CNG FAQ | RLD CNG


RLD CNG offers competitive solutions for natural gas refueling stations.  Before you begin a design the following questions should be answered.

1. Can I have a natural gas filling station at your site? Purchase from the National Fire Protection Agency the current NFPA 52 Standard. This code is the governing authority. Contact your local Fire Marshal as well as the Building and Safety Department to see if they object to a filling station. If not, can they help you through code requirements to implement your goals.

2. Do I need a professional design engineer? An experienced NGV station designer can size your filling station based upon your unique requirements and offer suggestions to improve performance or reduce station costs.

3. Do I have a local contractor that is qualified to install a refueling station?  Find and interview a licensed A or B contractor who have installed more than 2 refueling stations.

4. What utilities are available to install your filling station? You need to know the available, gas line size, gas pressure, gas quality and moister content per million cubic feet of gas. This is important for compressor sizing, filtration and sizing a dryer for the system. Is the volume of gas from the local utility enough to meet your projected needs? You will also need to know the electrical service available i.e. 480VAC 3 phase, or 208-230 VAC 3 phase. Most large compressor motors run on 460-480 VAC 3 phase power.

5. Will the station be used for private or public refueling? Is individual vehicle fuel accountability required? Do you have to bill a customer for a fill up or charge for a point of sale? In many instances, managers only need to know the total amount of fuel used by an entire fleet over time. If each vehicle must be accounted for, a dispenser will be needed with a certified card reader system which will impact the overall cost of a station.  Certified dispensers also add to the cost.

6.  There are many different designs of filling stations, large or small, and you need to determine the style of filling station needed. Examples are a time or slow fill, a fast fill or a combination station.  

What type of vehicles will be refueled, how large is the fleet amd when do you need the fuel? 

Time Fill is generally used in situations where vehicles return to the yard for many hours. Small time fill stations may utilize refueling appliances for compression. Larger time fill stations use compressors ranging from 40 hp to several hundred hp. A total fill cycle will usually require 8 or more hours. Cascade Fast Fill is generally used in situations where a number of smaller vehicles (10-30) are filled in a peak fueling period (30-90 minutes) or where large vehicles are fueled sporadically throughout the day.  Buffered Fast Fill is generally used in situations where large vehicles are fueling on a continuous basis. Unlike Cascade systems that primarily fill vehicles from stored gas, the Buffer system provides most of the vehicle fill directly from the compressor(s). The Buffer storage is utilized to allow the compressor(s) to continue to run loaded between vehicle fills. 

You will need to determine the number and type of vehicles that will be refueled, when they will be refueled and how often they will need to be refueled. This concept is known as station loading or how much CNG must be delivered in order to satisfy your fleet needs at the moment.  You will need to determine how much gasoline or diesel your current fleet uses in a day before they are converted. An average yearly history will suggest what you may need. You can then determine a daily average. In order to understand this in relation to a volume of gas, multiply the gasoline gallons by a factor of 124 and diesel by a factor of 136. So 10 gallons of gas = 1,250 cubic feet of gas. 

Depending on how modern your fleet, at what pressure will your vehicles operate? Typically, newer vehicles would store gas onboard at 3,600 psi. Older vehicles stored gas at 3,000 psi but this is now rare. It is also important to consider the fueling pattern and time frame that each vehicle needs to refuel at in order to function within the fleet. Designing a fueling station and sizing a compressor with proper storage is all based on demand. How much fleet fuel over what period of time? Do vehicles need to be fueled early in the morning, throughout the day or can they be filled overnight? You must decide the pattern.  Individual answers will determine if the fleet needs to be fast filled, slow filled or a combination thereof. This will also determine if you need a buffer or cascade storage system. This spread also determines the time element that a compressor has to fulfill a requirement and what size compressor you may need. Keep in mind that all vehicle fleets are unique.

7.  Finally, how will your demand grow over time? Many may want to start out by converting a portion of their fleet and grow their demand over time. This is important to know from the beginning so real estate can be allocated and future utility needs can be determined for additional equipment. Compressor sizing with or without redundancy would be a strong consideration. We believe in redundancy so a customer is never without fuel and the fueling station can be serviced with no down time or loss of revenue to the customer.

Website Disclaimer  -  General information and links on this website are offered in good faith to help educate the consumer on Government support, show major feasibility studies, inform on vehicle conversions and list examples of available refueling station designers, engineers and consultants to this industry.  Illustrations and information contained in this website are only from a point in time which may or may not reflect current trends or activity from State to State.  Referrals and links are listed only as a consumer aid and not meant to endorse anyone or any specific company.  RLD CNG accepts no responsibility for actions or business decisions by others

RLD Performance, P.O. Box 890066, Temecula, CA, 92589, (951) 676-4948, 9am-5pm Pacific Standard Time, M-F, stan@rldperformance.com