Defining the LCA Study
In defining how an LCA study will be carried out,
certain parameters must be addressed as well as how data and data quality
requirements are handled. The starting point for any discussion on topics such
as LCA goal and scope definition as well data and data quality requirements,
are LCA standards such as ISO 14044 and EN15804. This guide goes a step further
and narrows the room for interpretation found in standards, addressing topics
that are specific to road and rail infrastructure and taking into account the
developed PCRs for both road and rail (CPC 53210, 53211 and 53212).
4.1 Purpose of the Assessment - Goal and Scope Definition
4.1.1 Defining the Goal
An LCA can provide support for decision
making across all stages of the planning process as well as the development of a
climate declaration for a completed project. The specific goal at each planning
stage will vary to reflect the type of decision being taken. During feasibility
studies and early planning, the goal will relate to providing decision support
in selecting infrastructure solutions, e.g. selecting a specific corridor.
During the later planning stages and construction, the goal will be to identify
solutions for elements, components and materials with the lowest environmental
It should be noted that all assessments
will have a large degree of uncertainty due to these activities linked to
operation and maintenance taking place in the future and the assumptions that
will have to be made. It is therefore critical not to assume that increased
emissions occurring during construction will be compensated during operation
and maintenance, as there is a very high level of uncertainty.
The intended audience will include
decision makers and consultants that deliver the design as well as stakeholders
such as public authorities.
4.1.2 Defining the Scope
Product systems in order of complexity are defined as:
- Transportation system (e.g. combination of transportation solutions)
- Project (e.g. road/rail from point A to point B)
- Element (e.g. stretch of road, bridge, tunnel)
- Component (e.g. pavement overlay, railway sleepers)
- Material (e.g. asphalt type)
The functional unit of the LCA shall follow the principles
defined under ISO 14044 and will depend on the types of decisions being made.
When reporting overall emissions of road/rail infrastructure at a national
level, a representative functional unit is to be chosen that may differ from
what is suggested below.
For feasibility studies and early planning the functional unit
is to be defined as:
complete project in operation over the sudy assessment period. The result is
to be presented as a total as well as individualy for all life cycle stages of
For later planing stages and construction the functional unit
will vary for road and rail infrastructure and is to be defined as:
- Road infrastructure: one km of road. The road’s overall environmental impact and the environmental impact per km shall be reported together with the total amount of Annual Average Daily Traffic (AADT), speed limit, dimensions and number of lanes. The option to define the functional unit as one m2 of road may also be considered when supported by the study goal and the product system definition.
- Rail infrastructure: one km of railway (km of railway with a given function and number of tracks). The railway’s overall environmental impact and the environmental impact per km shall be reported together with type of vehicle operation (e.g, high speed, metro, etc.).
the PCR defines the functional unit of one m2 of road, while this guide defines
the functional unit as one km of road. It is expected that in the coming
revision of the PCR, the functional unit will change to one km of road, as is
defined in this guide.)
It should be noted that there are
many expected differences between road/rail through tunnel or bridge and the
details of each stretch should be described and presented together with the
defining the functional unit, it is common practice to identify the actual
function of the product or system. In the case of road and rail infrastructure,
this is the transportation of passengers or freight. It was briefly considered
that the functional unit defined should address the actual function of the
infrastructure. However, the impact on the results of assumptions made on
passenger load is too big and too uncertain.
The system boundarie should follow EN 15804:2019 and EN 15978:2011. Any changes of the system boundaries should
be stated in LCA reports to ensure transparency when communicating results. In this
guide, activities are addressed under each planning stage that require specific
Reference Service Life (RSL) and study assessment period
RSL is the service life of rail/road infrastructure which can be expected under
normal operating conditions. An RSL of 60 years is suggested. However, a longer
or shorter RSL may be defined when supported by the study goal and product
system definition. Elements or components might have a specific RSL that will
often be lower than 60 years. When assessing then environemntal impact at
element or component level, it is recommended to use the estimated service life
of each element or component, as provided by the supplier.
4.2 Data Quality
Data quality requirements set in this
guide vary with the applicable planning process stage of the LCA (see chapter
data quality sections in chapter 5). The requirements are less stringent during
early planning while they increase significantly during the later planning
stages and construction.
Further work on standardization of
emission factors, system boundaries and even RSL for elements and components
would allow for higher data quality and comparability of results. The example
of Norway where a number of LCA tools have aligned their methodology should be
viewed as a possible way forward at a national level, which could then be
implemented in the Nordics as a subsequent step.
4.3 Life Cycle Impact Assessment
The environmental impact categories
assessed in an LCA following this guide shall include Global
Warming Potential (GWP 100), defined as GWPFOSSIL according to EN
In addition, it is recommended that GWP
from land use and land use change (GWPLULUC) is reported, while reporting GWPBIOGENIC and GWPTOT is optional.
|GWPTOT = GWPFOSSIl + GWPBIOGENIC + GWPLULUC
When applicable, results should be
reported separately for GWPFOSSIL,
GWPLULUC, GWPBIOGENIC and GWPTOT.
Though this guide focuses on greenhouse
gas emissions, for an extensive overview of the environmental impact of the
rail/road infrastructure project, it is recommended that the environmental
impact categories assessed are not limited to GWP and instead include all core
environmental impact indicators specified in EN 15804:2019.