Technology behind Hydro T-ELTM Central to the formulation is the use of a novel Secondary Polyol Ester®
(SPE®
) base oil whose generic
chemistry and functionality is highlighted in Figure 1. Traditional polyol esters are well established in the lubricant industry, with proven performance across industrial, aviation, marine, and automotive applications, where they address limitations associated with conventional petroleum oils. SPE technology represents a further advancement of this chemistry, engineered with a high degree of oxygen incorporation, as ether bonds, within their novel molecular structure.
across a broad operating temperature range. It also exhibits outstanding oxidative stability, as evidenced by performance in both the dry turbine oil stability test (TOST) and the rotating pressure vessel oxidation test indicating strong resistance to oxidative degradation under prolonged thermal stress. In addition, the formulation provides effective corrosion protection for both ferrous and non-ferrous metals, alongside excellent demulsibility, ensuring efficient water separation in service. Load-carrying capability is confirmed by an FZG scuffing test failure load stage (FLS) rating exceeding 12, demonstrating robust film strength under high-load conditions.
Figure 1: Generic structure of SPE base oils and key functionalities.
This molecular design imparts several functional advantages. The elevated oxygen content contributes to enhanced thermal management through increased volumetric heat capacity, while the inherent polarity of the ester structure promotes strong surface affinity and robust film formation. In addition, these fluids exhibit intrinsic detergency and provide effective control of deposits, varnish, and sludge formation under high-temperature operating conditions. The highly branched architecture of SPE base oils also provides favourable low-temperature properties and contributes to improved hydrolytic stability compared to conventional ester systems. Moreover, the base oils are readily biodegradable, non-toxic and non-bioaccumulating. They have the U.S. Department of Agriculture (USDA) Biopreferred status and are EU Ecolabel LuSC-listed. Collectively, these characteristics make SPE technology well suited to demanding hydro turbine environments.
Equipment trials using Hydro T-ELTM Figure 2 illustrates the performance of the fluid in conventional laboratory tests. The product demonstrates a significantly elevated viscosity index compared to conventional petroleum-based turbine oils (typically 100-120), supporting stable viscosity
Figure 2: Performance Testing.
From an environmental perspective, the product delivers excellent performance, being readily biodegradable, non-toxic, and exhibiting negligible bioaccumulation potential. This combination of technical performance and environmental compatibility positioned the fluid as a high-performance alternative to traditional petroleum-based turbine oils. To support its laboratory performance, equipment testing was scheduled in two phases.
The first phase was an initial validation study conducted through a pre-trial at the GE Hydro Solutions Global Centre of Excellence in Switzerland, using a combined thrust and guide bearing test rig (Figure 3). This study was designed as a preliminary assessment to establish the suitability of the fluid
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