• Rahul Rao

The future's bright, the future's renewable.

by Yasir Aheer, Rahul Rao and Varun Rao


Summary:

  • Humans have relied on fossil fuels for millennia - wood, coal, oil and gas. The current climate change crisis make this reliance untenable.

  • Adoption of renewable energy is growing globally but most of our energy is still from fossil fuels.

  • Clean, renewable energy has previously been expensive but is now on par with or cheaper than traditional energy sources. This, combined with government subsidies, will force adoption rates to grow.

The Earth has been blessed with pockets of highly concentrated energy that we have been using for millennia to power our civilisation. From the wood that early man burnt to cook food and scare away predators, to the coal that powered early steam engines, to petrol and diesel that take us to work every day, to nuclear energy that powers some of our cities, we have always relied on mining the Earth’s resources for energy.


There are three problems with this approach. Firstly, the environmental impact of mining, whether for coal, oil, or uranium, is undeniable. Secondly, using these resources for energy is damaging to the environment. Oil and coal, which produce the lion’s share of all energy generated on earth, produce 100-200 times the greenhouse gas emissions relative to nuclear energy, a source that we have explored before. Thirdly, those large piles of energy are going to run out. We have an estimated 70 years’ worth of coal left, and even less for oil and gas. Sure, we have plenty of uranium left - another 200 years’ worth - but with the diminishing appetite for nuclear energy, that may not count in the long run. Although the earth’s hydrogen reserves are massive, nuclear fusion is yet to be proven workable on any reasonable scale. Where, then are we going to get our energy from?


The cleanest sources of energy (from OurWorldinData.org)


Enter renewables. Renewable energy takes many forms, such as biomass, solar, wind, and geothermal. Of these, the most used are hydroelectric, wind and solar and these are the ones this article deals with.


Historical global energy mix (from OurWorldinData.org)


Radiation from the sun hitting our planet can be used to generate energy in many ways. The obvious one is solar photo-voltaic that converts solar energy to electricity. With enough covered area, vast amounts of energy can be generated - something like 200W per square metre. Less obvious is solar thermal, where solar energy is used to heat up a fluid, which can then be used directly to heat areas or can be used to produce steam to drive turbines and generate electricity. With higher efficiencies than solar photo-voltaic, but also higher set-up costs, solar thermal is used for large-scale power generation.


Even if we miss out on the rays of the sun, we get second and third bites of the apple. Solar energy is responsible for air currents and wind. Windmills use massive rotating blades to capture some of the energy of air rushing by to produce electricity. When grouped together in wind farms, windmills can produce astonishing amounts of energy. For example, the Gansu Wind Farm in China’s Gobi Desert has a currently installed capacity of 8GW, with plans of expansion to 20GW. This image of the Gansu Wind Farm hardly does justice to its sheer scale.


A road winding through the gigantic Gansu Wind Farm (from EV Wind)


All this air rushing around produces collisions of different masses of air, some hot and some cold. When cold, dry air collides with warm, moist air, we see precipitation, generally in the form of rain or snow. Precipitation in mountains and on plateaus are where most rivers originate. As rivulets gather to form raging torrents, the opportunity for hydroelectric power generation grows. Dams on rivers can force them into driving massive turbines to produce electricity. Once again, China leads the way - the Three Gorges dam is capable of generating a whopping 22.5GW. Its reservoir extends 600km upstream of the dam and covers an area of 1045 square kilometres - larger than 25 countries in the world.


The result of these massive renewable energy infrastructure projects is evident in the figure below, which shows most of the world was producing much more energy from renewables in 2019 than in 2018.


Annual change in renewable energy generation globally between 2018 and 2019 (from OurWorldinData.org)


As with any technology, the effect of renewables will only be seen with widespread adoption. Historically, adoption has been difficult from a price perspective, with renewable energy infrastructure being anywhere from 1.5 to 4 times as expensive as the cheapest fossil fuel alternative. In the last 10 years, however, this argument has been weakened by the steady drop in the price of wind energy and the dramatic 89% drop in price of solar energy.



Change in cost of electricity from different sources over the decade 2009-2019 (from OurWorldinData.org)


Even so, household solar is sometimes difficult to install as the occupier may not be the home-owner. In Australia, over 30% of households were renters in 2016; neither for the renter, nor the owner does there exist sufficient incentive to bear the up-front cost of solar installation. Solstice, a US-based startup, has an innovative idea to overcome this challenge - the notion of a community “solar garden”, where households can pay for a share in a solar farm installed somewhere in the community.


Governments are helping out too. In Victoria, the state government subsidises solar installations for eligible homeowners to the tune of $1800, while also offering the option of an interest-free loan. In parallel, the federal government offers Small-scale Technology Certificates (STCs) with every installation of solar, wind and hydroelectric energy systems, which are exchangeable for discounts on the installation, or can be sold on the open market to offset the installation cost.


But all is not rosy in the garden of renewable energy. As with every decision mankind has made in his history, there are tradeoffs to be factored in. Renewable energy, too, has its environmental cost. Solar panels are made of materials that are difficult and expensive to recycle and too toxic to go to landfill. When the current generation of solar panels reach their end of life, they will require innovative solutions for safe disposal. Even their manufacture has questions over carbon footprint. Wind farms have a much lower energy density than solar farms and so must span much larger areas. There have also been concerns raised about undesirable mixing of atmospheric layers by big wind farms, leading to local increases in temperature. Hydroelectric energy has had its fair share of detractors too, as the damming of rivers causes the loss of large tracts of habitat for wildlife in the downstream regions, while also increasing the potential for flooding of upstream regions.


Parting Thoughts

With the climate change crisis undeniable, it appears that we must leave behind the age of fossil fuels and turn our gaze to renewables. Solar, wind, and hydroelectric power are all zero-emission technologies that do not (for the most part) contribute to greenhouse gas emissions. They all come from the sun, so there is no danger of running out anytime soon. Of course, they all have their drawbacks but the old adage “the perfect is the enemy of the good” stands true - these weaknesses are no reason to stick to fossil fuels. As we reach the climate change tipping point scientists have been warning us about, it may well be a case of now or never.


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Disclaimer: This article is based on our personal opinion and does not reflect or represent the views of any organisation that we might be associated with.

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