There is the million-dollar question! And one that is quick to answer without going into too much detail.  
Green Energy is energy that can be generated with little or no impact on the air, the environment and the resources planet Earth affords us.
But, not all clean or renewable energy is green. Confused? You won’t be if you read on!

Does ‘renewable’ mean the same as green?

No, not really and we’re going to throw ‘clean’ energy into the mix too, just to give you a better idea of what each phrase really means.

What is clean energy?

This is energy that creates little or no pollution when generated.
We’ll ignore the construction, manufacture and transport of any equipment needed as that is a whole new blog, so this is just about the method used to make electricity.
Nuclear would be the best example of ‘clean’ energy.
Nuclear is incredibly efficient, it creates heat through fusion, which has no greenhouse gases and over the last half-decade the use of nuclear power has reduced CO2 emissions by over 60 gigatonnes.
But, it does create some very tricky waste and uranium isn’t renewable, when it’s gone, it’s gone.
Hydropower would also be considered clean, rather than green, because although emissions are negligible, hydro-electric dams cause a great deal of harm to the environment in terms of displacing wildlife, destroying habitats and reducing biodiversity.

What is green energy?

Although all these terms can be a little interchangeable, green energy generally comes from natural sources.
By that we mean, wind, water and light.
Solar energy is at the forefront of the green energy revolution, especially in the domestic sector.
The sun is renewable, well for the next 4 billion years, the power it produces doesn’t create any greenhouse gases and reduces water use.
Wind power is the next on our list and, while it’s used more in utility scale electricity production, it’s harder to get approval for the construction of windmills.
Wind is renewable, if slightly unreliable, once again there are no greenhouse gasses produced from energy creation and, because the windmill is its own turbine, no water needs to be used.
Geothermal power isn’t as big in the UK as it is in places Iceland and the Scandinavian countries.
Taking natural hot water out of the earth and using as either direct heat or to spin a turbine.
It’s renewable, green and has low CO2 emissions.
The only geothermal power station we have here the UK is in Southampton, and it provides heat to the Southampton District Energy Scheme.
Wave/Ocean power is a very under used source of energy here in the UK, which is madness as we are a collection of islands surrounded by the sea!
So long as we aren’t taking the water out of the ocean, wave and tidal power are both considered green energy, although it is somewhat under used do to the cost being too high and technology not being advanced enough.
The power potential in both waves and tides is immense and the energy produced would be free from greenhouse gases, avoid the use of fresh water and the sea isn’t going anywhere anytime soon.

What is renewable energy?

All of the above, is the answer.
Renewable energy comes from sources that are not finite.
Finite sources are those that reduce the more we use them – like gas, oil, coal and nuclear.
Obviously, wave, wind, hydro and solar are all ‘infinite’ and do not deplete when we use them to create electricity – but there are other renewables that we can merely ‘replace’ … these are called Biomass.
Biomass is organic material that can be burned to create heat to warm water to create steam to turn turbines to create electricity.
As to can see from that tortured sentence, the only ‘green’ thing about biomass is the fact it’s renewable, you still need lots of water and it still creates CO2, but not nearly as much as fossil fuels.

What is zero-carbon?

Zero carbon means that the method you are using to make anything does not produce any CO2.
This can apply to electricity generation from wind, solar, hydro and geothermal. 
Net Zero, which is something we hear a lot about, means that we can mitigate the amount of CO2 produced by a process by taking an equal amount out of the atmosphere.
For instance, running a petrol car for a year, but you then plant 240 trees, you have become carbon neutral and achieved Net Zero Carbon.
It’s not something individuals do, generally, but as a society we should be working towards a carbon neutral future.
The government has committed to Net Zero Carbon by 2050, but many environmental scientists believe this is not soon enough.

Green energy: Pros and Cons

So, if green energy is so good, how come we still have none-green energy?
Mostly because of money and infrastructure, but this table gives us a good idea of what else is stopping us from going totally green and why we really need to start removing these barriers.

Cheaper to produceExpensive set up
Low Maintenance CostsLow infrastructure
Less CO2 and greenhouse gassesCan be un-reliable
Less pollution all roundStorage is an issue
Minimal use of waterLow Government support
Won’t run out 
Creates jobs 

The cons on this table aren’t exclusive to the UK, these are global problems that are the result of using fossil fuels for well over a century.

Governments and green energy

We can see in the table that low government interest is one of the barriers to green energy really taking over from fossil fuels, but that doesn’t mean that there is no government interest.
196 parties signed the Paris Agreement in 2016, which was a promise for all those countries to reduce their carbon footprints to Net Zero.
Most countries are set to miss the target as it stands, and the US was briefly in the wilderness while their 45th president was in charge, but scientists are urging governments to get their act together and start pumping money into alternative energy sources.
In terms of percentage of green energy used, as of 2021, the 3 top countries in the world are:
Norway – 45% – mostly Hydro
Brazil – 32.1% – mostly Biofuels and waste
New Zealand – 25% – mostly wind and solar
When it comes to amount of electricity produces the top 3 are:
China – 1020 gigawatts
USA – 325 gigawatts
Brazil – 160 gigawatts
Unfortunatly, the UK is a long way down any of these list and with the government concentrating on opening coal mines and investing in nuclear, it may be down to us as individuals to start our own green revolution in our homes.

What is green gas?

Green gas could be another great way to power the country without the usual infrastructure problems. 
It’s produced by introducing bacteria to biomass or food waste. The bacteria break down the material and release gas.
Green gas behaves in exactly the same way as natural gas does, so once it’s purified and turned into biomethane, it’s piped into the gas grid.
It’s then used in homes up and down the country.

The future of green energy

Will green energy replace fossil fuels?

Frankly, it’s going to have to at some point.
Oil, gas and coal are all finite resources. Once they are gone, they are gone.
Looking at current data and based on current consumption, we have 47 years of oil left, 52 years of gas and 133 years of dirty, dirty coal.
If we continue to burn fossil fuels at this rate, we will be pumping millions of tons of CO2 into the air, causing the world to warm and the air to become less breathable in certain areas.
In conclusion, the future of green energy looks good, but it needs to be the ‘present’ of green energy, not the ‘future’.

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