Want to know how TenneT manages the national high-voltage grid? And how we rebuilt our legacy system for balancing demand and supply of electricity in a volatile energy market? In this talk, we will show how we were able to implement a modular event-driven microservices architecture in a traditional JEE7 infrastructure environment. We will discuss the trade-offs that we made, lessons learned in realizing the system, and how we will further evolve to our cloud platform. In addition, we will give an insight into our agile transformation journey, and how this was essential to the success of the project.

1. October 31, 2010
Caspar Derksen
DrivingtheEnergyTransition
While keeping the lights on

3. Balancing the electricity grid

4. TenneT at a glance
Total grid
length
23,000 km
Number of
end-users
41
million
Investments
2019-2029
35
billion EURO
Grid
availability
99.99%

5. TenneT grid

6. Connecting COBRA

7. COBRAin IT

8. Waterfall projects
Heavy-weight governance
Big design up-front
Big bang releases
Complex IT landscape
Siloed applications
Logic in database and ESB
Manual testing and releasingContinuous change
Domestic market regulation
European market integration
Energy transition
Where we started

9. Our challenge
Rebuild Market
Management System
And incorporate new developments
while keeping the lights on
New approach needed
Agile way of working
Collaboration business and IT
From projects to products

10. Journey 2017
Architecture
Roadmap
Teams CI/CD
Scrum transition & XP
Middleware
SOA/BPEL failure

11. Journey 2018
Platform LiveProcess Manager
Scrum expansion
COBRA cable
Environment issues

12. Journey 2019
Java DevOps
Team Kanban Hackathons
Agile scaling
COBRA Cable operational

13. Technology stack
Stateless
Active-active
Distributed TX
JEE cluster

14. Resilience patterns
Source: https://www.slideshare.net/ufried/patterns-of-resilience

15. CI/CD toolchain

16. SOAvs event-driven
Source: https://www.thoughtworks.com/de/insights/blog/scaling-microservices-event-stream
Event
Stream

17. Event-driven microservices
Module
REST
Micro
Frontends

18. Legacy
B2B
Grid
Control
Safety
Analysis
EL PM MD TPR
Strangling the monolith

19. Legacy
B2B
Grid
Control
Safety
Analysis
EL PM MD TPR SPS TCA XBA EPD DS
Strangling the monolith

20. Microservices
Scale-up teams
Incremental migration
Roadmap to cloud
Alignment between teams
More infrastructure
Automation is a must

21. Platform approach
Shared
libraries
Common
architecture
Generic
modules

22. Platform approach
Shorter time to market
Much smaller code base
One rule one place
Alignment between teams
Design for reuse is a must
Short term vs long term

23. How to process many document types?
DTO
Domain
Model
XML
JSON
Relational
JAX-RS
JAXB
JPAMapStruct

24. Operating the COBRAcable
Receive
Capacity
Receive
Market
Plan
Create
Schedule
Send to
Safety
Analysis
Send to
Grid
Control

25. Aggregates and Domain Events
Capacity Received Market Plan Received Schedule Created
CapacityC MarketPlanC
ScheduleAggregateC
ScheduleC

26. Process Manager
Determine Schedule
Receive Capacity
Receive Market Plan
Create Schedule
Send to Safety Analysis
Send to Grid Control

27. Process Manager
Determine Schedule
Receive Capacity
Receive Market Plan
Create Schedule
Send to Safety Analysis
Send to Grid Control

28. CompositeTransition sendSPSToEms = petriNetBuilder.compositeTransition(TransitionId.SEND_SPS_TO_EMS);
CompositeTransition sendSPSToTProg = petriNetBuilder.compositeTransition(TransitionId.SEND_SPS_TO_TPROG);
// Setup structure
petriNetBuilder.start(ProcessDefinitionConstants.PLACE_ID_START).mark().andSplit(initialize, receiveOPC, receiveCBS);
petriNetBuilder.andJoin(createSPS, receiveCBS, receiveOPC);
// Send SPS to EMS
petriNetBuilder.from(createSPS).sequence(createSPSForEms);
petriNetBuilder.from(createSPSForEms).transition(sendSPSToEms);
petriNetBuilder.from(sendSPSToEms).end();
// Send SPS to TProg
petriNetBuilder.from(createSPS).sequence(createSPSForTProg);
petriNetBuilder.from(createSPSForTProg).transition(sendSPSToTProg);
petriNetBuilder.from(sendSPSToTProg).end();
// Match input events
builder.eventTrigger(receiveOPC,
EventMatch.builder()
.addPropertyMatch(ProcessDefinitionConstants.FIELD_EVENT_TYPE, EventType.DOCUMENT_AVAILABLE)
.addPropertyMatch(ProcessDefinitionConstants.FIELD_DOCUMENT_TYPE, DocumentType.OPERATIONAL_CAPACITY)
.build());
Builder for Workflow Patterns

32. Test automation
@Validation
Feature: Validate Energy Program - Generic: gate reopening
Background:
Given the test data for EPD has been set
And it is today at 15:00 hours
@ClearReopenedGates
Scenario: Generic validations - Energy program should be sent within gate reopening
Given an Energy Program document
And the following mail header details
| receivingDateTime |
| now |
And the following Energy Program details
| businessDay | senderMarketParticipant |
| tomorrow | 0000000000017 |
And the gate is reopened
When the EPD document is received
Then the EPD document should be stored
And the EPD module has sent a GATE_REOPENED user event
And the EPD validation status should be OK

33. Code quality

34. Modern stack (TENTATIVE)

35. Lessons learned
Middleware
Pets
Portfolio
Align
Adapt
Connect
IT
Business
Management
Buy-in
DevOps
Teams

36. Challenges ahead
Balance
Portfolio
Migration
Technology
Data
Mesh
Vision
Maintain
Evolve
Private
Cloud

37. Open Source

38. Liability and copyright of TenneT
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presentation – including all texts, images and audio fragments – is protected by copyright laws. No part of
the content of the PowerPoint presentation may be copied, unless TenneT has expressly offered
possibilities to do so, and no changes whatsoever may be made to the content. TenneT endeavours to
ensure the provision of correct and up-to-date information, but makes no representations regarding
correctness, accuracy or completeness.
TenneT declines any and all liability for any (alleged) damage arising from this PowerPoint presentation
and for any consequences of activities undertaken on the strength of data or information contained
therein.
Disclaimer

39. www.tennet.eu
TenneT is a leading European electricity transmission system operator (TSO) with its main
activities in the Netherlands and Germany. With over 23,000 kilometres of high-voltage
connections we ensure a secure supply of electricity to 41 million end-users. TenneT is
one of Europe’s major investors in national and cross-border grid connections on land and
at sea, bringing together the Northwest European energy markets and accelerating the
energy transition. We make every effort to meet the needs of society by being
responsible, engaged and connected.
Taking power further