Energy Savings Analysis

Question 1

Energy saings

Answer 1

= energy that is not used

“negaWatt”

Question 2

Measuring energy savings are difficult because

Answer 2

• Use and consumption can change (cold winter = more heating)
• Efficiency of power plants vary. (dependent on temperature of cooling water)

Question 3

Efficiencies given for products are not always true because

Answer 3

those are efficiencies given under “perfect” test conditions. Use in reality will affect them differently. Think of PV panels, wind turbines and cars.

Question 4

Term used to indicate efficiency of power plants

Answer 4

Design efficiency

Question 5

Volume effect

Answer 5

in/decrease of energy use because in/decrease of activity.

Question 6

Structure effect

Answer 6

in/decrease of energy use because of change in structure/activity mix.

Question 7

Examples of structure effect

Answer 7

• From one type of available tomatoes to a variety being available
• Modal shift in transport

Question 8

Savings effect

Answer 8

decrease of energy use by efficiency improvement. distinguish between volume vs. structure + savings.

Question 9

Frozen efficiency/intensity

Answer 9

“Freezing” the energy used

Question 10

How to get frozen activity baseline?

Answer 10

activity in base year X activity indicator in target year

Question 11

The frozen activity baseline:

Answer 11

• only accounts for product growth

- difference between frozen and actual can be explained by structure and savings

Question 12

Examples of activity indicators

Answer 12

GDP

Actual production

Question 13

Energy activity

Answer 13

= energy per e.g. steel. (Physical indicator)

Question 14

Energy intensity

Answer 14

= energy per GDP

Question 15

Structure changes can

Answer 15

interfere with savings calculations. Since they are not taken into account in a frozen baseline calculation, the end result of those calculations can be unrealistic.

Question 16

Indicators should be carefully chosen (example)

Answer 16

If you only have population and household data, you are neglecting changes in the building sector.

Question 17

The example of the car, where the reference situation is 2 people, 1 old car, 50km for 10 km/ltr, becomes 2 new cards, 50 km each for 20 km/ltr

Answer 17

In this example there is a volume effect: double distance is driven. Energy savings effect: doubling of efficiency.

Question 18

Car example with passenger km (pskm)

Answer 18

Reference situation is just like new situation 100 pskm, so no volume effect.
Structure effect since from 2 people in 1 car the change is 1 person in 1 car.

Question 19

Reference situation

Answer 19

= the comparison base in energy savings calculations

Should always be for the same size/categorie, so not a large and small freezer.

Question 20

Reference situation examples

Answer 20

• old situation
• an alternative (e.g. ICE car vs electric car)
• Average (type) use(d) (by households, etc.)
• Best available

Question 21

Trias energetica

Answer 21

1) Reduce demand
2) Use as much renewables as possible
3) use fossils as efficient as possible

Question 22

Combined vs. isolated analysis

Answer 22

The total savings effect from 2 or more measures can be less then when calculated separately. Example of insulation and boiler, which to install first?

In isolated analysis you can easily overestimate savings.

Question 23

HDD

Answer 23

Heating degree days

Question 24

CHP

Answer 24

combined heat and power production

Question 25

Reasons to make/use CHP

Answer 25

- Saves energy (and money?)
• Saves grid losses
• Reduces CO2 emissions
• Improves energy security
• Creates autonomy
  - Monopoly of power producers
  - Unreliable grid
  - Back-up facility

Question 26

Three aspects that help achieve maximum efficiency of CHP

Answer 26

• High overall efficiency
• High power-to-heat ratio
• a plant designed to meet (the base load) heat demand

Question 27

4 methods of calculation power efficiencies (CHP) that correct for heat

Answer 27

1) Power only
2) power & heat
3) Substitution method
4) power loss factor

Question 28

Power loss factor

Answer 28

(E out + Pout*loss factor) / Fuel input

Only in combined cycles, they have electricity loss when heat increases.

Question 29

Power only

Answer 29

Eout / Fuel in

Question 30

Power & heat

Answer 30

(E out + H out) / Fuel in

Question 31

Substitution

Answer 31

Eout / (Fuel in- Reference heat)

Where reference heat = Hout / reference efficiency

Question 32

The power loss factor is

Answer 32

a factor that for every additional unit of heat produced, loses X unit’s of electricity

Question 33

pKm

Answer 33

passenger kilometers
The amount of kilometers one passenger travels
2 people in a car driving 50 km is 50 pKm each, therefore 100 pKm total