Synergies between Renewable Energies

and Combined Heat and PowerMihail Ketov, June 12th 2018, Bucharest

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Climate Policy Targets lead to Energy Transition

Introduction 1

Emerging Usage of Renewable Energy Sources (RES)

German target: 50% share of RES in electricity consumption in 2030

Especially intermitted sources like wind and solar

➔ Increasing feed-in from RES must be integrated into electricity markets

0

50

100

150

200

250

300

Reference A B C B

nuclear lignite hard coal natural gasmineral oil pump storage misc. conventional wind on-shorewind off-shore solar biomass hydromisc. RES peak load

GW

Electricity System Development Scenarios

(by German Transmission System Operators)

2012 2030 2035

Source: network development plan 2017

Source: IAEW

windsolar

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Costs of Renewables on Downward Trend

Introduction 2

German RES capacity auctions (mandatory up from 750 kW)

Pay-as-bid principle based on merit order of bids (subsidy level and capacity)

Bids with lowest subsidy level will be granted until the total capacity reached

Total capacity based on expansion targets for each technology

Take place three times a year since 2015

➔ RES close to economic break even and thus subsidies not necessary

9,28,5

8,07,4 7,3 6,9 6,6

5,74,9

5,7

4,33,4

0

2

4

6

ct/kWh

10

Average Solar PV and Wind Onshore Auction Results in Germany

Solar PV Wind onshore auctions2015 2016 2017

Source: TenneT Market Review 2017

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Compare German RES feed-in 2015 and 2030 – Exemplary Week

In future RES feed-in will

1. exceed demand temporarily

2. nearly completely missing for up to two weeks

➔ Volatile and random RES generation needs to be compensated

➔ Flexible and secure generation capacity crucial in order to cover volatile

difference between demand and RES feed-in (residual load)

0

20

40

60

80

Intermittent Renewable Generation requires Flexibility

Introduction 3

0

20

40

60

80

Windenergie Photovoltaik Nachfrage

GW

feed-in / load

2015

GW

2030

demand

MO TU WE TH FR SA SU MO TU WE TH FR SA SU

wind solar

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Flexibility Option: Combined Heat and Power (CHP)

CHP plants provide thermal and electric power simultaneously

➔ High total efficiency due to usage of both energy types (up to 90 %)

Decreasing competitiveness of thermal plants

due to high RES share with low marginal costs

Increasing efficiency by using heat

Additional revenue due to heat sales

Target of German government:

25% of thermal generation with CHP

➔ CHP will coexist with RES during transition

0%

5%

10%

15%

20%

25%

German CHP Electricity Generation Share of

Thermal Power Plants

Combined Heat and Power as Efficient Generation

Introduction 4

Input and Output

CHPelectric power

thermal power

fuel

Source: Eurostat and BMWi

futu

re t

arg

et

high

efficiency

0%

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Installed CHP

Thermal and electric output

increased in Germany

➔ CHP increase parallel to RES

CHP by countries in Europe

Widely used technology

Installed for utility services as district

heating as well as for industrial applications

➔ Germany with most absolute CHP generation in Europe

CHP in Germany and Europe

Analysis 5

0

20

40

60

80Electric CHP Generation (2015)

Source: EurostatTWhel

a

40

50

60

70

80

90

100

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

the

rma

l

electric

Development of CHP Capacity in Germany

2009

20102011 2012

2013

GWel

GWth

Source: Eurostat

0

0

2014

2015

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

CHP process heating applications

Steam processes up to 500 °C

Hot water processes

Cooling

➔ Primarily used in chemical, paper

and food production

➔ Various technologies available depending

upon application

CHP Industry Applications in Germany

Analysis 6

0

10

20

30

40

50

CHP Applications in German Industry (2011)

CHP (own generation)heat network

TWhth

a

Source: Bundesverband Kraft-Wärme-Kopplung e.V.

010203040506070

0,001 0,01 0,1 1 10 100 1000

Brennstoffzellen (BZ) Gasmotoren (GM)

Mikrogasturbinen (MGT) Gasturbinen (GT)

Dampfturbinen (DT) Gas- und Dampfturbinen (GUD)

Technologies Available

eff

icie

ncy e

lectr

ic

power electric

%

MW

extraction condensing

heat recovery

backpressure

fuel cell (FC)

micro gas turbine (MGT)

steam turbine (ST)

gas engine (GE)

gas turbine (GT)

combined cycle gas turbine (CCGT)

GT

CCGT

STFC

MGTGE

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Heat Demand

Depending on connected heat consumers,

temperature and time

➔ Heat demands needs to be covered at all times

Heat Supply

CHP units provide heat and electric energy

simultaneously

Power-to-Heat (PtH) as heat generation for

peak load through electric consumption

Heat storages for equalizing demand

➔ Heat generation portfolio provides a

degree of freedom in unit commitment

➔ Flexibility given in electric generation (CHP)

and electric consumption (PtH)

CHP as a Part of Heat Generation Portfolios

Analysis 7

hydro/thermal electric load

heat

storage

heat only thermal

load

heat portfolio

. . .

. . .

. . .

CHP

. . .

PtH

. . .

RES

Coupled Electricity

and Heat Sector

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Industrial heating

Temperature independent process heat

Large-scale consumption

➔ High utilization and secure supply due

alternative generation units

District heating

Mainly in urban areas

Consumers mostly small scale businesses

and private households

➔ Volatile demand leads to lower utilization

and back-up capacities

➔ Both types can provide flexibility

Heat Portfolios in Germany

Analysis 8

Large Scale Heat Portfolios

industry district heating ~31 PJth/a

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

RES Integration and Market Incentives

CHP and PtH used to cover thermal demand

RES feed-in exceeds demand

→ PtH uses RES overproduction

→ Capacity for positive and negative residual load

→ Flexibility demand will result in corresponding incentives at the electricity market

➔ Integration of RES by using flexible CHP and PtH

➔ CHP and RES complement each other

Coverage of Residual Load with CHP and PtH

Flexibility 9

RES Overproduction

el.

ge

ne

rati

on

demand RES PtH

RES Missing

el.

ge

ne

rati

on

demand RES CHP

RES feed-in is missing

→ CHP fills electric demand gap

Synergies between Renewable Energies and Combined Heat and Power | 12.06.2018 | Mihail Ketov

Introduction

Intermitted and random feed-in from RES results in flexibility demand

Analysis

CHP with high total efficiency due utilization of thermal and electric output

Efficiency up to 90 %

Germany with the largest CHP generation in Europe

CHP will coexist with RES

CHP for heat provision used in chemical, paper and food production

Diversity of technologies for different production applications

Flexibility given by CHP in electric generation and PtH in consumption

Flexibility

Electricity market will reflect flexibility demand by price incentives

CHP and RES complement each other

Key Take Away

Summary 10

Institute for Power Systems and Power Economics (IAEW)RWTH Aachen University

Mihail Ketov, M.Sc.Mobile: +49 (0)162 80 252 88Mail: mihail.ketov@rwth-aachen.de Web: www.iaew.rwth-aachen.de

Director of IAEWUniv.-Prof. Dr.-Ing. Albert Moser

Any further questions?