If a new EV li-ion has 4X lead-acid capacity, even "used up" at 80% remaining leaves 3.2X new L-A capacity and years(5, 10, ..) longer life - which should have significant value.

The 2011 Leaf 73 mile range could handle 90% of typical daily trips. The 2013 model 83 mile range is positive.

New, high temperature operation Leaf batteries have been tested and could be available by April.

Meanwhile, http://green.autoblog.com/2013/10/23/nissan-leaf-with-2x-battery-capacity-tested-in-spains-ecoseries/

Smoothing out fluctuations in real time is one thing.
Storing solar energy overnight is another.
Storing solar energy from summer to winter is a whole other ballgame.

Renewables (apart from hydro) will need backup for the foreseeable future. Japan needs to restart its nuclear fleet.

Well that is one way out of the backup problem but your link points to another when it says Today, pumped hydropower storage is the only mature technology, and it accounts for more than 99% of energy storage capacity worldwide. This technology consists of pumping water uphill into large reservoirs when the sun is shining or the wind is blowing (or some other power source is able to generate electricity), and then letting it flow down again to generate power.

However, pumped hydro technology is, for the most part, limited geographically to mountainous areas.

Japan is a mountainous country. About 72% of Japan is mountainous, with a mountain range running through each of the main islands. Japan's highest mountain is Mt. Fuji, with an elevation of 3,776 m (12,388 ft). Since so very little flat area exists, many hills and mountainsides are cultivated all the way to the top. Also, Japan is situated in a volcanic zone along the Pacific deeps, frequent low-intensity earth tremors and occasional volcanic activity are felt throughout the islands. Hot springs are numerous and have been exploited as an economic capital by the leisure industry so geothermal power is a possible solution as well.

Storing solar energy overnight is another.
Storing solar energy from summer to winter is a whole other ballgame.

I had a thought earlier today: 'Is this true?'
It turns out the answer is 'no.'

It is true that there is more solar energy to be had in the summer but there is not "no solar" to be had in the winter. The idea that PV doesn't work in cloudy conditions is a myth. Of course you will get less light under the cloud cover that comes with winter but there will still be some light to work with so you size your array for the yearly average conditions in your area. Furthermore, outside of capacity there is also "relative efficiency." An array that gets only half the light may not produce only half the energy, some cell types will produce more and some less.

PV does not stop functioning, just because the skies turn cloudy. The so-called perfect conditions would be blue skies, sunshine, vertical rays on the modules and cool temperatures. PV modules are usually tested at Standard Test Conditions, however real conditions vary largely. Hence, power generated by modules under cloudy conditions is also tested. This is known as low-light condition performance.

When a solar power plant is built, professionals do an analysis not just of the cost of development and potential performance data, but they also take into account the area’s irradiation figures. Simulations are used to gauge the efficiency of a standard module under different light conditions and planners can then decide on the modules they wish to install. Thus, modules are tested under low-light conditions as well and if the right ones, with the lowest performance dips under cloudy conditions are selected, then PV power is still produced on grey days.

Read more: http://www.pv-magazine.com/features/solar-superhero/pv-doesnt-work-in-cloudy-conditions/#ixzz2ssgjvgc2

Distributed H2-FC-CHP is the best way to backup solar and wind electricity. Because the waste heat is largely utilized, round trip efficiency is very high. The waste heat obtained during electrolysis is also useable. An industrial economy needs very reliable electricity delivery, and cannot rely solely on the whim of electricity directly from solar and wind.

Energy consumption for living space heating is very high in the winter, and even in late fall and early spring. To go fully non-fossil fuel requires massive seasonal-scale energy storage from RE and nuclear energy.

Imagine a big snow storm and the aftermath in which powerlines are down for days to even weeks, and solar PV's are covered with snow. Which home will stay warm and will be fully powered? Answer: Those that are powered by H2-FC-CHP powered by H2 piping. If you're snowbound, you should at least be able to enjoy the convenience of modern technology in warmth and comfort, not being thrown back to the pre-industrial age!

The problem of solar PV's are covered with snow isn't actually that great. In climes where snowfall is likely solar panels are also tilted more steeply to capture the low angle sunlight. This tilt helps the snow remove itself from your panels.

http://www.youtube.com/watch?v=qOeUWe64uBg

Losses from snow cover end up being only ~1-2%;
http://www.appropedia.org/Effects_of_snow_on_photovoltaic_performance

"Sometimes snow actually helps solar cells," says Michigan Tech's Joshua Pearce. He's referring to the albedo effect, when sunlight reflects off snow. It can make a panel generate more electricity in the same way that it gives skiers sunburn on sunny winter days.
http://www.sciencedaily.com/releases/2012/10/121024175236.htm
http://www.thestar.com/business/2011/02/24/overcoming_solar_panels_winter_problem.html

What's more solar panels can actually be designed with winter weather in mind;
http://scirustechnologies.com/

Also, utility scale solar PV will likely use tracking panels. These can tilt themselves to vertical to shed any snow in seconds.

@ai_vin: We have solar panels on our roof, and benefit from 'net metering', that is, treating the grid as if it were a battery. A few facts on the ground:

1. Solar production under clouds is *far* lower than in direct sunlight. On 2/6 we produced ~14kWh. The next day it rained, and we produced ~2.6kWh. And of course for the majority of time, we produced 0kWh, because it was night and this is the winter.

2. One month last winter we produced 288kWh total. Same number of days later that spring: 658kWh. We use more power in the winter, so our production does not match our usage, even seasonally.

Solar and wind are not dispatch-able--you get the power when mother nature says, not necessarily when you need it. Our net-metering set up only works because our 'storage' is really backup generation from nuclear, hydro, and natural gas generation. Overnight storage (e.g. batteries) would probably double the cost of our system. Seasonal storage is not really available for us.

going 100% renewable is crazy.
Saying things like "you get more solar in summer and more wind in winter" is infantile.
The grid has to be managed minute by minute, not year by year.
As has been pointed out, the only large scale storage is pumped hydro, but this needs special geography, and is not very abundant.

Japan has a very dense population and very little flat land.
They do not have a lot of space for solar farms.
(Maybe they could put them on south facing hill sides, I don;t know).
The trick is to set an achievable goal, such as 20-40% renewable.
This you could do (at considerable cost by adding in a load of solar and a load of wind, but keeping most of your fossil stations as dispatchable power.

Also, they could unite their grids (which work at different frequencies [east and west] and generally beef up their long range transmission capability to move power around the island.

This will cost a fortune and make electricity very expensive, but the Japanese could take it.
They have very variable demand - after Fukushima, they were able to get people to reduce usage in a way they you couldn't expect in western countries.

This may be their "secret weapon" dispatchable demand.

[ My own preference would be to add a reasonable % of solar and wind, and restart the safest (say 50%) nuclear plants, while beefing up their cooling facilities so a Fukushima type disaster couldn't happen ].

[ I know this is preparing for the last disaster, but, since we don't what the next disaster will be, this is a good start ]

I have NO idea why the Germans turned their nukes off early - they live in a stable country. [ Politics, I suppose ]

100% renewable electricity is possible. Norway is nearly 100% renewable electricity with hydropower. In 2013 Denmark made an average of 33% of its electricity from wind power and a record average 59% from wind power in December 2013. We will reach 50% from wind power annually in 2020 and it will be done without any pumped hydro storage or batteries in the grid. We do it by building more transmission lines to neighboring countries. Neither has Denmark started to use smart metering at any scale that would allow electricity consumers to use more or less depending on fluctuating electricity prices.

The point is there are no technical problems with including much more renewable energy in the grid we just need to make it cheaper in order to compete with coal and natural gas. Fortunately both solar and wind is getting cheaper every year.

Going 100% renewable, outside of places which can deploy big hydro, is going to be extremely expensive. Wind and solar capacity factors are mostly under 30%, meaning you have to build 3X the capacity than you would to deploy nuclear, which can do better than 95%. Even then, there are long stretches when the sun does not shine and the wind does not blow, meaning you have also to build storage or some kind or dispatchable backup. Also, plant lifetimes are one half to one third that of nuclear, so capital costs are much higher than they look at first glance.

I will grant that it can be made to work, but it is not going to happen outside of the certain rich economies. Developing economies are building coal plants for baseload generation, because that is what is affordable and reliable, externalities be damned. Developing economies is where the bulk of the new power generation is going to be built going forward. We need a *cheap* low-carbon alternative, and that *could* be nuclear. Whether we will be smart enough to make that happen is a separate question.

NB: German CO2 emissions are going up, not down, as they replace nuclear with natural gas and *new coal plants*. How green is that?