The cost of being on-line

[Martin Naef]

On 24.06.2011 5:03, Tony Scharf wrote:
>> That still leaves plenty of space for de-centralized production. But you
>> might quickly find that your roof isn't large enough for the energy you
>> consume.

> This is a topic I actually have some inside information on.  My cousin
> works in solar research, specifically on the energy density problem
> (how much you can generate from how much surface area and at what cost
> per watt).  We are getting closer.  They have methods that can get us
> to the density we need and the efficiency of conversion we need,
> however the manufacturing process doesnt yet scale.  That problem

It has to scale, otherwise it won't work. Depending on size of house and 
the size of your roof, you can get close enough. But then I look at the 
more densely populated areas and I wonder if there's ever enough roof 
space... That's just domestic electricity - when you look at industry as 
well, you quickly need more. In Switzerland there are something like 
150km2 of roofs that are suitable for PV. That covers about the output 
of one of our larger nuclear plants on average (1GW). Switzerland has 
about 3GW of nuclear power, which covers almost 40% of our electricity. 
As you can see, there's quite a bit of roof space missing even if we 
double the efficiency.

But it really depends on where you live. In Switzerland, you can assume 
that average power is about 10% of peak power. In southern Italy or 
Spain, you can reach up to 25%. That's a lot better.

> isn't trivial, but there is a lot of resources going into it right
> now, and if Nuclear goes away, a lot more resources could be put into
> solar/wind than is currently.

The shift is certainly happening, and I support it. But it is going to 
take time, and there are a lot of questions that need answering - not 
the least how to keep the grid stable. If we assume that we replace the 
3GW average power with solar, we need around 30GWpeak installed. There's 
absolutely now way our grid can absorb such a peak. But if we cap the 
production it means we're not even reaching the 10% efficiency. That's 
when the economics break down again.

Martin