Monday, 13 February 2012

Why "renewable" sources of energy don't work in the real world

The issue here is incredibly simple: predictablity.

The whole point of renewable energy sources is that we want to use them instead of conventional power generation. So the ideal situation is that we want to get the power from a renewable source and while we're getting that, we want to scale down the power we get from conventional energy and when the renewable stops providing, we want to scale the conventional energy back up.

Now, if you look at turbines, the picture is terrible. The wind is incredibly capricious and turbines can only operate at best 30% of the time. But which 30% of the time is completely impossible to tell.

The same applies, to a lesser extent, to solar power. Clouds may or may not have an effect on the capability of the panels, a snow dump could close them off for an unspecified period and if you place them in areas that have good weather and are more reliable, you generally lose a massive amount of power transmitting it to places that it's needed, completely subverting the value of the energy generated.

Even wave power can be significantly affected by the weather and time of the month. Although it will almost always be generating some power, it will almost never be consistent.

So why is this a problem? Well, with current power stations it can take hours or even days to adjust the amount of energy that is being produced.

If the wind is blowing sweetly, waves are nice and even and the sun is shining and we're getting a massive spike of "free" energy, by the time we've slowed down our existing coal and gas and nuclear power supplies, the situation will have changed completely and there will be blackouts all over the country. There would be chaos everywhere, every day.

People are working on this, but even if we were to decomission all our existing power stations and replace them with these which would require more than 200 of these power stations to be built (at a non-trivial cost) plus the cost of decomissioning existing power stations, all of this would probably bankrupt the UK.

And let's assume we beat Denmark's generation of renewable power and get to 30% of power being generated renewably. Given that a reasonable estimate of Britain's energy capacity at the moment is about 100GW, that means that 30GW could be provided renewably at any one time. This means that even using the latest whizz-bang technology, and assuming a completely even distribution of renewable power, there could, at any moment, be a 6-minute period where the entire country shuts down.

In practice, it simply means that we would either have to still massively over-provide electricity capacity, and that areas which have more access to renewable energy would be much more likely to experience an outage.

It doesn't matter how much power wind farms et al generate: if they can't generate the capacity predictably, then even while we're getting that power, we can't reduce the amount of conventional capacity we generate, so we can't reduce our horrid "carbon footprint" no matter how many cunting turbines we ruin the cuntryside with.

Update: This may have potential. (OK, that was pretty shocking. I'm sorry I didn't offer more resistance. Etc.)

10 comments:

Joe Public said...

Until any of the proponents of "Alternative Energy" can boast they depend solely upon their chosen source, the rest of us will be Pragmatic Realists.

t said...

Their theory is that in the future we will all have electric cars, and when the wind is blowing too much, the excess power is used to charge the car up. If there's no wind when Eastenders comes on, the TV takes the electricity out of the car battery.

Now what could possibly go wrong with that??

PME200 said...

If this were a debate about state subsidies for the renewable industry I think it might merit some more thought.

As it is, I sadly see it as yet *another* authoritarian justification for interfering with the free markets and telling private companies what activities to engage in, or not.

It is surely up to them decide if this is a profitable commercial venture or not, Obo? :-)

Obnoxio The Clown said...

"It is surely up to them decide if this is a profitable commercial venture or not, Obo? :-)"

By providing endless subsidies at taxpayer expense?

microdave said...

"The supply from solar drops dramatically at night" - Only "dramatically". I thought it was completely dark during the night.

Except in Spain, where solar plants still register a supply at night...

"The new turbines can ramp up quickly, much as a jet engine can ramp up quickly to provide thrust for takeoff." - Since an aircraft jet (or Turbofan as they should be described) engine can go from idle to full power in a matter of seconds, why do these "Hi Tech" plants still take 10minutes to do the same?

As a power plant will have to run syncronised to the grid, once it's on-line there' isn't even a need to accelerate from idle revs. It's only a matter of varying the fuel flow to match the required load. This is exactly the same as a diesel genset would do, and with modern electronic controls should be no problem.

"If there's no wind when Eastenders comes on, the TV takes the electricity out of the car battery." - No fucker is ever going to syphon MY car battery to watch that waste of DNA...

Jill said...

It's the transmission that means any kind of scaleable solution likely won't work so well, renewable or non-renewable (I wish the debate wasn't ONLY on this single divide). But isn't there some improvement in DC cabling on the horizon to change all that? It would be great if the Sahara could be one big power plant and we could transport that energy. Until then, the solution is probably local. Housing estates, factories, office parks, these all need their own generation. Somehow. I recall a sci-fi short story in which the underclass provided power for residential tower blocks from their sardined body warmth... that's not a goer, snigger, but local does seem more sensible than constantly arguing over renewables vs non renewables?

Anonymous said...

I agree with the premise that energy supply must be predictable, and to that extent I think that only hydro-electric and tidal (not wave power)can become serious contenders. They can't fill the energy breach at the moment, so we either need to get fracking, or go nuclear.

Monty

microdave said...

@ Jill - you might want to look here: http://en.wikipedia.org/wiki/Desertec

It's been talked about for some time. I've also heard suggestions of using superconducting cables filled with liquid helium! But with the political turmoil in the region now, I don't think there's a snowball's chance in hell of this project ever being started.

Anonymous said...

Am I right in thinking Desertec would take energy from the Sahara and take it north..none going to Sub-Saharan Africa!

JuliaM said...

"... yet *another* authoritarian justification for interfering with the free markets and telling private companies what activities to engage in, or not."

Not that the pressure groups are doing that, and have been for some time, eh?

'Greenwash' It's popular.