Hello everyone,

One of our clients is considering the possibility of certifying an office building connected to a District Energy System (DES) that integrates a Combined Heat and Power (CHP) Plant. The project includes the installation of solar PV system directly connected to the building.

In what regards EAp2/C1 (Energy Performance) the approach followed was option 2 (Aggregated building / DES scenario) as described in “Treatment of District or Campus Thermal Energy in LEED v2 and LEED 2009 – Design & Construction. August 13th 2010”. Taking into account the fact th CHP electricity allocated to the building exceeds the Proposed Design (PD) electric needs, PD energy costs are exclusively based on fuel specific costs (natural gas).

The question is how to calculate the cost associated with renewable energy production (solar PV integrated in the building). Our suggestion is apply to the solar PV energy production the specific cost calculated as the quotient between CHP fuel specific cost and CHP electric efficiency (see example below).

  1. Proposed Design Cost: 50 k€/year (option 2  - Agregated building / DES scenario, excluding the contribution of renewable energy);
  2. Solar PV production: 100 MWh/year
  3. CHP gas specific cost: 40 €/MWh;
  4. CHP electric efficiency: 40%;
  5. CHP Electricity specific cost: 40 €/MWh / 40% = 100 €/MWh;
  6. Solar PV cost: 100 MWh/year x 100 €/MWh = 10 k€/year
  7. Renewable energy integration: 10 k€ / 50 k€ = 20%

Do you agree with this approach?

Thanks for your attention. I’m looking forward to your reply.