Fuel Cells for Power and Heat

Professor Nigel Brandon OBE FREng

Director, H2FC SUPERGEN www.h2fcsupergen.com

Chair, Sustainable Development in Energy RCUK Energy Senior Research Fellow

www.imperial.ac.uk/energyfutureslab

Introduction

• What is a Fuel Cell? • Why Fuel Cells for heat and power?

• The benefits of fuel cells to energy systems. • Fuel Cell technology status for power and heat.

Introduction to Fuel Cells Fluid-Flow Plate (FFP) Flow Channel

Membrane Electrode Assembly (MEA)/ Positive - Electrolyte - Negative (PEN)

SOFC

Cathode

Anode

2H2O +

4e

2O

O2

2-

+

4e

Cathode: O2 + 4e

-

2H2O + 4e -

H2

O2

H2

O2

H2

O2

O2

2H2

+

4e-

4H+ -

2H2O

50 m

GDL 200 m

Catalyst 10 m

15 m

2-

O2

4e

50 m

Anode: 2H2 + 2O

H2

-

-

ca. 1000m

O2

Cathode e an br m Me Anode

2H2

H2

PEMFC

2O

2-

Solid Oxide Fuel Cell

Anode: 2H2 +

+

-

4H + 4e -

Cathode:4H + O2 + 4e

2H2O

Proton Exchange Membrane Fuel Cell

Comparison of Fuel Cell Types

Fuel Processing Options

So why are fuel cells of interest? • Fuel cells have the highest known efficiency of any energy conversion device of equivalent scale – an efficiency which further increases at part load. Fuel Cells are an energy efficiency technology. • Hydrogen can be used as a fuel, but so can a wide range of other fuels including natural gas. • Efficiency is high on hydrocarbon fuels ~50% for kWe systems through to 60-70% for MWe scale gas turbine hybrids. • Fuel cells produce extremely low levels of NOx and particulates. They are also quiet and largely vibration free offering siting flexibility. •The UK has a strong track record in fuel cell development in both industry and academia, with leading companies in the field.

Natural Gas 1kWe, 100 kWe and 2.8 MWe fuel cell generators

Gyeonggi Green Energy park in South Korea has just opened with 59 MWe (21 x 2.8 MWe MCFC) baseload power and high-quality heat for district heating

Final Energy Consumption of Thermal Energy in the UK in 2006 Space heating and hot water in UK residential sector = 78Mt CO2 pa. In 2008

BERR, Energy Trends: September 2008 (Special feature – Estimates of Heat use in the UK). 2008, Department for Business, Enterprise & Regulatory Reform (now Department of Energy and Climate Change): London, UK. p. 31-42.

UK: Ownership of central heating

Source: GfK Home Audit from the Domestic Energy Fact File. Building Research Establishment.

Japanese ene-farm programme over 60,000 fuel cell mCHP units now installed in Japan

Fuel Cell Boilers for the Home (micro-CHP) Conventional

Fuel Energy 100%

Power station 50% losses

Delivered 45%

Transmission 5% losses

Micro-CHP

Fuel

Fuel Cell

Energy 100%

Fuel Cell 10% losses

Electrical 50% Heat

40%

Delivered 90%

Micro-CHP Technologies

Panasonic and Tokyo Gas PEMFC

Honda ECOWILL ICE with Storage

Honda ECOWILL ICE

Baxi Stirling engine

Ceres Power and British Gas SOFC

Residential heat and power demand 16 Space Heating and DHW Demand Electricity Demand 14

12

Demand (kW)

10

8

6

4

2

0

0

4

8

12 Time (Hours)

16

20

24

Heat and Power Demand over 1 Day in a Typical UK Dwelling

Environmental Drivers for m-CHP Systems CO2 Reduction – Thermal Demand Annual CO2 Reduction w.r.t. Reference System (kg CO2/year))

ICE

PEMFC

1500

1500

1000

1000

500

500

0 5000 10000 15000 20000 25000 30000

0 5000 10000 15000 20000 25000 30000

SOFC

Stirling

1500

1500

1000

1000

500

500

0 5000 10000 15000 20000 25000 30000

Flat Bungalow Terrace Semi-Detached Detached

•CO2 reduction is dependent on ability to displace grid electricity.

•Ability to displace grid electricity, and thus bring about CO2 reduction, is dependent on annual thermal demand and prime mover heat-topower ratio.

0 5000 10000 15000 20000 25000 30000

Annual Thermal Demand (kWh/year)

Hawkes, AD, Staffell, I, Brett, DJL, Brandon, NP, Fuel Cells for Micro-Combined Heat and Power Generation, Energy & Environmental Science, 2009, Vol: 2, Pages: 729 - 744

FC mCHP impact on national electricity demand (and infrastructure that serves this demand) Correllation of national load and FC generation in coldest week 60

el

National demand [GW ]

55

50

• Therefore, mass uptake of FC CHP would relieve stress on generation and T&D assets at times of peak demand.

45

40

35

30

• Strong correlation between heat-led FC electricity generation and national load during the coldest week of the year.

0

0.2

0.4 0.6 SOFC output [kW el]

0.8

1

Source: Gruenewald & Hawkes (2014), Chapter 6 (Draft), H2FC White Paper on Fuel Cells and Hydrogen in Low Carbon Heating (Provisional Title). A Report for the H2FC Hub, Imperial College London. Actual national electricity demand plotted against predicted 1kWe FC mCHP power output derived from measured thermal demand for 46 households

• Furthermore, FC outputs likely to displace high-CO2 power generation required at times of peak demand.

Systems of low carbon heating technology FC mCHP impact on load duration curve • Heat pumps (HP) are seen as a key low carbon heat technology, but are likely to increase peak power system load dramatically

Load duration curve for 46 dwellings 60

50

Combined Net Load [kW]

20% heat pumps 40

• If a mixture of HP and FC mCHP technology where introduced, FC output displaces HP consumption.

30 20% HP, 50% SOFC 20 Baseline 10

0

0

500

1000 Duration [hours]

1500

2000

Source: Gruenewald & Hawkes (2014), Chapter 6 (Draft), H2FC White Paper on Fuel Cells and Hydrogen in Low Carbon Heating (Provisional Title). A Report for the H2FC Hub, Imperial College London.

Measured data for heat pump load over 46 households over 2 months. Predicted load for FC 1kWe mCHP. With FC installation peak loads are reduced, and flatter load curve indicates higher asset utilisation.

• Net effect – mitigation of peak demand increase caused by HPs and flatter load duration curve.

FCs are resilient against a future highlyefficient building stock Added electricity generation from SOFC over Stirling engine 14

Additional electricity [kWh/day]

12

10

• Future energy system scenarios entail a high degree of thermal insulation in buildings, thus reducing heat demand

8

• FC-based CHP inherently has lower heat-to-power ratio than other CHP technology

6

4

2

0 −1

−0.8

−0.6 −0.4 o Heat loss rate [ C/hour]

−0.2

0

Source: Gruenewald & Hawkes (2014), Chapter 6 (Draft), H2FC White Paper on Fuel Cells and Hydrogen in Low Carbon Heating (Provisional Title). A Report for the H2FC Hub, Imperial College London.

Based on measured thermal demand over 46 households for stirling engine, and then predicted for FC mCHP against this thermal demand. The FC always generates more electricity and therefore value, increasing as building efficiency increases.

• Therefore, FCs can continue to generate heat and electricity when there is little heat demand - a future proof option

Annual sales (Mwe) and of Fuel Cell Systems by application and region

Fuel cell industry review 2013, Fuel Cell Today

Costs of mCHP Fuel Cell Systems Data from Japanese ene-farm programme Capital cost of larger FC systems FCE 2.8 MWe MCFC 1,800 £/kWe Bloom 200 kWe SOFC 5,000 £/kWe Clear Edge 400 kWe PAFC 3,300 £/kWe 2013 £15k/unit >60,000 units sold

I Staffell, R Green, The cost of domestic fuel cell mCHP systems, July 2012

Thank you [email protected]