This research aims to evaluate the main determinants of real water loss per unit length of the network in the Portuguese water sector, using data covering a 10-year period. The governance model, typology of the area, type of service, management model, total water conveyed, and total network length were found to be statistically significant determinants. The methodology employed Generalized Linear Models and Artificial Neural Networks, confirming the existence of interactions and non-linearity. From a public policy perspective, setting water loss targets based only on two variables - area typology and type of service – is not a robust approach.

Variable renewable energy (VRE) is not yet meaningfully participating in U.S. ancillary services (AS) markets. VRE participation in AS markets could provide a new source of revenue for VRE resource owners to offset declining energy and capacity values and a new tool for power system operators to address emerging system constraints. This paper uses a price-taker dispatch model and historical prices to estimate the economic value of standalone and hybrid (battery-paired) VRE participation in AS markets, from the resource owner and electricity system perspectives, in each of the seven U.S. independent system operator and regional transmission organization (ISO/RTO) markets where ancillary service prices are set. Across ISO/RTO markets, average (2015–2019) simulated incremental revenues from power regulation market participation were $0.0–2.9/MWh (+0–15% of revenue without participation) for standalone VRE owners and $1–33/MWh (+1–69%) for hybrid VRE owners. However, ISO/RTO reserve markets are relatively thin and have the potential to become saturated by energy storage projects that are currently in ISO/RTO interconnection queues. In most markets, standalone and hybrid VRE could provide power regulation reserves during periods with high power regulation prices, suggesting that VRE participation in AS markets could have high system value. The analysis highlights the relevance of separate upward and downward power regulation products and indicates that ISOs/RTOs might consider initially focusing on enabling hybrid VRE provision of AS.