MechChem Africa March 2017

⎪ Innovative engineering ⎪

The company has invested over R100-million in energy conserva- tionprogrammes andwill continue to work with Eskom while par- ticipating in various demand-side management programmes. “Fulfilling a prominent role in developing the nascent fuel cell industry in South Africa is part of Implats’ strategic objective to demonstrate responsible stew- ardship of our mineral and energy resources,” says Smith. Doosan’s PureCell 400 The scalable Doosan PureCell ®

A 2.2 MW fuel cell came online at a regional high school is in Connecticut in January 2017. The fuel cell is linked to a microgrid and will power the school during a prolonged power outage. Waste heat from the fuel cell will also be used to heat the high school.

400 can generate up to 440 kW of clean elec- tricity when new, reducing to 400 kW after ten years of use. In addition, the system produces nearly 500 kW of useable heat. The PureCell is designed to be powered by natural gas rather than hydrogen, which means it cannot make the claim that only water vapour is emitted. But it also means that it is ideal for fuelling from a piped gas supply. Doosan uses phosphoric acid fuel cells with highly concentrated pure liquid phosphoric acid (H 3 PO 4 ) as the electrolyte, which is saturated in a silicon carbide matrix (SiC). The electrodes are made of carbon paper coated with a finely dispersed platinum catalyst – hence Implats’ long-term interest. The operating temperature range is about 150 to210 °C, creating theopportunity toutilise the ‘waste’ heat for combined heat and power applications. When the heat can be gainfully used, Doosan claims an operating efficiency of up to 90%. Reliability wise, a remarkable 98% uptime across the fuel cell stack life of ten years is being reported. So not only do these fuel cells run cleaner and more efficiently, as a power generation alternative they are more reliable than nearly all other alternatives. The costs? Doosan claims a generation cost of 14 to 15 US-cents per kWh, which is within the range being reported in theDecember 2016 version of Lazard’s Levelised Cost of Energy (LCOE) Analysis – US$119-$182 per MWh or 11.9 to 25 UC-cents per kWh. The Lazard LCOE range for nuclear power in the USA is not that much cheaper: $97 to $136 per MWh. Arguments against renewable energy genera- tion from solar PV and wind generation are no longer restricted to costs. For PV systems, cost parity is alreadybeing claimed for someprojects. But their intermittent nature means that either storage solutions are necessary or renewable systems need to be coupled with traditional generation for continuity of supply – at night or when the wind drops. Hybrid renewable and fuel cell solutions?

For distributed solutions such as mi- crogrids, therefore, gas or diesel generators are often coupled with PV, wind or hydro plants to ensure continuity of supply regard- less of the available sunshine, wind or water flow. Fuel cells, which are already being widely used as backup power for cell phone towers and data centres, offer an ideal alternative to gensets for these distributed microgrid applications. They can be brought online quicklyandregulatedtosupplythegeneration shortfall whendemandexceeds that available from renewable energy plants. A PV system coupled with a fuel cell could well offer an ideal hybrid clean generation solution, one that is not far away for grid- cost parity and without the disadvantages of intermittency. The rise of FCEVs At a factory in Michigan in the US, General Motors and Honda plan to invest US$85- million to build hydrogen fuel cell stacks for the next-generation fuel cell electric vehicles (FCEVs). The joint venture, Fuel Cell System Manufacturing, will begin producing the fuel cell systems in around 2020 out of GM’s BrownstownTownshipplant southofDetroit, which currently produces battery packs for hybrid and electric vehicles. GM and Honda say that cooperating on developing fuel cells will slash costs and boost efficiencies. The goal is lighter, smaller, more powerful and less costly stacks that use hydrogen as the fuel to produce electricity to power cars. Fuel cells “are not a science project any- more,” saysGMexecutivevicepresidentMark Reuss, which is clear from the success of the Honda Clarity and the Toyota Mirai. In the fuel cell electric vehicle (FCEV) the drive train is 100% electric, with the fuel cell and its hydrogen fuel tank replacing the Li-ion battery pack used in electric vehicles. Clearly, the hydrogen-refuelling infra- structure is a huge hurdle, but even this is not that far away. q

March 2017 • MechChem Africa ¦ 43