Mount Pleasant officials outline $810,000 plan to replace aging PLEX meters with PLC TWACS system

Mount Pleasant City utility staff presented details at a public hearing on a planned three-year replacement of the city’s aging PowerLine Express (PLEX) metering system with a PLC-based TWACS (two-way automatic communication) system, estimating about $810,000 in total costs and year-one spending near $300,000.

The hearing opened with a brief welcome and then turned to Shane, a utility staff member, who described the procurement process and deployment plan. Shane said the city had solicited proposals after the original PLEX meters became unavailable for order and noted, “As of December 2024, we made the decision. The power department made the decision to go with the Clare TWACS.”

City staff said PLEX (PowerLine Express) meters have been difficult to source—the last orders arrived in 2024 and manufacturers stopped accepting orders in 2023—and vendor support will end in 2027. The utility reviewed multiple vendors over a roughly two-year RFP process and received six proposals, Shane said. Staff recommended a power-line-carrier (PLC) TWACS approach rather than a radio-frequency (RF) option because some meters in high-elevation areas of the city’s “Skyline” service territory sit low in vaults and would not reliably receive RF signals without new poles or other overhead infrastructure.

Why it matters: staff said the new system would preserve the use of power lines for communications (avoiding additional RF emissions in populated areas), support advanced metering functions such as 15-, 30- or 60-minute interval reads, net-energy monitoring, remote connect/disconnect, demand-response/load-control and faster outage detection. Shane described operational benefits: “If that meter is not detected within 15 minutes … it would automatically flag that meter out,” which staff said should improve outage response in remote cabin and winter conditions.

Costs, timeline and warranties: staff proposed a three-year deployment with roughly $300,000 of work per year. Line items discussed included about $251,000 for hardware and hosted software for two substations (year 1), MTUs priced at about $82,000 and a year-2 pilot of roughly 1,156 residential meters (year 2 meter allotment cited as about $99,000), and completion of single- and three-phase installations and CT-rated commercial services in year 3. Shane gave a ballpark total around $810,000 and said meters carry approximately five-year warranties while the system and hosted services were presented with a 15–20 year support commitment from the vendor. Staff also noted an annual hosting/subscription fee for software updates (cited roughly as $2,000 per year) and vendor-provided training for up to three city staff.

Funding and procurement: staff said they would incorporate the work into the utility’s capital facilities plan and budget across multiple years rather than borrow immediately. “No cost will come to us until we receive those items,” Shane said, adding that quoted prices would be honored by the vendor despite market cost changes. He also said the vendor would hold meter inventory at a Westco location (cited as St. George) and ship pallets on demand to mitigate current lead times (meters were described as having about a 36-week lead time).

Technical and customer considerations: staff said the chosen PLC/TWACS meters are not RF devices and that the system can be programmed for net-metering accounts and alternative energy (solar) connections, but those net-metering/alternative-energy meters must be programmed to the city’s standards. Shane described a plan to photograph each service during meter exchange, update mapping, and inspect meter bases and prongs to avoid poor physical connections. He also said the system would support features that reduce truck rolls, such as remote connect/disconnect.

Questions raised: a council member asked whether the replacements would affect standby generators; Shane answered they would not and that standby generators should continue to function through transfer switches. In response to a question about grant funding, staff said grants are generally not available for meter replacements and that the project is considered maintenance rather than new construction or transmission work. Staff noted the city could delay portions of the deployment if budget constraints require it.

Outcome and next steps: no formal council vote was recorded in the hearing transcript. Staff reported the power department’s internal decision (December 2024) to select the PLC/TWACS solution and presented the proposed three-year implementation and budget plan for council awareness and incorporation into capital budgeting. Staff said they would proceed with vendor coordination, inventory staging, meter programming details and field inspection processes.

The public hearing concluded after questions; staff closed by thanking attendees and saying they would provide warranty and contract documents to council as requested.