Tomas Martin

My U.S. Infrastructure and Employment Plan

Good article but natural gas-powered cars is a mistake, in my opinion. The US reserves of natural gas would be exhausted quickly if large numbers of cars started tapping into it, and the investment needed to upgrade gas stations would be huge. There's a similar investment needed to build infrastructure for electric cars but the difference is that electricity is not dependent on a resource that could run out. If you want to use natural gas, great. Build some gas-fired power stations (or even better, some concentrated solar thermal-gas hybrid plants in the desert) and use that generated electricity to charge up car batteries. That way you can use the car batteries as energy storage for a smarter grid, too.

Natural gas, like hydrogen, is a blind alley for transportation. Neither solves the problems we have with oil. Convert to natural gas and in fifteen years we'll have to convert again. Convert to hydrogen and all you're doing is generating electricity and then wasting some of it making hydrogen. Pickens is only promoting the natural gas angle so much because he owns a load of companies in that sector, as Californian voters thankfully saw when they voted down props 7 and 10.

Electric cars are the future and all these stopgap measures do is keep the current oil infrastructure happy. It's a short term measure that will give us the same problems further down the road. Investing in electric trains and cars will be a far better longterm use of the cash.

The rest of it, I strongly agree with.

The Long Case for Solar Energy

As an analyst in the renewable field, I've been to a few events by carbon capture professionals in recent weeks and have come away distinctly unimpressed. Even their best case scenarios don't have plants of any meaningful size until 2015 at the earliest - and they still haven't decided which method they plan to use! There are three main ways to capture carbon from coal - remove all the nitrogen prior to burning so that most of the gas after burning is CO2(the oxy-fuel method), scrub normal gas emissions using chemicals (the post-combustion method) and to convert carbon to mostly CO2 and H2 before bruning (pre-combustion method).

Technology takes time to develop and CCS is at least ten years behind solar, in my opinion. We have so far only seen small lab demonstrations of the technology and this stage of development is where the most delays occur. By the time a few hundred MW of test CCS are installed in the middle of the next decade, solar, wind, geothermal and even marine renewables may be too established and have come down so much in price that CCS is no longer a finanically attractive option. I think a lot of dirty coal plants capable of upgrading to CCS will be built and eventually converted but in terms of actually CCS-enabled plants, I'd guess we are 8-10 years away from even early commercial installations, equivalent to where wind was in the early nineties and solar was at the turn of this century.

The Long Case for Solar Energy

jay bird - indeed, it's pretty impressive and this is a technology well under the radar as far as I can tell. Essentially aside from the molten salt and the steam turbine, all that is required is glass and steel - very simple from a construction point of view compared to nuclear. That 14x is just for solar thermal too - it doesn't include Stirling Engines, concentrating photovoltaics, thin film or silicon photovoltaics.

The Long Case for Solar Energy

Triple-junction cells based on three different photovoltacis in a sandwich using III-V elements like Germanium instead of Silicon do regularly reach efficiencies above 40% (the record is 42.8% by DARPA, with typical commercial devices hovering around 38% at present: www.futurepundit.com/a...)

These devices are a lot more expensive however, and need the light entering the cells to be concentrated by a set of mirrors or lenses, so called 'concentrating photovoltaics' or CPV. Another concentrating tech focuses the light onto molten salt, which heats steam and drives a turbine. This Concentrated Solar Thermal (CST) technique has the advantage of storing the energy in hot salt reservoirs for 7-9 hours or longer after the sun sets, reaching close to 24 hour generation in desert areas. 400MW is currently installed but 14 times that is planned to be in place by 2013.

Photovoltaics is similarly booming. Efficiencies are as much as 23% (SunPower are I think the most efficient using normal silicon) and thin-film is at around 10-12%.

The key issue is not efficiency but cost. Solar thermal is booming because with salt storage it is already cheaper than nuclear and gas turbine plants and this price is expected to drop further. thin-film is less efficient but cost-wise is much closer to the target of $1 a watt. Some firms such as First Solar may reach that goal in the coming months.

As silicon supply increases (silicon manufacturers have made vast investments in recent years to catch up with the demand from PV) the price of PV will come rapidly down and then many analysts predict PV will really start to take off, although thin-film may become less attractive if silicon panels begin to match them in price competitiveness. Either way, Solar (which is around 7 years behind wind in growth cycles) will become a major player in the next five years.