Dr. Johannes Merkel, Head of Decarbonized Energy Systems, Siemens Energy
The energy industry finds itself in a unique situation. While political objectives are often a matter of debate, when it comes to the energy sector, the world is united behind one single goal: decarbonization. Such consensus is rare and offers an enormous opportunity for our industry.
At the same time, it’s clear that reaching this goal requires hard work. No doubt, a lot of necessary technologies have been developed, and some of them have been implemented. Buta lot more needs to be done by all of us – suppliers, utilities, and those in politics, who are responsible for the regulatory framework. And we need to do it together!
Enabling renewables: highly efficient gas-fired power plants
Let’s take a closer look. At the center of global efforts to reach net zero are renewables, namely solar and wind. Their shares continuously need to be increased. By 2050, IEA World Energy Outlook foresees renewables reaching 40-70 percent of electricity generation, and even more in some countries. But renewables are only part of the story. Their supply fluctuates. Therefore, it’s necessary to supply balancing as well as dispatchable power while ensuring grid stability. Only then can the share of renewables continue to rise.
So far, in many countries coal-fired power plants have been supplying balancing power and grid stability. Yes, they are being phased out. At Siemens Energy, we still believe thermal power plants to be part of the solution – gas-fired power plants, which supply dispatchable power relatively quickly. Also, they could be transformed from (L) NG to hydrogen in the future. The share of gas-fired power plants is roughly a quarter of the global power generation, and the annually added capacity is thought to be stable at 40-60 GW in most market scenarios. For instance, a new 877-MW Combined Cycle Power Plant (CCPP) with gas turbines by Siemens Energy, which is to be built in Komotini in northeastern Greece, will reduce CO2 emissions by up to 3.7 million tons per year compared to a coal-fired power plant. Undoubtedly, the coal-to-gas-shift is an important building block for a decarbonized energy system.
As much as hybrid power plants signal the future, a full-fledged decarbonized economy needs to go beyond that
Energy system design
But a building block alone doesn’t make a building. At Siemens Energy, we foresee and support a wide array of different measures supporting a future net-zero economy. Obviously, there are more elements that will shape it. And that’s why each customer’s individual needs can be met with a tailored mix of technologies. Finding this optimal technology mix that accounts for both technological and economic boundary conditions is a challenge. Overcoming this challenge is the key to energy transition. We call it Energy System Design, and it involves all available levers for decarbonization, enabling future-proof solutions.
To give you an idea of the diversity, let me describe three major approaches we see towards decarbonization. I’ll include examples to show that we don’t just talk the talk, but also walk the walk.
Necessary steps for a coal-to-gas-shift
As I mentioned earlier, the first approach we see concerns, the coal-to-gas shift. But a new CCPP like Komotini is not the only option. Some existing coal-fired power plants can also be converted into CCPPs, thereby reducing emissions while reusing infrastructure.
However, natural gas is still a fossil fuel. So, we also need to find ways to lessen its impact. One possibility is carbon capture. More importantly, we need to prepare gas turbines for clean fuels, mainly hydrogen. For example, Siemens Energy recently announced that its SGT-800 gas turbine has 75 percent hydrogen co-firing capability with a clear roadmap towards 100 percent . Two of these turbines are going to be part of the Leipzig Süd district heating power plant in Eastern Germany. Together we’ll demonstrate zero carbon gas turbine operation at utility scale.
Clearly, we’re not the only ones pushing this vision. According to major OEMs, new gas turbines should be capable of firing 100 percent hydrogen as of 2030. And together, we face the same hurdles. For one, hydrogen production needs to increase while production cost must conversely decrease. Moreover, the infrastructure for distributing and storing hydrogen is still largely missing.
Yet, the state of today’s hydrogen technology can be compared to the early days of wind and solar. As with these renewables, major investments need to be made for hydrogen production. Which is why a project like the world’s first Power-to-X-to-Power demonstrator named ‘Hyflexpower’ is highly relevant. At a paper factory in Saillat-sur-Vienne in France, Hyflexpower will use a turbine capable of firing 100 percent hydrogen. Driven by a consortium including Siemens Energy, the German Aerospace Center (DLR), other companies and universities, its first firing is planned for 2023.
There are obviously other means for supporting the exit from coal. For example, using turbine or generators to stabilize the grid with their rotating mass. Though not producing power themselves, they supply grid stability, which in turn allows more renewables being added to the grid. Siemens Energy is currently involved in several projects pursuing grid stabilization, e.g., converting two former power units for this purpose at energy company Uniper’s Killing holme site in Lincolnshire, UK.
Hybridization of power plants
Looking ahead, we see several more technological building blocks that can be integrated into future net-zero energy, heat, and cold supply. And that’s why it’s often apt to talk about “hybrid power plants”. These could include a mix of wind and PV, energy storage, and back-up power as well as intelligent control systems.
Nearly all decarbonized hybrid power plants will be tailored solutions. Let’s look at one example. Currently, one of the world’s first commercial hybrid power plants will be built in French Guiana. It will combine PV, batteries, an electrolyzer and a fuel cell. Scheduled to be commissioned in 2023, it will supply 10,000 households day and night with electricity generated solely from solar power. This will be possible by combining a 55-megawatt photovoltaic field with 40 MWh batteries, a hydrogen electrolyzer, and the largest fuel cell of its kind for power applications.
Also, different energy storage solutions could be integrated in a hybrid power plant. Next to hydrogen for long-term energy storage, we have batteries for short-term, or mechanical mid-term electricity storage solutions. They all enable power supply when renewables can’t.
As much as hybrid power plants signal the future, a full-fledged decarbonized economy needs to go beyond that. This deep decarbonization relies on sector coupling. It works by transferring renewable power to all energy-consuming parts of the economy, such as buildings, mobility, or industry. This is possible, e.g., with electrolyzers producing green hydrogen. It can be stored and used as feedstock for chemical industries, as fuel sources for fuel cell electric vehicles, producing very high temperature heat for process industries, and re-electrification.
Another lever of sector coupling with more short-term perspective is power-to-heat. Currently, there are promising pilot projects in this direction.
For instance, together with its partner Vattenfall, Siemens Energy is currently installing a heat pump in the center of Berlin. This novel high temperature heat pump supplies heat to an existing district heating system based on pump feeds into the district heating network that uses waste heat from a cooling chiller plant and electricity from renewables. It’s an environmentally friendly, innovative way of linking heating, cooling, and electricity.
Decarbonization is possible – we just need to act now
The net-zero economy we’re striving for is indeed a challenge. But the good thing is, many technologies have already been implemented in different parts of the world and with different partners. They demonstrate how transitioning to net-zero energy production can work, and how customers’ individual interests can best be served.
As we forge ahead, it’s clear that we need more pilot projects like that in Berlin and invest more in designing future-proof energy systems. From a political standpoint, governments could create financial incentives and establish regulatory frameworks that could tremendously help in the process of turning pioneering concepts for our energy future into reality.
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