A sensitivity analysis was performed in order to assess the importance of various factors regarding the final project proposal. It was divided into two main parts:
1. Influence of various factors on the financial result
First of all, all the analysed costs present a level of uncertainty. After a preliminary examination five different factors have been chosen for further investigation to present their impact on the final price of heat while maintaining the final profit at the same level. The results are presented in the following table.
Impact of different factors in the price of heat
It can be observed that the factor which affects the most the price behaviour is the capital cost. We believe that high attention should be paid to the detailed cost analysis prior to the implementation of this scheme. Another significant factor is the variation in heat demand due to parameters such as additional levels of retrofitting or the amount of buildings connected to the network.
2. Financial comparison with individual heat pumps
An alternative way of decarbonising the heat supply to the community can be the installation of air source heat pumps in every dwelling. An analysis was carried out in order to compare the results of the district energy network with this option. The assumptions made in this calculation were:
Cost of installation: £ 9,000 per dwelling, financed by a loan at 3% interest rate and payback period of 7 years
Average COP of 2.2
Heat pump to provide only space heating (75% of the total heat demand)
Domestic RHI to be paid for 7 years
The graph below shows a comparison of three different alternatives which include the air source heat pumps, the situation with the current fuel mix and the district energy scheme.
Comparison of cost of heating per dwelling
It can be seen that the most cost-effective scenario is the implementation of the district energy network.
