> Wind turbine speed doesn't change nearly as fast as you think it does.

Agreed. A single wind turbine has flywheel inertia in the blades, so it doesn't instantly stop and start. A whole wind farm changes even more slowly, because the turbines are typically spaced about 400 meters apart, and average wind speed is ~6 m/s, thus about a minute between turbines. Across many turbines in a wind farm, you are talking about ~10 minutes. Across a grid with multiple wind farms, the reaction time is even longer for a change in wind speed to propagate.

> People always say this about "Hollywood accounting" but I seriously doubt that the tax authorities (for instance) just let film companies make up their profit figure.

Hollywood was invaded by organized crime a long time ago through the stagehands labor unions. Read the credits on a film sometime. Do you really need 20 catering staff on call? The method is to pad staffing, with people who aren't really needed, or in some cases don't even exist. The movie production company writes off the expenses, with payrolls and invoices to make the IRS happy. They show a loss on the movie. But the padded expenses come back under the table.

It makes the IRS' job harder that many films are made by production companies organized by the job, hiring staff and laying them all off when the movie is done.

> There is no multi-billion dollar return for putting people on Mars.

Actually, there almost was, in the 1980's. A major TV network came to Boeing, where I worked at the time, and asked us how much for a Mars mission. We worked out a mission concept, and gave them an estimate. The network figured they could sell as much advertising for the mission as an Olympic games, but spread over a couple of years. Unfortunately the mission cost we came up with was twice the ad revenue, so it died at that point.

If you can boost the revenue with things like "Mars, the video game", and "Mars, the branded merchandise", and cut costs with modern technology, you *might* get it within reach of break-even. Throw in some government-funded science payloads, and it might work a profit.

Back then, there were only three TV networks, and they could command a big audience. I'm not sure a network could front that much these days, although they still compete for the Olympics.

With proper tech, the penalty for Mar's gravity well can be made pretty small. For example, one of the giant volcanoes on Mars sits right on the equator. It is so tall that the top is essentially in vacuum. So you can build an accelerator that throws things into Mars orbit. From low Mars orbit to Phobos you can use the Rotovator type space elevator.

Mars has advantages that loose asteroid's don't. Tectonics, internal heating, water, and other geological processes have sorted the planet into differentiated ores. But focusing on the Moon or Mars or Asteroids as if you have to choose one is as silly as focusing on only California, Minnesota, or Texas when expanding the United States. The right answer is to expand outwards in terms of difficulty, and using the fuel and supplies you can produce at one location to leverage getting to the next. The right answer is "everywhere in the Solar System", though some places will need to wait quite a while until our tech and needs demand using them.

The actual energy to reach Earth orbit, at retail electric rates, is about what Walmart sells bags of potatoes for. It costs way more than that because we basically are using weapons of war (rockets descended from ballistic missiles) to do the job. The cost of a ballistic ICBM is limited by the value of the targets it destroys, so cost was not seriously limited.

As soon as billionaires rather than governments got involved, where cost came out of their own pocket, sanity began to reign. Carrier airplanes to raise launch efficiency, using the expensive aerospace hardware more than once, etc. Launch costs have room to drop about 50-fold from today's prices, and still be well above raw energy costs, the way airplane trips are well above fuel cost.

From Earth orbit to Mars we can build a chain of "truck stops" that supply food, fuel, and other necessities, rather than launching it all from here. Physics says it makes much more sense to get your supplies from a nearby asteroid than the bottom of a deep gravity well (Earth). The particular locations would be Earth-Moon L1, Mars Cycling Transfer Orbit, and Phobos. We already know of 12,000 Near-Earth asteroids, and the region between and near Mars should have just as many. They are farther away, so our Earth-based telescopes can't spot them as easily.

Using local materials, we can gain another 50-fold price reduction for the trip. So instead of $1 billion/seat, we are looking at $400K per person, which a corporation may well finance to get people to the work location.

Developers are already building solar farms in the Atacama:

http://www.bloomberg.com/news/...

Not only is it very sunny, it is high altitude and cold. Less air above it means the sunlight is more intense, and solar cells are more efficient when they are cooler. The combination makes it the best place in the world for solar, aside from the fact nobody lives there and you need power lines to the coast, where people actually live.

I guess you don't have any idea how much land is disrupted when you strip mine for coal. It's a lot, and it continues as long as you need to feed the power plant. Solar is a one time installation.

Samsung in fact does make solar panels:

http://www.samsung.com/us/busi...

It has plenty of industrial use where what you want is heat, and not electricity. You don't get the conversion losses from heat to electrons moving. A big example is the 6% of the world's CO2 emissions that come from making Portland Cement (the binder in concrete). Making that product involves heating a mix of shale/clay plus limestone to high temperatures, which changes it chemically. Today it is mostly done by burning fossil fuels, but solar would work just as well.

> It is more expensive than PV

The proper comparison is to PV at the same installed capacity. Solar thermal started later, and therefore has had less of a learning curve. Also, heliostat mirrors are inherently cheaper than solar panels because a sheet of mirrored glass is simpler to make than a finished panel. Most of the cost comes from the steerable mount that aims the mirror at the tower, but there is a lot of room for improvement there.

> The number of birds incinerated

Could be reduced quite a bit with screens that keep them off the top of the tower. The problem is that birds like to perch on top of the tower, for the same reason they like to perch on trees and power lines. Unfortunately that is where all the mirrors point. Nobody compares the number of birds killed flying into windows or by cats (about a billion) to the number incinerated (hundreds? These plants are built in deserts, so there are not a lot of birds in the first place).

Current solar thermal plants don't use storage most of the time, since there are not enough of them to require it with the grid as a whole. For example, the 400 MW Ivanpah solar thermal plant is on the same power line as Boulder Dam. Ivanpah just displaces some of the water otherwise run through the dam, which can be used at other hours.

> Thermal energy storage doesn't work well for anything much smaller than a large industrial site.

That *used* to be true, before the development of hi-temp vacuum-powder insulation. It has about 6x lower thermal conductivity than fiberglass, and therefore lowers the relative heat loss on smaller units. It is being sold for industrial furnace insulation, which is a similar job to thermal storage.

Hot rock thermal storage is the cheapest long term option, because rock is as cheap as you can get for a storage medium. You blow air through a heat exchanger into the rock bed to store energy, then reverse the air flow to extract heat. The heat exchanger has boiler tubes to make steam. That then goes to a turbine the way most electricity is generated.

You mean photovoltaic doesn't match demand. Solar thermal with storage can meet demand whatever time you want. Not many plants with storage have been built yet, because they are not necessary. Solar is a small enough part of the grid that other sources can adjust. Once you get to about 20% penetration, you will need storage options, and they will get included.

Solar-Thermal gets the same performance as Nuclear-Thermal, except the reactor is 150 million km or more away. Both heat hydrogen gas to high temperatures, and therefore get the same exhaust velocity. Large solar concentrators are lightweight, and not hard to build in orbit. One the size of the Space Station (100 meter diameter) would generate 10 MW.

The nice thing about solar-thermal is it avoids all the issues with nuclear-anything. No Greenpeace protestors, no extra costs for nuclear security on the ground, radiation shielding, etc.

How about the same people who actually wired up rural areas, the Rural Electric Cooperatives? The TVA built dams and power plants, but the REC's did the local work. As cooperatives, they are customer-owned. The government helped them get started with loans, but those are long since paid off. The advantage of using the Electric Co-ops is they already have poles going everywhere necessary.