Japan’s IHI Corporation says a pilot of a thermal utilization system that converts all previously discarded surplus direct current (DC) power at solar power plants into carbon-free steam has “demonstrated stable system performance.”
IHI says its Renewable Energy Thermal Utilization System economically and flexibly converts renewable electricity into thermal energy, saving it for later use. It explains this is particularly useful for solar plants, which are susceptible to producing surplus electricity due to the variability of solar radiation throughout the day.
The test project, located at the Soma City sewage disposal plant in Fukushima Prefecture, began in April.
It involved IHI installing a 300 kW solar plant and 200 kW conditioner at the sewage disposal plant, to generate up to 200 kW of alternating current (AC) electricity.
To create the thermal utilization system, the company then installed seven Jokigen thermal storage electric boilers, manufactured by IHI Inspection & Instrumentation Co. Ltd, one of the corporation’s subsidiaries. IHI says it modified the boilers slightly to operate with both DC and AC power.
IHI found its thermal utilization system capable of absorbing up to 189 kW (27 kW per unit) of DC power. It says since April, it has used all the electricity generated and is operating stably. In June, the plant consumed 23.16 MWh of AC power and 11.86 MWh of DC power.
According to details on its website, IHI now foresees market expansion for its on-site thermal utilization system, with plans for commercialization.
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Whoa, couldn’t they get an efficiency greater than 1 by using a heat pump instead of electric boiler? On the other hand they used DC from the PV so skipping conversion to AC saved some, and they got a balance useful in that sewage plant.