Is switching to the latest, most energy efficient technologies and methods always a good idea? Do they save energy or waste it?
You might be surprised at how many new technologies and methods can actually end up using more energy than the old ones!
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 (PHS) plants, such as this one at Cruachan in Scotland, can often use more energy than they produce, 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 to pump water from one reservoir to another, the rest of the process is very efficient, and PHS is a valuable part of the energy mix.
You can think of PHS like a giant rechargeable battery. It’s a way to store energy that is very flexible, it can be turned on or off in about 10 seconds to meet any gaps in electricity demand over a large area of the grid. So here, it’s not so much wasting energy, as using more of it to create advantages elsewhere.
But it is important to consider where the electricity to pump the water to the top comes from, burning fossil fuels or renewables?
Heat pumps are becoming more and more popular as a way for people to heat their homes. They work in a similar way to a fridge, using liquids to take heat from the air or ground which is then pumped into the heating system to warm up or cool down your home.
They have a number of benefits. Heat pumps can save consumers money on their energy bill. They can both heat and cool your home so you don’t need a separate air conditioning system. Plus, heat pumps reduce peoples’ carbon footprint by allowing them to stop burning oil or gas for heating.
However there are some potential downsides to heat pumps. Depending on the type of heat pump there might be a lot of building work involved, the liquids used in the system can be harmful to the environment, and they do increase how much electricity people use. This can put a strain on the grid and means they might not be CO2 neutral if the electricity is generated from fossil fuels.
We are told that recycling is one of the best ways that we as individuals can help to combat climate change and pollution but is this really the case? What is the balance between saving and wasting energy here?
- Less raw materials extracted from the earth.
- Not as much rubbish in landfill sites or being burned.
- Reduction in pollution.
- Creates jobs sorting, collecting and processing.
- Increases environmental awareness.
- Some materials use a lot of energy to be recycled.
- CO2 emissions, recycling is often transported all over the world to be processed.
- Pollution, from transport emissions as well as harmful chemicals used to recycle some materials.
- Products made from recycled material aren’t always of good quality.
- Recycling plants are very unhygienic places to work.
- Recycling can make people think they’ve done all they need to do.
Some people think we shouldn’t worry so much about recycling and should focus on reducing how much we use and re-using what we do use to avoid a lot of the negative points of recycling.
What do you think is the most important part of Reduce Re-use Recycle?
Carbon Capture and Storage
Conventional power stations such as coal, oil and natural gas, as well as manufacturing and heavy industry release a lot of CO2. Currently it is believed to be too expensive to make all these processes fully green so CCS or CCUS (Carbon Capture Usage and Storage) is thought to be the answer.
By capturing the CO2 directly where it is produced, we can prevent it from going into the atmosphere and contributing to climate change.
As well as CO2, CCS can capture other pollutants before they are released into the atmosphere and the captured CO2 can be used to produce plastics, nutrients and foods which are more carbon neutral.
There are some challenges to overcome, the long-term safety of storing CO2 underground is still uncertain, leaks could be dangerous. Capturing the CO2 takes a lot of energy which means that more energy needs to be produced. It is expensive, but the IPCC (Intergovernmental Panel on Climate Change) estimates not using CCS will end up costing twice as much.
Currently a lot of the captured CO2 is stored in depleted oil wells, as well as supplying a storage location this also allows more oil to be extracted from the well. Many people think this defeats the point of capturing the CO2 in the first place.
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, there is a positive 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. When burnt to produce electricity the only exhaust gas is water vapour, and if spare renewable energy is used to make the Hydrogen (from wind turbines at night when demand is very low) it means we aren’t letting any potential energy go to waste.
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 one 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.