ERP has a Project Team that provides strong communication and seamless project delivery.  The key personnel identified below have the expertise to provide our clients with the highest level of quality, value, and technical proficiency.  The level of service offered by ERP reflects the experience, commitment to quality, and dedication of our professional staff.  

Greg Nelson - Partner of ERP

Greg Nelson

Greg Nelson is the founding partner and Chief Executive Officer of ERP.  Greg has over 20 years of professional environmental consulting experience leading business and technical teams focused on the energy sector.   Greg also has successfully developed over 5000 MWs of energy generation projects from natural gas, wind, solar, and biomass fuels. He is a recognized expert in environmental risk management, technical and financial assessment of environmental liabilities, and has assisted energy companies meet reserve estimation requirements in compliance with FASB standards.  He has led teams in developing governance around environmental compliance and regulatory policy.  Additionally, Greg has been successful in negotiating contaminated site closures in North America, the UK, and Europe.

Mr. Nelson has led due diligence evaluations of hundreds of energy assets for both buyers and sellers in individual and portfolio transactions ranging from $50MM to over $25B. Mr. Nelson has substantial experience developing and managing corporate environmental risk identification processes and has provided strategic support to business transactions on environmental risks, providing liability portfolio management services, performing liability cost quantification, and participating in state regulatory reform initiatives.

Mr. Nelson’s project experience includes site characterization and remediation related to a variety of industrial activities including: crude oil, natural gas, and refined products pipeline systems; chemical manufacturing plants; petroleum refineries; natural gas processing plants; underground salt cavern hydrocarbon storage facilities; truck and rail fuel storage and shipping facilities; oil and gas exploration and production fields; commercial real estate; and retail service stations.

As a Senior consultant to the energy sector Greg has demonstrated experience in the following areas:

  • Technical and financial assessment of environmental risk and liabilities to large utility and oil and gas companies

  • Transaction advisory services identifying and mitigating regulatory, decommissioning, asset retirement obligation, and remediation liabilities for coal, E&P, pipeline, and other fossil generation portfolios

  • Design and implementation of environmental liability portfolio management services, liability cost quantification, and risk transfer strategies for energy asset portfolios

  • Utility-scale project development support (due diligence, resource assessment, regulatory strategy, siting, permitting, financing, construction) for greenfield, mid/late stage, and re-power projects in the solar, wind, biomass, and natural gas arenas

trisha Elizondo - owner of erp

Trisha Elizondo

Trisha Elizondo is an owner and the Chief Operating Officer of ERP. She has over 15 years of experience in executing and managing complex environmental compliance, remediation, and demolition projects. She has managed large scale, multi-million dollar environmental projects in some of the most challenging technical and regulatory contexts. Her attention to detail and collaborative style works well with ERP’s client base, as well as with the regulators who oversee these complex projects.  Ms. Elizondo has served as Project Director for several multi-million dollar permitting and planning projects associated with power plant development and construction, transmission line planning, and environmental remediation.

Ms. Elizondo has managed the coordination of sophisticated and timely client deliverables, including merger and acquisition support, liability estimating, site assessments, demolition evaluations, remedial strategies, and compliance reviews. She has provided successful project strategies for investigation, remediation, and re-powering of various energy sector facilities.

While serving as a project manager, Ms. Elizondo has identified and completed environmental permit requirements, state and local agency notifications, hazard identification and mitigation, health and safety control and oversight, heavy equipment coordination and evaluation, and multi-subcontractor management.

Other project experience has included various permitting, ASTM Phase I Environmental Site Assessments, SPCC field surveys and plan preparation, Stormwater Pollution Prevention Plans (SWP3), demolition notifications, health and safety audits, and asbestos and lead abatement coordination activities.


Tamara Gleason

Tamara Gleason is a registered Professional Engineer with over 20 years of experience in the environmental consulting field managing programs and projects, and providing technical expertise across a wide range of environmental science and engineering projects with particular emphasis in site remedial investigations, design, and remedial action in complex regulatory and stakeholder frameworks. She has project management and technical leadership experience within the railroad, petroleum, aircraft, durable goods, chemical, energy, defense, food and beverage, metals, pesticide, thermal controls, landfill, paper and redevelopment industries.

Tamara has completed federal and state regulatory program site investigations, feasibility studies, remedial strategies and closures; brownfield redevelopment; construction management; NAPL management strategy; sample program management, quality documentation and auditing; environmental health and safety compliance plans and reporting; due diligence and baseline environmental assessments; permitting; cost estimation and reserve services; grant, loan and other funding assistance; specification writing and review; hazardous waste management; public and stakeholder communication assistance; and environmental information management. She has experience in project management, regulatory agency negotiation, cost estimation, and remediation while working primarily within the CERCLA, RCRA, state Superfund, and State Voluntary Program areas.


Brian O’Mara

Brian O’Mara is a Vice President for ERP. Brian is passionate about helping clients manage environmental risks ranging related to contaminated land and water, vapor intrusion, other EHS non-compliance and sustainability matters.  He has a degree in Geological Engineering from Michigan Tech, has worked as a Professional Geologist (New Hampshire #365) and has 30 years experience with a variety of infrastructure, water, buildings and environmental projects.

Brian has supported dozens of environmental-liability risk transfer and fixed price remediation projects over the past 20 years and has supported hundreds of transactions with thousands of industrial/commercial assets globally.  Brian has successfully delivered projects in 40 US states and more than 40 other countries across six continents.  His experience includes a variety of industries including: automotive and aerospace, building materials, chem-pharma, conglomerates, power generation, metals and mining, oil and gas, technology and waste management sectors.        

Brian’s technical expertise includes:

  • Merger & Acquisition and Divestment Support. Brian has successfully helped clients close hundreds of deals with challenging remediation liabilities and other EHS non-compliance matters since 1991. He has worked for strategic and financial buyers and sellers, leading industrials, financial, legal and insurance clients on deals ranging from single facilities to large portfolios with sites in dozens of countries across six continents.

  • Site Assessment and Remediation. Brian has extensive experience in understanding data gaps and risks at contaminated sites. He is expert in determining remediation liabilities which comes from years of designing and implementing regulatory closures for hundreds of sites globally. His expertise achieving regulatory closure under risk transfer and fixed price remediation contracts which provides him unparalleled perspective. Brian is a regulatory expert for contaminated sites management under Michigan DEQ Part 201, CERCLA and RCRA programs and has deep regulatory experience in MA, NJ, Brazil, France, Mexico, China, India and the UK.

  • Environmental Advisory Services. Brian has deep experience in advisory services including: developing environmental due diligence and post-merger integration, peer review and remedy optimization reviews, liability portfolio strategy development, liability risk management and quantification, environmental reserves management, environmental insurance underwriting and claims, expert witness and reporting and dispute arbitration.


Jennifer Loeffler

Jennifer Loeffler has built a strong technical foundation while developing her environmental consulting career.  Focusing within the renewable energy market, Ms. Loeffler has developed experience at all levels of a project’s lifecycle, from site selection, due diligence and constraints review, permitting and regulatory coordination, to community engagement, construction oversight, operations, and decommissioning. Her greatest strengths lie in her technical ability, specifically in the execution and management of environmental studies and anticipating how new regulations can impact renewable energy projects.

Her project scopes are wide-ranging and reflect her ability to take on diverse challenges. These scopes include site assessments, environmental due diligence and constraints reviews, protected species surveys, avian and eagle surveys, botanical surveys, wetland delineations, habitat assessments, Phase I and II Environmental Site Assessments, permitting evaluations, federal, state, and local regulatory coordination, stormwater permitting, SPCC Plans, drainage studies, biological monitoring, and environmental and safety audits for renewables energy projects across the US.           

Jennifer Klingshirn

Jennifer Klingshirn is involved in wind and solar project industry support and has conducted environmental and project due diligence of energy projects during various stages of development, construction, and operation throughout the US. Ms. Klingshirn has completed critical constraints and permitting analyses for proposed wind and solar projects across multiple states and has experience completing and overseeing onsite field assessments, including biological surveys, habitat assessments, cultural resources surveys, and wetland and stream assessments. Biological assessments have included reptile surveys and avian and eagle point count surveys throughout Texas and Oklahoma.

Ms. Klingshirn has communicated and coordinated with various federal, state, and local agencies and officials extensively and has completed formal regulatory consultation as part of federal and state permitting and compliance requirements. She has completed due diligence for several portfolios of wind and solar projects for both financing and acquisition. In addition, Ms. Klingshirn has completed site work and reporting for Phase I Environmental Site Assessments (ESA) and Spill Prevention, Control, and Countermeasure (SPCC) Plans. 


Jerry Hobbs

Jerry Hobbs has more than 12 years of real-world experience in mapping and geoscience. He is particularly passionate about GIS, spatial analysis, and data management, with a deep affinity for cartographic excellence. He is a determined, effective solutions developer with a diverse skillset that includes many years of hands-on experience working with multiple geospatial, design, and data management software platforms. He has extensive knowledge of geospatial technology concepts and practices; and a keen ability to absorb new information, integrate modern workflows, and utilize new technologies.


Sean Martin

Sean Martin brings with him close to 20 years of professional environmental consulting experience. Mr. Martin has successfully provided permitting support on solar energy generation projects in North Carolina and Virginia. He has extensive experience in the areas of Clean Water Act permitting, NEPA documentation and compliance, threatened and endangered species surveying in multiple states, and coordination with regulatory agencies including the USACE and the USFWS. Mr. Martin’s background in municipal and transportation infrastructure, commercial development, and ecological restoration has provided him with a broad range of experience working with a diverse set of clients, stakeholders, regulatory agencies. He has strong project management background working on large, complex projects, and he has successfully overseen project development from early due diligence and permitting through to construction and post-construction compliance. Mr. Martin’s skills include stream and wetland delineations, ecological restoration design and monitoring, Phase I Environmental Site Assessment reporting, GIS resources mapping and modeling, and CAD drawing.

Daniel Roberts

Daniel Roberts is a Professional Wetland Scientist with significant experience in Clean Water Act compliance.  Mr. Roberts has significant experience in completing jurisdictional wetland and stream delineations, threatened and endangered species assessment surveys, environmental assessments, natural stream restoration design and monitoring, and NEPA/SEPA.  Mr. Roberts has been involved in complex projects related/associated with after the fact permitting and responding to notices of violations.  Mr. Roberts has extensive experience in technical writing, permitting, and working collaboratively with regulators to ensure his clients objectives can be reached.