[ExI] Energy options

Keith Henson hkeithhenson at gmail.com
Sun Mar 13 15:15:01 UTC 2011

Re the business of powering the world with nuclear reactors, there may
be better and less expensive ideas.

It's easy to make an engineering/economic case for low cost space
based solar power *if* you have a way to get the cost into space down
to around $100/kg (to GEO).

That takes raising the exhaust velocity to~ 9 km/sec and the only way
we know to do that is beamed energy.  It's not going to happen soon,
but even Fox news has covered beamed energy proposals recently.

First pass estimate ~$100 B to build the spacecraft and lasers to power them.

After the day-night problem (except for SBSP) the big problem with
solar is that it is dilute and often obscured by clouds.  So you need
to spread out huge areas to capture it.

StratoSolar is a proposal to take weightless (floated by hydrogen)
collectors up above the clouds and most of the atmosphere.  I have
been working on it for over a year.  It's a very difficult and wide
ranging engineering problem, but there are some rather interesting
concepts.  For example, a 150 year old technology allows the plants to
run full time for an incremental cost of around 1/8 of a cent per kWh.

To build a full scale unit (1 GW) would take on the order of 1 percent
of the estimate to build the transport infrastructure to do SBSP.

But even after a year and a dozen spread sheets I am not sure makes
sense to build one.


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