projects represent 55% of this growth
  • China alone accounts for almost 45% of global solar PV expansion
  • CSP is expected to grow 87% (4.3 GW) over the forecast period, 32% more than in 2012‑17
  • [some of the barriers facing CSP expansion individually are] technology risk, restricted access to financing, long project lead-times, and market designs that do not value storage continue to challenge CSP deployment



Examples Of Solar PV & Solar Thermal Worldwide – Largest Solar Farms, & Countries With The Most Solar PV & Solar CSP

You can view lists of the largest solar PV and solar thermal power stations at:



Countries with the highest installed capacity:

  • In 2018, China, Europe, the US, Japan and Germany had the highest installed capacities of Solar PV in MW.
  • In 2016, Spain and the US easily had the highest installed capacities of Solar CSP in MW.