Hi all,
We are working on a project that is being served by a district energy system both for heating and cooling.
The energy rates have been estimated according to the instructions provided within “Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 - Design & Construction (DES v2), dated August 13, 2010”. Since a flat rate structure is being used for all energy sources (meaning the cost per unit energy is the same throughout the year, and there are no demand charges), then these flat rates simply become the virtual energy rates for the project. Hence, electricity rate is 0.18 $/kWh and natural gas rate is 0.07 $/kWh.
In terms of virtual DES rates, those have been calculated based on the equations found on page 14 of the same document:
District Chilled Water Rate:
• Units of $/ton-hour = Virtual Electric Rate (in $/kWh) x 0.85
District Hot Water Rate:
• Units of $/MBTU = Virtual Fuel Rate (in $/MBTU) x 1.59 + Virtual Electric Rate (in $/kWh) x 3
Given that 1 ton-hour equals 3.52 kWh and 1 MBTU equals 0.293 kWh we have concluded that:
District Chilled Water Rate should be set to 0.043 $/kWh and District Hot Water Rate to 1.95 $/kWh.
Are those calculations correct? If yes, this results in extremely high building energy costs which cannot be justified. Also, this would affect building's performance on the renewable energy credit (EAc5) as cost savings due to the PV system would be negligible compared to that huge total building energy cost.
Any ideas how to deal with this?
Thanks.
Kind regards,
Nikos
