Published Date 2/21/19 7:00 AM
What is heavier: a kilogram of stones or a kilogram of gold?
This question may seem confusing, but the answer is simple… they both weigh the same!
However, they are not really the same in terms of their other characteristics, and I’d bet that the vast majority of readers would rather take a kilogram of gold than a kilogram of stones. The reason is that the perceived value of the former is generally far greater than that of the latter.
In the same way, I could pose the following question: what is the higher amount of energy between a kilowatt-hour of electricity and a kilowatt-hour from crude oil?
Once again they are the same! But everything else is not really the same, as what can be done with each is very different.
Here physics and thermodynamics come into play: they teach us that the quality of electricity is by far higher than that of crude oil. In concrete terms, using an example we can say that if we used the same kilowatt-hour of electricity in our car, we would drive much further than with the same kilowatt-hour from petrol.
Electricity is our gold!
It is no coincidence case that since its advent, humans have invested massively in electrical network infrastructure. Still to be completed after more than a hundred years, we still pledge huge public investments for the growth and adaptation of the electrical network. This represents the hardware infrastructure that powers our homes, our factories and maybe one day also our transport.
The International Energy Agency (IEA), one of the most reputable global organisations focussed on energy matters, has dedicated ample space to electricity in its annual reports, the World Energy Outlook. The following is an excerpt from one of the latest releases:
“Electricity supply worldwide is set to diversify and decarbonise, with low-carbon generation overtaking coal before 2020. Coal-fired power’s share of generation is projected to fall from above 40% now to 28% in 2040. By then, wind, solar and bioenergy-based renewables combined increase their market share from 6% to 20%. China generates almost all its incremental power from renewables, nuclear and natural gas. Globally, by 2040 producing a unit of electricity is projected to emit one-third less CO2 than today; but emissions from the power sector still rise by 6%.”
In other words, electricity generation is at the forefront of decarbonisation, however what has been done so far globally is not going to be sufficient to offset the growth in CO2 emissions due to the considerable increase expected in global energy demand. Some continents have however performed better than others. In particular, Europe has been able to curb emissions related to electricity generation above all via energy efficiency and the switch to renewables thanks to incentives. These two factors have resulted in much better results in containing CO2 emissions than from other measures implemented, such as the Emission Trading Scheme.
The effects of Norms and Regulations standards and regulations that have driven R&D activities and the industry towards more efficient solutions have probably so far made the biggest contribution to the offset of global warming due to the greenhouse effect.
The World Energy Outlook also goes on to describe the evolution of the electricity network, especially regarding renewable sources:
“The relationship between electricity demand and generating capacity is set to change: every new unit of generation is likely to necessitate the provision of 40% more capacity as over the period 1990-2010, as the renewables share of capacity soars. The reason is that the capacity factor of renewables such as solar and wind is lower than that of thermal power, the preferred plant choice of the earlier period. Accordingly, installed power capacity is projected to approach.”
I can rephrase this with reference to two very important sources in the renewables mix. Wind and solar are two sides of the same coin. The wind or breeze we feel when on holiday at the seaside are the direct effect of solar irradiation to earth. And they are both kinds of energy of lower quality (density) than that of fossil fuels: again, this comes from the physics and thermodynamics that helped solve the initial questions. Moreover, wind and solar are stochastic forms of energy, which counter programmed power generation in conventional thermal (i.e. coal, or gas-fired) plants. But the issue is this: everyone wants to turn on their TV or any other household appliance when they want. And not only when the wind is blowing. As a consequence, electricity generation plants and the network must bear the burden of providing power whenever renewables are not available.
The complications to obtaining clean energy on a large scale are increasing, however luckily the advent of more sophisticated methods is helping support the adaptation of electricity networks. Smart grids and smart devices are the key to success in the transition into the evolving energy mix. The shift towards sustainability has just begun, and it will take decades before another stable asset in the electricity network will be met. Much will also depend on the evolution of the transport sector. However, in the first instance, it will again be a matter of energy efficiency. This is still today the main game changer in sustainability.