The Ministry of Defence (MOD) is one of the United Kingdom's largest landowners with approximately 600,000 acres consisting of some 4,000 built and rural sites. Providing water and wastewater services to the remote, rural sites can be quite a challenge, including providing power for the water meters at these sites. The meters are often a considerable distance from the nearest power source, and installing the electrical wiring required isn't cost effective.

Now, Severn Trent Costain has successfully pioneered a novel solution to this challenge: using solar panels to power remotely located water meters. The panels replaced conventional alkaline batteries, which were encased in waterproof battery packs. The pilot project at 30 MOD sites across England has created significant savings for the Ministry, which has approved the installation of additional solar-powered units at other sites. The project has been recognized for its energy conservation and carbon reduction benefits, too, as it recently received a prestigious national award.

The solar-powered water meters are a part of Severn Trent Costain's Package C contract, under which it provides water and wastewater services to 1,300 MOD sites. These sites typically include military barracks, offices, technical facilities and residential accommodations. The photovoltaic panels that power the meters generate a minimum of five watts of energy. They are suitable for most outdoor locations and require minimal installation time and labor. An internal back-up battery can power the meters for up to three weeks, depending upon actual usage.

Severn Trent Costain used the trial period to rigorously test the potential of the solar panel system's ability to maintain the continuity of data produced by the meters, even under adverse conditions such as very low sunlight levels. In addition, it was discovered during the course of the trial that using solar panels had improved the availability of data for incident and leakage monitoring. The additional solar power allows SMS transmitters to remain permanently on and accept and respond to requests for real-time data. And the reduction in electricity usage has diminished the carbon footprint and environmental impact of the MOD sites where the systems were tested. Using solar panels also means fewer maintenance visits and the elimination of visits required for routine battery changes. Finally, the water meter transmitters and batteries that were replaced by photovoltaic panels can be re-used as spares for other equipment.

Following the successful initial trial, Severn Trent Costain is extending the use of the panels to an additional 20 sites. If ultimately used to power all 1,100 meters installed within the 1,300 sites covered by the Package C contract, the solar-powered meters would save £100,000 a year in energy costs and eliminate the anticipated replacement of approximately 7,700 alkaline batteries over the duration of the contract.

The project earned a Highly Commended award in the team category of the MOD's 2012 Sanctuary and Energy Awards in the energy individual class. These awards recognize individuals and teams for their efforts in the United Kingdom and overseas to conserve energy and reduce carbon emissions.

According to Simon Wear, network control manager for Severn Trent Costain, "In the right conditions solar power meters are proving a real benefit to Severn Trent Costain's flow metering. They reduce waste in battery replacements and also the emissions and costs involved in maintenance visits."


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