You would be surprised at how many technologies and energy saving methods can actually end up using more energy than other methods!
The decision that needs to be made is whether the extra energy used is worth it for sustainability, reducing waste, or other positive outcomes that they may bring.
Here are just a few energy efficiency methods that it may surprise you are not as efficient as you would think…
PUMPED HYDRO STORAGE
Pumped hydro storage plants, such as this one at Cruachan in Scotland, can often use more energy than it produces, due to the energy needed to pump the water from the lower reservoir to the higher reservoir at times of low demand, like at night.
However, does this energy use make using these types of generation pointless? Not at all! Despite using energy in pumping water from one reservoir to another, the rest of the process is very efficient, and PHS is a valuable part of the energy mix.
It is flexible, able to be turned on and off in around 10 seconds in order to meet any gaps in electricity demand, and for large areas. So here, it’s not so much wasting energy, as using more of it to create advantages elsewhere.
We are told that recycling is one of the best ways we can cut down on energy use. This is due to the amount of energy saved in manufacturing when using recycled material such as plastic, paper and glass, versus making these materials from scratch.
And this is important. However, a lot of energy goes into recycling these items in the first place. From picking up the recycling from your home or local recycling centre, transporting it to specialised centres, and the energy in the recycling process itself, for example, heat energyneeded to melt glass down.
Hopefully, these specialised recycling centres will be nearby, but there can be a lot of travel miles moving recycling around not only the UK, but to as far away as China! The carbon dioxide (CO2) produced on transporting recycled material around from your home to the recycling plants is another problem to factor in.
In fact, recycled plastic can sometimes be transported from the UK to China to make any number of new products, which can then be shipped back to the UK. That’s quite a trip!
As well as energy use, recycling can also add chemicals which contribute to greenhouse gases, therefore creating more problems and not being as clean as we think of it being.
But recycling also cuts down on waste sent to landfill, and reduces the amount of raw materials that need to be mined.
CARBON CAPTURE AND STORAGE
Conventional power stations such as coal, oil and natural gas, as well as manufacturing plants such as iron and steel plants and oil refineries, give off carbon dioxide when burning fuel.
One way of reducing the amount of carbon dioxide that is produced, is to capture it before it reaches the atmosphere, and store it underground.
It’s clear that the less carbon dioxide we release into the atmosphere, the better for our climate. However, CCS actually requires more energy in order to work.
To keep power plants producing the same amount of electricity as they already do, but capturing the CO2 at the same time, can use up to 40% more energy than before!
And this doesn’t include the extra energy used to transport the captured CO2 to where it will be stored underground and building costs.
Again, we need to make sure that reducing the amount of carbon dioxide in the atmosphere, doesn’t use too much extra energy when doing so.
Hydrogen is an alternative fuel that in the future could be commonly used for heating and transport, and as a storage option for renewable electricity.
It can be produced using different methods, and from fossil fuels or renewables. Once again, producing hydrogen requires using more fuel or energy in the process.
But like the other examples in this article, there is a positive flip-side we need to take into consideration when looking at this extra energy use.
Hydrogen has a number of uses, both as hydrogen, and when combined with other elements. Oxygen is a by-product (something produced by creating something else) when we get hydrogen from water (electrolysis).
THE REBOUND EFFECT
All of the above examples could be classed as what is known as the ‘rebound effect’ or the Jevons’ paradox.
This states that as we become more efficient in saving energy, through better technology or something similar, that we can actually end up using more energy as a result.
Take a driverless car. If you are saving fuel by driving more efficiently, and in turn saving money from not having to refuel as often, aren’t you more likely to use the car even more? This would then mean that you might end up using the same amount, or more, energy than before!
William Stanley Jevons (the guy who came up with this idea), noted that improvements in technology during the industrial revolution helped us use coal more efficiently. However, this also meant using even more coal in different areas of our lives and across lots of different industries.
All of these examples mean we have to think more carefully about balancing the energy trilemma; sustainability, accessibility and security.