18-20,000GW of renewables.

How does that # compare to current use? How much of the current capacity can we keep and still meet emissions targets (CO2 350)?

Cheers

Personal note: I checked out that link and found it quite interesting. There are substantial differences with what I am advocating in that they want to create *new* ecovillages that are basically off-the-shelf. However, the machine shop part of what they are doing fits perfectly with my plan for areas with little or no industrial capacity.

How do you end up with 2 kW?

In central Europe a 2 person household can easily live with less than 1000 kWh electricity per year (using efficient lamps, efficient fridges etc.).
That's 0.057 kW per person.

If you chose a Tesla roadster for transportation (no public transportation, which would more efficient) you'd need 0.11 kWh/km or 2200 kWh to travel 20,000 km per year.
That's 0.25 kW per person.

As far as heating and hot water is concerned: It's been shown numerous times that a well insulated house using its roof to heat the building doesn't require any additional energy for heating and hot water purposes.
Here's an example of multifamily house that provides 100% (including snowy winter) of its heating needs and hot water with its roof area alone in central Europe:
http://www.jenni.ch/picture/AktuellesBild/Baustelle51a.JPG
And all buildings actually need roofs anyway.

The International Monetary Fund says losses from the global financial crisis are set to rise to more than $US4 trillion:
http://www.sbs.com.au/news/article/1016299/Financial-crisis-to-cost-four...

With $4 Trillion just lost in one year, one can actually finance over 13'000 thinfilm photovoltaic factories from Oerlikon, which would produce 2,133 GW of PV per year:
That's 87,466 GW by 2050.
http://www.oerlikon.com/ecomaXL/index.php?site=SOLAR_EN_press_releases_d...

a good quality of life, too. That turns out to happen with around 2kW of electricity per person.

For context, 2kW is roughly 18,000kWh/yr, which is about 50% more than current US electricity consumption, around 3x the consumption of older EU members (UK, etc.), and around 6x the consumption of newer EU members (e.g., Poland).

Germany consumes 180Mbtu/person, or 52,000kWh/yr, which is 6kW. However, of their 14.5 quads of primary energy consumption, 3.5 quads are coal, 3.5 quads natural gas, and 5.5 quads oil. Coal/NG are predominantly used for electricity at ~3:1 efficiency, or for heating (for which electric heat pumps are about 3x more efficient), meaning that they're equivalent to 1.2 quads of electricity each. Oil is mostly used for transportation, for which electric cars are ~6x more efficient and for which electric rail is 3x more efficient (than diesel rail, >10x more than trucks). Accordingly, those 5.5 quads of energy are equivalent to roughly 1-1.5 quads of electricity (assuming electric vehicles).

Hence, Germany is using the electricity-equivalent of about 6.5 quads of energy, or about 2.5kW per capita. Based on that, it seems like 2kW is likely to be an overestimate of what's needed for a good quality of life.

It seems like you're using a 2:1 factor to convert from primary energy to electricity; however, a more typical factor is 3:1 (that's a typical power plant efficiency, and the factor BP uses in their analyses), suggesting a figure of about 1.5kW. That's before any kinds of efficiency improvements other than converting to electricity, though, suggesting the actual value is likely to be lower still. Moreover, you don't seem to be taking into account at all the fact that roughly half of world primary energy consumption (most coal and natural gas, plus a significant amount of oil) is burned at about 30% efficiency to make electricity.

So 2kW is not a terrible figure, but it's very likely too high. If you're going to assume quite a few efficiency increases - and you seem to - then 1kW is probably a better estimate, and 2kW represents a luxurious lifestyle. Electricity is astonishingly more useful than thermal energy.

Consider the following situation. We are getting all of our energy from a single source with fixed costs and a fixed yearly flow rate. We know however that this energy source is going to be exhausted in a few decades time and that all of the available alternatives are substantially more expensive. In spite of the fact that investing in energy production from one or more of these new sources is going going to make us poorer in the short term, we still ought to start doing so even before the cheaper energy source has been exhausted. I am assuming, of course, that the productivity gain from these alternative energy sources is positive even though it is smaller than that of our current energy source.

Admittedly planning an energy descent is a very difficult business, and I think that you are right to question whether our current renewables policy has much long term intelligence behind it. If grid strengthening and large scale storage are required to make wind energy useful in the absence of fossil fuels we should be funding these things today. Unfortunately energy descent cannot be planned if we remain committed to stock market growth as the only possible definition of economic health.

Or do we really have enough money to do both?

Yes.

The funds used during the last 8 years expanding Suburbia with homes 2.5x larger than 1950 (for smaller families), 10x the retail space/capita of 1950, and associated highways, roads, parking spaces, sewers, water systems, new distribution electrical grid can easily finance both if redirected.

To paraphrase Kunstler, this has been the greatest misallocation of resources in the history of humanity. Directed towards useful and productive investments (which can provide additional capital through production), there is more than enough capital.

The question becomes: do we need to add a lot of wind turbines to what we have now, or would be better off just using less of what we have now?

The answer is we need to add a lot of wind turbines to what we have now, AND we would be better off just using less of what we have now.

It is AND when dealing with positive investments.

Conservation & efficiency investments should be made in parallel with massive renewable energy investments.

I install a gas tankless hot water heater and use less NG for heating water. I install better windows, caulk and seal openings and add more insulation > use less NG for winter heating and less electricity for summer air conditioning. I install a mix of CFLs & LEDs and use less electricity for lighting. I install a more efficient a/c and save some more electricity. I buy an Apple MacMini (33 watts) and and efficient LED screen (say 55 watts) and save some power that way.

All good (none of above reduces my quality of life). I rent out two rooms and save even more/capita (my life is affected + or - depending).

The capital investment to more than halve my domestic energy consumption is trivial and pays for itself in a handful of years (rent from roommates MORE than pays for all). On a macro scale, no national limitation on investment capital for installing more WTs.

Scrap coal fired plants early, before they are fully depreciated. Take the burden of coal off the post-Peak Oil economy and the environment.

Alan

If we do start using very much less energy, the question becomes: do we need to add a lot of wind turbines to what we have now, or would be better off just using less of what we have now?

The former. Firstly, because if we wanted to avoid catastrophic climate change, yet at the same time insisted on getting most of our energy from fossil fuels, we'd have to use about 10-15% as much energy as we do today. That's 10-15% of the worldwide energy consumption, which - if we all reduce to the same consumption - means India doesn't reduce at all, and the West reduces to 2-5%. That seems difficult, both technically and politically.

Secondly, because reducing consumption still doesn't deal with the problem of a depleting resource. It just puts off the problem. It's like getting an extension on your credit card and cutting your spending so it's only 150% of your income instead of 1,000% your income. It's definitely an improvement, but you're still in over your head and will eventually drown. So we have our fossil fuel crisis in 2070 instead of 2030 or whenever. We're exporting our problems to the future.