Thornton SOAY Solar Farm and Greener Grid Park

At Thornton SOAY Solar Farm in East Yorkshire, Headland Archaeology uncovered a rich Iron Age to Roman landscape including settlements, agricultural activity and extensive metalworking evidence. Working closely with Statkraft and other stakeholders, the team excavated over 300 trenches and two mitigation areas, revealing far more archaeology than anticipated. The project not only protected important archaeological remains but also helped shape a sensitive and cost-effective development strategy.

Headland Archaeology was commissioned by Statkraft to undertake archaeological evaluation through trial trenching and an area of Strip, Map and Record (SMR) excavation ahead of construction works associated with the Thornton Solar Development. The investigations revealed a significantly greater density of archaeological features than had been anticipated based on the available evidence.

A total of 333 trenches were excavated across 23 fields, along with two areas of SMR totalling 2,400m² located within and adjacent to National Grid non-operational land. Cropmark evidence across the scheme had suggested a high potential for settlement and agricultural activity, which was confirmed by the results of both the trenching and SMR works, which exceeded reasonable expectations. This increase in archaeological findings was managed effectively by the Headland team in close coordination with the client, enabling timely completion of the fieldwork, a full site evaluation, and the continued engagement of all stakeholders.

The site revealed a complex landscape of Iron Age to Roman period archaeology, with some indications of earlier settlement activity and medieval agricultural use. The most intensive activity was dated to the 2nd–3rd centuries AD and included well-defined settlement areas containing a large assemblage of pottery and environmental material, along with several zones of metalworking activity, yielding over 200kg of industrial waste.

The high quality of the excavation work facilitated a smooth interface between Headland, the client, and the archaeological curator. This collaboration supported the development of a clear programme for further archaeological mitigation and agreement on alternative construction techniques to avoid damaging areas of highest archaeological potential. These negotiations minimised additional costs to the client, while providing robust protection for subsurface remains and enabling the discharge of the planning condition, subject to the completion of agreed follow-on works.