Based on 2022 Building Energy Efficiency Standards, Section 100.2 – Calculation of Time Dependent Valuation (TDV) Energy
Time Dependent Valuation (TDV) energy is a method used to evaluate a building’s energy efficiency by considering not just how much energy it consumes, but also when and where that energy is used.
Imagine two buildings that consume the same total amount of electricity over a year. One primarily uses electricity at night when demand on the power grid is low, while the other consumes most of its electricity during peak daytime hours when demand is high.
Even though their total energy use is identical, the second building places a greater strain on the energy grid because it draws power when electricity is more valuable and in high demand. This is where TDV comes in—it assigns different values to energy use depending on:
✔ Time of day – Electricity is worth more during peak hours when demand is highest.
✔ Energy type – Different energy sources (electricity, natural gas, etc.) have varying impacts.
✔ Location – Some areas experience higher energy demand than others.
For example, using electricity on a hot summer afternoon carries a higher TDV cost than using the same amount of electricity in the middle of the night. This is because the grid must work harder and rely on more expensive or less sustainable power sources during peak demand.
Why TDV Matters
Under TDV, a building that consumes more energy during peak hours may need to be more efficient overall to stay within its energy budget. This encourages strategies like:
✔ Load shifting – Running appliances and HVAC systems during off-peak hours.
✔ Energy storage – Using batteries to store energy when it’s cheaper and releasing it when needed.
✔ Passive design – Incorporating natural cooling and shading to reduce peak-hour energy use.
By considering not just how much energy is used but also when it is used, TDV promotes smarter energy choices that benefit both building owners and the power grid.
Exam Question
How does Time Dependent Valuation (TDV) energy account for the value of energy use in building performance evaluation?
A) It measures the total energy used by the building over the entire year without considering when or how the energy is used.
B) It adjusts the energy use by applying multipliers that change depending on the time of day, type of energy used, and the building’s location and type, reflecting the impact of energy use on the grid.
C) It calculates energy use based on the average energy consumption across all hours of the year, without considering specific times or types of energy.
D) It only considers the energy used during peak hours of the year when calculating the building’s energy efficiency.
Answer
B) It adjusts the energy use by applying multipliers that change depending on the time of day, type of energy used, and the building’s location and type, reflecting the impact of energy use on the grid.
TDV energy gives more value to energy used when the demand is high and less value when demand is low. For example, energy used during a summer afternoon, when everyone is running air conditioners, is more impactful than energy used late at night. This system ensures that buildings are designed to be efficient not just in total energy use, but in how that energy is used throughout the day and year.