Suggestions to Achieve 2050 Net-Zero Emissions (as of 2021)

Ryoichi Komiyama, Chair
 Research Committee on Nuclear-Renewable Harmonized Energy Systems,
the Japan Society of Mechanical Engineers

The government of Japan in October, 2020 announced a policy to achieve net-zero emissions of greenhouse gases by 2050 (hereinafter “2050 net-zero emissions”), expressing that Japan will make great effort to realize energy efficiency, maximize the use of renewable energy, and promote advance nuclear energy technology prioritizing its safety in order to ensure stable energy supply. To achieve the sustainable net-zero emission target for the future, the government must maximize the use of carbon-free technologies such as renewables and nuclear energy in electricity sector, and promote energy-conservation and electrification in non-electricity sectors such as industry, service, household and transport sectors, thereby innovating our country’s energy systems. As the electrification becomes more common, the roles of electric energy systems will be even more important than ever in the economy and people’s lives. As academic experts, the research committee on nuclear-renewable harmonized energy systems has examined a desirable electric power supply structure to be realized by around 2050 and issues to be resolved on the basis of scientific views on the feasibility and business potential of the related technologies. The following sections show our suggestions on: 1) an energy system to achieve net-zero communities; 2) infrastructure and investment that support the system; and 3) a desired energy system pursued after 2050. We hope that these will be reflected in the sixth Basic Energy Plan currently being developed in spring 2021.

Suggestion 1—Establish renewable, resilient, and reliable energy system in addition to realize enhanced S+3E to achieve a net-zero carbon society.

A sustainable net-zero carbon society will be achieved by employing safe, economically efficient, and environmentally benign energy systems that ensure stable energy supply. The electric power sector must eliminate the use of fossil fuels—the major sources of greenhouse gases—that Japan relies on imports. Furthermore, the power sector must keep seeking the best possible combination of energy sources that can offer stable electricity supply at reasonable prices. No matter what types of energy, the power industry needs to pursue their enhanced safety, and improved efficiencies of electric power generation, the economic competitiveness, and environmental friendliness to achieve greater safety, energy security, economic efficiency, and environment (called S+3E in Japan). On top of that, renewable, resilient, and reliable energy sources (3R) are essential for energy system innovation based mainly on the use of renewables to achieve 2050 net-zero emissions. These “S,” “3E,” and “3R” correlate with each other, and the correlation should be taken into account as a new viewpoint in developing the energy system that can flexibly adapt to the innovation. The enhanced S+3E+3R in 2050 would be achieved by the best combination of flexible and unconventional technologies derived from innovative and ambitious ideas. While gaining the public’s understanding, the government of Japan should establish development policies and set goals for each power source. For that, the government should assess the technologies based on their development status, the degrees of deployment, the public communication, and their economic potential and security for energy, resources, and technology. If necessary, the government should correct their strategies reasonably and flexibly.

Suggestion 1-1          Maximize the use of renewable energy resources. Establish clean, stable power sources that complement renewables.

Maximize renewable energy resources. As of 2019, non-variable renewables such as hydro, geothermal, and biomass account for 10% of the total renewable energy generation, whereas variable renewable energies (VREs) such as solar and wind do 8%. Hopefully, further development of both renewables would allow them to meet the target ratio of fiscal 2030’s electricity generation, 22% to 24%. To achieve 2050 net-zero emissions, renewables should be implemented to the maximum, for which Japan should be aiming at 55% or higher for the ratio of renewables in total, equivalent to 605 TWh for an assumed aggregate electricity demand of 1,100 TWh. The non-variable renewables are expected to reach 15% by the year 2030, equivalent to 165 TWh for the assumed demand, which would be their upper limit due to Japan’s geographic conditions. Nevertheless, Japan should pursue to increase as much applications of non-variable renewables as possible to go beyond the limit. The fraction of VREs, on the other hand, are targeted at 40% or higher, equivalent to 440 TWh for the assumed demand, as the primary power source of the nation, considering their variabilities in a day—surplus electricity during the daytime and power shortage in the evening. While ensuring their economic rationality, Japan should maximize the use of VREs. Especially for offshore wind power generation to be used more in the future, the power industry must overcome challenges lying ahead, including their construction method (floating or fixed-foundation) and the development of technology tailored to installation sites.

Develop energy storage technology. Maximizing the use of VREs requires power grid stabilization and flexibility. Assuming that electricity demand in 2050 is about the same as that of today, dispatchable resources should be ready to provide power system with up to 90 GWh, which is estimated the maximum power shortage per day, to prevent blackout caused by power shortage in the morning and evening. As dispatchable resources, power industry needs to urgently develop carbon-free energy storage technologies, such as electric power storage including pumped-storage hydro and electric vehicles (EVs), and thermal storage and heat-to-electricity conversion, which also require reducing their costs.

Develop dispatchable, clean, and stable power sources. To maximize the use of renewables, it is necessary to maintain dispatchable stable power sources. The biggest challenge in thermal power plants, one of controllable energy sources, is to achieve zero carbon dioxide (CO₂) emissions. This would be hopefully solved by reducing emission thanks to improving their power generation efficiency, utilizing low-carbon fuels such as hydrogen and biomass, and achieving a strategy called CCUS, which stands for CO₂ capture, utilization, and storage. One of the innovative power generation technologies is a hydrogen thermal power technology, for which the government currently encourages the demonstration project by importing the hydrogen fuel which can be produced at a low cost in foreign country. Thermal power with CCUS can supply about 5% of electric power generation produced in Japan, if Japan can build multiple coastal sites that can store over one hundred million tons of CO₂ (Japan’s annual CO₂ emissions are about 30 million tons). To realize economical CO₂ storage and to secure as many sites as possible in this small country, the government’s continuous support is important in order to encourage the technology development by domestic companies as well as international cooperation. Given that the large-scale application of VREs could negatively affect the synchronization of electric power grids, a clean technology with thermal power plants should be established, because they provide inertia to stabilize the power grids. Another clean power source, nuclear power, should be utilized more as well, because it also provides inertia, dispatchable capability (load following operation), and multi-purpose heat generation (for heat storage, and production of hydrogen or carbon fuels, for instance). Therefore, the nuclear power plays the flexible role of complementary energy to VREs. This flexible nuclear power has been operated in some countries such as France, Germany, and Canada, attracting attention from international organizations. While seeking the best combination of these zero-emission stable energy sources together with renewable energies, Japan should continue developing the electricity and heat storage technologies, and should maintain the stable power sources of 35% or higher of the nation’s electricity, which is equivalent to 385 TWh for an assumed aggregate electricity demand of 1,100 TWh.

Develop distributed power sources and innovative technology. Japan should establish new distributed power sources and should positively pursue developing innovative and ambitious technologies. The distributed sources can generate electricity on or near electricity demand areas through their flexible installation and can utilize local available resources. This promising system contributes to not only local energy self-sufficiency but also promotion of renewables. One example is a smart community enabling integrated control of energy supply, where VREs are a main power source with a support of rechargeable batteries for the power supply to private EVs, public transport, and other common equipment in the community. This integrated control of energy demand and supply is expected to reduce a burden on grids and can play an important role for more resilient systems. Japan should pursue the utilization of innovative and ambitious technologies, beyond conventional technologies and ideas, such as a Vehicle-to-Home (V2H) concept for which an EV as a highly efficient way of using renewables can supply necessary power for home, and small modular nuclear power reactors replacing fossil power plants which is being considered in U.S. The government should promote the development of digital technologies and to introduce regulations/systems that make them available.

Reinforce power grids. The blackout caused by the 2018 Hokkaido Eastern Iburi earthquake showed that frequencies should maintain constant for stable electricity supply. Additionally, the policy to expand VREs as main power sources would increase the amount of power produced in Hokkaido, Tohoku, and Kyushu areas. To adapt it, inter-regional tie lines should be reinforced with higher capacity than ever as early as possible.

Increase in distributed power sources. Given that population ageing and rural depopulation would be realized in Japan, more distributed power sources and grids would play a significant role of strengthening power system resilience, in addition to supporting renewables to become mainstream of electricity supply. This would also contribute to reducing the overall system cost of electric power transmission, if this can lighten a burden on bulk power grids by deploying vast quantities of remote distributed grids, which can supply electricity with isolated power system without relying on bulk grids, or local micro grids, which can be isolated from bulk grids to continue power supply during a disaster. This could create a new electricity business form, called energy resource aggregation business (ERAB), such as virtual power plants (VPP) that aggregate and operate multiple distributed resources and peer to peer (P2P) trading where electricity is directly traded between distributed power generator and consumer.

Promote hydrogen use. Develop fuel cell technologies. Natural disasters are threats which might happen at any time in Japan. Together with the construction of net-zero society, Japan needs to develop disaster-proof energy technologies and systems. Availability of various energy sources in disasters are indispensable in terms of energy resilience. To address this, it is necessary to ensure storable, independent, sustainable, and zero-emission power sources that can replace oil and coal. Japan, therefore, should develop hydrogen production technologies using nuclear process heat and surplus electricity from renewables, establish cost-competitive supply chains for hydrogen production, and deploy hydrogen storage and transport technologies, and establish fuel cell technologies. The government should promote and expand the hydrogen use including infrastructure development.

Suggestion 1-3          Develop reliable energy systems.

Regain trust of nuclear power. Electric utilities have been restarting nuclear plants aiming at the ratio from 20% to 22% in annual total electricity generation in 2030. However, after the enforcement of new regulations in 2013, licensed units are only 16, which are less than half of the operable units in Japan. Even if all units including future applicable units were to be operated and extended their operation periods to 60 years, the nuclear power plants, one after another, will enter their decommission phase after 2040, thereby decreasing by about 10 GW by 2050. Given that it takes 20 years from site selection to operation, nuclear power plants need to maintain generating 53 GW to accomplish 30% of the total energy generation in 2050. This requires a prompt decision on replacement of decommissioned plants, corresponding to at least equivalent output to the decommissioned plants. The government should clearly state in the energy policy that Japan will continue using nuclear power. To regain trust of nuclear power, Japan should get a perspective to overcome four challenges: 1) improvement of safety and economic competitiveness for nuclear power plant technologies, 2) safe decommissioning of the Fukushima Daiichi Nuclear Power Plants, 3) selection of a final disposal site for radioactive waste, and 4) practical application of the nuclear fuel cycle that enables the use of spent fuels stored in Japan so far.

Highly efficient and decarbonized thermal power plants. Thermal power plants burning fossil fuels, such as coal, oil, and natural gases, emit large amounts of greenhouse gases. They, however, can contribute to decarbonization by using low-carbon fuels and achieving high efficiency and CCUS. The government needs to present to the public the clear role of the thermal power plants which offer dispatchable capability of flexible output generation and stable power supply.

Recognize challenges arising from renewables. Considering site limitations for renewable energy installation in Japan, it is necessary to drastically improve the efficiency of renewable electricity generation. Various issues about VREs are arising as a result of recent rapid penetration of renewables gaining momentum by a feed-in tariff (FIT) scheme. The examples are environmental damages; deforestation and natural disasters including landslides by heavy rains and others are due to the increase in solar photovoltaic panels, and noise pollution is caused by windmills. These devices would bring serious issues on their waste disposal around 2040 which would reach their end of life. Since the low energy density of renewables needs an enormous number of units for positioning renewables as main power sources in Japan, the government should develop appropriate systems for their waste disposal by renewables suppliers and a policy to recycle the materials as much as possible in addition to grasp the correct facts on the waste disposal. Moreover, the government needs to recognize and resolve various issues on their maintenance, environmental problems, and vulnerability in natural disasters. In Germany, mass installation of VRE systems has led to rise of electricity bills, increase in CO₂ emissions accompanied by the use of thermal plants to keep up with electricity demand, and power output suppression caused by insufficient power grid capacity. With all that in mind, the government should recognize these risks, expand renewables, and promote technology innovation.

Suggestion 2—Create an incentive system that motivates to invest in the development and maintenance of next-generation energy infrastructures and sustainable supply chains.

Since there is considerable uncertainty lying ahead in the pathway to energy transformation and decarbonization to be achieved by 2050, the government should seek ambitious multi-stream scenarios and address them with all their efforts. For energy innovation based on such uncertainty, Japan needs to develop infrastructures, such as next-generation power grids and distributed grid system. The energy innovation would create new industries and implement novel technologies introduced from abroad into various business areas. However, to ensure independent energy supply and to get benefit from them to domestic industries, Japan needs to develop them as domestic technologies with robust domestic supply chains. Moreover, it should promote the export of Japanese technologies, bolstering domestic industry competitiveness. Such infrastructure and supply chain developments require continuous investment. To motivate investors, the government needs to clarify their future prospects. Toward 2050 net-zero emissions, the government should offer incentives to induce such investments.

Suggestion 2-1          Develop early next-generation energy infrastructures.

Looking ahead to 2050, Japan should establish and start implementing next-generation energy infrastructure technologies around 2030, because it would need several decades as lead-time for the development of energy infrastructures such as decarbonized energy innovation, updating next-generation power grids, and distributed network systems. In particular, a rapid increase in EVs is expected in transport industry. To adapt this, the government should support to boost more EV charging stations as well as the installation of power generation facilities and charge controllers responding to the EV demand.

Suggestion 2-2          Develop and maintain sustainable supply chains.

Support developing carbon-free supply chains by domestic technologies. Structural materials priced competitively with abroad are needed for businesses such as solar and on-shore wind power generation, which domestic small-scale enterprises can easily start. The government, therefore, should positively fund research and development on cost reduction. By doing so, energy innovation is expected to adequately create a business cycle within Japan, in which these would be established as domestic technology and the profit would be given back to the country’s economy via domestic supply chains. Furthermore, the government needs to design a scheme so that business owners would be motivated to incorporate such innovative technologies for which excessive economic burden would be prevented.

Clarify the roles of stable energy sources. Support next-generation technologies. Of stable energy sources, thermal power generation is an important power source that can be dispatched on intermittent output of renewables which are expected to increase. Keeping that in mind, Japan needs to promote the development of CCUS and hydrogen combustion technology toward 2050. After the Great East Japan Earthquake in 2011, new construction of nuclear power plants is suspended, resulting in about 10-year blank of technological and infrastructural advancement. The U.S., which experienced about 30-year moratorium on nuclear plant construction, is struggling to recover labor productivity and supply chains in the nuclear industry as they enter a period of nuclear plant replacement. To prevent such situations in Japan, the government should define the roles of nuclear power, improve its safety and economic competitiveness, and rebuild the infrastructure. In a short or medium term, thermal and nuclear power generation would make a transition to next-generation technologies, which need initial investment including research and development to deploy such technologies to Japan. After defining the roles of nuclear and thermal power generation, the government should develop a financial support scheme for them.

Suggestion 2-3          Establish stable energy market.

To encourage business owners who begin novel technologies, there must be a stable market where they can trade under fair competition. For predictability of private investment decision, the government should clearly show its attitude and the policies, thoroughly assess electric power system reform to be transitioned soon, design a scheme that stabilizes the market, and create an investment environment to encourage industry in energy infrastructure development. To achieve this, the profitability of total electric power systems needs to be evaluated with adequate analysis on the costs of power transmission and distribution as well as power generation. If the predictability of competitive energy market is reduced and the uncertainty in return on investment is increased, investors will be demotivated for investing new power sources. As a result, energy economy relying solely on deregulated market might cause an unstable power supply situation. To avoid this, one of important issues is steady profit of dispatchable energy sources in the energy market of the future where VREs would play a major role.

Suggestion 3—Develop a comprehensive decarbonization strategy toward negative emissions after 2050 to drive technology innovation.

The report, Global Warming of 1.5℃, issued in 2018 by the Intergovernmental Panel on Climate Change (IPCC) claims that—on top of 2050 zero emissions—the world needs to balance emissions and further removal of CO₂ (so-called negative emissions). To realize carbon negative emission society after 2050, Japan needs to address preparatory activities for negative emissions before 2050.

Suggestion 3-1          Encourage electrification in non-electricity sectors. Develop energy society to mainly use zero-emission power sources.

For shifting to a carbon-negative society, effective approaches are decarbonization of end-use sectors together with electrification in addition to improved energy efficiency and zero-emissions power systems. The electrification is an important policy for net zero emission in 2050. The electrification is required to be increased even more from the level of only 26% in final energy consumption as of 2018. Although household sector may achieve 100% electrification by 2050, industry and transport sector will need drastic reform. This will involve not only enhanced electrification technology in manufacturing processes, improved efficiency of internal-combustion-engine vehicles, and CCUS but also discontinuous innovation. Furthermore, effects of digital transformation on the electrification needs to be assessed.

Suggestion 3-2          Promote innovative technology development to achieve negative emissions.

Japan needs to continuously promote technology development based on a very long-term strategy in order to achieve carbon-negative energy systems expected after 2050. There are a wide variety of technological options such as a process called bioenergy with carbon capture and storage (BECCS), and biochar.

Suggestion 3-3          Deploy early nuclear fuel cycle toward sustainable decarbonization.

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