Complex sentence: The final design operated for the next 25 years and produced surplus electricity which Blyth offered to the people of Marykirk to light the main street of the town, however, his offer was rejected as the people thought electricity was "the work of The Devil".
Split into simpler sentences: The final design operated for the next 25 years and produced surplus electricity which Blyth offered to the people of Marykirk to light the main street of the town. But his offer was rejected, as the people thought electricity was "the work of The Devil".