Guest Contribution "COMPRESSOR DAY 2020 goes virtual"
Gasunie Transport Services
To meet the 2050 emission targets set in the Paris Climate Agreement, the energy transition will require a complete overhaul of the current fossil fuel-dominated energy system. Although electricity produced from sun and wind is seen as the main source of energy by 2050, a major part of it has to be converted to molecules (such as hydrogen) to meet the demand of the chemical and fertilizer industries, and other forms of final consumption, all of which are difficult to electrify. The gas system also allows to accommodate green and CO2 neutral gases from biomass and imports.
TenneT and Gasunie, the electricity and gas transmission system operators (TSOs) in Germany and the Netherlands, have joined forces to answer questions regarding the future energy system. These questions address such matters as how both infrastructures interact, which energy will flow through which part of the infrastructure, and how to obtain a match between supply and demand, both in terms of space and time. In the joint study, reported in February 2019, Gasunie and Tennet focused on the system integration on a national scale, including coupling of gas and power networks and with a special role for hydrogen.
System integration in the Netherlands
Electricity supply based on wind and solar power is very volatile by nature. Although generation sometimes exceeds demand by an order of magnitude, there are also times when wind and solar power generation is very low (‘Dunkelflaute’), resulting in dramatic undersupply. The analysis we performed shows that coupling power and gas grids gives the energy system valuable flexibility, additional transport capacity and the possibility of seasonal storage. The existing gas transmission grid has enough capacity to fulfil its fundamentally changed role in the future energy system, although some technical adaptations are needed due to the different characteristics of hydrogen. Provided that proper guidance can be given to where power-to-gas (P2G) facilities will be located, coupling electricity and gas infrastructures may significantly alleviate the long-term expansion needs for electricity infrastructure.
Include power investment plans (Tennet)
Due to the increasing total electricity demand in combination with a growing RES supply, the electricity transmission infrastructure needs to be expanded already before 2030. In its current investment plan, TenneT has already secured the enforcement of several high voltage lines from landing points for offshore wind to inland markets. Also, a number of new lines will be built to industrial areas before 2030.
The network configuration of 2030 has been used as the starting point of the analysis. After 2030 the electricity network will have to be expanded further. The anticipated expansion need after 2030 is strongest in the scenarios with High Electrification (EL & RES and EL & RES+).
Include gas investment plans (Gasunie)
In all scenarios, a high share of the final energy demand is assumed to be covered by hydrogen as energy carrier. To enable this, an EU-wide hydrogen grid needs to be developed. This can be done efficiently by refitting of existing methane transmission infrastructure. At this moment, Gasunie foresees a hydrogen network consisting of converted methane pipelines that connects the five large industrial areas in the Netherlands with each other, with hydrogen storage in the Northeast of the country and with industrial areas in Belgium and Germany, e.g. the Ruhr area.
PtG will play a significant role in any scenario that will materialize. The hydrogen backbone of 2030 including its further expansions to 2050 seems perfectly situated to enable transport and cavern storage of large quantities of hydrogen: all Dutch methane pipelines are suitable for hydrogen transport and large numbers of pipelines will become available due to decreasing natural gas demand and supply in the Netherlands.
Both the existing electricity and gas infrastructure will play a crucial role for the energy system of the future
We have found that electricity and gas will play complementary roles in future energy systems, where wind and solar power are the major primary sources of energy for both Germany and the Netherlands. In the scenarios this renewable energy is mainly supplied to end users as electricity or as a green gas. The advantage of transporting electricity directly to those sectors where electrification is feasible is that it avoids energy conversion and the associated energy loss. Green gases, meanwhile, will provide an option for those sectors where electrification is harder to achieve.
Our analysis shows that coupling electricity and gas will give the energy system the flexibility it needs. The existing gas transmission grid has enough capacity to fulfil its fundamentally changed role in the future energy system, although some technical adaptations are needed due to the different characteristics of hydrogen. Provided that proper guidance can be given to P2G locations, coupling electricity and gas infrastructures may significantly alleviate the long-term expansion needs of the electricity transmission networks. However, considerable expansion of the electricity grid after 2030 will still be required due to the expected growth in demand from end users and the fundamentally changed energy supply structure based on renewable energy sources.
We can conclude that the energy system of the future will require a strong integrated gas and electricity backbone, including storage facilities to secure supply to all forms of final consumption at any moment in time.
Although additional electricity storage will be available by 2050, only gas storage provides a solution for seasonal storage
An energy system based on wind and solar power will require vast amounts of storage to cope with fluctuations in supply, ranging from ‘frequency restoration’ to ‘seasonal storage’. Significant installed capacities of electricity storage (e.g. batteries, pump storage) have been taken into account in various scenarios. However, the energy volume of such storage options is still limited. Existing underground gas storage facilities, on the other hand, can absorb large quantities of renewable energy for seasonal and long-term storage via P2G conversion. While depleted gas fields will be available, it is anticipated that hydrogen storage will mainly be in the form of salt caverns. It follows from the scenario calculations that several dozens of these will have to be built in the Netherlands and/or Germany to provide sufficient capacity and volume. Gas from storage provides the main source of energy to the entire system during ‘Dunkelflautes’. As such, gas and electricity storage are also complementary.
Location, capacity and operation of P2G installations are decisive factors and must be aligned with both electricity and gas TSOs
Coupling the electricity and gas transport infrastructure with P2G installations gives the overall energy system additional flexibility. However, under scenarios with a high penetration of wind and solar power, the use of P2G causes a massive increase in electrical peak load, as a result of which it can worsen the infrastructural bottlenecks if the capacities and locations of these P2G installations are not properly aligned with the grids.
Our analysis of results indicates that locating P2G installations near renewable production facilities can reduce the need for electricity grid expansion. This is especially the case when the overall P2G capacity is relatively high in comparison to renewables. It is not a given however that P2G installations always relieve grid constraints. Significant electricity and gas grid constraints may still arise if, from a grid perspective, the operation of these installations is suboptimal. Therefore, appropriate incentives for the operation of P2G units must be put in place to ensure efficient grid operation.
Socially acceptable solutions for an integrated energy infrastructure require a new level of public and political support
Increasing peak demand in the electricity grid, as is the case under all scenarios that were researched in this study, will result in an increased use or even overloading of transmission lines. According to the methodology chosen for this study, this can lead to a need for additional electrical grid expansions in addition to the long-term measures until 2030 that have already been confirmed, both technically and politically.
We have identified two crucial aspects for the realisation and success of the energy transition: political willingness to construct new electricity transmission lines to accommodate the predicted demand growth by end users and the creation of a clear supportive regulatory framework for the integration of P2G plants and hydrogen storage in the system in order to minimise the total number of grid expansions.