From the analysis of the costs of the different alternatives and hypotheses considered for the decarbonization of the buildings it can be concluded that the biomethane is the cheapest fuel per unit of energy, considering the needs of seasonal storage, followed by electricity and, finally, the synthetic methane, according to The report prepared by Frontier Economics consultant and published by Fundación Naturgy.
The buildings (homes and services) represent in Spain, 30% of the final energy consumption and about 25% of the total greenhouse gases emissions, so, in a context of decarbonization, the use and implementation of new sources of renewable energy is a priority.
According to the aforementioned report, fossil fuels are 63% of the consumption of buildings and are mainly used for heating and sanitary hot water. This use causes your demand to be very seasonal, concentrated in winter.
At present, this seasonality does not imply a big problem given the low cost of storage of natural gas and the liquid fuels that are used, but, in the event that all consumption of fossil fuels of the buildings in our country were electrified, the seasonal storage of electricity would be necessary, calculated around 44% of it.
Two options
The authors of the study consider that, to achieve renewable energy consumption in buildings, there are two viable options: the electric heat pump and biomethane or other renewable gases.
In this regard, they indicate that the electrification of the buildings would cause an increase in the peak demand of the system, which increases the firm energy capacity needs that guarantee the supply of said demand.
Specifically, they estimate that the electrification of the fossil consumption of the buildings would generate an additional firm demand around 28 GW, which represents 67.5% of the current tip demand. With all this, the sum of the current peak demand and the additional needs for the electrification of the buildings (without considering the additional electrification of other sectors) results in a total need of about 70 GW of firm energy.
A great challenge
In a context of a renewable electricity sector in which nuclear energy or gas does not participate, this is a great challenge due to the reduced firmness provided by solar and wind technologies. For example, the renewable capacity currently only provides about a third of the necessary firm capacity if the consumption of the buildings will be electrified.
The experts emphasize that in order for renewable energies to meet the electrical demand at all hours of the year, without storage, it would be necessary to install 397 GW of solar and 323 GW of wind, which is equivalent to almost quadruply and sexuable the power currently installed of wind and photovoltaic solar, respectively.
On the other hand, electrification would cause an increase in electricity consumption of only 5% in the months of July and August, but that percentage amounts to 60% of it in December. That is, electrification will lead to important needs for production, transport and distribution of renewable electricity, particularly in the winter months.
Efficiency
The report also analyzes the efficiency of the supply through the heat pump throughout the entire value chain, placing between 48% and 73% depending on the climatic zone and the degree of isolation of the building, considering the needs of seasonal storage. Likewise, the costs of the heat pump increase if part of the electricity they consume must be stored seasonally.
On the contrary, the greater efficiency of the seasonal storage of the biomethane compensates for the lower efficiency of the condensation boiler, leading to a global efficiency of the 85%value chain. Data that adds to the advantage of using biomethane in existing transport and distribution networks, so it would not require additional investments in this segment and equipment installation costs by consumers would be much lower.
Without a doubt, it is a great challenge, but also a great opportunity to transform the park built towards a model that uses energies Clean and more sustainable.