That's pretty difficult in the UK, because most energy is used for heating. You can do OK in the summer though.

No, because that was just one short period.

Rates aren't going to go down for decades, because even after we've built enough turbines to replace all the existing power stations, we'll still need to build enough to drive our vehicles, heat our buildings and replace gas and coal use in industry.

We've all gotten too used to cheap, dirty power.

That's just the gas that is used to generate electricity. The UK uses a lot of gas for heating too, especially at this time of year.

Really not very much. Here's a nice, real-time chart. https://gridwatch.co.uk/

A steam engine that runs on the waste heat of a jet engine. Sort of.

That's the nature of a two party system. You get more votes if you position yourself fairly close to the other party. That way you get a bigger share of the 'middle of the road' voters.

If the democrats were any more left-wing, they'd get fewer votes.

You don't get to vote for someone you like, just the party you dislike least.

That's always been the problem. If you spread your defences along the border, the enemy can concentrate and punch through anywhere they like. Instead you need a decent reserve that can stop an attack and hopefully cut them off.

If you really don't want to ever lose any ground, you need significantly superior forces right at the border - which looks like you're about to invade and really worries the nuclear power on the other side.

The problem there is the same reason swappable batteries for EVs never caught on. You'd need all the vehicle manufacturers to agree on a design, and the filling station networks would have to agree to accept each other's old bottles. And that has to still work if you drive from the US into Mexico, or Europe to Asia.

There are lots of CNC etch-a-sketch projects around. It's a really good way to learn the basics of CNC and robotics.

https://www.geekmomprojects.com/etchabot-a-cnc-etch-a-sketch/

Then you get projects like this: https://www.v1engineering.com/zenxy-v2-sand-table/

People often quote the Hindenburg disaster showing that hydrogen in dangerous, but if you look carefully you can see that the hydrogen has floated up above the rest of the airship, and is burning well away from anything important.

It can mix with air to form an explosive, just like gas/petrol vapour or propane/butane - but when spilt, it's less likely to hang around and be a fire risk than a heavier fuel.

I love the idea of a skyhook - they seemed like an idea that could only work on paper, until Space-X started landing boosters on barges.

I can see how you could visit it, then it drops you off when you go home, but if you use it to launch things into orbit, doesn't it lose energy?

I've seen proposals where it flings things to the moon or mars, and recovers energy by catching incoming mining products - but could you use it just to put things in orbit?

The next logical step in most discussions about space elevators is that you can taper them.

However, you're right, it's still not practical with even the best current materials, even if it's hair-thin at the ground, it would need to be impossibly large at the orbital end.

That's a false equivalence though, as towers are compressive structures (that buckle before the material fails), while a space elevator could be in tension. A 1km tower is hard, but we regularly hang cables 1km down to the seabed, or for suspension bridges.

In Red Mars a space elevator on Mars is sabotaged, and it is long enough to wrap right around the planet when it falls...

Right now the biggest problem is that it's really expensive, and takes a long time to build. Investing billions that won't start pay interest for at least 10 years isn't attractive to banks that need to show a profit every year, or governments that have to face an election every 4 years.

That's one of the reasons why small modular reactors are interesting. You don't have to invest so much before you start to see a return.

It's also why wind is doing so well. It's easy to borrow the cost of a turbine, or even a wind farm, and it starts making money pretty quickly.

Battery swaps would be much easier for mine trucks than long distance truckers, because all the batteries would be owned by the same company and the mine truck is never far from the charger.

A long-distance truck in Europe would probably be in a different country every time it needs a battery swap, so not only would the battery format have to be standard across all brands, but the billing system would have to handle multiple companies supplying batteries and charging infrastructure. Unless someone like Tesla could roll out a world-wide monopoly.

Yes, not needing to roll out charging infrastructure across the world (or agree one standard) make this much easier than cars.

Even a forklift battery is far too heavy to lift by hand. The battery handling is part of the system. I'd imagine the truck would be able to lift and lower its own battery, and they'd use a long lead to power the truck between batteries.

And flying higher means the air is thinner, so there's less drag. So even if the engine is less efficient, the overall flight can be more efficient.