Local Supply Chain
From the research completed to identify whether a local biomass supply chain could be achieved, it was evident that between the options of LRF and SRC crops, SRC crops would be the most viable source of biomass fuel. In particular, willow could provide a suitable option due to the flexibility of the crop.
Since the lifecycle emissions are sensitive to the counterfactual land use, land selection has to be carefully considered. Selecting land which has a previous land use such as an unmanaged forest could produce more emissions than the quoted emissions from the UK electricity grid. However, if the land replaced was cropland or pasture, the life cycle emissions are over 500 times smaller, so this would be the preferred land type for plantations of SRC willow.
It should be noted that to ensure a secure supply chain, established on cropland, farmers would need to be incentivised. This is because farmers will be put off by the wait for the first crop, which is 3 years, and so to promote energy crop plantations, incentives would need to be used. Additionally, due to the ever increasing population of the UK, another factor which would need to be taken into consideration is the displacement of food crops.
To ensure the potential advantages of storage are realised, storage would need to be sized correctly. This will need to take into consideration the capacity, losses and costs of the storage units. Thermal storage in particular is still an embryonic form of technology, which is not widely utilised in large industries due to the associated high costs and risks.
Out of the options considered, a hybrid technology of using steam accumulators as primary storage system, coupled with tanks of molten salt as a secondary storage system appear to be a viable solutions for large industries with a high heat demand. This technology is still immature and would need more development before there is any significant uptake by industry.
Finally, an objective for this project was identified as “provide a model to simplify assessing available demand-supply-storage combinations”. A model was constructed in order to meet this objective. The model allows storage, demand and supply inputs to be altered allowing a comprehensive analysis to to completed in order to identify the best technological combination for energy autonomy. This model has been used in the GSK Case Study but it is applicable to other industrial plants.