Lecturer: Mr. Keiichiro Sakurai, Senior Researcher, Society and LCA Research Group, Safety Science Research Division, National Institute of Advanced Industrial Science and Technology (AIST)

Mr. Keiichiro Sakurai, Senior Researcher, Society and LCA Research Group, Safety Science Research Division, National Institute of Advanced Industrial Science and Technology (AIST), gave a lecture entitled “Using Solar Power Effectively: Trends, Issues and Future”.

After receiving his PhD from Kyoto University, Mr. Sakurai joined AIST (formerly Research Institute of Electrical and Electronics Engineers of Japan) and has been involved with solar cells for more than 20 years.
He has been involved in solar cells for more than 20 years since then. He is currently involved in supporting local governments to decarbonize their energy systems.

The following is a brief summary of the lecture.

-Recent Trends in Photovoltaic Power Generation

Half a century after the development of solar cells as we know them today, the price has dropped to 1/1000th of the cost of generating electricity.
More than half of the world is now in areas where it is cheaper to shut down thermal power plants and build new solar or wind power plants.
As for new power sources, more than 80% are now renewable (solar and wind as the main sources), and the situation has changed rapidly, especially in the last 10 years.

As solar power becomes more widespread, more than 30% of the world’s electricity would come from solar and wind power by 2030, which could exceed the amount generated by fossil fuels.
If all the world’s energy were to be supplied by renewable energy alone, it would be less expensive than it is today.

The estimate by Lawrence Berkeley National Laboratory in the U.S. shows that 90% of electricity in Japan could be zero-emission by 2035.

-Climate Change and International Competition

There are two reasons why the introduction of renewable energy should be hastened: economic reasons and the issue of global warming, which is clearly man-made with regard to global warming.
As a result, we are seeing an increase in extremely hot days and guerrilla downpours, which are expected to affect water resources and ecosystems, decrease food production, expand deserts, increase flood and drought damage, increase refugees, induce wars.

Sea level rise during this century could be on the order of meters, making it more economical to reduce greenhouse gas emissions even at the expense of money.
It has been estimated that an average temperature increase of 2.5 degrees Celsius would cost the global economy 0.2 to 2% of GDP. (AR5)

It is important that measures be taken over the next decade to address this current situation.
The fact that the risk of climate change is very high and the situation is dire is now leading to massive support for domestic related industries.

China, in particular, is investing heavily, as if it is waging an economic war of attrition against the backdrop of global warming.

In order to realize reduction of CO2 emission, it is necessary not only to simply convert electricity to zero-emissions, but also to electrify areas that have previously used fossil fuels to simultaneously proceed with electrification and zero-emission power , while keeping electricity emissions low.

-Principles and Environmental Performance of Solar Cells

Zero-emissions power is plentiful, and hydroelectric and geothermal power alone can exceed the world’s electricity consumption.
It is estimated to be many times that amount for wind power and dozens of times that amount for solar power.

The amount of solar energy that falls to the earth is equivalent to nearly 10,000 times the energy currently consumed by mankind!
The area needed to supply the world’s electricity with solar cells is only a small portion of the Sahara Desert, and since the sand of the Sahara is silicon oxide, solar cells can be made from it.

The amount of resources for photovoltaic power generation is unlimited for mankind.

The principle of solar cells is that the energy of light is extracted as electric power instead of being discarded as heat while using semiconductors in this process. When light hits normally motionless electrons, they start to move, and electricity is produced when the electrons collide and vibrate, which normally becomes heat. Before it becomes heat, the semiconductors are used to extract the power.

Although the installation emits some greenhouse gas, the entire lifecycle of the electricity supply is low emission.
Renewable energy is environmentally friendly because it can recover electricity equivalent to several times more than the energy consumed for manufacturing and has a low potential for heavy metal pollution.

Solar cells are mostly produced in China, where emissions reductions are also progressing, and in some areas emissions are already lower than in Japan.

-Diversifying the Use of Photovoltaic Power Generation

Japan is relatively a small country, but there is no need for deforestation when including abandoned fields or rice paddies no longer cultivated.
Even including constraints, Japan’s electricity demand can be met by renewable energy. On the other hand, fossil energy imports cost 30 trillion yen over the last year, and we need to reduce our economic dependence on them.

The price of solar modules is falling, and even if modules are imported, photovoltaic power generation is one of the cheapest energy sources.
Moreover, they can be recycled and expected to improve performances such as conversion efficiency.

In addition to successful examples of farm-based solar power generation, other applications include vertical installation of solar panels (double-sided) in pastures and areas with heavy snowfall, solar panels on water that can control water evaporation, solar panels integrated into building materials that can also be part of a building’s design, and solar panels mounted on vehicles.

To address the weakness of being dependent on weather conditions, weather forecasting and acceptance can be made more active, the power transmission and distribution network can be strengthened to compensate for regional differences in weather conditions, and storage batteries, which have become less expensive in recent years, can be used.

Electric vehicles can also be used for electricity supply and demand.

With battery prices steadily decreasing, design guidelines for housing may change in the future.
The introduction of EVs, solar power generation, and storage batteries will probably become essential to meet the needs of decarbonization while ensuring insulation, earthquake resistance, and durability.

-Recycling of solar modules

The transparent resin (adhesive) is extremely difficult to break down, but the PV Reborn Association’s technology is low-cost and can be removed without burning, so I think there will be a need for this in the future.
In my personal opinion, I think this is a world-class technology.

The spread of renewable energy is expensive and risky, but it can simultaneously contribute to the economy, energy, and environment.
Solar power generation has become the most important because of its cheapness and speed of diffusion.

We urge you to take advantage of this solar energy. Recycling is possible.