Measuring whether municipal climate networks make a difference: the case of utility-scale solar PV investment in large global cities

ABSTRACT

With cities being responsible for up to 70% of energy-related carbon emissions, municipal governments worldwide are becoming increasingly aware of their responsibility to act. Many large cities have committed to mitigation by becoming member of a municipal climate network, such as the C40 or the Compact of Mayors. However, there is no consistent assessment of whether membership of such networks translates into measurable outcomes. To fill this gap, we propose the use of novel outcome variables, combining financial data with geospatial information. As a starting point, this paper compares utility-scale investment in photovoltaics (PV) within the administrative boundaries of large global cities, combining the Bloomberg New Energy Finance database with information from Google Maps. We analyse 512 global cities with a population of above 1 million, and consider the impact of 5 networks and 2 reporting platforms. The results suggest that membership of the C40 network has a positive effect on utility-scale solar PV investment, while no such evidence is found for any of the other networks or reporting platforms under study. Based on our findings, we recommend that municipal climate networks increase their efforts to trigger city regulation that is conducive to solar PV investment. More generally, measuring early indicators, such as low-carbon investment, can help municipal climate networks in their role as ‘commitment brokers’ for climate action on the ever-more important city level.

Key policy insights

• Cities have considerable policy space to foster utility-scale solar PV investment within their administrative boundaries.

• While some large global cities exhibited significant growth in utility-scale solar PV, many others with good solar potential did not have a single project by the end of 2016.

• Outside of China (where city boundaries often include rural areas), Tokyo tops the list with utility-scale solar PV projects by far, followed by San Diego and Rome.

• Membership of the C40 network appears to make a positive difference to PV investment, unlike other networks or reporting platforms.

• Outcome measures like low-carbon investment can be used more generally to assess the climate action performance of cities.

KEYWORDS:

• Mega cities
• climate clubs
• transnational municipal networks
• urban energy systems
• urban sustainability

Acknowledgements

The authors thank Jean-Michel Glachant, Claudio Marcantonini, participants of the 6th Conference on the Regulation of Infrastructures at EUI Florence in June 2017, and participants of the IAEE International Conference at Groningen in June 2018 for helpful comments on earlier drafts of the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 Thereof over 250 projects in large cities (population >1M) outside China; see section 4.2 for details.

2 For the relationship between urban PV capacity and population size, population density, and region, see Kammen and Sunter (2016) and IEA (2016b).

3 An example for the type of portfolios included in the dataset is the Masdar PV Portfolio, consisting of 2.3 MW capacity across 10 roof-mounted installations on mainly government-owned buildings in Abu Dhabi.

4 While Bloomberg claims high accuracy of their data, we could not independently verify this. However, it appears justified to assume that locations are sufficiently precise to decide whether or not projects are situated within a certain city.

5 We used the Google Maps Geocoding service between 15 March 2017 and 31 August 2017 to process data.

6 https://carbonn.org/

7 While 22% of all large global cities are in China, the share of Chinese members that are large global cities is 0% for ISCI, 2% for ComoM, 4% for WMCCC, 5% for PACT, and 9% for C40.

8 These data were obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program.

9 In a few cases where GDP and/or market risk premium data value is not available for a country, the regional average (as per the World Bank classification) is used.

10 For the Compact of Mayors, joining cities have a maximum of three years to meet requirements, such as registering a commitment (on Carbonn or CDP), compiling an inventory, creating reduction targets and a measurement system, and ultimately establishing an action plan to deliver (Compact of Mayors, 2015).

11 As a cross-check, the installed capacity of all solar PV projects in the BNEF database until the end of 2016 adds up to 252 GW for utility-scale (>1 MW) projects and portfolios only, which is 79% of the global PV capacity (which also includes small installations) of 320 GW, as reported by Fraunhofer ISE (2017).