Alternate fuels?

[lynx]

The Us and European countries need to mandate hybrid motors for autos and require solar panel on new construction. If most homes could produce 20% of their own power look at the energy savings per year.

At the moment, hybrid cars cost more to make (in energy terms) than they save in their expected lifetime, so as a so-called "green" option it is anything but green.

Similarly, photovoltaic solar panels of the size used in roof panels will take a long time before the energy cost of production is recovered, but at least in that case there's a chance of an energy profit in the long term.

A better option is a solar hot water system. These systems need no expensive technology, and are actually more efficient. A large proportion of household energy use goes in heating water. Creating electricity with a PV system, only to use that electricity in an inefficient water heating system is ludicrous when the sun's power can be used to heat water directly.

Of course, what we really need to see developed is a combined hot water/PV system in the same panel. There are plenty of so-called hybrid systems, but in fact they are simply separate systems on the same roof. Hot water systems tend to utilise the IR/red end of the solar spectrum, PV systems extract most of their energy from the blue/UV end of the same spectrum. I envisage that such a system would heat the water first, with the PV cell sitting behind to pick up the remaining energy. I know that the feasibility of such systems is being examined, but I'm not sure what progress has been made at present.

[bblogs]

No, I mean nuclear power-stations, providing power for battery-driven cars

+1. It'll take a long time for the big men to take the risk, but when desperation sets in....