I am resuscitating this thread. Very valid points were raised by people from all sides of
the fence. It's been three years since, so maybe there are new arguments, maybe some people's points of view have evolved (nah...), and maybe new people want
to pitch in.
We now have an electric racing formula with F1 drivers and fully electric cars in
the roads that respond
to any functional parameter commonly used
to define a car. Also renewable generation
is moving away from being a barely noticeable portion of
the energy mix. In 2013 in Spain, eolic energy was
the main single source of consumed electricity with 20.9% of
the mix (20.8% for
nuclear), and renewables produced 42.2% of
the total. That's average over
the whole year.
http://economia.elpais.com/economia/201 ... 04329.html
I also wanted
to bring in what for me
is new info. It was an often raised point back then that since only very small amounts of already produced energy can be stored, many renewables were a no-
go, as similar back-up capacity
is needed for low production periods, and that often comes from coal and gas (and more money). A completely new distrubution or storage infrastructure would have
to be created at an enormous cost.
Recent reading has brought new possibilities in conversion of electricity
to gas
to my attention, and as it looks, slowly
to mainstream media attention too.
http://en.wikipedia.org/wiki/Power_to_gas
To summarize some of
the most important points. Electricity can be converted
to H2 and then back
to electricity with a 40% efficiency, 60% including electricity and heat.
This H2 gas can be mixed with our existing natural gas supplies
to a 2% concentration without risks nor infrastructure changes, meaning that excess energy can simply be stored there.
If this H2 gas
is further processed, it can be converted
to methane with
the Sabatier reaction:
CO2 + 4H2 → CH4 + 2H2O
The necessary CO2 can conceivably come from captured CO2 in
the future.
The whole electricity -> methane -> electricity cycle has a 34% efficiency, up
to 50% including electricity and heat.
Now
the kicker:
This methane (natural gas) can simply be injected in the current natural gas distribution network.
http://en.wikipedia.org/wiki/Hydrogen_e ... wer_to_gas
Depending on
the sources consulted
this includes 100 to 700 days worth of the energy consumption in many places. This is with the existing infrastructure, conduction pipes, etc. At zero cost. And it automatically includes both storage and transport.
To me this
is new information, although WB hinted as much in page 11 back in
the day. Not every country will have Germany's natural gas infrastructure, but other countries have other advantages, and all have a significant gas infrastructure. Simply
the fact that more or less everywhere there are months worth of storage capacity, and storage in about
the most convenient form possible (methane
is also easy
to liquify and transport), means that
the technology
to move away from carbon, natural gas or
nuclear is here about now.
The production capacity of all renewables combined
is not here yet,
the electrolysis capacity
is absolutely nowhere near enough; but if we accept
to get back only 50% of
the excess production from good days,
the potential scenario in which there
is no wind, no sun, no hydro, etc, has simply disappeared.
The question of whether we use energy from coal, oil, gas, from
nuclear centrals or energy that in one
way or another comes from
the sun or
the moon
is an economical and political one, and no longer a technological one.
Interestingly, this makes not only renewables a viable (expensive) proposition, but also 100%
nuclear a valid proposition (that I don't want
to be anywhere near, but that
is another question).
Nuclear is good at base load generation, but not at responding
to load changes. It
is slow
to start or stop a reactor, and extremely slow
to bring new centrals
to the net if needed. Having
the option of converting
the excess
to methane and burning it in
the existing natural gas power stations, and capturing
the CO2 produced, means that
nuclear could potentially feed
the whole grid, including load variations, with close
to zero CO2 emissions. Technologically speaking at least.
