To be able to analyse existing and possible future scenarios of the Island`s energy demand and supply relationship, a specific level of information about heating and electricity`s demand and production on the Island of Gigha, needs to be obtained. In this case – at least hourly consumption and generation data is necessary. Despite the fact that monthly generation meter (2015-2017) readings for all wind turbines and general annual consumption data for each sector and energy type was acquired, it was quickly identified that the this data acquired from GREL's director and the energy audit [1] would not be sufficient.
The electric demand profile for the current energy system on the island was constructed as outlined below. Any resultant changes for each scenario were then applied to create a separate demand profile for each 2030 scenario. These were inputted to HOMER to create a separate model for each scenario. Four main contributing sectors to the demand were identified, as shown below. The spreadsheet used to calculate the electric demand can be found below - see 'Electric demand Gigha' sheet.
The electric demand profile for the current energy system on the island was constructed as outlined below. Any resultant changes for each scenario were then applied to create a separate demand profile for each 2030 scenario. These were inputted to HOMER to create a separate model for each scenario. Four main contributing sectors to the demand were identified, as shown below. The spreadsheet used to calculate the electric demand can be found below - see 'Electric demand Gigha' sheet.
| gigha_heat_and_electric_demand_profiles.zip |
Industry
Approximately 51.54% of the total electricity used is consumed by the industrial sector. Total annual figure of 1,655,663 kWh was taken from the energy audit. Halibut fish farm represents 95% of this consumption. It`s running 2 out of 3 (100 kW, 100 kW and 75 kW) water pumps for lifting water to a height of 6m, 24/7 all year round, resulting in 180 kW base load. The remaining 78 903 kWh is used by Scottish Water site and a Salmon fish farm.
Creation of hourly load profile for the industry was quite straight forward, applying 180 kW fish farm`s load for all 8760 hours of the year. Due to lack of public information, it was not possible to build more detailed profile for remaining 78,903 kWh, so they were spread out evenly (9.01 kW) across the year.
Approximately 51.54% of the total electricity used is consumed by the industrial sector. Total annual figure of 1,655,663 kWh was taken from the energy audit. Halibut fish farm represents 95% of this consumption. It`s running 2 out of 3 (100 kW, 100 kW and 75 kW) water pumps for lifting water to a height of 6m, 24/7 all year round, resulting in 180 kW base load. The remaining 78 903 kWh is used by Scottish Water site and a Salmon fish farm.
Creation of hourly load profile for the industry was quite straight forward, applying 180 kW fish farm`s load for all 8760 hours of the year. Due to lack of public information, it was not possible to build more detailed profile for remaining 78,903 kWh, so they were spread out evenly (9.01 kW) across the year.
Public and Commercial
299,376 kWh or 12% of total electricity is consumed by the public and commercial sector. It includes a post office, grocery shop, hotel, cafe, fire station, surgery, community centre, police station, school and rentable holiday homes. Due limitations of this project and lack of detailed information, some simplifications were made. Under this sector, the electric heating and domestic appliances load of 10 holiday homes, were added - see heat demand profile. To emphasise that these properties are rarely rented out during the winter, it was assumed that only 10% capacity is used during winter months. To emphasise increased consumption during tourist season, remaining 233,961 kWh were spread out during the year applying following assumption:
299,376 kWh or 12% of total electricity is consumed by the public and commercial sector. It includes a post office, grocery shop, hotel, cafe, fire station, surgery, community centre, police station, school and rentable holiday homes. Due limitations of this project and lack of detailed information, some simplifications were made. Under this sector, the electric heating and domestic appliances load of 10 holiday homes, were added - see heat demand profile. To emphasise that these properties are rarely rented out during the winter, it was assumed that only 10% capacity is used during winter months. To emphasise increased consumption during tourist season, remaining 233,961 kWh were spread out during the year applying following assumption:
- 80% of the average hourly load is applied from 15th of April till 15th of September
- 20% of the average hourly load is applied in the rest of the year.
Domestic appliances
Domestic appliance hourly load profile was based on “Energy saving trust`s UK average household profile. And then scaled up accordingly to represent all domestic properties on the island.
Domestic appliance hourly load profile was based on “Energy saving trust`s UK average household profile. And then scaled up accordingly to represent all domestic properties on the island.
Domestic Heating
Domestic heating profile is based on calculated heating load for domestic properties, in more detail here. For the current load profile, information from the energy audit was applied. Electric heating usage in domestic properties differs - 18 properties heating load is met 100% by electricity, remaining 48 properties which use fossil fuel or biomass as main source of heat, meet at least 30% of their heating load with electricity. For the 2030 scenario demand profiles, the domestic heating demand profile was altered to include full implementation of heat pumps for all dwellings.
Domestic heating profile is based on calculated heating load for domestic properties, in more detail here. For the current load profile, information from the energy audit was applied. Electric heating usage in domestic properties differs - 18 properties heating load is met 100% by electricity, remaining 48 properties which use fossil fuel or biomass as main source of heat, meet at least 30% of their heating load with electricity. For the 2030 scenario demand profiles, the domestic heating demand profile was altered to include full implementation of heat pumps for all dwellings.
The component parts outlined above were combined to create an electric demand profile for the island, this was validated using figures from the energy audit. A separate demand profile for each 2030 scenario was created by implementing any changes that would alter the demand of the above sectors. This included the implementation of heat pumps to meet all domestic heating demand, to see the calculated financial benefits of this, see here. The 2030 scenario demand profiles were used as the basis for the HOMER model of each scenario, as described here.