Powering to Climate Mitigation
- Apr 4, 2014 5:00 am GMT
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The recently released Intergovernmental Panel on Climate Change (IPCC) report Climate Change 2014: Impacts, Adaptation, and Vulnerability identifies with high confidence eight “key risks” presented by climate change, which the scientific consensus says is mostly caused by human activities that increase greenhouse gas concentrations in the atmosphere.
As is apparent from the following EPA chart based on data from the 2007 IPCC report, fossil fuel use is by far the greatest greenhouse gas contributor.
According to USA Energy Information Administration data for 2006, 86% of all of the primary energy the world consumed in that year, 13.62 terawatts, came from fossil fuels, while hydroelectricity and nuclear power combined to provide about 13% in roughly equal amounts and the remaining 1% came from the renewables, geothermal, wind, solar and biomass.
In order to avoid the IPCC risks Jared Anderson outlined here, carbon emissions have to be reined in, which will require finding 14 terawatts (TW) plus of clean energy as populations increase and demands are made for improved living standards by the world’s poorest.
Although all clean energy sources are an improvement over fossil fuels, only hydroelectricity and ocean thermal energy conversion (OTEC) have the potential to instantly rollback some or all of the environmental damage that is currently occurring and threatens to increase.
According to the UC San Diego paper, How Much Dam Energy Can We Get? 1.6–2.3 TW of hydro electricity is technically feasible globally but economic feasibility drops this to between 1.0 and 1.4 TW.
The OTEC Thermal Resource on the other hand has been put by Gerard Nihous, Department of Ocean and Resources Engineering, University of Hawaii, at about 14 TW; enough in and of itself to replace all the world’s depleting fossil fuels in perpetuity.
Key amongst the risks identified by the IPCC is storm surge, coastal flooding, and sea-level rise for coastal communities.
The greatest storm damage to coastal communities is produced by tropical cyclones that develop when ocean surface temperatures to a depth of at least 50 meters exceed 26.5 degrees Celsius. These are also the best conditions for producing OTEC power, which moves the heat that otherwise drives cyclones to deeper water. At a depth of 1000 meters the coefficient of expansion of sea water is half that of the tropical surface thus sea level rise is reduced by moving heat to that depth with an OTEC deep water condenser.
Atmospheric warming leading to the melting of polar icecaps poses the greatest sea level risk.
The movement of surface heat to deeper water occasioned by stronger than average trade winds has lead to the atmospheric warming hiatus of the past 15 years. OTEC would replicate this result and thus rein in the greatest sea level risk as well as virtually all of the other threats identified by the IPCC.
As pointed out here, OTEC is effectively an air conditioner for the planet.
Severe ill-health and disrupted livelihoods for large urban populations due to inland flooding is the second of the IPCC’s risks. Warmer ocean surfaces produce increased evaporation leading to terrestrial downpours in some places while warming land produces evaporation that can lead to drought and food insecurity and loss of rural livelihoods, the fifth and sixth of the IPCC’s risks, in others.
Cooling the ocean’s surface and reining in atmospheric warming with OTEC mitigates these problems as does moving excess water from areas that are becoming wetter to regions that are drying out, with such movements creating opportunities for additional hydroelectric power generation.
OTEC ocean and atmospheric cooling also limits the third, fourth and eighth risks, which are extreme weather leading to breakdown of infrastructure networks and critical services; mortality and morbidity during periods of extreme heat; and the loss of terrestrial and inland water ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for livelihoods.
Massive OTEC moderates atmospheric temperatures by moving heat into the ocean deep and also would benefit marine and coastal ecosystems, the seventh risk, as outline here.
The latest IPCC report declares, “Throughout the 21st century, climate-change impacts are projected to slow down economic growth, make poverty reduction more difficult, further erode food security, and prolong existing and create new poverty traps . . . without swift and decisive action to limit greenhouse gas emissions from fossil fuels and other sources, the world will almost surely face centuries of climbing temperatures, rising seas, species loss and dwindling agricultural yields.”
These outcomes are not written in stone.
As Chris Field, one of the co-chairs overseeing the report said in a Guardian article, “It’s much more about what are the smart things to do then what do we know with absolute certainty. If we want to take a smart approach to the future, we need to consider a full range of possible outcomes and that means not only the more likely outcomes, but also outcomes for truly catastrophic impacts, even if those are lower probability,”
I submit, the smart approach to climate-change, is to power our way out of it.
Low probability, catastrophic impacts or an energy deprived future are not legacies I wish to leave my grandchildren.