I would add to to Eraldo's list also: Farsi et al. 'Economies of Scale and Scope in Multi-Utilities' The Energy Journal 29(4)2008 with an interesting case study of Switzerland. On the other hand, but you probably know it, RT Silva from your hometown wrote an interesting article on interconnectivity.

Best regards (also to Eraldo),

Mariusz

There is a convergence occurring between the business realities of the utility industry, the energy demands of modern society, and the sustainability requirements of the environment in which we live. This convergence is driving the development and implementation of a new type of power system. 

https://library.e.abb.com/public/877ae9cf6d3253cec1256df0003690c7/854_Utility%20communications.pdf

Fraquelli, Giovanni, Massimiliano Piacenza, and Davide Vannoni*. "Scope and scale economies in multi-utilities: evidence from gas, water and electricity combinations." Applied Economics 36.18 (2004): 2045-2057.

Piacenza, M., & Vannoni, D. (2004). Choosing among alternative cost function specifications: an application to Italian multi-utilities. Economics Letters, 82(3), 415-422.

Farsi, M., & Filippini, M. (2009). An analysis of cost efficiency in Swiss multi-utilities. Energy Economics, 31(2), 306-315.

http://doc.rero.ch/record/11829/files/Filippini_EE_2009.pdf

http://www.siepweb.it/siep/oldDoc/wp/174.pdf

http://doc.rero.ch/record/11330/files/filippini_EJ_2008.pdf

Dear Colleagues,

Good Day,

Please, see the the following attached papers that related to the thread, I hope you will find them useful for your work....

Dear All,

Thank You very much. I will use All the informations that You sent!

Best wishes,

Vanessa

This is an excellent question.   In addition to the many helpful answers already given, there is a bit more to consider.

A thorough study of multi-utilities is given in

https://www.researchgate.net/publication/24075357_Scope_and_scale_economies_in_multi-utilities_Evidence_from_gas_water_and_electricity_combinations

See, also:

https://www.researchgate.net/publication/283008699_Use_of_Heat_Pump_along_with_Multi_Utilities_for_Domestic_and_Light_Commercial_Market

https://www.researchgate.net/publication/46557361_Economies_of_Scale_and_Scope_in_Local_Public_Transportation

Article Scope and scale economies in multi-utilities: Evidence from ...

Article Use of Heat Pump along with Multi Utilities for Domestic and...

Article Economies of Scale and Scope in Local Public Transportation

Dear Professor James F Peters,

Thank You very much for your valuable information.

Best Regards,

Vanessa

Multi Utility Sustainable Infrastructure Strategy Multi Utility Sustainable Infrastructure Strategy (MUSIS) An Alternative Approach to the Provision and Funding of Utility Infrastructure

http://www.inventapartners.com/files/Investing_In_Newham_Inventa_Presentation.pdf

Dear Krishnan,

Thank You very much for lays great and useful indications!

Vanessa

A multi-utility duct is an underground structure that contains more than two types of public utilities and includes its own drainage, ventilation, lighting, communication, power, monitoring systems, access facilities etc.

http://members.igu.org/html/wgc2006/pdf/paper/add11683.pdf