Subject: Comments to Draft Specifications for Application of UNFC-2009 to Renewable Energy Resources: from Paolo Conti, PhD, DESTEC Department of University of Pisa and Italian Geothermal Union (UGI)
12 September 2014
I am a member of the International Geothermal Association (IGA) and of the IGA-R&R Committee. Note that the following comments are my own and do not represent the views of the IGA. Instead, they have been shared with qualified colleagues of DESTEC Department of the University of Pisa, Italy. The submitted comments are related to some general features of the document, without going deep in classes definition (PART III). If the observations are accepted, the author is available to give his contribution for future developments of the document.
COMMENT #1 (P3 – Definition of renewable energy)
In the current definition, the term “renewable” is related to exploitation conditions of a generic energetic source. Therefore, “renewable” does not regard only the specific source (solar, hydro,…), but it depends mainly on the conversion process operated by the so- called “project” (Part. II letter B).
The wording “.. energy that is derived from natural processes (…) that are replenished at a higher rate than they are consumed” does not suit well with biomass and geothermal applications (and maybe hydro), as there cannot be a perfect synchronism between exploitation and replenish rate. E.g. when we use trees or corps, we have to wait for new plants: biomass can be considered renewable only respecting the growing time of new plants. Geothermal energy is analogous. Thus, the conditions “at a higher rate than they are consumed” seems too strict to me, unless a proper integral time-scale is defined for the conversion process.
The actual discriminant factor to consider an energetic conversion process “renewable” (or not) is the level of alteration of the primary source. As other comments say, one source is renewable if its replenishment rate is similar or higher than utilization one. We can discuss on what “similar” stands for, or about a proper reference time scales for each source, but, in my opinion, a suitable definition should be focused on the sustainability of the conversion process. It could read: “Renewable energy is energy that is derived from natural processes (…) that are exploited with a sustainable average rate (during the life time of the project), without significantly affecting the original availability of the source”. At the end of the project lifetime, we have to stand sufficiently close to the conditions that occurred at the beginning of the operation.
The use of terms like “similar”, “sufficiently close”, “significantly” seems necessary in order to avoid too strict definitions resulting inapplicable to actual renewable energy systems.
COMMENT #2 (P2 – the use of the term “extraction”)
I do not think that the term “extraction” suits well with energetic processes and sustainability concept: the term “conversion” seems more appropriate.
COMMENT #3 (P2 – difference with fossil fuels or solid minerals)
According to comment #1, I propose to integrate the sentence “The main difference with fossil fuels or solid minerals is that, during the life time of the project, the renewable energy source is being replenished” with the following “..at a sufficient rate in accordance with the natural time scales of the source”.
COMMENT #4 (P2 – “Renewable Energy Sources and Resources” definitions)
The two proposed definitions do not seem totally clear and coherent with the standard terminology of energetic matters. In particular, the term “source” is generally used with a too generic meaning. The application of these guidelines will be probably more effective if established terminology is adopted, i.e. “Resource” and “Reserve”. These two terms have been widely discussed during the past decades and their definitions have reached a sufficient level of spread worldwide (e.g. McKelvey diagram or Muffler and Cataldi, 1978). The concepts of “marketable product”, “reference point”, “available technology” (and others) have been already included in energetic jargon, therefore, I think that the document should be based on the established terminology as it is appropriate also for renewable energy matters (with minor adjustments).
COMMENT #5 (General consideration about (F) and (G) axes for renewable energy assessment)
A clear evaluation of the “sustainability” of the project should be included in the reporting code. As mentioned in comment #1, the concept of “renewably” is strictly related to a sustainable operation. Therefore, the F-axis should be clearly focused on the feasibility and sustainability of the project. Thus, F1 category should include also an evaluation of the operational strategy of the plant, analyzing the whole conversion process from primary sources to marketable energetic products.
G-axis is focused on the description of source characteristics and its energetic potential. The terms “Geological knowledge” (deriving from UNFC-2009) can be replaced with: “Resource base knowledge” (letter R).
Comments from from Paolo Conti, PhD, DESTEC Department of University of Pisa and Italian Geothermal Union (UGI), to Draft Specifications for Application of UNFC-2009 to Renewable Energy Resources.
12 September 2014
I am a member of the International Geothermal Association (IGA) and of the IGA-R&R Committee. Note that the following comments are my own and do not represent the views of the IGA. Instead, they have been shared with qualified colleagues of DESTEC Department of the University of Pisa, Italy. The submitted comments are related to some general features of the document, without going deep in classes definition (PART III). If the observations are accepted, the author is available to give his contribution for future developments of the document.
COMMENT #1 (P3 – Definition of renewable energy)
In the current definition, the term “renewable” is related to exploitation conditions of a generic energetic source. Therefore, “renewable” does not regard only the specific source (solar, hydro,…), but it depends mainly on the conversion process operated by the so- called “project” (Part. II letter B).
The wording “.. energy that is derived from natural processes (…) that are replenished at a higher rate than they are consumed” does not suit well with biomass and geothermal applications (and maybe hydro), as there cannot be a perfect synchronism between exploitation and replenish rate. E.g. when we use trees or corps, we have to wait for new plants: biomass can be considered renewable only respecting the growing time of new plants. Geothermal energy is analogous. Thus, the conditions “at a higher rate than they are consumed” seems too strict to me, unless a proper integral time-scale is defined for the conversion process.
The actual discriminant factor to consider an energetic conversion process “renewable” (or not) is the level of alteration of the primary source. As other comments say, one source is renewable if its replenishment rate is similar or higher than utilization one. We can discuss on what “similar” stands for, or about a proper reference time scales for each source, but, in my opinion, a suitable definition should be focused on the sustainability of the conversion process. It could read: “Renewable energy is energy that is derived from natural processes (…) that are exploited with a sustainable average rate (during the life time of the project), without significantly affecting the original availability of the source”. At the end of the project lifetime, we have to stand sufficiently close to the conditions that occurred at the beginning of the operation.
The use of terms like “similar”, “sufficiently close”, “significantly” seems necessary in order to avoid too strict definitions resulting inapplicable to actual renewable energy systems.
COMMENT #2 (P2 – the use of the term “extraction”)
I do not think that the term “extraction” suits well with energetic processes and sustainability concept: the term “conversion” seems more appropriate.
COMMENT #3 (P2 – difference with fossil fuels or solid minerals)
According to comment #1, I propose to integrate the sentence “The main difference with fossil fuels or solid minerals is that, during the life time of the project, the renewable energy source is being replenished” with the following “..at a sufficient rate in accordance with the natural time scales of the source”.
COMMENT #4 (P2 – “Renewable Energy Sources and Resources” definitions)
The two proposed definitions do not seem totally clear and coherent with the standard terminology of energetic matters. In particular, the term “source” is generally used with a too generic meaning. The application of these guidelines will be probably more effective if established terminology is adopted, i.e. “Resource” and “Reserve”. These two terms have been widely discussed during the past decades and their definitions have reached a sufficient level of spread worldwide (e.g. McKelvey diagram or Muffler and Cataldi, 1978). The concepts of “marketable product”, “reference point”, “available technology” (and others) have been already included in energetic jargon, therefore, I think that the document should be based on the established terminology as it is appropriate also for renewable energy matters (with minor adjustments).
COMMENT #5 (General consideration about (F) and (G) axes for renewable energy assessment)
A clear evaluation of the “sustainability” of the project should be included in the reporting code. As mentioned in comment #1, the concept of “renewably” is strictly related to a sustainable operation. Therefore, the F-axis should be clearly focused on the feasibility and sustainability of the project. Thus, F1 category should include also an evaluation of the operational strategy of the plant, analyzing the whole conversion process from primary sources to marketable energetic products.
G-axis is focused on the description of source characteristics and its energetic potential. The terms “Geological knowledge” (deriving from UNFC-2009) can be replaced with: “Resource base knowledge” (letter R).
Comments from from Paolo Conti, PhD, DESTEC Department of University of Pisa and Italian Geothermal Union (UGI), to Draft Specifications for Application of UNFC-2009 to Renewable Energy Resources.