2. Cars that get 75 MPG to 200 MPG, capable of carrying four passengers or more, cost competitive with normal cars.

The old argument for hypercars remains valid. Carbon-fiber low-weight aerodynamic bodies combined with hybrid drives and low rolling-resistance tires can produce 75 MPG or better even in gasoline driven cars.

Carbon-fiber bodies are comparable in price to those made from steel, despite carbon fiber being more expensive than steel. They can be made in one piece, with built-in color, saving painting and assembly labor costs. In general, hypercars uses fewer but more expensive parts; there is no reason to think they need to be more expensive than conventional cars. You can now buy carbon fiber bodies, quantity one, for around $5,500. In wholesale quantities the price would drop. Driven by electric batteries, they can get still better results -- 90 MPG equivalent powered by the current U.S. grid, 200 MPG equivalent powered by a renewable electric grid.

3. Modified hybrids using existing designs like the Prius, with plugs, larger batteries, and upgraded software.

The result is a Plug-in Hybrid Electric Vehicle (PHEV) with half the emissions of an existing hybrid. This lets them travel the first 12 to 40 miles from grid electricity, using gasoline engine only for longer trips. Many people have transformed their personal hybrids to PHEVs on a one-off basis.

4. Retrofitted solar space and domestic water heating on existing buildings, with inexpensive seasonal storage, economically providing 90% of climate control and domestic hot water energy.

Expensive synthetic zeolites have long been known to store heat in about one fifth the space water-based thermal mass requires. Back in 1994, Chinese scientists showed that natural zeolites, which are inexpensive and common minerals, can perform as well as expensive artificial ones for temperatures at or below the boiling point of water -- perfect for domestic space and water heating. They might also be suitable to drive solar air conditioners and refrigerators.

Since many individual buildings don't have roof or south wall space suitable for solar collectors, natural zeolites may also lower the cost of district heating, making small-scale district heating practical among low numbers of buildings.

5. Flying Energy Generators (FEG) generating wind energy at 2 cents per kWh, before subsidies.

A FEG -- née "gyromill" (see picture at top) -- is essentially a tethered helicopter with a wind turbine attached. The helicopter flies up 15,000 feet and the wind turbine generates electricity that is sent down the tether. These things have been demonstrated, but only for a few hours at a time. Yes, they generate net energy. The helicopter's consumption is negligible compared to what the turbines produce.

Why bother? Because wind blows much faster and at much higher speeds at that height. Ground-based wind turbines produce about 29% to 35% of nameplate capacity. FEGs produce from 40% to 90% of name plate capacity, with 50% or better being fairly common. Since capital costs are the main cost of wind farms, better utilization of capital brings the price per kWh down quite a bit. (Surprisingly, the capital being utilized is not that much more expensive than a conventional wind farm per KW of capacity. Tethers and weird helicopter-like things are not priced all that differently from towers.)

Are there any major disadvantages? Well, tethered helicopters make air traffic problematic. Civil aviation would have to be excluded from a few mile area around any place FEGs are installed. But currently, tethered balloons for drug interdiction exclude civil aviation from a larger area than it would take to provide 100% of U.S. energy via these things.

These are highly speculative and experimental, but the potential is huge. It's one of those ideas that's crazy without being stupid. This strikes me as a good case for "casting our bread upon the waters".

6. Breakthroughs in turbines closer to the ground.

So far, efforts at small-scale wind have focused either on conventional horizontal turbines or unconventional vertical turbines. Neither has resulted in the cost reductions we need. The Selsam wind turbine uses multiple horizontal-style turbines on a tilted tower, getting some of the low capital costs of vertical wind and some of the higher efficiency of horizontal ones. (It has potential for utility-scale wind too.) As in any R&D, there are no guarantees, but as of now we have a cost/output curve, only the extreme ends of which have been tested. This turbine explores the area of the curve in between. The claim to have discovered a sweet spot is plausible -- a compromise with lower cost per kWh hour than either extreme. Paul Gipe, who probably knows as much about wind electricity as anyone in North America, seems to have been impressed.

7. Five cents per kWh solar PV.

We could have been doing this for long time. I'm going to be lazy and quote myself on this:

We've known how to make reasonably inexpensive solar cells for some time. The problem is that because they are currently so expensive, the market for them is limited. Because the market is limited, no one wants to risk investing in a big enough factory to take full advantage of the economies of scale in mass production. One proposal to overcome this was made by a consultant to Greenpeace back in 1999 (PDF): invest about a billion (in today's dollars) in two factories, one to produce silicon cells on a large scale, the other to produce silicon on a large scale, so the solar industry is not dependent on computer waste for raw materials. That probably would have lowered the price of solar cells to the point of power at 5 or 10 cents per kWh. Once the market was established, other players could come in with higher quality and lower prices and crush the early adopter -- probably with better technology such as thin film. In effect, government intervention would produce a sacrificial lamb to break the deadlock.

8. Supercritical carbon dioxide replacing more toxic cleansers and solvents.

It's already been doing this to some extent in dry cleaning and food service equipment cleaning. In the long run, we can hope to see carbon dioxide under intense heat and pressure save water, energy, and reduce toxic chemical use in the computer and electronics industries, in pharmaceuticals, and in solar cell manufacturing.

9. Mini and micro reactors (not the nuclear kind) saving energy and water, and reducing the use of toxic chemicals.

Manufacturing will (for the foreseeable future) include energy-intensive processes, use toxic chemicals, and require a certain amount of ultra-purification. But in most cases, such steps can be segregated from the manufacturing process as a whole and take place in ultra-clean mini and micro reactors. By segregating energy-intensive processes from other steps, you save energy by applying it intensely only where needed. By segregating steps involving highly toxic chemicals, you lower risk of contamination and make recovering and reusing such toxics easier -- saving the energy needed to produced them. By performing steps requiring "clean-room" environments within micro-environments, you minimize the energy needed to maintain these environments and apply ultra-cleanliness only where needed.

It was recently suggested that such reactors be required, not to protect the environment, not to protect workers and people who live near the plants from accidents, but to protect against terrorist threats. Part of that skewed risk perception David was talking about, isn't it?

10. Improved desalinization technology, with environmentally sound ways to dispose of the brine.

Wind, undersea currents, and wave power will probably power desalinization. The brine could perhaps be diluted back to near its original salinity with additional sea water before it's dumped back into the ocean.

The water produced will probably cost double what we currently pay for mining the world's water tables. As with energy, we can find ways to generate more GDP per unit of water -- our agricultural, industrial, and domestic water arrangements are all intensely wasteful. Still, we have been overdrawing on non-renewable water resources, and as the world warms, fresh water is going to be harder to get. Even after efficiency, we will probably be forced to depend in part on desalinated water. Water is more precious than gold.