WorldWide Drilling Resource

58 NOVEMBER 2013 WorldWide Drilling Resource ® DC Backup Power (UPS) that isn’t Monstrous in Size and Cost Part 1 by CJ Kirst project management professional Conley Equipment Company Power choices can vary: convention- al grid (utility)AC power, diesel generators, solar, wind, and DC battery backup. While batteries have been used for decades, as have generators, the uninterruptible power supply (UPS) systems are typically thought of as having short run times, long enough to cover the gap between utility AC power going out and the generator kicking in. However, due to site locations, the UPS option can be overlooked as a longer run time option due to the concern for foot- print requirements and cost. For example, a 500 volt-amp UPS that may only pro- vide 5 amps of power for low-load equipment like SCADA (supervisory con- trol and data acquisition - a computer system used to monitor and control equipment), could provide a three-hour runtime. If the end user is looking at an alternative power source that needs to provide 24 hours of backup power, the common extrapolation is to multiply the size and cost of the three-hour runtime UPS mentioned above by eight. Suddenly, DC backup is no longer an affordable option and takes up too much space. This is not to say larger scale power distribution centers (PDCs) don’t include UPS technology. These PDCs are com- monly designed with large battery banks, chargers, inverters, and switches, and are located within mobile PDC buildings or roll-off skids next to wellheads. These configurations tend to consumemore space and cost more than the conventional “all- in-one” UPS box or cabinet and yet may still only provide a three-hour or less runtime. Each application is unique; the spec- ification may be ideal in one location and then not make sense in another. Maybe the end user’s site is unmanned and it takes two days to get someone physi- cally to the site. In that case, a 24-hour runtime is required. In locations where the sun is not as dependable as others and solar autonomy (days of battery backup stored from solar power) is max’d out, the DC backup option may be ideal especial- ly if the generator’s tank size isn’t suffi- cient. Producers are constantly dependent on offsite, programmable logic controllers (PLCs) to control pumps, valves, switch- es, etc. due to the sheer number of well- heads and strategic plans to limit the manpower onsite. One man can monitor and control multiple sites from one offsite facility, but he cannot afford for any of this equipment and/or the metrics monitoring production to be down. This is a 24/7/365 industry - time is money. But you can utilize UPS technology that is economical and does not consume oversized space. Next month, we will cover some examples and budgets. CJ CJ Kirst may be contacted via e-mail at admin@ worldwidedrillingresource.com