Today, our product group director, Olivier Marcus, gave a presentation1 on the maintenance of irrigation reservoirs and power dams with a range of specially developed DOP dredges. Here, I am happy to elaborate on his message and share with you highlights from his presentation. As you may have noticed from my previous posts, reservoirs are a long standing interest of mine. It was one of my first commissioning jobs at my previous employer. It made me aware, that reservoirs and power dams are not always the clean energy and sustainable solution that they are usually presented for.
Don’t get me wrong, we need these kind of structures to pass on our planet in a better state to the next generation, than we received it ourselves. As with everything: we have to take care of these responsibly.
Dams and reservoirs have mainly two problems. First, if the bottom of the reservoir hasn’t been cleared before filling with water, there is a lot of biomass available. Especially in warm and shallow lakes, the decomposing material can generate a lot of carbon dioxide. The CO2 footprint of the generated electricity might even be higher than from diesel driven power plants2. So much for the green image of hydro power. Second, the interrupted sediment transport will cause the reservoir to fill up. Eventually the storage capacity isn’t enough anymore and the operation has to be abandoned. So much for the sustainable part of the image.
The first problem should have been tackled during the building phase of the power dam. Maintenance during operation for the second problem. The simplest method is to flush the reservoir through the bypass. But you can’t flush all the sediment. The heavy particles up stream will remain in place. And you smother the life of the river downstream. A more effective method is to use dredges. Over the years, we have supplied several of these vessels, each specifically engineered and built for their own location.
In an initial survey of these dredging opportunities, we found some common features and could develop a range of DOP dredges specific for reservoir maintenance. The transport capacity of the river should be matched by the capacity of the dredge. Often resulting in a range suitable for a DOP pump. Their flexibility makes the dredges adaptable to work on all the different areas in a reservoir.
It’s been more than ten years after our first introduction of these nifty little dredges3 and with the experience gained, it was time to present you a next generation that could assist in achieving a sustainable power generation and a more environmental friendly operation. Main innovation is that this new range is also available in an all-electric version. Which should make sense, if it is going to work at a power dam. Always discuss this with the power dam operator, as they are not very fond of plugging in a dredge. They fear distortions and fluctuations on their ‘product’. Than consider alternative clean energy from solar or wind and lastly the old reliable diesel option. With a lot of reservoirs already losing their capacity, there is a lot of opportunity for these type of dredges.
- Hydropower & Dams Asia, Damen
- Hydroelectric power’s dirty secret revealed, New Scientist
- Multi functional small dredging solution for maintanance of deep irrigation reservoirs and hydro power dams, CEDA