Kinney County, Texas, USA

Zier Solar and Energy Storage Project in Kinney County, Texas

Status: Under construction


In 1999, Texas established a Renewable Portfolio Standard (RPS) as part of its power industry restructuring legislation under Senate Bill 7, which was designed to increase the delivery of renewable energy and the associated environmental benefits to the people of Texas. The RPS initially mandated that electricity providers collectively provide 2,000 MW of additional renewable energy capacity by 2009. In 2005, the Texas Legislature approved a much more aggressive RPS, increasing the state mandate for total renewable energy to 5,880 MW by 2015 and 10,000 MW by 2025. Texas has already exceeded these goals. In 2019 the state had an installed capacity of 30,507 MW, generating 87,985 GWh of electricity from solar and wind sources.

Moreover, pairing energy storage systems with renewable energy generators is the simplest and most efficient solution for addressing the intermittent nature of solar and wind resources. Battery storage capacity helps smooth out the delivery of variable or intermittent resources by storing excess energy produced during periods of high wind or solar output and delivering it during periods of peak electricity demand.  


The project consists of the design, construction, and operation of a 160 MWAC solar park using bifacial monocrystalline photovoltaic modules mounted on single-axis tracking arrays and a 40 MWAC, two-hour battery energy storage system (BESS). The project will be interconnected at the existing Lower Colorado River Authority (LCRA) Transmission Services Corporation (TSC) Pinto Creek Substation operated by the Electric Reliability Council of Texas (ERCOT), through a new 3.67-mile overhead transmission line. The electricity generated by the solar park, as well as the products generated or enabled by the BESS (ancillary services and energy arbitrage), will be sold to a private off-taker under an energy hedge agreement and/or in the wholesale electricity market.[1]

[1] Ancillary services are those required to support the reliability of the electricity grid. For ERCOT these services include regulation up, regulation down, responsive reserves and non-spinning spinning reserves. Energy arbitrage refers to the practice of storing electricity generated by the solar park (or purchased from the grid) during off-peak periods and discharging it during peak periods.


The solar park will increase the installed capacity of renewable energy resources, which will help reduce future demand on traditional fossil fuel-based energy production and thus help prevent the emission of greenhouse gases and other pollutants from such power generation. It is expected to generate 414.31 GWh of electricity during the first year of operation, which is equivalent to the annual consumption of 30,286 households. In addition, the BESS is expected to store electricity generated by the solar park and/or the grid and deliver up to 13.5 GWh of electricity a year, which will allow the system operator to manage the grid more efficiently and reduce the use of ramp-up/ramp-down fossil fuel power generating plants.  Altogether, the project will help prevent the emission of an estimated 186,398 metric tons/year of CO2, 132 metric tons/year of NOx and 132 metric tons/year of SO2. The BESS will also support a more reliable power grid by minimizing power disruptions and reducing energy losses resulting from mismatches in supply and demand.

Project Financing

Total Project Cost Reserved
NADBank Funding US 65.7M - NADBank Loan