In secondary school, we learn that sun is the primary source of energy on earth. This means the sun rays falling on earth eventually power up everything, from automobiles to microwaves to elevators in a multi-storey building.
An example easy to relate to is the fuel used in car engines. That fuel is derived from rock formations that take millions of year to form under intense heat and pressure. The rock formations are further derived from buried plants and animals. Plants use solar energy for food production, what we know as photosynthesis. Animals eat these plants before getting eaten up by animals.
In a microwave, the electricity used has likely been produced by burning coal. Whatever may be the fossil fuel being consumed, their ancestry is headed by the Sun.
The problem is we are currently using solar energy at a stage by when it has undergone tremendous modification and now sits in the form of fossil fuels that when burnt, releases CO2. This CO2 was meant to stay underground but we are forcibly putting it back into the atmosphere. This CO2 has a hobby of trapping heat that raises Earth's temperature. The climatic after effects of this is something very hard to predict accurately but they are surely troublesome to life as we know it.
Humanity was not lucky to have observed an alternate solution to this until 1839 when Edmund Bacquerel discovered the photo voltaic effect, the ability of certain elements to absorb solar energy and use it to produce current and hence energy as we need it. This is magical because, instead of waiting for solar energy to be first converted to fossil fuels and then converting it into usable forms, we can now convert it directly into usable energy. A task that took millions of years can now be done in a few seconds. This unfathomable comparison proves that advancement in energy production took a terribly wrong turn as the industrial advancement pressed hard on the pedal.
The long standing narrative about switching to solar energy being super expensive hence impractical was not very accurate. We know the cost of anything is driven fundamentally by supply and demand. Better supply and better demand drives it to the 'cheapest' price possible. But since getting the supply and demand drivers upto speed takes time, saying something is expensive is heavily contextual to time. What is expensive today will get cheaper over time only if we make it happen. The first motor wagon by Karl Benz was super costly, so was the first attempt to dig coal out of ground, both in the context of their time.
And intuitively as well, in the long run, a task that takes a few seconds just cannot be more expensive than its counterpart consuming a few hundred million years!