Due to the (usually) temporary character of dewatering, calculating the cost of a dewatering job has not previously been an issue. However, that has changed in the last decade due to the worldwide price increase of fuel. So, now the decision between electric and diesel motors has become a much more prominent one and while an electric (submersible) pump may appear easier and more cost-effective compared with a diesel pump, there are other factors to consider.
Choosing the right pump is critical to ensure maximum performance and cost-effectiveness. Dewatering typically takes place on a construction site and there are certainly circumstances when a diesel pump makes the most sense, particularly when there is no electric power supply! That said, with environmental regulations and the rising cost of fuel, there has been a shift in the popularity of electric submersible pumps.
High altitude negatively affects gas and diesel engine pumps performance, this is due to the lower pressure, which makes it harder for the pumps to do their jobs with the same efficiency as they would at sea level.
In addition to this, as the oxygen levels thin out and become less dense, the diesel engine would require a wider throttle opening to be able to pull in adequate amounts of air. This means more fuel being burned and therefore a greater cost.
Compared with electric pumps, where atmospheric pressure does not affect them at all and they can continue to operate at full capacity, delivering great performance without additional fuel costs.
When a dewatering project is long-term, electric-driven pumps will often be installed with a central power generator. While this means that logistics are easier due to only filling on fuel tank instead of several, you are likely to suffer efficiency losses in the generator and as a result the total fuel consumption will be more.
In addition, diesel-driven dewatering pumps are available with noise levels as little as 46 db at 10 m, giving them another advantage over electric driven pumps.
That said, maintenance is required more regularly than the electric-driven variety. New techniques have resulted in diesel engines requiring an oil and filter change only every 250-300 hours and running them without maintenance up to 1500 (while still having factory warranty is possible).
Compared with an electric pump which have been built to be extremely durable and wear resistant, meaning maintenance fees over time are much more affordable and at lower frequencies.
There is a disparity in the initial purchase price of diesel and electric pumps, but this becomes far less important when calculating the total cost of ownership during the pump’s lifetime. The efficiency and maintenance costs mean that a break-even point can be reached within months.
In fact, you can save up to 50% or more using electric power compared with diesel fuel.
In recent years there has been a drastic increase in companies embracing cleaner ways to run equipment engines.
Bearing that in mind, burning fossil fuel such as diesel to power a water pump and therefore producing greenhouse gas emissions is something to avoid as much as possible. Electric pumps in this case are a far more environmentally friendly option. Even more so if the electricity comes from solar, wind or some other renewable energy source.
Additionally, electric pumps are much quieter, which can also be an advantage depending on the location of the site.
Another consideration is that diesel-driven pumps need to be avoided in areas where there is a high risk of an explosion and also in areas there could be damage to wildlife or water because of a spillage.
Even with all of this in mind, it is important to remember that during pipeline dewatering, the time frame of having a pump in one place is often very short. Therefore, a more flexible solution is needed that does not require transporting bulky extension cords, with the added risk of them becoming damaged by heavy equipment. In these situations, there is an argument that diesel-driven pumps could be the most effective choice.
All these points considered the most crucial decision is selecting the pump that will be most effective for the project at hand. That way you can be sure the job is being completed as efficiently and cost-effectively as possible.