Guidelines for the calculation of Life Cycle Costs of NbS. Costs of infrastructures: elements of method for their estimation.

In this guidance report we tailor the general LCC methodology for the specificities of NBS and produce a general guideline for demo cases to calculate in a standardized way the TCO of NBS which could be then integrated in the cost-benefit analysis. Life cycle costs (LCC) are also named Total Cost of Ownership (TCO), which considers “total cost of acquisition, use/administration, maintenance and disposal of a given item/service”. In relation to NAIAD task 4.1, the LCC methodology corresponds to the calculation of‘implementation costs’. While Life Cycle Costs for grey infrastructures assets are greatly standardized and contractors and procurement authorities count with databases with context- specific cost figures per unit for different types of assets and expected distribution of Capital Expenses (CAPEX) versus Operative Expenses (OPEX); such level of knowledge is not yet in place for Nature Based Solutions (NBS). It is for this reason that in this deliverable, after introducing the general LCC methodology, we will focus on working out this generic methodology for NBS. In this guidance we assess the life cycle costs of NBS by providing an overview of the temporal and spatial distribution of costs related to NBS. Compared to grey solutions, NBS are expected to have different types of maintenance and asset management tasks. Besides that, green options contain a share of nature’s volatility and adaptability, due to their biophysical characteristics, resulting in a different risk profile. Different costs and risks influence the structure of financial liabilities, requiring different types of partnerships between public, private and communityactors. LCC information can support an argument for cost-effectiveness, i.e. lower costs generating a similar functionality, compared to other infrastructure solutions, which stimulates investment.