HOT|COOL NO.2/2021 - "Economics, Finance & Money"

More specifically, the main efficiency gains are:

More heat extracted from geothermal wells since lower temperatures of the geothermal fluid can be returned to the ground

Less electricity used in heat pumps when extracting heat from heat sources with temperatures below the heat distribution temperatures since lower pressures can be applied in the heat pump condensers

More excess heat extracted since lower temperatures of the excess heat carrier will be emitted to the environment

More heat obtained from solar collectors since their heat losses are lower, thereby providing higher conversion efficiencies

More heat recovered from flue gas condensation since the proportion of vaporized water (steam) in the emitted flue gases can be reduced

More electricity generated per unit of heat recycled from steam combined heat and power (CHP) plants since higher power-to-heat ratios are obtained with lower steam pressures in the turbine condensers

Higher heat storage capacities since lower return temperatures can be used in conjunction with high temperature outputs from high-temperature heat sources

Lower heat distribution losses with lower average temperature differences between the fluids in heat distribution pipes and the environment

Ability to use plastic pipes instead of steel pipes to save cost

The table discloses the chicken and egg problem or the catch 22 if you prefer. In countries with a district energy tradition and CHPs, boilers, or short and low term storage, the CRG is in the range of 0.16-0.07 euro/ MWh ˚C. Not until these countries lower temperatures AND start using low-temperature heat sources like geothermal, solar, or waste heat, the CRG becomes appealing and in the range of 0.68-0.51 euro/MWh ˚C.

(CRGs) were defined and explored using lower temperatures in heat distribution networks for various heat supply options. They concluded that the cost reduction gradients for new heat sources (e.g., heat pumps, solar collectors, geothermal heat, and low-temperature excess heat) are approximately five times higher than those for traditional combustion in CHP plants. This is shown in the table on next page.

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