The business was established in Clondalkin in South Dublin in 1950 by Jack Nielsen.
The first product was turf. Then other fuels were added, logs, Bord na Mona peat briquettes, and McMullans Kosangas. About 1960 J. L. Nielsen & Co. began importing English coal. This was the core business with a delivery service to private households and a growing number of shop outlets. The firm next began producing and distributing its own high quality brand of peat moss. The founder died in 1978.
With the advent of the oil crisis the business was able to expand and for a time had another premises on the north side of Dublin. It also diversified into heavy haulage and engineering. Up to that time the business had experienced two periods of decline in the market, followed in each case by recovery. Then came the legislative initiative banning bituminous coal. This had a major impact on the companies involved in the market. Almost all the household names disappeared or were taken over. Nielsen survived. Entering the twenty-first century, the business went thru a period of retrenchment followed by further diversification. It has built up a niche market for charcoal for ethnic restaurants and has embarked on the first stage of a planned development into renewable energy and environmental technologies.