Re: Power satellites was and the rest of you
At 12:04 Tuesday 04-03-14, Keith Henson wrote: [...] Time to displace fossil fuels is a bit over two decades from the start. Will probably take at least that long before second- and third-hand used electric vehicles get cheap enough for those who today cannot afford anything newer than that in a gasoline-powered vehicle to start being able to afford to replace their current vehicles that they have to have to get to work, school, the grocery store, the doctor, etc. It's also highly unlikely that things will change enough any sooner than that in most places in the US and elsewhere outside of a few densely-packed urban centers like NYC for most people to be able to do without individual powered transportation for those necessary trips: IOW, most places I've lived the bus or other public transportation is only good for going downtown in the morning and coming back in the evening after regular business hours, and not even that from many places where people live, and most people have too far to go or have disabilities or other health conditions which would prevent them from walking or riding a bicycle to/from work, even when it's not raining or other inclement weather, or their job requires them to arrive in a suit or other specified attire, looking and smelling fresh, and stay that way all day, and the business doesn't have and probably has no place to install locker rooms with showers. Then there are the ones who have to carry tools or samples or other bulky items with them, and pretty much everyone who has to bring groceries home or take kids to the doctor or multiple kids to multiple schools, music lessons, soccer practice, etc. . . . . . . ronn! :) An Active List Again? Maru ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Power satellites was and the rest of you
On Mon, Mar 3, 2014 at 11:00 AM, Ellen S. zoo...@hotmail.com wrote: snip Solar energy beamed down from outer space? I don't know anything about that. Try http://nextbigfuture.com/2013/09/propulsion-lasers-for-large-scale.html The big objection to solar and other forms of renewable energy is the cost. It's 10-20 times what we need for a vibrant economy. Gail Tverberg makes a case that is $30-50 dollar a bbl oil. Over that and the economy can't grow enough to cover past commitments. Energy is fungible if you can afford the conversion cost. For making synthetic oil out of CO2, water and electric power, the power has to be in the 1-2 cents per kWh to make oil in that range. Power satellites will do that _if_ we can get the transport cost to GEO down to $100/kg. That's about a hundred fold reduction from the current price we pay to lift communication satellites to GEO. It is also ~100 times more than the minimum energy cost if you had something like a moving cable space elevator. Between the Skylon rocket plane and a big propulsion laser, the math works out that at half a million tons per year or more we can get the price down that low. It would be trivial to get humanity off fossil fuels if there was a less expensive energy source. So why space? Five times the sunlight as the best places on earth and more like 10-20 in cloudy places. Materials cost, 1% of what it takes on the ground because no wind and no gravity. In GEO, the sun shines 99% of the time so there is no need for storage. Energy payback time? Under two months. Time to displace fossil fuels is a bit over two decades from the start. Start might have happened last July with the Skylon engine development being funded. Sounds hopeful? Would you like to help on the technical issues? Even more we need people to spread the idea that there is at least one solution to the economic, energy, carbon and climate problems. Keith ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
