[terryf]

You did miss two things - distribution networks and industrial customers. Those are the two problems that nobody seems to be solving yet.

Basically, high-voltage electricity is distributed with networks that are dumb and old. The generation and usage is very carefully balanced with heavy users and large producers, because the network does not have storage capacity. It also has very little tolerance for power imbalance, the frequency cutoffs in the old equipment running most of the network are rather severe (in high-voltage networks, frequency increases with more power being fed into the system).

There are already extremely severe network problems in Germany for example where quite a bit of power comes from solar and wind. (I worked as an embedded sw engineer doing software that controlled solar inverters for a while)

The problem with upgrading distribution network is of course the MASSIVE amounts capex needed to replace it.

The other problem is industrial consumers - an aluminium smelter requires a certain amount of power coming in 24/7 or the ovens will freeze and if they do, restart is basically impossible. There are many other factories with similar problems. Given the trend towards just-in-time production and shipping, the chain of events that leads to massive disruption in the global trade can start from a fairly small shutdown with large snowball effects.

I'm not trying to put down green power generation, just saying that getting the price down to reasonable level is just one part of the puzzle.

[crdoconnor]

>The problem with upgrading distribution network is of course the MASSIVE amounts capex needed to replace it.

No. This is primarily a political issue not a question of lack of resources, and the capex and difficulty required is, while high, typically overestimated by a large degree.

The main problem is that the networks are usually owned by monopoly utilities with interests in power generation. How much do you think they want to upgrade if the net result is more competition? Hell, they'd probably pay not to have to upgrade.

>There are already extremely severe network problems in Germany for example where quite a bit of power comes from solar and wind.

"Severe" would suggest blackouts or at least brownouts like California had in 2001.

>The other problem is industrial consumers - an aluminium smelter requires a certain amount of power coming in 24/7 or the ovens will freeze and if they do, restart is basically impossible.

If you must do something impossible, do it at least... twice :) ??

http://www.renewablesinternational.net/german-aluminum-firm-...

"Over the past 12 months, German aluminum giant Trimet has ramped down production twice on request from German grid operators."

Yes, they didn't shut it off entirely, but this demonstrates that smelters who can vary their electricity usage are actually part of the solution, not the problem.

(provided Germany didn't overpay them to ramp down that is... which they may well have)

[brrt]

> The main problem is that the networks are usually owned by monopoly utilities with interests in power generation. How much do you think they want to upgrade if the net result is more competition? Hell, they'd probably pay not to have to upgrade.

This... is exactly what is happening :-). Utilities and network operators are trying out ways to give incentives to customers who can respond with negative load (i.e. turning the power down). It makes economic sense because the alternative is increasing production at immense speeds, which is quite costly and inefficient (often using diesel generators, and a lot of them). Aluminium smelters like the examples you give (and quite a few other businesses) are doing precisely this.

Also note that an aluminium smelter works by electrolysis, not by pyrolysis (which is what GP seems to suggest?), which is why they use so much electricity and why they can in fact turn it on and off at a whim.

[raverbashing]

Yes, by electrolysis. Of molten minerals. This also consumes energy

"Alumina is dissolved in molten cryolite, typically at 960 °C"

https://en.wikipedia.org/wiki/Aluminium_smelting

[pif]

> an aluminium smelter requires a certain amount of power coming in 24/7

Absolutely! A key point regarding energy is that you must be able to plan its availability. Lacking major improvements in energy storage, it boils down to predictability for energy production. Unfortunately, solar and wind miss it.

[zamalek]

Regarding customers such as aluminum smelters: I wonder if nature could cope if we used fossil fuels for only them.

Another thing, while wind/solar might might be approaching the cost of fossil fuels I suspect the story may be different for developing countries. In South Africa we have power capacity problems and what was the decision? Build the biggest coal power plant in the southern hemisphere.

If we want to solve climate change developing countries are going to be a very severe problem. The people in charge have no interest in fore-sight.

[brrt]

Actually, yes. Global atmospheric CO2 concentrations will (probably) stabilize if we reduce output to about 5% of the current level, by outflow to the deep ocean (which is a vast reservoir). But that is still very difficult to reach, especially with business as usual.

[kaybe]

That gives us the 1000 years of ocean turnover. Is that enough?

[dagw]

The other problem is industrial consumers

Hydro and geothermal are 'green' solutions that can manage pretty constant power levels 24/7. Just make sure your factory is close to those type of power plants and you'll be fine.