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Posted: Jan 21, 2016
Assessment aims to maximize greenhouse gas reductions from bioenergy
(Nanowerk News) In the wake of the Paris climate deal, there’s plenty of buzz about how to cut carbon emissions to keep global temperatures within 2°C of pre-industrial levels and how to do it as cheaply as possible. But, the authors of an Atlas award-winning study to assess global electricity say, the quest for a more sustainable future isn’t only a question of economics and the environment.
According to the United Nations, sustainability “calls for a decent standard of living for everyone today without compromising the needs of future generations.” In other words, in limiting energy consumption as much as possible, social considerations will also be key.
“The mistake is sometimes made of associating sustainability solely with caring for or respecting the environment,” said Juan José Cartelle Barros at Spain’s Universidade da Coruña. “Sustainable development is something more. It covers aspects related to the economy, society and the environment. Thus, it is time to think about electricity generation in a broad sense, covering all three pillars in depth.”
In the September 2015 issue of the journal Energy ("Assessing the global sustainability of different electricity generation systems"), Cartelle Barros and his colleagues set out to do just that, producing a new model for assessing the global sustainability of the most common conventional and renewable power plants. Their model is based on the MIVES method (which stands for Modelo Integrado de Valor para una Evaluación Sostenible or Integrated Value Model for Sustainability Assessment), which has been applied before to the sustainable design of concrete structures and the selection of materials for use in pavements, among other applications. It had never been put to use in the energy sector.
Their MIVES-based model makes it possible to calculate a single global sustainability index for each power plant type based on a combination of environmental, social and economic factors measured in completely different ways. The method involves several steps: defining the problem to be solved, establishing the criteria to be considered and their relative importance, defining and evaluating the design alternatives and, finally, making decisions.
The researchers applied their model to evaluating 10 common energy systems based on 27 parameters. Those parameters included costs, from obtaining the fuel to operating the plant; environmental impacts, such as global warming, ozone depletion, and noise; and social dimensions, such as jobs, population displacement and visual impact.
With the exception of biomass fuels, their model shows renewable energies consistently come out on top. Their analyses found that renewable energies have a sustainability index between 0.39 and 0.80, with 0 being the lowest relative contribution to sustainability and 1 being highest. By comparison, the sustainability indices of conventional power plants ranged from 0.29 to 0.57.
The best options based on the current model include temperature solar-thermal plants, wind farms, photovoltaic solar plants and mini-hydroelectric power plants, in that order. However, the researchers explain, it’s important to note that there will not be a single best solution. Rather, the best solution for limiting energy consumption while meeting the needs of the people will vary from place to place based on many factors. There will also be considerable subjectivity and uncertainty in weighing among the options.
This new model is only a first step, the researchers say, providing a kind of snapshot of the most common power plant alternatives. They are now working to produce a model to include uncertain and changing conditions.
Ultimately, a sustainable energy future will need to look beyond existing approaches to electricity generation.
“We have the obligation of achieving a responsible consumption with the objective of ensuring that future generations can satisfy their own needs,” Cartelle and his colleagues said. “In this respect, it is important to remark that every hour and a half the sun provides the equivalent of all primary energy we consume annually. Moreover, the oceans store annually the equivalent of more than three thousand times the world primary energy consumption in a year. Developing ways to make use of these sources should be a priority.”