With the introduction of steam power there was an increasing need to coal to be available to replenish the bunkers when warships were deployed. As early as 1835 Portland was suggested as a coaling depot, given it location midway between Plymouth and Portsmouth and adjacent to the French naval port of Cherbourg. The initial stocks of coal were kept in float barges, often hulks of old warships.
By 1844 proposals were being made for purpose built and plans for purpose built coaling wharfs but nothing really came of these until commercial concerns such as Royal West India Mail Company and P & O Steam Navigation Company entered into contracts for coaling jetties, supply coal by rail. The cost of this coal was a little more but it was more efficient and arrived in better condition. In 1850 most naval ports only had the facilities to coal two ships at any one time. Clearly insufficient for a large fleet of steam ships.
In the early years, coal was stored in either in purpose built stores or left on the key side. Purpose built stores still survive at various locations such as Ascension Island and Portland.