Carbon neutral premises in 2035: energy from the ground

Senate Group aims to make government property carbon neutral by 2035. This ambitious project is now on the home straight with regard to heating systems. In Defence Properties Finland, heat pump and wood pellet solutions have turned out to be the winning choices for heating.

In tendered buildings, heating is procured as a service. The heating supplier is responsible for the design, construction and maintenance of plants replacing oil heating under a 12-year contract.

Current status: strict overall goals are reached without haste

Defence Properties Finland aims for a 60% reduction in emissions during 2020–2025. At the same time, savings of €2 million in electricity and energy costs should also be delivered.

“Renewable energy will help us to reach these goals. Since Senate Group’s electricity has been carbon neutral since back in 2018, the focus now is on updating energy systems. There are only small properties remaining for which competitive tendering is underway,” says Tomi Suomalainen who heads the Facility Management Team at Defence Properties Finland.

Competitive tendering is technology neutral. The bidder decides the proposed technology to produce heat at each site.

“The main requirement is that the form of heating meets EU regulations for renewable energy. The bidder awarded the tender is ultimately determined on the basis of overall best value for money.”

In competitive tendering, wood pellet solutions have proven to be the most-effective form of energy in a building the size of an apartment block. Whereas on the other hand, ground source heat or air or water pump technology is a cost-effective option in buildings the size of a single family home when the investment review period is 12 years.

“Ground source heat is the only option in museum sites. Because of the cultural environment, new visible structures that change the general appearance of the built environment cannot be built on them,” Suomalainen explains.

The Finnish Defence Forces seek to phase out the use of oil without compromising security of supply. Systems using renewable fuels have been installed in oil-heated sites since 2014 and Defence Properties Finland currently still has a total of 60 oil-heated sites.

”At the largest sites, oil heating is still used as a backup. In the event of a power outage, electricity-intensive systems like ground source heat pumps might have to be stopped due to a shortage of generator electricity. Then the former oil heating is used,” says Energy Specialist Mikko Nurhonen at Defence Properties Finland.

Relevance going forward: domestic energy will improve security of supply

The ground source heat and wood pellets used by Defence Properties Finland are renewable, domestic energy sources.

“They improve the energy economy of our properties and are additionally the cheapest and most sensible way to produce and buy heating energy. The fact that the fuel is Finnish also improves security of supply and the regional economy,” says Mikko Nurhonen.

A ground source heat system pays for itself in an average of 5½ years or even immediately.

“One of our properties in Kouvola consumed around 17,000 litres of oil a year. Oil heating also incurred regular oil burner servicing, chimney sweeping and chemical safety measures such as upgrading chimneys. In the near future, this work would have resulted in additional costs of around €100,000. We switched from oil heating to a ground source heat system, which delivered considerably more savings than the costs of installation.”

The amount of thermal energy in Defence Properties Finland’s 17 wood pellet heated sites is around 15 GWh. There are six other special properties (garrisons or depots) tendered. The heat in these is mostly produced using wood chips and the support fuel is peat. The thermal amount is around 60 GWh, 20% of the heating need.

“District heat accounts for the majority, or almost 200 GWh of heat. Fuels at sites are still mixed but are turning green,” Nurhonen says.

Between one and three tankers of oil are consumed a year at separate sites.

“Compared to that, the savings potential of tendered renewable energy is roughly 20-25%. The heating bill for the first quarter is already lower than earlier,” Nurhonen says.

Did you know? Wood pellets and chips meet 75-85% of Defence Properties Finland’s heating need

The chips used for heating are chipped wood, which often results as a by-product of forest management and the woodworking industry. Chipping surplus wood contributes to forest management and sustainable energy production.

Wood pellets on the other hand come from sawmill industry residues such as wood shavings, sawdust and sanding dust, which are compressed into pellets. The thermal value of wood pellets is more than 4.8 MWh/1,000 kg, which corresponds to around 450 litres of oil.

Wood chips meet around 70-80% of Defence Properties Finland’s heating need and wood pellet heating plants account for 5% of the heating need.

“When we tendered heating at small sites, the tender was awarded to a heating supplier with a plant in Finland and whose raw material comes from plane shavings created as a by-product of the woodworking industry,” Tomi Suomalainen says.