Dutch grids seek closer co-operation [NGW Magazine]
Dutch state-owned gas and power grid operators Gasunie and TenneT have carried out a study into future energy use and how to best meet that demand in a zero-carbon world.
All scenarios point to a dual gas and power system, similar to the one that is being pushed by the European Commission, as the best bet – although the study did not mention carbon capture and storage which leaves uncertainty over the longer-term role of gas.
The European transition towards a renewable energy system is entering a new phase as 2020 approaches, with plans by EU member states now required to specify how the 2030 Climate and Energy Framework targets should be met. This means producing plans on how to begin decarbonising heat networks as well as the remaining power networks. The EC has already indicated that it believes the dual-system approach is best and has been pushing countries to come up with joint industry plans.
Gasunie and TenneT, which are both active in Netherlands and Germany, undertook the scenario-based study Infrastructure Outlook 2050 as part of the Dutch draft Climate Agreement and in order to meet national obligations under the Paris Climate deal. The scenarios vary according to total power demand and the degree of international connectivity, but all point to similar conclusions: the best way to achieve a zero-carbon energy system is through a combined use of the gas and power networks.
Being state owned may explain why both companies are now fully behind this approach, but if each set of national gas and grid operators comes up with their own solution to the same problem, that might be less efficient than a Europe-wide grid that can make the best use qwa
of local weather conditions and energy storage assets.
One of the key messages of the study is that electricity, heat and gas will need to be increasingly integrated in order to absorb the large fluctuations in solar and wind power production. And there will need to be close collaboration between both sets of infrastructure to guarantee the reliability of such a future energy system.
“The study shows the requirements and limitations of a future energy system based on solar and wind energy. With these highly fluctuating sources of energy, we need strong gas and electricity infrastructures that are seamlessly co-ordinated,” said Gasunie CEO Han Fennema. “If our Outlook 2050 makes one thing clear, it is that linking TenneT's network to Gasunie's will provide the flexibility required by the energy system; it will also keep the system reliable and affordable."
The report concludes that as well as a strong gas and electricity backbone, the new energy system would require gas and power storage facilities, to secure supply to all forms of final consumption at any moment in time. This and the integration of electricity and gas grids will create new transport and storage opportunities for businesses.
Hydrogen is expected to take over from natural gas at some point as the main gas in the future energy system. Large quantities of hydrogen would be made from (surplus) solar and wind energy, also known as power-to-gas (P2G). The report emphasises the importance of P2G installations to be positioned close to sustainable electricity production facilities, thus avoiding the high costs associated with expanding the electricity network.
Although electricity storage will be widely available by 2050, the study finds that only gas storage is able to provide the vast amounts of stored energy required to meet seasonal swings in demand and supply in northern Europe, in a system based on solar and wind power. Gas storage would provide the main source of energy to the entire system during what the report calls ‘Dunkelflaute’: periods of little sun or wind and demand is high. These are typically most extreme between 1700 and 1900 on a January evening.
High latitude countries with established pipeline networks are best suited to the dual-system, large-scale gas storage approach. By coupling electricity and gas grids, renewable energy would be able to gain access to existing underground gas storage facilities in Germany and Netherlands, which could store the surplus renewable energy in gaseous form on a seasonal basis.
While there is already enough underground storage in the form of salt caverns or depleted oil and gas fields already to store the energy required in synthetic methane which is normally produced from hydrogen, or biogas, the same energy equivalent in the form of hydrogen would require far more space than is available, although compression or other technical solutions could be found.
What role for natural gas?
While the report is clear about the need for hydrogen, it does not mention carbon capture and storage (CCS), even in the context of production of hydrogen from methane, as is the case with the plan at HyNet in northwest England.
In fact, it sees little role for natural gas: “Electrification, where feasible, remains the best option, with sustainable gases such as green hydrogen elsewhere,” said the report. There is certainly no mention of large-scale CCS to store CO2 emissions from continued natural gas use in industry – unlike Norway – or power plants, although it is not ruled out either.
Shorter term, natural gas is still expected to be the main back-up option to renewables in the Netherlands, and efficient CCGTs run on natural gas with CCS could also still contribute alongside green gases to the zero-carbon system envisioned by Gasunie and TenneT.
Although elements within the future energy system are not yet economically viable, it is expected that costs will drop further, thanks to economies of scale and advances in technology. It also notes that the electricity grid in both Germany and the Netherlands will require considerable reinforcement owing to the growth of peak demand under all scenarios, as demand from transport (EVs) rises. This in itself is going to be expensive.
TenneT and Gasunie say there must be the political willingness to build the required electricity grid connections – something which has been difficult in Germany recently, where protestors have blocked the installation of lines bringing wind power to southern Germany. They are also pushing for new P2G facilities – something the EC also recently emphasised was required soon on a larger scale – and the regulatory framework to support their integration into the system.
For all German and Dutch scenarios, the research found that the total annual volume of gas that will need to be transported by 2050 – synthetic methane and hydrogen – will be either comparable to, or even higher than today’s volume of natural gas. The existing gas transmission grid is expected to have enough capacity to cope with flows in the future energy system, although some technical adaptations are needed to address the different characteristics of hydrogen.
Using Outlook 2050 as a basis, transmission system operators Gasunie and TenneT will now carry out an integrated infrastructure study for the period 2030-2050, to be available by 2021 when trends in gas and power use should be clearer.
Renewables and gas demand link
No matter how secure the gas supplies appear to be, things can go wrong. In March 2018, when Great Britain was being ravaged by the ‘Beast from the East’, transmission systems operator National Grid issued a gas deficit warning for the first time since the system was introduced in 2012.
The warning followed a series of gas supply outages, including South Hook LNG terminal, Norway’s Kollsnes gas processing plant and the Balgzand-Bacton Line between Britain and the Netherlands.
This resulted in reduced supplies from Norway and the Netherlands, leading within-day gas prices to reach a record high of 350 pence/therm (p/th), or about $46/mn Btu in today’s money. However, roll ahead nearly a year, and there is a marked difference in gas prices, with day-ahead prices falling to a 16-month low of 45.6p/th February 19, low for the depths of winter.
This year though it has been low wind that has driven gas demand, the analysts said February 26. “With higher levels of wind capacity, total gas demand for power falls and thus contributes to the lower gas prices. However, given that wind output is intermittent, gas-fired power stations are still required to act more flexibly.
“During the ‘Beast from the East’ gas demand went above the level expected from a 1 in 20-year cold spell demand forecast. Recently, we had exceeded the forecast on several occasions but not down to extreme weather. The two events this year – 23 and 31 January – both occurred when wind output was low.
“This goes to show that lower overall gas demand for power does not prevent demand spikes, particularly in a more renewable power system where gas provides flexible provision as mitigation against variability in renewable output,” the company said February 26.