## 3 LCC Implementation in GPP in Greece--Methodology
### Limitations and Barriers  
With the definition of LCC and the types of costs involved, various limitations arise requiring caution in order to avoid questionable results, before the application of the LCC by public authorities. Data are not easily collected. Those that can be obtained from suppliers and relate to purchase and usage costs (acquisition costs, etc.) are easy to access. However, it is difficult to get data concerning, for example, maintenance costs, since this information is not always available to contracting authorities.  
Numerous barriers in applying LCC have been pointed out. [PERSON] et al. [13] summarize these barriers as both internal and external to the organization. Examples are the price, since sustainable procurement is considered \"expensive\", the lack of acquaintance with LCC approach, the lack of staff skills, refusal to change, lack of common methods from authorities to pilot adoption process and uncertainty regarding the benefits linked to this approach. Furthermore, the majority of barriers to LCC usage are directly associated to the lack of adequate knowledge of LCC processes and mechanisms [35; 36; 37].  
Equally important is the issue of the complexity of environmental externalities, which makes their monetization a difficult challenge. The uncertainty that characterizes environmental decisions at all stages of decision-making and the unpredictable effects of climate change are a major obstacle. More specifically, LCC aims at unifying environmental problems into a single monetary unit. Environmental externalities associated with a product are mentioned in Art.68 of the Directive EU/2014/24, provided that their monetary value can be established and proved. Environmental externalities are unadjusted environmental consequences of production and consumption that have an impact on consumer utility and business costs outside of the market process [24]. The procurement directives clarify that LCC can include costs of environmental externalities, as well as direct costs. It is therefore necessary to determine the cost of externalities. In the EU LCC tool, purchasers have the option to include or exclude the cost of CO\({}_{2}\)-eq emissions and to identify the corresponding costs as externalities. This cost identification should be in line with therequirements defined in article 68.2 of Directive 2014/24/EU on public procurement. A proposal is to use 90 EUR/tonne CO\({}_{2}\)-eq. One of the arguments for including external costs is the polluter pays principle, which is a recognized approach in the European Union [35]. Questions arising in the context of LCC are whether there are other types of externalities that can be factored in, leaving aside environmental costs. Among these are social costs, which are harder to assess but yet important [23].  
Finally, another important aspect of LCC tool utilization is the avoidance of double counting in order to ensure that the evaluation results do not lose their reliability. The cost of delivery and installation, which may be included in the purchase cost, and the cost of maintenance for the period that the service is covered by the guarantee are typical examples [28]. Double counting can take place during the input phase; therefore, the cost information should be specific when evaluating tenders.