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energy engineeringThe integration of more and more renewable resources is a trend gaining momentum in the energy industry. Increasingly, customers are deploying distributed energy resources (DERs) and connecting them to the electric utility grid. These new power generating resources coupled with the industry need for a more robust and secure transmission system are contributing to additional levels of complexity in the overall grid. The demand for scenario-planning, analysis, and design optimization across a more dynamic grid is also increasing. These market developments require electrical and power system designers to demonstrate proven experience with core system engineering and a record of success with design and development of digital control, power quality and associated protection systems.

ASSET Engineering has a significant proven track record of successfully executed energy projects including biomass, solar, and wind. Our team of engineers and designers is adept at meeting the challenges of these technologies and mitigating the associated risks and constraints.

For more detailed information about our Core Services and Competencies, please visit the Why ASSET? page on our site.

Select Projects

Wind Projects

Na Pua Makani (Oahu, Hawaii)
Na Pua Makani is a 25MW wind generation facility located on the North shore of the island of Oahu in Hawaii. The windfarm is interconnected to the local Hawaiian Electric Company (HECO) transmission system through a new 46kV HECO switchyard. Wind generation is created by eight (8) Vestas V136 turbines rated at 3.45MW each. The windfarm substation consists of two (2) 34.5kV collector circuit breakers, a 46/34.5kV power transformer rated at 30MVA, and a 46kV power circuit breaker. The windfarm connects to an adjacent HECO switchyard which consists of a single 46kV circuit breaker fed by several miles of a 46kV transmission line.

Project procurement and construction is managed by Site Constructors, Inc (SCI), with ASSET serving as the lead engineer in the design of the substation, collection system, and HECO switchyard. Design efforts included developing and coordinating the physical design, civil designs, and electrical relaying protection and controls. Specific coordination of designs included general arrangements, foundations, elevation, and control buildings. ASSET was also responsible for developing the SCADA interface for the HECO switchyard, windfarm substation, and the wind turbine control system. Real-time automated controllers (RTAC) are utilized to manage the process data flow between the turbines, substation, and switchyard.

ASSET developed collection system drawing packages including the physical lay-out, cable routing and duct bank design, cable sizing, and installation details for pad mounted transformers and junction vaults. Grounding systems within the collector were also developed by ASSET and included grounding systems for the various turbine foundation designs. Along with power circuit design, ASSET designed the communication systems from the substation to the wind turbines.

ASSET accommodated differing drafting and drawing standards by the owner (AUTOCAD format) and the utility (Microstation format). All switchyard designs are developed in compliance with utility standards and requirements.

Huntington Windfarm (Huntington, Oregon)
Huntington is a 50MW wind generation facility located in eastern Oregon that is installed on the Idaho Power (IPCO) 138kV transmission system. The project was originally developed by Oregon Windfarms and later sold to D.E. Shaw Renewable Investments (DESRI). Construction and testing was completed in November of 2016.

The wind generation is created by twenty-five (25) GE wind turbines rated at 2.0 MW each, and interconnected to the utility transmission system through a 138/34.5kV substation. The substation consisted of a 55MVA (at 65 degC) power transformer feeding a 3-bay structure with three (3) 34.5kV circuit breakers. The collection system consisted of approximately 15 miles of overhead and underground circuits interconnected with 34.5kV sectionalizing cabinets and monitored through pad mounted metering enclosures.

Project procurement and construction was managed by Site Constructors (SCI), with ASSET serving as the lead engineer in the design of the substation, collection system, and the electrical relaying protection and control systems. ASSET was responsible for developing and coordinating the physical design including general arrangements, site work, foundations, elevations, and control building. Based on the clients need for a compressed schedule, and single point of contact for the substation components, ASSET facilitated the addition of Dis-Tran to the project team. Dis-Tran was sole sourced based on ASSET’s relationship that dates back to 1983 for our managing principal and 2000 with the company and our combined history of over sixty successfully executed projects.

Engineering analysis of the complete
windfarm system included arc flash evaluation, relay setting development, and reactive compensation determination. Contract standards with the utility required power factor correction at the point of interconnection. The reactive compensation study determined that a capacitor bank was required, and thus cap bank control logic was developed and implemented by ASSET based on the results of the study.

ASSET was also responsible for developing the SCADA interface between the utility, the wind turbine control system, and the owner’s third-party management software. Real-time automated controller (RTAC) programming was created to process data flow with the GE WindCONTROL, WindSCADA, and substation interfaces. Furthermore, the SCADA interface with IPCO was created to provide remote park control for voltage and generation setpoints. Finally, the owner’s third-party management system was installed to provide long-term operation of the facility. The RTAC managed and successfully executed the flow of data and information among these three SCADA interfaces.

ASSET developed collection system drawing packages to include the physical layout, cable routing and duct bank design, cable sizing, and installation details for pad mounted transformers and junction vaults. Grounding systems within the collector were also developed by ASSET and included grounding systems for the various turbine foundation designs. Along with power circuit design, ASSET designed the communication systems consisting of fiber, POTS, and ethernet networks located from the substation to the wind turbines. The ASSET scope was completed on schedule and within budget in December 2016.

Edison_Mission (1)Edison Mission Energy (Willard, New Mexico)
High Lonesome Wind Farm Electrical System Studies. Developed the system model for the entire 115kV/34.5kV 100 MW system comprised of Clipper 2.5 MW machines, including the collector and wind turbine generator. Prepared load flow study to compute real and reactive system losses to the point of substation interconnection for reactive compensation design. Developed short circuit and relay coordination studies and prepared setting sheets and manufacturer settings files. Calculated grounding transformer sizes and prepared their purchase specifications.

Mountain_Air_Wind_Farm (1)Mountain Air Windfarm (Mountain Home, Idaho)
230‐34.5kV substation interconnection with Idaho Power Company.
Two (2) 125MVA transformers servicing collector system with 60 turbines.

Horse Butte Windfarm (Idaho Falls, Idaho)
115‐34.5kV substation interconnection with Idaho Power Company.
One (1) 120MVA transformer servicing collector system with 55 turbines.

Sawtooth Windfarm (Elmore County, Idaho)
138‐34.5kV substation interconnection with Idaho Power Company.
One (1) 25MVA transformer servicing collector system with 14 turbines.

Bennett Creek – Hot Springs Windfarm (Mountain Home, Idaho)
138‐34.5kV substation interconnection with Idaho Power Company.
One (1) 47MVA transformer servicing collector system with 20 turbines.

Cassia Windfarm (Hagerman, Idaho)
138‐34.5kV substation interconnection with Idaho Power Company.
One (1) 33MVA transformer servicing collector system with 14 turbines.

Echo Windfarm (Hermiston, Oregon)
69‐34.5kV substation interconnection with PacificCorp.
One (1) 67MVA transformers servicing collector system with 38 turbines.

Pakini_Hawaii (1)Pakini Nui Windfarm (Hawaii)
69‐34.5kV substation interconnection with Hawaii Electric Light Company (HELCO).
One (1) 25MVA transformers servicing collector system with 14 turbines.
Scope also included design of adjacent HELCO Kamao’a Switchyard.

Solar Projects
S E I A Solar Energy Industries logo
Midlands Solar Farm Substation (Orangeburg, South Carolina)
Adani was the developer for this 72MW solar project located in Orangeburg, SC. Their construction arm contracted with ASSET Engineering for comprehensive engineering, design, equipment, material supply, installation and commissioning of the required 115 kV-34.5 kV interconnection substation. This substation interfaces with the adjacent SCE&G switchyard at 115 kV and to the three collector circuits at 34.5 kV. The substation is comprised of a single power transformer, 115 kV breaker, three 34.5 kV collector circuit breakers, one breaker and provisions for a 34.5 kV capacitor bank, and accompanying structures and buswork.

ASSET’s tasks included but were not limited to the substation general arrangement plan, elevations, and purchased specifications for the purpose of conceptual approval from which ASSET awarded a subcontract to a substation material packager who detailed the design, specified all minor equipment and connectors, design and detail steel structures and buswork. The Protection and Control engineering included the following tasks and deliverables:

• Single line diagram
• Relay panel front view, material lists, and construction details
• Three line diagram and AC elementaries
• DC control elementaries
• Relay panel wiring diagrams
• Short circuit study
• Relay coordination study, settings, and settings files for devices in the substation relay panels, but not including any settings for the inverter protection
• Cable list and interconnection diagrams

The Electrical System Studies included:

• Transient overvoltage study
• Insulation coordination study
• Reactive capability study
• Reactive compensation study, with specification of capacitor bank to meet the PPA‘s power factor requirements
• Harmonics predictive study, based on inverter spectrum, background transmission harmonics, and a utility model of impedances, sources, and capacitor banks for at least five buses from SCE&G switching station. The study demonstrated that harmonic filters were not required in accordance with IEEE-519.

Butler Solar Facility (Taylor County, Georgia)
103 megawatt photovoltaic facility to be constructed in Taylor County, Georgia. Southern Power acquired the project from Community Energy Inc. and selected First Solar to build, operate, and maintain it over the thirty year period of the power purchase agreement. First Solar awarded ASE the contract to provide a safe and reliable connection to Georgia Power’s electrical transmission grid. ASSET is supporting ASE by providing substation electrical engineering for the low voltage AC and DC systems, protection and controls, and several engineering studies including short circuit, reactive compensation, load flow, and harmonics.

Taylor County Solar Facility (Taylor County, Georgia)
146 megawatt photovoltaic facility to be constructed in Taylor County, Georgia. Southern Power selected First Solar to Engineer, procure and construct the new facility. Southern Power will own, operate, and maintain it over the twenty-five year period of the power purchase agreement with several local electric cooperatives and energy companies. First Solar awarded ASE the contract to provide a safe and reliable connection to Georgia Power’s electrical transmission grid. ASSET is supporting ASE by providing substation electrical engineering for the low voltage AC and DC systems, protection and controls, and several short circuit, reactive compensation, load flow, and harmonicsengineering studies including short circuit, reactive compensation, load flow, and harmonics.

TopazTopaz Solar Farm (San Luis Obispo County, California)
550 MW photovoltaic (PV) power station
Comprehensive system studies including; load flow study, capacitor bank sizing, short circuit study, protective device coordination study, arc-flash study, and underground cable thermal ampacity study.

Desert Sunlight Solar ProjectDesert Sunlight Solar Project (Desert Center, California)
550 MW solar project
Comprehensive system studies including reactive compensation analysis, voltage drop load flow analysis (for LGIA documentation), harmonic and flicker analysis, relay coordination and protective device settings.

Agua Caliente Solar Project (Yuma County, Arizona)
290 MW solar project
Comprehensive system studies including reactive compensation analysis, voltage drop load flow analysis (for LGIA documentation), harmonic and flicker analysis, relay coordination and protective device settings.

California Valley Solar Ranch – CVSR (San Luis Obispo County, California)
250 MW solar project
230‐34.5kV substation with relay coordination and protective device settings.

Catalina Solar Project (Bakersfield, California)
143 MW solar project
Relay coordination and protective device settings.

NRG AvraNRG Avra Valley Solar Project (Avra Valley, Arizona)
34 MW solar project
46‐34.5kV substation with relay coordination and protective device settings.

Biomass Projects

Hu Hunua Biomass PlantHu Honua Biomass Plant (Hawaii)
30MW Biomass Facility
This facility was an old sugar mill located on the “Big Island” in Hawaii that is being repurposed as a biomass energy plant producing 30-megawatt (MW) electric power using locally grown eucalyptus biomass as the fuel source.

ESI of Tennessee was successful in landing the engineering and design for the project. ESI specializes in the design, engineering, procurement and construction of steam and power generation facilities. ASSET provided support to ESI for the condition assessment of the existing power distribution equipment, electrical engineering and studies to support the protection and controls for the generator and grid connection to the Hawaii Electric Light Company system. Our original scope was completed in 2013. The balance of the work is scheduled to be completed in 2015 and 2016.

AGE Biomass (Albany, Georgia)
34.5 MW Biomass Facility
The Combined Heat and Power (CHP) Project is a biomass plant that provides power to the electrical grid via connection to Georgia Power, while also providing steam for use throughout the Proctor & Gamble facility in Albany, Georgia. The project owners are Albany Green Energy, LLC, which is a joint venture between Proctor & Gamble and Constellation Energy, and DCO Energy, LLC, which served as engineering/procurement/constructor for the project. ASSET Engineering provided substation design and electrical engineering services in support of the project.

Local generation consists of a 54.5 MW generator connected to indoor 13.8 kV switchgear. Bulk power is placed on the utility grid via a 115-13.8 kV 55/73.33 MVA GSU transformer and a 115 kV transmission line between the GSU Substation and the Georgia Power switchyard. Balance of plant loads are served via multiple lineups of 4160 V switchgear and 480 V switchgear and MCCs. These voltages are derived from numerous step down transformers fed from switchgear. ASSET performed as the Owner’s Engineer by reviewing all electrical specifications, material quotations, and manufacturer’s submittals for the above equipment.

ASSET provided comprehensive design services for the GSU Substation, including detailed general arrangement plans and elevations, bills of material, grounding, conduit, foundations, and steel structures. ASSET also provided detailed relay panel front views, bills of material, AC & DC schematics, wiring diagrams, interconnections, cable schedules, and similar drawings associated with the protection of substation equipment. Using commercially available software, ASSET designed the grounding grid in accordance with IEEE Std. 80 and evaluated the current rating for all medium voltage power cables in accordance with the Neher-McGrath method. ASSET also provided drawings for the 115 kV transmission line, including route plan and profile, bills of material, pole top details, sag-tension charts, and guying details.

ASSET performed a comprehensive system study for the entire CHP Facility, including load flow, short circuit, protective device coordination, motor starting, and arc flash evaluation. ASSET provided settings files for all protective relays, which consisted of a mix of SEL and GE products. Other protection settings were provided in easy-to-use tabular format.

One project challenge was evaluating the electrical system for probable and possible system configurations and operating conditions. Load flow was evaluated for several scenarios until a balance was struck between voltage drop during motor starting under heavy loads and voltage rise under lightly loaded plant conditions.

Another project challenge was the small footprint allotted to this generator step up yard and switchgear. Built adjacent to the existing Proctor & Gamble mill, the turbine generator and generator step up substation were oriented to reduce the transmission line length and to route the transmission line within privately owned property, lessening permit requirements. Though provided space was limited, adequate space inside and surrounding the substation and switchgear permit maintenance and equipment replacement.

The project was completed on schedule and under budget. ASSET’s scope of services ended with the successful acceptance testing in November, 2016.

Green Power Solutions Power Plant (Dublin, Georgia)
34MW Biomass Facility
This project was a joint venture between ASK Partners and SP Fiber Technologies to install a new cogeneration facility on site at the SPFT paper mill in Dublin Georgia. The new plant provide 34MW of base load power to the Georgia Transmission grid while also providing steam for use in the processing of recycled fiber. In order to take advantage of the renewable resource aspect of the steam generation at the SP Fiber Technologies Facility, the generation connected to the SPFT 138kV Bus needed to be reconfigured to connect to Georgia Transmission 138kV Facilities. Additionally, the new entity owning and operating the Steam Turbine, Green Power Solutions (GPS), planned to upgrade the Turbine Control System while also replacing the 1950s vintage protective relays with modern relaying technology.

ASSET Engineering supported the project by acting as Owner’s Engineer for designing the modifications required to separate the relaying in the existing switchyard into two entities (SPFT and GPS). This also required coordinating the new relaying interfaces between the SPFT Relaying and Georgia Transmission and the GPS Relaying and Georgia Transmission.

ASSET worked with the New Turbine Control Vendor to coordinate the implementation of the new primary and back-up generation protection relays. This work included development of the protective settings for the new SEL-300G relays, oversight of FAT, and management and oversight of commissioning.

nipponNippon Paper (Port Angeles, Washington)
20MW Cogeneration Facility
Updated the electrical system model for auxiliary and generator additions. Evaluated operating modes for the generator, load flows were calculated at different production and levels and initial voltage and power factor settings were recommended. System coordination and protective relay settings were reconfigured throughout the system for the new generation source. Arc flash hazard study was performed for all generation system additions. Developed a protection and controls design and relay settings for the 69 kV substation, and developed a test and energization plan for the entire system.

Ameresco / Savannah River Nuclear Site
New 13.8kV Power Distribution Line
ASSET has supported this client with several different 13.8 kV line designs for construction, extension, and upgrades at this site. The longest line was a 9,000LF+ overhead line which connected a biomass cogeneration plant to the existing MOX Substation. ASSET’s responsibility included the line routing, surveying of the proposed path, development of plan and profile drawings, calculation of pole, phase, shield, and guy wire sizes, creation of all construction details for grounding, guying, pole top assemblies, underground terminations at each end, underbuilt fiber optic cable mounting/splicing/termination. ASSET coordinated and participated in the final staking of the poles and supported the installation contractor with sag-tension requirements. Over a multi-year period, ASSET has designed an additional five new or extended distribution lines at this site.

Distributed Generation Projects

Brandywine Cogeneration Facility (Brandywine, Maryland)
230MW combined cycle power generation facility
Comprehensive electrical system study of the entire facility, from the incoming 230 kV transmission line down to the 120/240/480 V level. The system study included load flow, short circuit, protective device evaluation/coordination, and arc flash evaluation. The study also evaluated the impact of the 4000 kW diesel generator to the electrical system.


Narrows GSU Installation and Switchyard Upgrade (Murfreesboro, AR)
The Army Corp of Engineers contracted with the Gardner Zemke Company to replace the existing Generator Step-up Transformers (four units circa 1950) with new units and to add an alternate station service transformer off the primary bus to provide additional capacity and redundancy to the facility. Garnder Zemke served as the general contractor and overall project manager for the project and supplied all equipment except the new step-up transformers. ASSET Engineering was hired as the electrical engineer and commissioning agent for the entire project. The major scope elements of this project included: installation of anew 69kV Circuit Switcher on the outgoing bus, new station service transformer, new switchgear with the AC and DC auxiliary options, new conduit rack for routing power and controls from the alternate station service equipment, new Generator Step-up Transformers, and upgrades to the existing controls and alarm annunciation within the existing control room.

ASSET’s scope included: developing the demolition plans and details for removal of the old equipment, developing the engineering and design package for installation of all the new equipment, developing the testing plan, and commissioning plan.

One significant challenge ASSET has encountered involved finding drawings and documentation for equipment and an installation that is over 60 years old. ASSET has overcome this challenge by collaborating with plant operators and performing extensive site investigations to document the current condition. This effort will reduce the amount of unknowns and the risk associated with them during construction.

The engineering and design was completed in March with construction completed in June of 2018.


Monterrey Mexico MicroGrid / BESS (Monterrey, Mexico)
The project is a new power plant in northern Mexico outside of Monterrey. The generating plant is comprised of seven Wartsila 23.5 MW reciprocating engines fueled by natural gas and producing power at 13.8 kV. The plant serves two major customers. Both customers are served on 115 kV transmission lines into their existing substations. The load presented by these two customers varies from a combined 12 MW to 75 MW, and this necessitates the control room running two to six engines at any one time. The seventh engine was installed as an in-service spare to permit planned maintenance or unplanned repairs to one of the six. The units will be run in rotation to more evenly distribute the hours of operation among the seven.

The plant does not use an engine for spinning reserve, but instead uses a Battery Energy Storage System (BESS) which is electrically connected to the 13.8 kV bus. The BESS is rated for 14.2 MW power for an energy rating of 12 MWH. Batteries do not fully populate the inverter capacity and the overall available rating is 12 MW. Powin Energy is the BESS integrator, using its lithium ion batteries in strings of 170 KW operating at 800-900 VDC. Batteries are arranged in four air conditioned containers, each one approximately 8’ wide x 40’ long x 8’ high. The battery strings supply power into DC combiner boxes which in turn are cabled in underground conduit to six (6) SMA 2.475 MW Sunnycentral storage inverters. Each inverter’s 434 VAC terminals are close coupled to GE Prolec oil-filled transformers rated 2500 kVA. To utilize standard underground distribution dead-break fittings, power transformers are daisy-chained in groups of three into two circuits connecting to the generation switchgear breaker.

ASSET performed as the Owner’s engineer, and also performed some of the engineering and design tasks not included in Warstsilas or the BESS integrators scope, including the following:

• Collaboration with the owner and his BESS specialist to electrically size the BESS.
•  Performed the frequency transient study for multiple engine loss, load loss, and load step increase cases for high and load level to validate the BESS sizing and predict its performance to improve power quality during electrical events.
•  Reviewed and assisted the owner in his understanding of his operating plan to quantify the number of generators at various load levels.
•  Specified the storage inverter transformers for purchase. ASSET’s experience in renewable energy work in this specification resulted in transformers and transformer switching which allowed a deliberate stepped energization of AC components and cabling.
•  Coordination of communications between Powin and Wartsila for their battery grid controller to engine control link.
•  Developed switchgear protective relay settings for the connection of the BESS and to coordinate with settings present in main and tie breakers.
•  Inspection and verification of integration testing in Germany at the SMA factory between Powin’s grid controller driver and SMA’s inverters. Also participated in SMA’s demonstration in their lab of frequency regulation during transient events.
•  Performance of a protection, control, and metering audit of the EPC contractor. We were onsite to overall concepts, review wiring, relay settings, relay settings files, and test procedures. This effort was followed by a summary presentation to client infrastructure and electrical managers and engineers.
•  Inspection of client substation to determine its readiness to receive power and reported on deficiencies to be remedied before energization.
•  Developed a low profile three-circuit 115 kV transmission structure concept to reduce the overall structure height from 120m to 75m. This design was implemented by the T-line EPC firm.
•  Rationalized the conductor change to a high temp, higher ampacity cable for a future, requiring no change to the purchased transmission structures.

The power plant went on line late September 2018. The BESS went online October 18. As of October 20, both customers were totally served by the generating plant with the BESS as the spinning reserve and transient frequency regulation. This operates as a true islanded microgrid, electrically isolated from the utility. This is presently the largest isolated microgrid with battery storage in service worldwide.

The next step for this plant is to develop a connection through the utility for this generating plant to sell to remote customers. ASSET has developed the concept for a ring bus switching station to connect this generating plant to the off takers loads and an export feed on an existing 115 kV transmission line which the plant owner is negotiating its purchase.