Renewable Energy vs Fossil Fuels vs Nuclear: Comparison

Below, we compare renewable energy sources, fossil fuels, and nuclear energy.

We asses these types of energy sources across different metrics and measureables, such as cost, efficiency, performance, and more.

We use some of these metrics and measureables in a separate guide we put together discussing what the ‘best’ energy sources might be.


Summary – Renewables vs Fossil Fuels vs Nuclear Comparison

Firstly, What Are These Energy Sources?

– Renewables

Renewable energy generally includes solar, wind, water (hydroelectric, wave, tidal), and geothermal energy. 


– Fossil Fuels

Fossil fuels generally include coal, natural gas and oil


– Nuclear

Nuclear energy generally includes energy that comes from uranium and nuclear fuel


Indicators We’ve Used To Compare These Energy Sources

There’s different metrics that can be used to compare different energy sources.

The metrics and indicators we’ve used in the guide below are:

Cost (producer side cost

Consumer side price (i.e. the price of electricity, and looking at electricity supply as a service)



Variability (& Intermittency)



Power density

Capacity factor

Energy independence and reliance



Safety (and hazards)

Environmental and wildlife impact (and overall sustainability)

Economic impact and potential benefits

Other miscellaneous technical and practical aspects


Other Notes

The information in this guide is generalised information only.

The features and performance of each energy source ultimately differ in each geographic location, and they have their own variables and factors to consider that impact them.

There’s also the consideration of how technology develops in the future.

As just one example, with renewable energy, better storage capabilities in batteries, and technology like artificial intelligence technology and systems can play might play a role in more sustainably using or maximizing renewable energy in the future

Because of this, each individual energy source and energy grid needs it’s own individual assessment, rather than relying on a generalised comparison or assessment.


Onto the comparison points …



We put together a separate guide specifically outlining the cost of renewable energy vs fossil fuels and nuclear energy.


Price Of Electricity (For Consumers)

Price of electricity is the price the end consumer of the electricity pays

This is differentiated to cost which is the cost to supply the energy source/to produce a unit of electricity (when considering all the supply costs)

Something that should be noted is that some links can be made between individual energy sources and their impact on the price of electricity.

But, it can be difficult to get the true price of electricity for each energy source because it can be difficult to fully account for/include all direct and indirect factors that impact the price of electricity.

One example of this might be illustrated with some types of renewable energy.

Where the price of electricity from variable energy sources like solar or wind energy is reported for example, the question might be asked whether more indirect factors like the cost to run backup energy (from gas generators for example), or the cost to provide batteries for energy storage has been accounted for.

Additionally, have taxes or subsidies to support certain energy sources been accounted for?

Delivering electricity to the consumer is a service – there’s more than just the cost to set up and operate an individual energy source to consider … you have to look at other cost factors that contribute to the overall cost to provide that service to the consumer 

Additionally, electricity prices differ in different cities and towns because the energy grids and factors impacting the energy sector and electricity generation differ everywhere.

This may lead to the same energy source having a  different impact on electricity prices in different geographic locations.

Below is some general information on what factors might impact the price of electricity in general, and also how different individual energy sources might impact the price of electricity …


Factors That Might Impact The Price Of Electricity In General

The causes of electricity price increases or decreases can differ in different countries and States

For example, in some countries, taxes can make up a large % of electricity prices, but in others, there can be other factors at play.


[Prices for electricity can be dependent on many factors] (


How Gas Energy Might Impact Electricity Prices

Inefficiency of some old gas plants may lead to higher electricity prices in some regions


[Inefficient old gas plants can contribute to high electricity prices – like they currently do in South Australia] (


How Renewables In General Might Impact Electricity Prices

Renewables may sometimes lead to more expensive electricity

This may especially be the case if taxes and support schemes require consumers to pay for green energy development on top of the actual costs to supply electricity


How Wind Or Solar Energy Specifically Might Impact Electricity Prices

Wind and solar may bring wholesale electricity prices down in some regions of the world

Subsidies paid for wind and solar may be responsible for a % of the price paid for solar and wind generated electricity though


[Excess power produced by wind and solar can bring renewable electricity prices down because the ongoing cost to run and maintain these energy sources is close to zero]

In South Australia, from 2013 to 2018, wind and solar generation … brought wholesale prices down … [and] in the 2017–18 financial year [in South Australia], renewables [like wind and solar] reduced wholesale prices by an average of about 30 per cent, or about $37 per megawatt hour

… subsidies paid for [wind and solar] … was $11 per megawatt hour of electricity produced



How Nuclear Might Impact Electricity Prices

The price of nuclear generated electricity may be linked to nuclear capital costs and also operation costs

In some countries, because of lower costs, nuclear generated electricity might be much cheaper than others

Nuclear might be priced out of some countries’ energy markets because of the cost


[Nuclear can cost far less in places like Korea, in China and the UAE, compared to countries in the West where the cost can be twice as much …]

[… these costs can be reflected in end consumer electricity prices]

[Factors like design, construction management and supply chain and workforce can impact the cost of nuclear]



[Nuclear electricity is currently priced out of the Australian electricity market because of the cost of nuclear energy] (



Subsidies differ between States/provinces/regions of a country, depending on the energy related policies of different governments

Some governments have introduced large subsidies on renewable energy with a push to meet green energy and climate targets by 2020, 2030 and 2050.

Some governments still have subsidies or forms of protection on coal power and other fossil fuels with the goal of economic growth, or other economic goals.

Separate to subsidies, there can also be other tools that governments use for different energy sources, such as penalties, fines, and so on.

Some governments have carbon pricing and ‘polluter pays’ penalties.

Older coal plants and other energy sources that rate higher in emissions and air pollution may be subject to carbon taxes, and pollution fines and penalties.

Carbon credits are a related concept where high emitters have to buy credits (to fund carbon sinks) for their emissions.

Older higher emitting fossil fuel plants may be affected by carbon credits.



We’ve put together a separate guide on the efficiency of renewables and also fossil fuels:

Efficiency Of Fossil Fuels vs Renewable Energy


Efficiency Of Different Energy Sources

From the data below …

Coal, oil and natural gas (in that order) might be some of the most inefficient energy sources

Wind might be the most efficient, with geothermal in second


In the US, the following energy sources might retain the following % of energy input when converting fuel to electricity:

[Note – these %’s are the national average – so, the actual % can vary State to State]

Coal – 29% (least efficient, and retains just 29% of its original energy)

Oil – 31%

Natural Gas – 38%

Biomass – 52%

Solar – 207%

Nuclear – 290%

Hydro – 317%

Geothermal – 514%

Wind – 1164% (most efficient, and creates 1164% of its original energy inputs when converted into electricity)



Efficiency Of Fossil Fuels vs Renewable Energy discusses the efficiency of fossil fuels vs renewable energy in their report

Our paraphrased summary of what they might indicate is:

– Fossil fuel energy might be wasteful and include loss at every stage from mining fossil fuels, to using the fossil fuels resources for energy (during combustion), to managing the waste and waste by-products

– Renewable energy on the other hand might be simpler, involves no combustion, and there’s less conversions that have to take place (which might minimise loss and waste of energy)



Variability is how consistent or intermittent the power supply from an energy source is.

Traditional energy sources like fossil fuels and nuclear are not variable energy sources.

As long as they have fuel available, they can deliver a consistent power supply.

Some renewables like geothermal and some types of hydro energy might be able to deliver a reasonably consistent energy supply too

Some renewables on the other hand, like solar PV and wind, are variable energy sources as they rely on the sun to be out or the wind to be blowing to generate electricity

There are ways to manage the variability of solar and wind though, with energy storage batteries (that can store surplus energy for use at a later date), backup energy sources (that can ramp up and dispatch energy on demand) being a few examples.



We’ve put together a separate guide on the potential reliability of renewable energy in this guide.



Dispatchable energy sources can be turned on and off to meet changing electricity demands.

To do this – they have to deliver stable power, and they have to be able to ramp up and down on demand.

They are essentially more flexible forms of energy that have better control over when power can be delivered, and when it’s not.

Fossil fuels like coal and natural gas, some types of hydro energy might be considered dispatchable.

If used within certain limitations, nuclear might be considered dispatchable in some ways too.

A non-dispatchable enemy source has limited ability to change it’s power output at will to match changing demand from electricity grid users.

Energy sources dependent on changing factors like the weather, such as solar and wind, might be considered non-dispatchable.


Power Density

Power density refers to the amount of energy per unit an energy source 

There can be a flow on effect of power density, such as how much land an energy source takes up

Fossil fuels and nuclear might have good power density

Some renewables might have less power density than fossil fuels and nuclear

However, although some renewables might have less power density than fossil fuel, they may have some benefits over other energy sources when it comes to land use

Waves might have the highest energy density of the renewable energy sources


What Is Power Density

… power density is … the average electrical power produced in one horizontal square metre of infrastructure (


Power Density Of Renewables vs Fossil Fuels


Because of power density, renewables can take up up to 1000 times more space than fossil fuels

Biomass, hydro and wind … take up the most space

Natural gas and nuclear [might take up the least space]


Renewable Energy Source With The Most Energy Density

Waves have the highest energy density of renewable energy sources, compared to others like wind, solar, biomass and geothermal (


Potential Benefit Of Renewables Over Fossil Fuels

… while renewable energies take up more space, that space will be less polluted, and can be developed for multiple uses such as farming around the base of wind turbines (


Capacity Factor

Capacity factor might be a measure of the % of time of the year an energy source is producing maximum power has a chart with data showing the capacity factor of different energy sources

Paraphrased, in order from highest capacity factor to lowest:

[Nuclear – 92% (means nuclear power plants are producing maximum power more than 92% of the time during the year)]

[Geothermal – 74.3%]

[Natural Gas – 56.6%]

[Hydro was in fourth at 41.5%, followed by coal at 40.2%, wind at 35.4%, and solar at 24.9%]


See the report for the full data on the capacity factor of different energy sources


Energy Independence & Reliance

A country might have more energy independence if they get most of their energy domestically.

A country might have a foreign energy dependence (be reliant on other countries) if they get most of their energy internationally (i.e. they import most of their energy) 

There might not be one single metric that can help compare fossil fuels, renewables, and nuclear when it comes to energy independence or dependence.

It may require looking at individual countries and where they get most of their energy from. 

It could also involve looking up the countries with the most fossil fuel and most uranium resources and reserves.

Some general examples of energy dependence or energy independence of the different energy sources might be:

– Some countries may rely heavily on Russia for their natural gas

– The UK may import majority of their natural gas from Norway 

– Some countries may have good domestic brown coal resources

– In countries where there is adequate sunlight or wind, renewable energy may make these countries less reliant on importing fossil fuels from other countries



Availability refers to how available each energy source is for different countries – both physical and financial availability.

Fossil fuels are physically abundant in some countries but not others.

But, they may be relatively easy for countries to import them for those that need them.

The same goes for uranium for nuclear energy.

Renewables are not available in all countries – they are dependent on having the natural climate for sunlight or wind, or access to hydro resources, geothermal resources, and so on.

Renewable energy might be transported or traded between states or countries – but this can be expensive as it might require the investment in new infrastructure like power transmission lines and interconnectors



Scarcity refers to how abundant or scarce resources are in a given country, and what the total resources, and confirmed reserves might be.

Fossil fuels are considered finite, and there’s is only a certain amount left that are both physically accessible and economically feasible to extract.

Uranium is finite at this stage, but advancements in science and certain technologies regarding how nuclear reactors work and our ability to obtain uranium from the ocean, may push uranium supplies into hundreds and thousands of years of supply in the long term (this is still a big ‘if’ at this stage though).

We’ve put together guides on the remaining fossil fuel and uranium resources:

How Much Fossil Fuels Are Left, & When Will We Run Out?

How Much Uranium Is Left, & When Will We Run Out?


Comparatively, renewables like solar and wind energy are are an almost infinite resource.

The sun is expected to last billions more years.

But, some reports indicate that renewables still use finite resources for the manufacture of equipment like solar panels, and fossil fuels for things like lubricants and greases for wind turbines



Across some metrics, fossil fuels might be the most ‘harmful’ energy sources to humans, whilst renewables and nuclear might be safer


Environmental & Wildlife Impact, As Well As Sustainability 

Environmental impact from energy sources can be a result of different stages of the energy lifecycle

Environmental effects can be a result of mining/extraction of the resource, combustion, and even waste management

Some examples of the potential environmental impact of the different energy sources might be:

– Fossil fuels and also uranium are both considered non renewable resources

– The mining/extraction of fossil fuels, and also uranium may have an environmental impact

– There may be carbon emissions and also air pollutants from the combustion of fossil fuels 

– There’s waste management required for fossil fuel by-products (like coal ash, which contains heavy metals), spent nuclear waste, and renewable energy equipment that’s reached the end of it’s lifespan

– Both renewables and nuclear might be clean energy sources whilst in operation, but may have a sustainability footprint for the manufacture of renewable energy equipment, and the construction of nuclear reactors

– What is interesting to note is that some reports indicate that large scale renewable energy transitions in some countries can involve the unsustainable use of raw materials for solar panels, wind turbines, and other equipment. There’s also fossil fuels required.

– The water footprint of each energy source can be considered – fossil fuels, especially coal and oil tend to use a lot of water in mining, refinement (for oil), and for cooling at power plants.


Below are some separate guides we’ve put together on the potential eco impact and sustainability impact of the different energy sources:

Impact Of Energy & Electricity Production On The Environment

Impact Of Energy & Electricity On Animals & Wildlife

Carbon Footprint Of Each Energy Source

Water Footprint Of Each Energy Source

Land Footprint Of Each Energy Source


Economic Impact & Potential Benefits

Fossil fuels have played a very important role in growing and maintaining some economies in the past.

However, renewables may have made progress in terms of providing economic benefits in recent times.

As one example, renewable energy tends to produce more jobs per dollar invested, and more jobs per unit of electricity produced.

Some reports point out though that renewables can cost more, and this money could be spent on job creation elsewhere in the economy.

But, fossil fuels may also have an indirect environmental and public health cost, which could weigh these costs out.

You can read more about potential economic impact in these guides:

The Economic Impact & Benefits Of Renewable & Clean Energy

How Many Jobs Renewable & Clean Energy Creates?

Does Renewable & Clean Energy Create More Jobs Than Fossil Fuels?


Potential Pros & Cons

Guides on pros and cons of various energy sources can be found here:

Pros & Cons Of Renewable Energy

Pros & Cons Of Fossil Fuel Energy

Pros & Cons On Nuclear Energy


Which Energy Source Is Best … Renewables, Fossil Fuels, Or Nuclear?

There might be no definitive way to answer this question.

We put together a separate guide discussing different aspects of the different energy sources.

A very brief summary of some of the different energy source categories is


– Fossil Fuels

Have been used as a cheap/affordable, energy dense, reliable source of energy in the past to build economies and society

However, in modern times, there’s been concern about the potential environmental impact from emissions and pollution (although, new coal power plant technology might address some of this), as well as them being considered a non-renewable resource

Natural gas is considered by some to be a ‘transitionary’ energy source from coal in some countries, whilst others debate the merit of this.


– Renewable Energy

Some reports point out the potential environmental and sustainability related benefits of renewables compared to fossil fuels

However, other reports point to the potential drawbacks of renewables too


– Nuclear

There might be a different perception of nuclear in different countries

Some countries might see the benefit in nuclear, some might want to move away from it, whilst some may be neutral on it


Further Resources on Renewable Energy, Fossil Fuels, & Nuclear Energy

Considerations When Choosing Different Energy Sources In The Future





1. Various ‘Better Meets Reality’ guides














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