RENEWABLE ENERGY: What's YOUR main cause for concern?

[Mw Roofline]

The fact is, eventually we will have to move over to renewable energy, when non-renewable resources run out...

When your childrens children become grandparents.

 

[joe-90]

Renewable resources are a red herring. The world needs CHEAP energy and anything renewable usually uses more energy in production than it gives back. You can't get more energy back form a battery than you put in - renewables have the same problem. You end up using more oil with transport, fertilisers and pesticides than you get back -so just use your oil.

 

[Space cat]

so just use your oil

But, as you've said yourself many times, oil won't last forever. As supplies get harder to find, the price will inevitably go up. Renewables certainly aren't cheap and probably never will be. As I said earlier, in a solar future we'll all be paying a lot more for our energy.

I must say that some of our current efforts at harvesting solar power haven't been very good. How many wind turbines have been built where the wind isn't reliable? How many solar panels have been erected where the sun doesn't shine very often?

There are a few places on the planet where solar power arrives in a concentrated form (hydro-electric power is solar in origin) but, for the most part, it's spread wide and thin. I would suggest that the best way to harvest solar power is to let plants do it. They're very good at it and don't need much maintenance. What we have to do is stop taking the cheap option, namely burning the edible bits, and perfect the process of turning cellulose into fuel. Methanol springs to mind.

Only nuclear power can give us cheap energy on a grand scale and I'm sure that's what we'll get, though maybe not in my lifetime. The downside is that it'll allow the population explosion to continue until we run out of hydrogen. (That's the one element you can't make in a fusion powered factory.) What will we do then; take it from Jupiter? Just how big will Earth be by the time we've consumed all four gas planets?

 

[sooey]

Just how big will Earth be by the time we've consumed all four gas planets?

Ringworld???

 

[thatbloke]

So far we have 250,000 tons of nuclear waste, this waste will stay harmful to humans for 100,000 years.
Thats quite difficult to comprehend until you really think about it.

Put it this way , our present storage systems are only good for 10-20 years.

Some time in the next 100,000 years statistically we are due an ice age, How do you store radioactive waste for 100,000 years , sealed up so the radiation cannot leak from whatever container you choose through an ice age?
Only one country in the world is trying to address this problem.

If you have not yet watched this, and you think nuclear power is an answer then I would urge you to watch it.
Providing you can sit through the advertisements at the start.

 

[sooey]

What are you bovvered about? You've got one of them simpson cars haven't you? Powered entirely by your own sense of smug self satisfaction.

 

[thatbloke]

 

[Space cat]

So far we have 250,000 tons of nuclear waste

I tried to watch that video but our IT department blocked it so I'll have to wait until I get home but, reading between your lines, I guess it's about nuclear power as we have it today, which is fission.

Fission is the not so easy but very dirty way. At best it will fill a gap until we either (a) adapt to a non-nuclear future or (b) get fusion working properly. Fusion isn't entirely clean but it doesn't produce the long-lived heavy nuclides that come out of a fission reactor. The free neutrons can even be used to process that waste into something safer.

 

[thatbloke]

I guess we may make it safer but that still wont deal with the waste we have now, also underdeveloped countries with young nuclear lives will have to catch up.

 

[sooey]

Some time in the next 100,000 years statistically we are due an ice age, How do you store radioactive waste for 100,000 years , sealed up so the radiation cannot leak from whatever container you choose through an ice age?

Shove it in an irish gypo's wallet.

 

[Space cat]

As an aside, when the oil runs out, whilst we can run vehicles on alternative power, what are we going to do without plastic??!

No problem. We use oil because it's cheap but you can also get hydrocarbons out of plants. The chemical industry is pretty sophisticated these days.

Ringworld???

I looked that up. It's an intriguing idea but it would be damnably difficult to build - and the bit about spinning it to simulate gravity is decidedly dodgy. Somewhere in the back of my mind I have 570 m/sec as the maximum surface speed of a rotating shaft before it flies apart. Discworld would have to move at a whopping 1,200,000 m/sec to simulate Earth gravity. For anything bigger than a space station, we'd better stick with real gravity derived from real mass.

Without going into too many calculations, I can see that Megacity Earth would not grow to an unmanageable size before the oceans ran dry so the question becomes "Do we bring Jupiter's hydrogen back here or start building artificial planets, carefully spaced around our current orbit?"

Or do we start taking birth control seriously?

 

[thatbloke]

Ringworld,

This is an artificial ring about one million miles wide and approximately the diameter of Earth's orbit (which makes it about 600 million miles in circumference), encircling a Sol-type star. It rotates, providing artificial gravity that is 99.2% as strong as Earth's gravity through the action of centrifugal force. The ringworld has a habitable flat inner surface equivalent in area to approximately three million Earth-sized planets. Night is provided by an inner ring of shadow squares which are connected to each other by thin ultra strong shadow square wire.

Glad you boys arnt in charge.

 

[sooey]

I looked that up. It's an intriguing idea but it would be damnably difficult to build

No it wouldn't ........ you'd just need to know the chemical formula for scrith.
Seriously though it's a sci- fi writers idea of one possible future. But it's adapted from a theoretical possibility called a dyson sphere, which is something that a more advanced civilisation is postulated to be able to build. It's basically a complete sphere which encircles a star and captures all of the energy it emits. It's made using all of the materials in the system surrounding said star, which was why I thought you may find it interesting.

 

[Space cat]

The Dyson sphere is a more promising design than Ringworld because a sphere is an inherently stronger structure, but gravity would still be a problem.

There is no gravity (other than solar gravity which, at our current distance, is about 0.0006g in the wrong direction) on the inside of a hollow sphere so we would have to live on the outside. Normal Earth gravity would exist on the outside of a spherical shell of similar density a little over 4,000 km thick. Sadly, we don't have that much mass in our solar system.

Heat is another problem. A planet receives solar energy as a disc but loses it to space as a sphere with four times the surface area. To get around this we would need to build the Dyson sphere twice as far from the Sun - but then we would need four times the mass that we don't have already.

 

[Plantoid]

Well it's a wee while since the yes and no brigade have ranted at each other on the thread.

Though to confess I did find both sides of the picture did have a bit of something for me .

I've got a few quid I can either bung in a financial institution and hope there is some thing still left in a couple of years or I can try and put it elsewhere that is of use to me today & for a few years in the future

I've done a bit of research this last few weeks ( before i discovered this site ) and find that the department of energy now suggesting that the ROI on a 4 KW set up is around 6% on average .( several of my Certified Engineer pals tell me it could well end up being much better long term if I take things up in the next few months ).

That's now looking a good place to me to now put my money as the installation costs are a fraction of what it would have cost say 4 years ago when the idea of PV generation first seriously crossed my mind .


I'm a little bit concerned about reliability , that there may be a different picture of things emerging now we have a few sheets of realtime / in use data to look at.

So before we take the plunge and do what we think is best for us, can any of you installers , businesses users or guys and gals that have it on your domestic dwellings tell me ... " Has the reliability of the panels & inverters progressed much or are they similar to that of 4 yrs. ago when I think I was offered a 10 year panel warrantee & a 7 year inverter guarantee ?
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