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ES Partners Provides Energy Concierge Services

ES Partners was established in 2006 to provide energy concierge services to a growing client base in the commercial and residential real estate industries, publishing, technology, and other sectors.  As the energy marketplace has become increasingly complex, our role is to simplify decisions for clients through education and guidance.  Our founder, Bill Costello, spent several years on the ESCO side of the table and decided to bring that knowledge directly to bear on the client side of the table, acting as a trusted advisor on all energy decisions. 


Having spent 16 years of his career at Con Edison, the local utility, in a variety of customer facing roles, and then transitioning to Con Edison’s deregulated subsidiary (Con Ed Solutions) at the outset of energy deregulation in New York in 1997, Bill provides our clients with a unique perspective on the energy market. This unique perspective is a key competitive advantage for our clients.

Energy procurement has been the core service provided by ES Partners and our offerings have expanded into the following client services:

  • Demand Response participation
  • Renewable Energy procurement
  • Energy Efficiency opportunities and evaluations
  • State and Utility Energy Efficiency rebate administration
  • Local Law 84 Compliance – Energy Star ratings
  • LEED support services
  • Utility Rate Negotiations
  • Utility Service Expediting
  • Utility Budgeting & Tracking


Founded Upon Years of Energy Industry Experience

Bill Costello founded the company in 2006 to bring his vast knowledge of the energy industry to his clients.  Bill holds a BS in Electrical Engineering from Pratt Institute (1984) and has an MBA in Finance from St. John’s University (1991).  This powerful combination of technical understanding and thoroughness, combined with financial acumen, provides a solid foundation for understanding client energy issues and developing actionable strategies to maximize returns.


Bill has extensive experience negotiating third party electricity and natural gas deals on behalf of his client base.  His experience covers the entire procurement process:

  • Initial client engagement
  • Utility data collection and analysis
  • Issuance of RFPs
  • Analysis and leveling of third party supplier RFP responses
  • Recommendation of appropriate procurement strategy to meet clients' risk tolerances
  • Contract negotiation
  • Client onboarding with third party suppliers
  • Third party bill review to assure contract compliance


Our role is to be the client's eyes and ears in the market, tracking energy market movements, staying abreast of regulatory issues that could affect your energy budget, and identifying energy market buying opportunities as they present themselves.


Additionally, Bill is well versed in a variety of energy issues such as developing and executing energy efficiency projects, objective evaluation of the financial impacts associated with an energy efficiency project, renewable energy credits, demand response programs and associated client revenue and responsibilities. Due to his length of service with utilities, Bill has an insider’s knowledge of what it takes to expedite service requests through the proper channels to completion.

Knowledgeable Support Throughout Every Energy Project

Cissy Bai joined ES Partners in February 2016 after graduating from Columbia University with an MS Degree in Chemical Engineering. She brings with her a great passion regarding energy technology and energy markets. This passion was initially sparked during a Marketing & Sales internship with Dow Chemical Company in 2013. There she participated on a research team that presented the technical and financial benefits of installing solar panels on the Shanghai Dow Center, a project that provided a combined $1.5 million annual savings for the company.


Cissy developed an expertise in data analytics as part of her master’s research at Columbia University. She obtained enormous experience creating mathematical models to monitor data performance and applying trend analysis to support decision making. Cissy brings these same skills to energy budget modeling, energy market analysis and utility rate modeling.  She is proficient with Microsoft Office and data analytical tools, including R programming language.


Cissy’s responsibilities as a Operations Research Analyst - Data Analysis include creating compelling reports, visualizations, and presentations for external corporate clients. She is specialized in analytics related to our clients' energy portfolio. She contributes towards the creation of a series of models that will help the business with decision making processes surrounding energy management, hedging, forecasting, etc. of their portfolio of assets. She provides key input into product development and contributes to industry trend analysis.


She holds a BS in Chemical Engineering from the University of Washington, Seattle, with specialty area in Environmental Engineering, and Fuel Cells and Energy. She has LEED Green Associate Credentials.

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