Daniel, Your 40% overall efficiency only includes rankine cycle and leaves out
Mirror losses Air dispersion of mirror flux Steam generator ambient radiation losses 10 hour only per day generation Transmission losses Overall number is much lower. On Friday, June 1, 2012, Daniel Rocha wrote: > Solar irradiance is ~1kw/m^2. 1GW/km^2, then. It goes up to 1.3GW/km^2 if > balloons at stratosphere are used. > > 2012/6/1 Chemical Engineer <cheme...@gmail.com> > > Daniel, > > Double check your math...i get 38 sq km per gigawatt during daylight with > clean mirrors > > > On Friday, June 1, 2012, Daniel Rocha wrote: > > Well, at 40% efficiency, you need 1.6Km^2 for every gigawatt, So, 30X30 > km2 will do it. Maintenance is hard but in terms of area, it is not > something spectacular. > > Consider the reservoirs of the 2 most powerful hydroelectric dams: > > Itaipu reservoir has 1350km^2 http://en.wikipedia.org/wiki/Itaipu_Dam > > Three Gorges Dam has has 1045km^2 > http://en.wikipedia.org/wiki/Three_Gorges_Dam > > And new technologies are being developed for peaceful purposes. Not in > stupid drones. > > > 2012/6/1 Chemical Engineer <cheme...@gmail.com> > > Jed, > > Just a fact check. You don't know how many times I have heard that " a > solar site 100 miles to the side in the Mohave could generate all of the > power requirements for the US". > > Some numbers based upon most efficient claimed CSP plant: (approx 2 to 3 > times more efficient than PV but much more expensive) > > 370 MW Nominal generation requires 3500 acreas (largest, most efficient > claimed US solar thermal plant being constructed) > 350,000 mirrors (assuming they are clean) > Generates power ~10 hours/day > > To cover peak US demand of 768,000 MW you would need 781 MILLION mirrors > that only cover you 10 hours per day. The 110Mile x 110Mile plot is idle > at night. With thermal storage you would need to more than double the area > if you wanted to store during the day and generate at night, taking up > > 60% of the Mohave. > > You can double this area for utility scale PV which, although cheaper is ~ > half the efficiency of CSP/acre, in which case you would need a larger > Mohave. You also need to develop weather technology to keep all clouds out > of the desert... > > Also, your "Robots" will need to clean 781 million mirrors per month > (monthly cleaning cycle) in the heat and sand of the desert. Plus where > will you get the water to clean them or power for your army of hundreds of > thousands of robots? If you cannot clean 781 MILLION mirrors per month you > will need more, less efficient dirty mirrors and more space > > You will also pay 4 times more for this electricity than you are paying > now. > > Also, from a strategic defense standpoint, it would be very easy for an > enemy to blast one large nuke off over the desert and shatter all of those > mirrors. > > I am OK with distributed PV on rooftops but get the crap out of the desert > and give the BILLIONS to homeowners to subsidize installations. Solar City > has a much better business model. > > I admire your creativity and regurgitating green fluff but I think you are > drinking your own bath water and they are WASTING OUR MONEY > > > > > > On Thu, May 31, 2012 at 3:55 PM, Jed Rothwell <jedrothw...@gmail.com>wrote: > > Chemical Engineer <cheme...@gmail.com> wrote: > > > You mention projects that are advancing human civilization and many were > great investments. Are you OK spending billions on green projects that > have 1/100th or less the energy density/potential of existing fossil fuels > . . . > > > Which projects do you mean? I am not aware of anything like that. > > The energy density of uranium fission plants is not as good as existing > fossil fuels, because uranium ore density is so low, but I still prefer > uranium reactors to coal-fired plants. > > The power density of solar cells is low but as long as they are cheap it > does not matter. (Energy density is meaningless in a solar cell or wind > turbine; the > >
