Renewable Sources for Central Heating

by
Giuseppe Gillespie

21/11/2022

Traditional oil- or gas-powered heating systems produce massive amounts of CO² and accounts for most of the emissions in the residential sector. Renewable-sourced heating systems can significantly reduce or eliminate the carbon cost of heating your home and help save on your annual energy bills.

Solar Water Heating

Particularly effective in warmer climates and the Summer months, solar water heaters convert energy from the sun into electricity that can be used to heat your home.

The initial cost of solar panel installation and setup can be quite high, but it’s a wise long-term investment. According to irishtechnews.ie, the time it takes for a 3-bedroom house in Ireland with 4.1 kWh of solar panels to pay for themselves is ~7 years, or 6^[1] if you avail of a Sustainable Energy Authority of Ireland (SEAI) Home Energy Grant.

You can also sell excess energy generated from solar paneling back to the electricity grid; for example, in Ireland:

The Government Microgeneration Support Scheme allows households with a registered microgeneration device to sell any excess electricity back to Ireland’s electricity grid. This payment is called a Clean Export Guarantee (CEG)^[2].

Geothermal Water Heaters

Or geothermal heat pumps, use a series of subsurface piping to harness the latent heat from the Earth and transfer it throughout your home; for cooling, the process is reversed.

The Earth is similar to a massive solar battery and geothermal heat pumps are an extremely energy-efficient way to harness this power; for every 1 unit of electricity used, the heat pump is capable of producing 4 units giving it efficiencies in the range of 500%.

Geothermal heat pumps provide a clean source of renewable energy, requiring no fuel and producing significantly lower pollution than traditional oil- or gas-powered systems.

According to the EPA, a geothermal heating and cooling system can reduce energy consumption and corresponding emissions by more than 40 percent as compared to an air-source heat pump, and by over 70 percent as compared to standard heating and cooling equipment^[3].

Similar to solar panel systems, this energy-efficient tech has a substantial upfront cost. According to Bord Gais Energy, in Ireland: Ground and water source heat pump systems should cost between €17,000 and €28,000. The average running cost of heat pumps ranges between €600 and €1000 per year^[4].

Again, there are grants available from SEAI to help home owners cover costs of heat pump installation, ranging up to €4,500 for apartments and €6,500 for houses.

In Ireland, Ashgrove Renewables offer a product range of residential Geothermal Heat Pumps.

Wood Burning Stoves

In days gone, most households relied on fireplaces to provide a central point of heat. These were only ~10-30% heat efficient as they were localized to a single room.

Combining style and functionality, modern boiler stoves can offer up to 85% efficiency and interconnect to your home’s existing heating system:

So long as the wood comes from a sustainable source, wood burning stoves/boilers are a viable, low-emissions and cheaper alternative, or supplement, to oil- or gas-powered heating systems.

Almost Carbon-Neutral Biomass Boilers

Biomass boilers are similar to traditional oil- or gas-powered boilers, providing water and space heating for your home, however, they use sustainably-sourced materials such as wood chips or wood pellets as their fuel source.

A few videos here explain biomass and the environmental role biomass boilers have played:

Biomass boilers may not be 100% carbon neutral, widespread adoption can lead to massive deforestation if sustainability is neglected; conversely, it could lead to widespread reforestation if consumer reliance on hydrocarbons grow; nonetheless, they are a substantially greener solution than traditional heating systems and sit at ~ a halfway point in costs compared to heat pumps.

See also this overview of Biomass Boilers from enerpower.ie

Heating Controls

In addition to the type of heating system you employ, the way in which it is used can play a significant role in its overall efficiency. The lower the temperature on your thermostat, the less you’ll pay for your heating bill and the less CO² emissions will be released.

Smart meters, or a programmable, or an active thermostat, provide controls to fine-tune your heating system. Smart meters work with your existing boiler and allow you to:

• Heat only when you need to, saving energy costs and reducing carbon emissions
• Set up daily schedules for space and water heating
• Accurately measure your heating system’s performance
• In the case of a multi-room setup, allow you to efficiently heat individual rooms rather than the entire house
• Many solutions offer a smartphone app for heating system control

References

[1]: H. Fox, “What feed-in tariffs mean for solar in Ireland,” Irish Tech News, 18-Jul-2022. [Online]. Available: https://irishtechnews.ie/what-feed-in-tariffs-mean-for-solar-in-ireland/. [Accessed: 20-Nov-2022].

[2]: “Microgeneration for Homes: Electric Ireland,” Microgeneration for Homes | Electric Ireland. [Online]. Available: https://www.electricireland.ie/residential/microgeneration. [Accessed: 20-Nov-2022].

[3]: “Geothermal vs. air-source heat pumps – united air temp,” UAT, 13-Jun-2022. [Online]. Available: https://www.unitedairtemp.com/blog/geothermal-vs-air-source-heat-pumps/. [Accessed: 21-Nov-2022].

[4]: Bordgaisenergy.ie. [Online]. Available: https://www.bordgaisenergy.ie/home/heat-pump-guide. [Accessed: 21-Nov-2022].

About the Author

Giuseppe Gillespie is an infrequent Irish writer often forced to write about himself in the 3rd person as he is not famous enough to merit someone else doing it for him. He has informed me (who is definitely not him) that he hopes this could change in future, as well as his fondness for ending things with a preposition, notwithstanding. For more see: gillespie-writing.com