[semi-extrinsic]

Sorry, that's just missing the mark. In northern latitudes, where most of the world's energy consumption is currently located, the seasonal variation in solar influx means a 100% solar solution needs to do energy storage for months at a time. Continuing with the Germany example, the monthly-average production of solar power in January is ~ 1/15th the production in July.

And I don't believe we will ever be able to get the whole world up to current western consumption levels. More to the point, we really shouldn't, as current consumption levels in the west are clearly unsustainable.

[ghshephard]

Not sure who downvoted you (I leveled you up) - I spent about 30 minutes researching seasonal variation of solar power in northern climates (http://www.reuters.com/article/2012/10/16/us-column-wynn-ren...) and your numbers check out. "For example, aggregate solar power generation in the first week of January was only 7 percent of peak production in the final week of May

The northern climates, then, are a challenge for solar, even with lots of storage. Fair point, and something to think about.

But, as to your second point, about how we shouldn't get the whole world up to current western consumption levels - I don't know about you, but I like hot water in the morning, air conditioning on a hot day, clean clothes from the washing machine, baked goods at home, and and a warm house on a cold winters day. I agree that efficiency is important (all of those things can be delivered more efficiently - same value with less energy), but I certainly wouldn't suggest that everyone in the world shouldn't have access to them, and more.

[semi-extrinsic]

(I'm not able to reply to ghshephard, so I put it here.)

My point about not getting everyone up to western consumption levels isn't mainly about the things you mention. It's more about the use-and-throw-away culture, plus the general inability of people to make stuff themselves. Imagine the impact if people started mending stuff and clothes, cooking their own food, taking the bicycle with a trailer to the local market to do the weekly shopping, etc. Not just on reducing direct and (mainly) indirect energy consumption, but on public health and general happiness levels! There's so much of our energy consumption that doesn't improve our lives in any meaningful way.

[ghshephard]

I won't argue about how we live in a terribly consumer-fixated culture - totally agree with you. Ironically, at this exact moment, I'm writing a review on Amazon, about how much I like my 15 year old Kaito KA007 hand-cranked radio. It's never seen a single battery, yet I've had it with me on camping, business trips, burning man - everywhere. 60 seconds on the crank gets me 20 minutes of radio. I hope to have it with me another 15 years.

Likewise, my Mountain Equipment Co-Op Backpack that I've had for 18 years - I've had that with me every single day for 19 years, it's my laptop case, my tool case, my document holder - In the Amazon Jungle, Luxembourg, and with Network Engineers in London, Dubai and Singapore. I've used the heck out of it - and it's still going strong.

So, I'm totally on board with having a very few things, that you take good care of, and last a long time.

But - this is a separate conversation (somewhat) from energy usage. Heat, Pumping/Processing water, cooling - they all have some physical minimum amounts of power. And even if you are living a hyper-efficient 40 gallons/day life style (Northern California, see http://www.nytimes.com/interactive/2015/04/01/us/water-use-i... ) versus the rest of the world (See: http://www.data360.org/dsg.aspx?Data_Set_Group_Id=757) - there are some physical limits as to how little energy you can use and still maintain a comfortable lifestyle. We can only be efficient so far - eventually we're going to have to find a way to provide lots, and lots, and lots of power to everyone in the world, if they want to live a comfortable lifestyle.

Thankfully, much of that comes from having warm homes, and hot water - something that Solar does an admirable job of providing (bringing it all back to the original thread).

[semi-extrinsic]

I agree wholeheartedly with all of this. But I think reducing consumption is probably the most significant thing a person can do to lower their CO2 footprint. My rule of thumb (which is fairly good across a surprising range of goods for ones that I've tested) is that at least 500g of CO2 is emitted for every dollar you spend, whether that's on electricity with our current typical fuel mix or on a cheeseburger or a plane journey. So if your electricity bill is say 5% of your monthly expenditures, electric energy usage is just responsible for 5% of your total CO2 emissions. This is very ballpark, but you get the idea.