Towards Nearly Zero Energy Buildings

TOWARDS NEARLY ZEROENERGY BUILDINGS
Webinar

23/01/2014
Dr. Andreas Hermelink

Content
> Introduction
> Nearly Zero-Energy Buildings (nZEB)
> Reporting template and analytical framework for Member States
> Specific issues around the nZEB definition
> Benchmarks for nZEB
> Convergence between cost-optimality and nZEB?
> Conclusions and Recommendations

2

© ECOFYS | 23/01/2014 | Dr. Andreas Hermelink

Introduction – What‘s the issue?
> Emissions gap report Cancún:
Scenarios that give the world a
chance to stay below 2 °C have:

> World GHG Emissions peak before
2020

> World GHG Emissions in 2050
50-60% below 1990 level

> Due to the high share of
industrialized countries in GHG
emissions, Europe has a target of
80%-95% GHG reductions.

3


A roadmap for moving to a low carbon economy
in 2050, EC 2011, Minimum Reduction vs. 1990

0%
-10%
-20%

Cross sectoral

Power

Buildings

-20%

-30%

-37%

-40%
-50%

2030

-54%

2050

-60%
-70%
-80%

-80%

-90%
-100%
4


-93%

2020

-88%

A roadmap for moving to a low carbon economy
in 2050, EC 2011, Maximum Reduction vs. 1990

0%

Cross sectoral

Power

Buildings

-10%
-20%
-30%

-30%

2020

-40%
-53%

-50%
-60%

-68%

-70%
-80%
-90%

-95%

-100%
5


-91%
-99%

2030
2050

Content
> Introduction

6


Definition of Nearly Zero-Energy Buildings
> Energy Performance of Buildings Directive’s (EPBD), Article 9:
– [A nearly Zero-Energy Building is a] “building that has a very high
energy performance… [ ]. The nearly zero or very low amount of
energy required should to a very significant extent be covered by
energy from renewable sources, including renewable energy
produced on-site or nearby.”

2019/2021

7


today

building stock

Nearly Zero-Energy Buildings: Key Questions

2019/2021

today

building stock

> Burning questions
– Options to achieve nearly zero-energy buildings?
– What about the share of renewables?
– What is “nearly zero”?
– Do nZEB need to be cost-optimal?

8


Nearly Zero-Energy Buildings: Close Up
> Residential & non-residential buildings
> All NEW buildings
> Included services: heating, domestic hot
water, cooling, ventilation, lighting
(commercial buildings) and auxiliary
energy => NOT: plug-loads, appliances

> First, reduce energy needs for these
services to cost-optimal levels

> Second, cover the nearly zero rest (very
significantly) from renewable sources

> Annual GHG emissions 2050:
appr. 3 kg CO2 / m2a in building stock

> => nZEB also means nearly zero
emission building!

> Today there is no more specific definition
in Europe which is common sense!
9


Content
> Introduction
> Reporting template and analytical framework for Member
States


10


Request for National nZEB Plans
> Member States shall draw up national plans for increasing the number of
nearly zero-energy buildings (EPBD Article 9 paragraph 1).

> The National plans shall include:
– Application in practice of the national definition of nearly zero
energy buildings

– Intermediate targets
– Policies and financial or other measures for the promotion of
nZEB

> “The Commission shall evaluate the national plans … notably the adequacy
of the measures envisaged by the Member States… .” (EPBD Article 9,
paragraph 4).

> After having received the national plan the Commission “… may request
further specific information regarding the requirements set out in
paragraphs 1,2 and 3”
=> common reporting format on nZEB is helpful

11


Template for National Plans
> Reporting template
– provided by the European Commission to MS; developed by Ecofys
– Also serves the Commission as an analytical framework.
> Categories included
– Starting point
– Application of the definition of nearly zero-energy building
– Intermediate targets (qualitative and quantitative)
– Intermediate targets also for new buildings occupied and owned by
public authorities (by 31 December 2018)

– Policies and measures for the promotion of all new buildings being
nearly zero-energy buildings after 31 December 2018 resp.

– Additional information
– Possible improvements (self-assessment and possible improvements)

12


Template for nZEB definition
> How do member states define the nearly
zero-energy buildings? Do they fulfill the
EPBD/RED requirements?

> Table for reporting the detailed
application of the definition of nearly
zero-energy buildings in practice.

13


Template for nZEB definition

14


Content
> Introduction

15


Different Physical Boundaries for Supplying
Energy from Renewable Sources, 1

on-site

nearby

off-site

> “the nearly zero or very low amount of energy required should be covered to a
very significant extent by energy from renewable sources, including [but
not saying: “being” or “limited to”] energy from renewable sources
produced on-site or nearby”.

> Main arguments to include off-site: provide sufficient number of choices for
building owner, ensure equal chances, reflect reality of renewable supply
16


Single Building and Off-Site Supply

import
export

on-site

nearby

off-site

> Two different physical boundaries for demand and supply
> Balancing import and export
> Balance gets easier when focus switches to building owner as „legal system“
=> high share of RE possible without any on-site renewables

18


Metric and Period of the Balance
> EPBD requires national nZEB definition to
include a numerical indicator for the energy
performance. Which metric to use?

– Delivered energy => primary energy factors
(PEF) => Primary energy

– PEF sometimes intransparent, for electricity
steep decrease forecasted

– Switch to CO2 might happen in the future
> Period of the balance
– EPBD: Net balance over one year (include
heating & cooling)

– Question of length of sub-intervals
– The shorter the sub-interval, the more
ambitious it is to achieve (nearly) zeroenergy balances => aim: less stress for
(electricity) grids
19


Period of the Balance – „Load Match Index“
> Different sub-intervals
for a 1 year period:

– 1 year
source: Koch et al. 2011

– 1 month
– 1 day
– 1 hour
> Balancing „PV on the
roof“-export with
import from grid;

> PV system sized for
annual „net 0“

> Result: The net ZEB can only “live” without importing energy for 25% of a
year’s hours; e.g. all nocturnal hours need energy imports.

> Annual sub-interval over-estimates renewable share
> Currently monthly balances seem to be a viable solution.
20


Variations in nZEB definitions
80

Number of available
definitions/labels

70
60
50
not defined

40

no

30

yes

20
10
0
option1:footprint

option2:on-site

option3:off-site
generation

option4:off-site
green electricity

> 71 nZEB definitions from 17 EU and 2 countries beyond have been analysed
> graph shows which boundary is explicitly allowed/forbidden/not mentioned
for renewable energy (heat & electricity)

21


Content
> Introduction
> Reporting template and analytical framework for Member States incl.
specific issues around the nZEB definition


22


Approach for deriving benchmarks

> Cost-optimality methodology
> Dynamic simulation of multiple variants (office, single, 4 climate
zones/cities, new/retrofit, 2010/2020, private/societal
perspective) => clouds of variants

> Defining primary energy benchmark area
> Calculation of renewable share within benchmark area
> Classification of energy needs within benchmark area
> Feedback-loop with global cost

23


Cost-optimality: Definition of “global costs”

> Global cost calculations (EN 15459) result in a net present
value of costs incurred during a defined calculation period
> initial investment
> annual costs for every year (running costs)
> final (residual) value
> disposal costs

> Two different perspectives to be taken
> macroeconomic perspective (excl. taxes and subsidies, including
carbon costs etc., macroeconomic discount rate)

> financial perspective (incl. taxes and subsidies, excluding carbon costs
etc., market interest rate)

24


Derivation of cost optimal level

1
€/m2
2

3

4

5

6

„Cost optimal
range“

Economic
optimum

kWh/m2a

25


Financial and environmental gap today

26


Defining the primary energy benchmark area

27


Defining the primary energy benchmark area

The “benchmark area” is determined in the following way:
• Determine the variant with minimum net primary energy,
• Consider an increase of 15 to 25 kWh/m2y,
• At this new level of net primary determine the variant with minimum global cost,
• Increase global cost by 15-25%
28


Results net primary energy ranges
Simulated net primary energy ranges in different European
regions and building categories

29


Results energy needs

Simulated energy needs for heating and cooling in different
European regions and building categories

30


Results onsite share renewables
Simulated shares of onsite renewables on total primary energy
demand in different European regions and building categories

31


32

Paris - Office - New Building - 2010
Financial Persp. (RIR = 4%, Tax included)

100%

3500
3000

80%

2500
60%

2000

40%

1500
1000

20%

500

0%

0
EN < 15
kWh/m2

15 < EN < 30
kWh/m2


30 < EN < 45
kWh/m2

45 < EN < 60
kWh/m2

60 < EN < 75
kWh/m2

EN > 75
kWh/m2

Global Cost - 30 years [€/m2]

% of Building Variants within classes of
Energy Needs for Heating and Cooling

Feedback loop with global cost

Summary results energy needs

Energy needs (being the sum of heating and cooling) turned out to
be in the following low ranges for the following climate zones:

> Zone 1: Catania (others: Athens, Larnaca, Luga, Seville, Palermo):
15-45 kWh/m2a (new office), 15-30 kWh/m2a (new SFH)

> Zone 2: Budapest (others: Bratislava, Ljubjana, Milan, Vienna): 1545 kWh/m2a (new office), <15 kWh/m2a (new SFH)

> Zone 3: Paris (others: Amsterdam, Berlin, Brussels, Copenhagen,
Dublin, London, Macon, Nancy, Prague, Warszawa): 30-45
kWh/m2a (new office), here variants having the same average
global cost were found in the classes <15 kWh/m2a and 15-30
kWh/m2a as well; <15 kWh/m2a (new SFH)

> Zone 4: Stockholm (Helsinki, Riga, Stockholm, Gdansk, Tovarene):
15-30 kWh/m2a (office), <25 kWh/m2a (SFH)

33


Content
> Introduction

34


Cost-opt vs. nZEB – The Commission‘s view

> After 2013, all new buildings and renovations shall be based on
cost optimal requirements.

> How is it with cost optimality of nZEB after 2020? Do they have
to be cost optimal as well? (i.e. what if the technologies
necessary for reaching nZEB will not be cost optimal?)

35


Cost-opt vs. nZEB – The Commission‘s answer

> Basically cost optimality and nearly zero energy buildings are two
different concepts. Nevertheless, the minimum energy performance
requirements for new buildings after 2020 (i.e. NZEB) will have to
be cost optimal as well. In best case (depending on circumstances, like
investment costs and energy prices and depending on the exact definition
of nearly zero energy buildings by the respective Member State) the
technical requirements derived from the two systems get close to
each other around 2020 to allow a smooth transition.

36


Gap in life cycle costs

2020

Financial and environmental gaps between nearly zero-energy building,

2010

Financial and environmental gap between nearly zero-energy building

cost optimality of system costs, energy prices and and cost optimality in 2021 factors expected
Changes and current requirements in 2011
primary energy

 Cost optimum clearly moves to lower net primary energy between 2010 and 2020
37


Content
> Introduction

38


Conclusions and Recommendations
> nZEB usually are correlated with very low energy needs (close
>
>
>
>
>

39

or equal to Passive House)
Buildings constructed with very low energy needs have global
costs over 30 years lower or comparable to buildings with high
energy needs
These results seem relatively robust towards changes in various
economic parameters, e.g. the assumed interest rates
The economic attractiveness of low energy need buildings
grows when considering the scenario of constructing a building
in 2020
The cost optimum in all cases moves towards zero
This result is reinforced in case energy prices would rise more
significantly than assumed


Conclusions and Recommendations
> It is likely to be a good economic investment to continue

support for innovation and to completely close the gap between
cost-optimal and zero energy
> Not to forget: Buildings with low energy needs have
supplementary benefits like higher thermal and visual comfort

> nZEB as a cornerstone for EU 2050 climate targets
> On-site RE currently in the focus, but
> Off-site RE must get a viable nZEB option as well
– Equality, even chances, avoid discrimination
– Community and large scale production
> Only demand reduction and RE will succeed

40


Please contact us for more information
Dr. Andreas Hermelink
Ecofys Germany GmbH
Am Karlsbad 11
10785 Berlin
Germany
T: +49 30 297 735 79-50
E: a.hermelink@ecofys.com
I: www.ecofys.com

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Towards Nearly Zero Energy Buildings

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