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by explaining how Lange II aligns with the company’ s wider generation portfolio and regional planning strategy.
“ We operate under an integrated resource plan that models future generation needs for our customers in western South Dakota and eastern Wyoming,” he details.“ From that plan, we identified some older engines and combustion turbines that were built in the 1960s-70s that original manufacturers just don’ t support anymore. That’ s where the motivation for Lange II came from – to replace those black start turbines( BSUs) with more resilient units.
“ Because of this, with Lange II we were looking at new opportunities there for generation resources, and we really wanted to have something with dual-fuel capability to replace these BSUs,” Derek continues.“ From that, we landed on RICE( Reciprocating Internal Combustion Engine) units and, after vetting several different RICE manufacturers, we selected Wärtsila – specifically their 50DF engines. We wanted a large resource that could provide near-100 megawatts in order to complement the retirement of the older generation resources and to offer resiliency during the winter months, with the capability of these engines to run off both diesel and natural gas. They’ re also some of the largest shaft generating RICE units in the world.”
With the final Lange II development set to incorporate six dual-fuel units upon completion, it was paramount that the project team identified the right model to thrive under the area’ s specific conditions and support its increasingly dynamic energy grid, and Derek affirms that Wärtsila’ s RICE units were the perfect fit.
“ One great thing about Wärtsila’ s RICE units is that they are highly responsive; you can generate a full load – 99.6 megawatts – in less than five minutes from a cold start. If the units are online and running at a minimum load, they can resume to a full load in less than 60 seconds. These units are also really beneficial in today’ s market where there’ s more renewables on the grid as they allow us to keep the grid stable and resilient when renewable energy might be unreliable( due to changes in sunlight levels, wind, etc.),” Derek explains.“ The other key benefit of the RICE engines is that they consume low amounts of water – just about a half-gallon per hour per megawatt( that’ s less than one gpm with all six units running full load). In fact, this water usage comes from a closed loop cooling system; the only other major use of water is in the turbos to keep them clean. With these turbos, the RICE engines can also accommodate higher elevations; we’ re
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