Sustainability Death Match | Renewables vs. Energy efficiency

Can't see the wood for the trees

A pal of mine is building up his house, and he’s determined to install both solar heat collectors and photovoltaic panels on the roof. He asked me for advice and, talking about that, he came up with a horrific idea that made me shiver with unease by his tone of conviction “well…I’ll have electricity and hot water from 100% renewable power: I can forget at last about turning off the lights or caring about closing the hot water tap [… ]” (I cut the rest for the sake of politeness).

As a freak in the field, it seems to me very difficult not to traduce this into something like “why caring about saving energy if I can use as much as I want for free”. Or rather: why saving energy or applying energy efficiency measures, when there is free inexhaustible energy? To give an answer without beating about the bush or being pedantic is hard. But I believe such an interesting (and common) question is worth a try.

A few words about renewable energies

As renewable energy we include all that derived from solar radiation, gravity, geothermic, and life. Heat, wind, tides, waves, oceanic and river currents, water reservoirs, biomass, electromagnetic radiation, and more. Renewable power provides enough energy to cover several times the energy needs of our planet (including human activities). To give some data, solar energy alone furnishes 173 TW of energy to the Earth, with more than 1kW/m2 of solar radiation on the surface (depending on latitude, season, etc.)

These energy sources are at our disposal to replace or to give support to the demand we have been satisfying with harmful non-renewable energy ones. As technology evolves, we can benefit from renewable energies in more practical, efficient and extensive ways.  

So, if there are renewable sources everywhere, they can be found and exploited massively, and belong to all people… ¿why should we invest into saving them? Let’s take some time to reflect on it.

So different yet so alike

We all have our personal way to use energy. There are those who take the car and those who prefer walking; those who systematically leave the lights on and those who live in the dark; those who (like me) are obsessed with green energy labelling, and those who buy fridges with TV screen embedded and Wi-Fi system; those who still use their grandfather’s car to commute  and those who by the latest PHEV or EV model. But they all have something in common: they all worry about the price of their monthly energy bills.

And that’s a reason for many consumers to go for renewables. The idea of taking advantage of energy sources that are free, widely available, and clean, is quite appealing… enough to not worry about consumption and bills anymore. Huge mistake! This paradox is called the rebound effect. We’ll discuss about this in another occasion, but it refers to a well-intentioned plan turning out to produce an opposite effect. This is a clear example. 

The tough reality

No matter the install: it must be calculated to satisfy a certain consumption demand. Obviously, the higher the demand expected, the higher the size and complexity of the system, and so the higher the price of acquisition, exploitation, maintenance, amortisation, ROI, etc. Likewise, we cannot expect a system designed to produce 10 kW of electric power and 90 L/day of hot water, to yield 15 kW and 150 L/day, only because we squander energy. Not happy with it? Oversize your install and pay.

Another interesting fact. Devices are rapidly becoming more energy efficient, but we also become more dependent on them (the rebound effect attacks again). Once upon a time, we had a cathode-ray tube TV for all the family; today there are flat-screen TVs in every room. The traditional gas cooker has been replaced by an induction stove, a microwave, a kettle and a modern coffee machine. This is a major issue when it comes to energy efficiency.
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In line with this, saving energy by incorporating efficient devices to our lives is the first step to save money and emissions, but only if we don’t compromise consumption for comfort. 

So, what's the aftermath of this death match?

The result is a fair draw with both approaches merging into an energic handshake. To be economically and technically feasible, renewable energies must rely on energy efficiency measures. On the other hand, energy efficiency is not a solution in itself. It doesn’t imply clean energy sources. It’s only a means to produce more energy with less resources, regardless this latter.

Thus, we need efficient renewable energy to attain our goals of sustainability. Efficiency in production and consumption, and renewables to decarbonise our society. Eco-efficiency is the real winner!

So, pal of mine: if you really want to save money, do take rational use of electricity and hot water seriously. Do not have all devices on and do not abuse from consumption because it is “free” (now, we know it’s not). Otherwise, you might find yourself going to the corner bar to charge your phone, or taking a shower at your neighbour’s. 

What do you think? Are you a born energy saver? Do you have renewables at home? Feel free to share your ideas and comments below :)