Prime Power Systems — Beyond the Grid

Is Gas a Viable Fuel Source?

Prime power systems run on natural gas. Diesel can work in limited circumstances, but emissions compliance costs make it impractical at prime scale for most applications.

Fuel choice is rarely the question. The question is whether the gas infrastructure at a given site can actually support the plant — and Carter’s role is to help evaluate that early, before equipment is specified or commitments are made.

A nearby pipeline does not guarantee a viable fuel source. What matters is whether that pipeline can deliver the required volume at the pressure the generator sets need — continuously, at full load. Local distribution networks move gas from transmission pipelines, but their delivery capacity has limits. A large prime installation may require a dedicated interconnection with the transmission system itself, which involves different stakeholders, different timelines, and different costs than tapping a local line.

Projects that resolve these questions early move forward smoothly. Projects that assume gas availability often discover the limitation later, when it is harder and more expensive to address.

Grid Relationship Is a Primary Design Input

A prime power system isn’t simply a generator plant running continuously. Depending on how it’s designed and what utility agreements are in place, the same system can operate in multiple modes — each serving a different purpose for the facility.

Understanding which modes a facility wants to support is a design input, not an afterthought. Carter engineers work through these questions early, because control architecture, switchgear configuration, and grid interconnection requirements differ depending on how the system is expected to operate.

• Island mode. The facility runs entirely on its own generation, independent of the grid. This is the baseline operating mode for traditional prime applications and provides full operational independence when grid supply is unavailable or unreliable.
• Grid-parallel operation and demand response. When connected to the grid, a prime system can operate alongside utility power, supplement it, or export generation back to the grid. Facilities can contract with utilities to supply power during peak demand periods — earning revenue for generation they’re already capable of producing, sometimes simply for having capacity available and ready to dispatch.
• Peak shaving. When electricity costs spike during high-demand periods, generators run behind the meter to power the facility’s own load rather than drawing from the grid. This reduces demand charges without exporting power.

Site Shapes the System

Prime power systems are designed around how a facility actually uses electricity — not just how much it needs. That distinction drives most of the early engineering work Carter does with developers, engineers, and facility operators.

• Load profile. Facility electrical demand isn’t constant. Equipment starts and stops, production cycles shift, startup loads spike. Carter engineers evaluate how demand changes across normal operations — including peak events and unusual conditions — to ensure the system is sized and configured to handle real-world variability.
• Redundancy. Redundancy cuts both ways. Too little and the facility is exposed when a unit goes offline for service. Too much and generators run underloaded, below their efficient operating range. Carter works through the right configuration for each application.
• Site conditions. Elevation, temperature range, humidity, and air quality all affect how gas engines perform. Carter engineers evaluate these against site data before equipment is specified, using engine performance modeling tools to confirm how units will perform under real conditions.
• Permitting and interconnection. Air permits and grid interconnection run on their own timelines — sometimes straightforward, sometimes not. Carter helps identify these requirements early in project development, before they become schedule constraints.