This is homework my daughter brought home from school.

It needs a little correcting:

"So why don't we switch everything over to solar power? The simple answer is that fossil fuels are more efficient and cheaper than solar energy"

Is it really more efficient to fight wars and run pipelines for oil, ship it across the planet in super-tankers, refine it with electricity, transport it in trucks to service stations where more electricity is used to pump it into your car which burns it and wastes 80% of the energy in it as heat, noise and vibration; or perhaps just charge your electric car from solar panels at home?

Or mine coal with diesel and human lives, load it on trains to transport it to a power station, then set it on fire wasting about 2/3 of the energy in it as light, heat and pollution; or perhaps just make use of probably the world's most plentiful solar resource and drop a load of panels somewhere in the outback, coupled with batteries and pumped hydro storage for overnight supply, and run your house from that?

As for cheaper, it would take $3b and 8 years to build a new coal plant. The industry isn't doing that, it's investing in renewables instead. Coal and oil is only cheaper if you are ignoring government subsidies, and the sunk and externalised costs (eg. health).

"Solar power is a weak source of energy"

It's strong enough, and cheap enough, for this to be nothing more than a weak argument from a dying industry.

"Although some experimental solar-powered cars have been made, they cannot go very far or very fast and are very expensive"

We literally drop our kids at school in a car we fill up with solar power. It can go anywhere there is electricity (look around - is there a power point near you? We can fill up from that), is faster than our new diesel SUV (that we reluctantly bought for towing and 7 seats), and cost us just over $20k.

"People are hopeful that one day we will be able to use solar power to take hydrogen gas out of water"

The only people hopeful of that are large oil companies, who hate the idea that you can charge your car at home and make them irrelevant. No more drilling, pipelines, refineries or service stations. All of those are still needed with hydrogen, because you can't make it yourself. This is not true for solar panels on your roof.

Almost all actual hydrogen production today is done with fossil fuels, not solar.

Even huge ships are already replacing their diesel motors with electric plus battery, charged at their ports. Given time, they won't need hydrogen either.

The only thing that might still absolutely NEED fossil fuels in our lifetimes will be long-haul flights (massively damaging for our planet, please reduce!), and rockets to leave our atmosphere.

It's things like this that make me really upset, when our school gets a lovely new playground it desperately needs funded not by the government, but the happy smiling people at South32 Illawarra Coal and AGL.

References:

https://www.smh.com.au/politics/federal/coal-or-renewables-which-is-cheaper-20190311-p513cs.html

https://en.m.wikipedia.org/wiki/Fossil_fuel_power_station

https://electrek.co/2017/10/26/toyota-elon-musk-fuel-cell-hydrogen/

https://youtu.be/rE_M1n-ClOA

https://youtu.be/1SafVI7vKs4 - we rode on this!