About Us



 Based in Boulder, CO, EPSIM Corporation is a consulting practice serving the public electric utility sector, large energy loads and industrial gas processes. The combined expertise and experience in specialty engineering and utility management fosters the incubation of ideas that transcend traditional silos of consulting. As a result, EPSIM is uniquely positioned to develop, implement and manage innovative client solutions aggressively and efficiently.  

The use of our Terms and Conditions allows us to control our insurance costs while protecting all parties’ liabilities. Occasionally we are asked to use a client’s contract form, in which case we must pass through any incremental cost from insurances.      

EPSIM invoices on a Time & Expense basis, NET-30, based on our standard rates. Our monthly progress invoices fully document each activity billed to the nearest 15 minutes.  Expenses are billed at cost, contingent upon our client’s prior approval. We track and report progress and remaining budget monthly if required by our clients. Overseas projects are invoiced and paid in US Dollars.      

Q: Consulting services are costly. Do we really need EPSIM?  
A: Absolutely.  Except for some cases of damage control, the services of an independent expert are an investment, not a cost. Clearly, to build a relationship of trust, our services cannot result in a net cost to our clients. More often than not, our services have resulted in 10:1 or higher benefit return to our clients. We work closely with our clients to meet or stay below their budgets.   

Nils Tellier, PE



   Nils Tellier, PE, founded EPSIM in 2012 to serve the gas process,  cryogenic industries and wholesale electric market customers. He has nearly thirty years of experience with cryogenic processes - including his NTCI Inc. practice founded in 1996 - and over fifteen years with electric utility operations. 

Mr. Tellier is a Professional Engineer licensed in Arizona and Colorado.  He is a retired officer from the French Navy (Groupement Fusiliers Marins).  He is fluent in French and Spanish.

Dr. Francis Campos, PhD


 Francis Campos received a PhD in chemical physics from Purdue University and did postdoctoral work at the Joint Institute for Laboratory Astrophysics in Boulder, Colorado. He then spent 24 years as an engineer developing and manufacturing magnetic recording heads for data storage products. His interest in improving the analyses on which decisions were based while adhering to shrinking budgets led him to develop customized calculations and visualizations using freely available statistical packages. He is now independently providing cost efficient, customized analysis to EPSIM customers.