If you are an environmentally aware reader, hardly does a day go by when we do not see the word ‘renewable energy’ as the savior of humankind. Solar, wind, tidal, and the well-established hydroelectric energy, are championed globally due to their clean, emission-free nature and receive advocacy in a nearly by-default way, while other energies usually face intense criticism while being vilified as dirty and obsolete. Are those so-called energies of the future that flawless?
Despite its cleanliness, an inherent shortcoming of renewables is its intermittency. Since antiquity, humankind has longed for the capability of weather controlling through ancient rituals such as rain dances or sacrifices, with unsurprisingly erratic outcomes (this was why monks were almost always placed high in the social ladder, when times were good, it was their own achievement, when times were bad, it was the king and his subjects who did not pay the adequate tribute to the deities, what a low-risk, high-reward job). Nevertheless, our ability to control weather is strictly constrained within creating or eliminating rain – one of which was the opening ceremony of the 2008 Olympic in Beijing).
This lack of control means renewables are at the mercy of the deities’ whim, their first inevitable flaw. Many people wholeheartedly advocate the year-round use of renewables over fossil-fuel powered ones. What they often fail to notice is that during the intense dry seasons, with heatwaves covering most parts of Vietnam and hardly any rainfall, it is usually the coal-fired power plants which prevents the grid from outages and keeps your air-conditioning running at night, relieving you from this inferno.
Hydroelectricity generation is impossible when water levels at a reservoir reach a dead-pool level, which is exacerbated by intense evaporation and no additional rainfall, rendering it impractical for a dam to work continuously. For wind turbines, they are high-maintenance owing to their significantly higher numbers of moving parts, prone to unpredictable wind patterns; for example, most could only work at maximum efficiency with winds blowing to them at a certain angle. While there are now technologies which allow the turbines’ angle adjustment based on wind conditions, this entails more cost and risks of malfunction because even more moving parts are involved. Tidal power may sound good on paper, but the amplitudes of tide vary daily as they are dictated by the relative position between the Earth, the Sun, and the Moon. Hence, its productivity peaks during full-moon or moonless periods (which is when our city is submerged under water due to high tides), while being far less productive during crescent-moon phases as water flow remains stagnant. If you have read (perhaps reluctantly) the poem ‘Sóng’ by Xuan Quynh in high school, you may have learned why wave energy is unreliable.
Solar energy is a stellar candidate in Vietnam (pun intended) as a comprehensive option to achieve net-zero objectives. Gifted with abundant annual solar irradiance, it is irrational to ignore this energy source as a tropical country in which many regions’ numbers of annual sunshine hours exceed 2,000. However, other factors are at play here. Costs are indubitably one of them, given the fact that solar energy often requires an entirely new electrical grid for safety reasons. The explanation for this new transmission system is that solar energy also suffers from intermittency. Imagine a cloud mass passing through blocking the panels from our much-needed sunshine. Our existing electricity infrastructure is equipped for centralized and predictable sources, such as fossil fuels. Solar power’s maximum output could lead to overcapacity of the existing grid, while an overcast day could cause voltage and frequency fluctuations, potentially engendering malfunctions or complete grid failure (nationwide blackouts).
Capitalists are always bound to devise new ideas and initiatives for our problems, such as battery systems, but the prices are more than prohibitive. A battery system for 1 million households could cost 8 billion dollars at the minimum. This cost and the overhaul of the entire electric grid, with substation transformers, high-voltage power lines, could account for a large percentage of a country’s total GDP, which is beyond the reach of most developing countries. Unfortunately, investments for nighttime solar electricity generation must also be considered, as solar panels are largely so-lame panels during nighttime. There are certain models for this, such as the aforementioned battery systems. Another paradigm is the integration of dams and solar panels, in which the excess energy will be utilized to pump water to higher elevations and stored behind a dam, and this is in turn converted into energy during nighttime. While being sound in theory, investment costs could amount to billions of dollars, discouraging both private and public sectors. And more often than not, we consumers have to bear the costs of innovations and technological marvels.
Almost every one of us wishes to go clean, but when it comes to the bill, we become much more gentle and hesitant.
