All climate change effects would be less harmful with greater efficiency.
It is said that, worldwide, we waste approximately 60% of energy and 35% of all the food we make.
What does that mean?
In terms of energy, that means that, for every 10 gallons of fuel we burn, we waste 6 gallons. Also, it means that if we would use that energy better, we would, on average, travel 625 miles, instead 250 miles with the above-mentioned 10 gallons of fuel. If we take that a gallon of gasoline costs $3.50, instead of paying $87.50 for a 625-mile trip, we would pay $35. In the grand scheme of things, it also means that there would be fewer tanker trips and that overall we would save more fuel.
Also, consider this: combustion engine thermal efficiency is terrible—only 30%. That means that you are literally throwing away 70 gallons for every 100 gallons used, and well-to-wheel efficiency is even worse: only 14%, meaning that, for each 100 gallons extracted from a well, only 14 are useful while 86 gallons are wasted, due to inefficient technology.
What would happen if we would get energy from renewable sources and then use it directly, or first convert it into hydrogen, or synthesise fuels like methane, gasoline, or ammonia?
The direct approach with batteries has 73% overall efficiency, while using hydrogen is hugely wasteful, due its efficiency of around 22%, and synthesising fuel for ICE (internal combustion engines) has an even lower efficiency: 13%.
In order to travel the same distance with the ICE, we would need almost 8 times more solar panels.
As solar has a relatively low ROI, using cars in inefficient ways would add to the overall cost, therefore making the initial investment more expensive than any existing technology.
What does that mean in terms of CO2 and global warming?
Instead of emitting roughly ~10 Giga tonnes of Carbon, we would emit only 4GtC, significantly slowing down global warming’s progress and its effects.
What about solar panels and renewable energy?
Most current solar panels are up to 22% efficient.
We can argue that they are cheap, but they have their own issues, like space requirements, longevity, scalability, infrastructure, cost, and pollution during the production phase (some types more than others).
Although there is plenty of space in the world’s deserts, in order to replace all energy sources, we would roughly need an area the size of Spain (505,992km2). Although this is a relatively small area in comparison with the planet’s size, it is still huge. Cost-wise, in order to install everything, it would require a significant amount of money: ~$250 trillion. Taking into account that the world's GDP is roughly $80 trillion, it is obvious it would be impossible to replace our energy infrastructure’s current needs in a short time.
Looking from one's home perspective, where 10kW per household would satisfy these requirements, we could cover an area of around 56m2. That is not a lot, but, even then, we are forgetting Tesla cars, for instance, that use ~80kWh (solar panel area 448m2) on a daily basis.
Usage of renewable energy sources with ICE in this instance would require 3640m2 (56 + 3584), or a roof with sides of 60 by 60 meters. Knowing that a typical American football field has an area of 57600 square feet (5350m2), it is obvious that, for powering an inefficient ICA car with currently-existing solar panels, we would need to cover more than half of the football field per single household with one car. At this point, it is worth remembering that there were around 1.8 vehicles per U.S. household in 2013; in 2017, that number is a bit higher.
Now, try imagining all that on a global scale—where human energy needs are measured in terra Watts.
Doubling solar panel efficiency from 20% to 40%, which is not huge, would mean halving the total necessary space for solar panels, therefore reducing the price and work necessary to install all of them.
To satisfy all human energy needs, we wouldn't need the area of Spain but roughly that of the United Kingdom.
Smaller area requirements mean less material used during production, fewer minerals, less energy during production, and, in the end, faster implementation—instead of taking 10 years, it would be possible to do the job in 5 years.
Now, imagine 100% efficiency, and everything reduced by 5 times: space, material, energy, installation time, and overall cost. Unused space, even deserts, could be used to grow food or to re-grow forests. With 100% efficiency, solar panels on cars’ roofs would be much more feasible; we could power cars directly, significantly reducing battery size, and again have a very long range.
But, what about night driving?
With efficiency that high, we could power cars by directed streetlights—although more or less I am joking, this is not very far from reality.
Be careful the next time someone says that efficiency doesn't matter. It does, and, although it is not everything, it is a great deal of things. If you are one of those guys claiming that efficiency is not the issue, this text is for you. For everyone else, I hope it was informative. The next time someone dares to say that efficiency is not important, you can “slam” him or her with this article.