Al Gore

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The problems with combined heat and power (CHP critique part 3)

"Combined Heat and Power" (CHP) or "cogeneration" systems for producing both heat and electric power are generally mature and really can reduce emissions of CO2 compared to other fossil-fuel technologies. But there are two problems with typical discussion of CHP:

(1) Fossil-fuel-based CHP cannot be a long-term solution on climate or energy because they still burn fossil fuels, and therefore still emit a lot of CO2. Reducing that by 20% or even 50% is not enough; we need to take steps that over the next 30-40 years will bring fossil CO2 emissions close to 0.

(2) Efficiency claims for CHP systems are frequently greatly overstated. Heat is lower-quality energy than electricity, and only at high temperatures does it become close to comparable. Efficiency claims for CHP systems that use high-temperature heat are not so far off, but CHP systems that make use of low-temperature waste heat have much lower thermodynamic efficiencies than usually claimed.

The inflated efficiency claims often lead to assertions that CHP is the "largest" or one of the largest potential solutions. But the number of applications that require high-temperature heat where CHP efficiency really is quite high are limited. And the modest efficiency gains with low-temperature waste heat use, which could be much more widely applied, don't lead to very much improvement in overall energy use. The combining of heat and power production in CHP systems can reduce our fossil CO2 emissions by a few percent, but much more than that is needed in coming decades.

Useful energy can only be used once

It's understandable that with all the concern about climate change and talk of "peak oil" that the central issue in both cases, our use of energy, has received a lot of attention. It is also understandable that with that attention have come many instances of what may charitably be called "optimistic business plans", acclaimed for some time, even quite lengthy periods of time, as "the" solution, or a "core" solution to our energy problems. There are some real solutions out there; there is also a lot of hype and hucksterism. With this and one or two follow-on articles I hope to help people not so familiar with the underlying science get a better grasp of the distinction.

Character assassination in climate science: the Michael Tobis story

Climate scientists and those who understand the threat from global warming have long been puzzled by the apparently limited concern among average members of the public for the issue. That has started to improve in the last few years, particularly in response to Al Gore's efforts. Oil and coal companies have long funded efforts to confuse the issue, but recently claimed to have reformed. The media has frequently been inadequate to the job, we know that. But the most important reason for public confusion on global warming seems to trace not so much to the influence of money, corruption, or incompetence, but ideology.

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