Supply Chains
There have been a number of studies undertaken into the feasibility of starting more biomass supply chains in Scotland. Some of these studies (e.g. Roser et al [25]) have based their research on models that are in use in Scandinavian countries that already have well established biomass infrastructure. These studies have generally been focused on the transport and processing of biomass, not in to the land used to grow the fuel.
Roser et al [25] noted that in the north west of Scotland there are many monoculture forests, made up of Lodgepole pine and Sitka spruce, that are due to be cut down and either replaced with a mixed species forest or the land returned to original peat-lands. There is little demand for this wood to be used as biomass in the north of Scotland, especially on an industrial scale, leading to the need for it to be transported south.
They concluded that using forest energy from the north west highlands of Scotland could be feasible and cost effective. They found that the biggest difficulty is transport due to the road infrastructure in the north of Scotland.
Their study highlights that the price of biomass fuel is sensitive to many factors and to compete with more conventional fuels needs to be kept low.
Transport Emissions
As Roser et al [25] also noted, transport can be an important factor in consideration to the overall cost of biomass and it can also have a large impact on the life cycle emission attributed to transportation.
Using the DECC BEAC [26] tool it is possible to make a comparison between different transportation means.
If transporting biomass from the west cost of Scotland to Glasgow, the portion of life cycle transport emissions from transport are 9 kg CO2.e/MWh. From the North West cost of Scotland the emissions are 26kg CO2.e/MWh, both of these distances are using lorries.
The life cycle emissions from transport alone by road, rail and sea, from North America are 30-34kg CO2.e/MWh. If these values are compared to the transport emissions within Scotland it highlights the importance of controlling the supply chain carefully.
CO2 Emissions from Transport (kg CO2e/MWh)
Land Under Wind Turbines
Often, potentially usable land can be difficult to find as much of it is already in use. Because of this, the idea of using spare land under wind turbines was considered. This land is often unused and infrastructure such as roads are already in place. There are some drawbacks to using this type of land. Wind farms can often be in remote areas, leading to long transportation distances. Furthermore the land is not always suitable for growing crops. In Scotland, the soil is often peaty or the land occupied by forestry, therefore these areas should be avoided to ensure a low life cycle carbon impact of the crop [30].
Using information from Scottish Natural Heritage [27], Soils-Scotland [28] and Digimap [29], a study was undertaken to investigate how much usable land is available on the types of sites that are described above.
From approximately 16 major Scottish wind farms investigated, only around 50km2 of suitable land was available.
An excel document with more information is available to download here.
Hadyards Wind farm: Scottish Power
It should be noted that technical issues may arise in the turbines from tall forestry or crops under the blades but this was not part of the investigation.