Articles

ANDRIANOS engineers, with a high level of knowledge in heating technologies and the energy market, have prepared a useful comparative study of the main thermal energy production technologies.

Part A: Fuel Energy Cost

The first step was to compare the different available fuels (energy sources) that a consumer can choose, depending on the heating system installed in their building. The fuels studied are:

• Oil
• Bulk LPG (for tanks)
• LPG in cylinders (bottled)
• Natural Gas
• Electricity
• Pellets
• Firewood

By using the calorific value of each fuel (lower calorific value) and the current price per unit of fuel, the energy cost of each fuel was calculated in Euros per Kilowatt-hour (€/KWh). The results are shown in the table below:

Fuel Energy Cost in Euros per Kilowatt Hour (€/KWh)

The key observation is that natural gas, firewood, bulk LPG (for tanks) and heating oil are the most economical fuels, while electricity has the highest cost. Of course, the comparison only concerns the fuel and reflects how much thermal energy (KWh) is produced with €1 from each fuel. 

The results are quite different when considering the heating system, the thermal energy production technology, and the degree of efficiency of the system in each case.

PART Β: Cost of Thermal Energy in €/KWh

For the comparison of the different thermal energy production systems, the most widespread systems in Greece at the moment were chosen for study. These are:

• Old Oil Boiler
• Conventional Oil Boiler
• Modern Condensing Oil Boiler manufactured after 2017
• Wall Mounted Condensing Gas Boiler
• Wall Mounted Condensing Natural Gas Boiler
• Old Conventional Boiler with Natural Gas Burner
• Heat Pump, in climate zone A
• Heat Pump, in climate zone B
• Heat Pump, in climate zone C
• Electric Heating (Heat emitters / Heat accumulators / Electric panels / Electric boilers)
• Pellet Boiler
• Energy Hydro Fireplace
• Energy Fireplace - Closed Champer
• Traditional Open Chamber Fireplace

*Detailed data and the degree of performance of each system can be seen in the table at the end of the article.

By combining the prices and calorific value of the fuels with the degree of efficiency of each heating system, we obtain the following results for the cost of thermal energy production in Euros per Kilowatt hour (€/KWh):

Cost of Thermal Energy in Euro per Kilowatt hour (€/KWh) depending on the heating system

Results:

• The first and most obvious conclusion is that the Heat Pump remains the most economical (in use) way of heating this year as well. The electricity consumption of the Heat Pumps (which have particularly high degrees of efficiency) is particularly favorable (€0.052/KWh in Climatic Zone A). Similarly, in Climatic Zone B and C, Heat Pump achieves an energy cost equal to 0.056€/KWh and 0.063€/KWh respectively.
• Next are Natural Gas Condensing Boilers (€0.093/KWh) as well as old Natural Gas burner boilers costing €0.119/KWh, thanks to the reduction in the price of natural gas.
• Then they follow LPG in a tank, using a modern condensing boiler, where this combination results in a cost of 0.132€/KWh and the Energy Water Fireplace has a cost equal to 0.134€/KWh.
• The next most advantageous option for heating is the Modern Oil Boilers with Condensing technology, where without calculating the heating allowance, they achieve a cost of €0.145/KWh. [It should be noted that oil as a fuel has particularly high taxes: €0.28/lt Excise Duty (Excise Tax), i.e. approximately 40% of its value as well as 24% VAT. To understand the difference, the corresponding taxes on Natural Gas are Excise Tax of €0.00108 (i.e. only 1%) and VAT. only 6%.].
• Next are Conventional Oil Boilers (€0.160/KWh).
• The next most economical option is the Closed Chamber Energy Fireplaces (€0.188/KWh) and then the Condensing Boilers for use with LPG cylinders (€0.189/KWh) and the old oil boilers (€0.196/KWh),
• Next are Biomass Boilers (pellet) with a cost of €0.204/KWh.
• The most expensive solutions are the systems with electric resistances (€0.301/KWh) and the even more expensive solution of the traditional open chamber fireplace (€0.375/KWh).

Part C: The cost of heating over time

Taking corresponding data from the oldest available studies of the National Technical University of Athens, ANDRIANOS engineers have mapped the changes in heating costs over time, from 2017 to today. The results are shown in the table below, which also shows the average heating costs for the last five years.

Conclusions

Heating costs increase over time for all fuels and all systems.

3 categories of systems are created in terms of usage costs:

A. HEAT PUMPS < 0.10 €/kWh
B. BOILERS solid - liquid - gaseous fuels 0.10-0.20 €/kWh
C. EL. RESISTORS AND TRADITIONAL FIREPLACES > 0.30 €/kWh

Sources and Acknowledgments

For the implementation of the above study, information was obtained from the literature, from corresponding study of the NTUA and Dr Efthymiadis, while some basic assumptions were made regarding the average degrees of performance of the heating systems based on the know-how, experience and especially the knowledge of the market of the ANDRIANOS engineers.

Regarding fuel prices:

• Oil: The retail prices of heating oil were taken from the Observatory of Liquid Fuel Prices http://www.fuelprices.gr/
• LPG: Bulk LPG and cylinder LPG prices were sourced from market professionals.
• Natural Gas: The price of Natural Gas was derived based on average commercial prices for October 2023 supply charges combined with existing (regulated) transmission & distribution charges and other charges.
• Electricity: To calculate the cost of KWh, the Household Tariff C1 of PPC (greek: ΔΕΗ) October 2023 was used, including the state subsidy.
• Pellets: The Pellet price was obtained from market professionals and refers to imported certified pellets.
• Firewood: The price of firewood was obtained from market professionals.

Methodology:

For the preparation of Part A of this study, the energy sources (electricity & types of fuel) shown in the table below were used.

With the above values, the cost of fuel energy was calculated, taking into account the Lower Calorific Value and the Cost of Fuel in the studied time period.

For the preparation of the B part of the present study, the heating systems were analyzed.