The annual running costs of each of the heating technologies for a typical 4-bedroomed house with typical usage of 17000kWh for heating and 3500kWh for hot water. The approximate costs per kWh were obtained from
In order to get the cost per unit of delivered heat, the efficiencies of using the different technologies have to be taken into consideration. This is done using the formulae
Where η is the efficiency of the system (Heat lost across heat exchange. Pipe work and radiators are not considered for ease of calculation)
The cost of Biomass fuel is increasing year on year like everything else, but as more suppliers of wood chip and wood pellets enter the market, increased competition is keeping prices down.
Currently it is much cheaper to heat your property using biomass fuel than heating oil, LPG or electricity. Natural Gas remains the lowest price fuel source at the moment, but the RHI payment scheme is designed to compensate biomass users for the increased fuel costs.
What is significant, especially for those users currently using oil, is that there has historically been no seasonal spike in biomass prices in response to cold weather conditions. In contrast, suppliers of heating oil have received a lot of bad press in recent years with accusations of profiteering being levelled as they increase prices virtually overnight as the temperature drops.
According to the data from table 5.1, the annual costs for running wood pellet technologies are cheaper than running the other technologies. Electricity is the most expensive technology to run annually. Running other renewable technologies on their own, such as GSHP and ASHP, is seen to be cheaper than most of the fossil fuel technologies apart from natural gas, which is seen to be relatively cheaper. Just as before, the COP of the GSHP and ASHP will vary with temperatures and, in the colder seasons, lower temperatures will lead to decrease in COP causing more electricity to be used and so increasing the cost of running these technologies.
The table above shows the potential annual savings and possible increase in costs of replacing current fossil fuel technologies with renewable ones. It is observed that replacing current technologies with wood pellet technologies will cause the greatest savings across all technologies.