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Hydropower: energy produced from moving water

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Answer 1: How can the power of water be captured?

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Answer 1: How can the power of water be captured?

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-Ocean thermal energy conversion: harness the energy of moving water from ocean waves and the tides to capturing energy released from variations in ocean temperatures

-hydroelectric dams: When a large river is dammed, a reservoir is formed behind the dam. The buildup of water in the reservoir creates an enormous amount of pressure; water diverted from the top of the dam flows through long pipes, called penstocks, to turbines below. As the water rushes past the curved blades of the turbines, they spin and generate electricity.

-run-of-the-river hydroelectric system

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Miho, Yuna, Sayana

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Renewable energy
-energy from sources that replenished over short time scales or that perpetually available
Sustainable energy
-energy from sources that are renewable and have a low environmental impact
Biomass energy
-energy from biological energy material such as plants and animal waste.

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Answer the question (likely the key concept).

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Answer the question (likely the key concept).

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Answer 1. What are the characteristics of a sustainable energy source?
The characteristics of a sustainable energy is to be renewable energy and have a low environmental impact.
Sustainable energy sources are those that are readily replenished and that have impacts that are acceptable;  it must be used at or below the rate of replenishment rate.
Answer 2.
What types are commonly used?
Hydroelectric are commonly used as renewable energy.
In U.S. , Hydroelectric is accounted for 41% of electricity production by renewable sources.

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Takaharu, Hiroshi, Yusuke

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Wind power
- energy contained in the motion of air across Earth's surface.
Wind power is considered as a one of the popular renewable energy.

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Turbines like windmills, are mounted on a tower to capture the most energy.

Pros;
effective at  large scale and a small scale.
abundant in some area.
pollution free.
low environmental impact and carbon footprint.
lowest-cost renewable energy sources.
creates jobs.

Cons;
wind is unpredictable and intermittent.
not all areas are windy enough to support it.
wildlife area killed by windmills.
considered an eyesore by some.
usually must be paired with other energy sources to meet needs.

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smart grid: A modernized network that provides electricity to users in a way that automotically optimizes the delivery of electricity.
Smart grid could improve efficiency and smooth out the flow of electricity.

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Power can be generated on the sea, so there is little direct impact on the human body.

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Ririka, Seika, Reine

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Miyu, Kokoro

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Solar power: energy harnessed from the Sun in the form of heat or light

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energy demand
Renewable energy
Electrycity

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Fossil fuels are the leading fuel

for electricity production. The use of renewables is rising, but so is the use of fossil fuels, due to a rise in energy demand.

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Solar energy is captured through heat and light of the sun. It can be used in two ways: active technologies and passive technologies.
Pros: Solar energy is the most popular form of renewable energy.
The methods and process of it are simple, safe, no noise, and clean.
Cons: It is intermittent and expensive to start. It causes long payback time, so it takes long time to save enough money in operation costs to pay for equipment.

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・True cost pricing... Factoring in the health and environmental costs of fossil fuel energy raises its costs above renewables, making them the most cost-effective choice
・Diversification...The use of a variety of renewable options will better meet energy needs as the strengths of one help offset the weaknesses of another
・Energy storage... Finding cost effective ways to store excess electricity can address the problem of intermittent production
・smart grid... The power grid needs to be updated and enhanced to better match electricity supply with demand and to handle fluctuating power supply of renewables

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All 47 prefectures in Japan, 80% have problems with solar power energy in one way or another.
For example, there were landslides in 2018 and 2020 on the solar panel-covered slopes in Okayama prefecture.

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Solar panels cover an area of 82 hectares in the western Japan city of Akaiwa, Okayama Prefecture, in this photo taken from a Mainichi Shimbun helicopter on June 1, 2021. (Mainichi/Kenji Konoha)

Solar energy, expected to replace nuclear power as a main source of electricity, has turned into a big headache across Japan, as solar power stations have proven to be eyesores and their impact on the environment destructive.

A Mainichi Shimbun survey found that of all 47 prefectures in Japan, 80% have problems with solar power energy in one way or another.

Known as the "sunny land" because of its many fair-weather days, the western Japan prefecture of Okayama is highly suited to solar power generation. Upon entering the city of Akaiwa -- renowned for its white peaches -- the profusion of solar panels makes the gentle slopes of the mountains look like they've been coated in black "sumi" ink.

Wholesale oil distribution giant Idemitsu Kosan Co. began operating a mega solar power plant in Akaiwa in April 2021. A total of 320,000 solar panels cover an area of 82 hectares, and pump out 65 million kilowatt-hours per year.

According to residents, there were landslides in 2018 and 2020 on the solar panel-covered slopes.

"My rice paddies were buried in sand and mud," a local 62-year-old farmer told the Mainichi Shimbun. "Things like this didn't used to happen." Another farmer said, "Sand and mud have come flowing down and muddied the waters, and I'm worried about how it'll affect rice cultivation." Boars, possibly having lost their natural habitats, have also come down from the mountains.

Idemitsu told the Mainichi, "In 2018 (at the time of the landslide), we were still in the midst of building regulating reservoirs and other disaster prevention facilities, but now we have carried out additional construction so that the solar power plant can withstand unexpected heavy downpours, and we also conduct patrols." As for secondary damage done to water quality and crops, Idemitsu said, "A third-party body surveys abnormalities in water quality as needed, but we cannot answer any questions about the causal relationship between the growth of rice and muddy water."

In a Mainichi poll of all 47 prefectural governments across the country, 37 said they "have problems" with solar power plants. When combined with the two that said they are "worried about future problems," over 80% of prefectures are concerned about problems with solar power. When asked what type of problems the prefectures faced (multiple answers permitted), 29 said mudslides, 28 said damage to landscapes and 23 said environmental destruction.

* * * * *

Japan's rush to expand solar power occurred against the backdrop of the collapse of nuclear power's safety myth, caused by the March 11, 2011 meltdowns at Tokyo Electric Power Company Holdings' Fukushima Daiichi Nuclear Power Station. But, contrary to its eco-friendly image, solar power has become a hotbed of public hazards that threaten forests near communities and residents' daily lives around the country.

But pulling back on solar power expansion is unrealistic. Implementing climate change measures is a task of utmost urgency that we all face across the globe. What is being sought is down-to-earth discussions on beefing up supervision of contractors who install solar panels, and regulations to prevent damage on the sites where solar panels are installed.

Debate on energy raises many points ranging from environmental problems to national security issues. There are vested interests for each source of energy, and the main policy debate players tend to be politicians, bureaucrats, and those in the business world, as well as some researchers. However, the composition of the energy we use directly affects everyone's lives and corporate activities. There is not one person that this debate does not touch.

Ten years have passed since the Fukushima nuclear crisis began. Let us all take a close look at society, economics, and politics, and re-think what forms of energy our country should choose, in the full knowledge that any decisions will impact us as well.

(Japanese original by Yuki Takahashi, Naoko Furuyashiki and Daisuke Oka, Business News Department)

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80% of Japan's 47 prefectures have problems with solar power plants - The Mainichi

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Solar energy, expected to replace nuclear power as a main source of electricity, has turned into a big headache across Japan, as solar power stations have proven to be eyesores and their impact on the environment destructive. A Mainichi Shimbun survey found that of all 47 prefectures in Japan, 80% have problems with solar power energy in one way or another.

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Oil, or natural gas. Fossil fuels are also the primary fuel for electricity production, accounting for 63% in 2016.However, renewables will increase by 40% by 2040 (compared to 2010). Therefore, we rely on society's assesment of the costs

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fujitu has reduced 10% of energy use by installing smart grid at 45 places after Tohoku earthquake.

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スマートグリッドとは、通信端末やネットワークなどのIT技術を組み込んだ次世代型の電力網のことです。

スマートグリッドのもっとも身近な例が、「スマートメーター」を活用した電力ネットワークです。スマートグリッドは、北米を中心にヨーロッパで導入が進んでいますが、日本でも関連技術が盛んに研究され、大手電力会社が導入をはじめています。

スマートグリッドのスマート（smart）は「賢い」、グリッド（grid）は「電力網」を意味します。「賢い電力網」とは、従来の電力網とどのような点で違うのでしょうか。

ポイントとなるのは、「需要に合わせた発送電」と「再生可能エネルギー」です。この記事では、「スマートグリッドとはなにか」という疑問に答えつつ、スマートグリッドの課題や実社会への貢献について解説します。

スマートグリッドとはIT技術を活用した次世代電力網

スマートグリッド（smart grid）とは、情報通信技術（ICT）を活用した次世代の電力ネットワークのことです。

その特徴から、「賢い電力網」と呼ばれることもあります。スマートグリッドの代表的な例として、「HEMS（Home Energy Management System）」や「スマートメーター」が挙げられます。

スマートグリッドという考え方は、大規模な停電に悩むアメリカで生まれました。アメリカ全土には、およそ30万キロメートル以上にわたる電力網が敷設されていますが、深刻な老朽化が進んでおり、地域の特性やピークタイムに応じた電力需要の変動に対応できませんでした。実際に2003年には、アメリカ東部のほぼ全域に渡って、大停電が発生しました。

また、その3年後の2006年には、カリフォルニア州の多くの地域で162分間におよぶ停電が発生しました。こうした状況を打開し、リアルタイムな電力需要の変化に応じて効率よく送電を行うため、IT技術を取り入れたスマートな電力網の導入がはじまりました。

スマートグリッドの特徴は、大きくわけて2点あります。スマートグリッドでは、電力を供給する発電所と、住宅や事業所といった電力消費地がネットワークで結ばれ、双方向でデータをやりとりします。これにより、供給サイドはリアルタイムで電力需要を把握できます。

また、スマートグリッドを通じて、電気の発電量や供給量を遠方から調整できるため、必要な電力を必要なだけ送信できます。電力ピーク需要に合わせ、柔軟な電力供給を行うことで、停電などのリスクを回避できるのがスマートグリッドの特徴です。

スマートグリッドが考案されたのは、大規模停電を防ぐためでした。しかし、近年では再生可能エネルギーの利用を促進するための手段としてもスマートグリッドが注目されています。太陽光発電、風力発電、バイオマス発電といった自然エネルギーは、発電量が不安定なため、既存の電力網に組み込むのが困難でした。

スマートグリッドであれば、電力需要に応じ、複数の電源から電力を融通できるため、再生可能エネルギーのデメリットをカバーできます。

スマートグリッドの仕組みと使われている2つの技術

スマートグリッドにより、計画的な発送電を行うために欠かせないのが、各家庭や事業者に配備された「スマートメーター」です。また、発電所から送られてくる電気だけでなく、太陽光発電や風力発電を活用し、クリーンエネルギーの地産地消が進められています。

その場合は、「HEMS」のような電力コントロールシステムのほか、パワーコンディショナーや蓄電池が必要です。スマートグリッドは従来の電力ネットワークと異なり、多くの情報通信技術が使われています。

スマートメーターは、都市部を中心に導入が進みつつある次世代電力量計です。

従来の電力量計と異なり、メーターにはマイクロコンピューターや通信機器が内蔵されています。スマートメーターは従来の電気メーターと同様に、各家庭や事業所での電力使用量を計測するほか、電力の消費量データを検知する機能や、電力量を遠隔制御する機能を持っています。

スマートメーターで各家庭や事業所の電力消費量のデータを集め、ネットワークを通じて電力会社の監視制御装置に送信することで、電力の消費予想を立てられるようになりました。

従来のグリッドは、供給サイドから各家庭や事業所などの需要サイドへ一方的に送電を行う中央集中型のシステムでした。アナログ式の誘導型電力量計では、月間消費量や積算消費量しかわからなかったため、一定量の送電しか行なえませんでした。スマートメーターの普及により、時間単位や地域ごとの電力需要のピークにあわせ、柔軟に発送電を行えるようになりました。

スマートグリッドにクリーンエネルギーを取り込む場合は、それぞれの発電設備の発電量をコントロールするHEMSが必要です。太陽光発電、風力発電、バイオマス発電、またはエネファームのような小型コージェネレーションシステムを導入する場合、電源が分散されます。

HEMSのような電力コントローラーが、住宅・事業所全体をネットワーク化することで、分散された電源と家電・住宅設備を効率的に結びつけられます。そのほか、自然エネルギーを取り入れたスマートグリッドを実現するには、自家発電による直流の電力を交流に変換するパワーコンディショナーや、発電量の不安定さを補うメガワット単位の蓄電池が必要です。

スマートグリッドが果たす3つの役割・メリット

スマートグリッドを導入すると、3つのメリットが得られます。スマートグリッドは各家庭や事業所での電力使用量を「見える化」するだけでなく、電力の需給バランスをきめ細かく調整できます。

また、自然エネルギーをスマートグリッドに組み込めば、電源を分散させて電力網をより安定させられます。ここでは、スマートグリッドが実社会に果たす役割について、具体例を交えながら解説します。

スマートメーターで電気の使用量を「見える化」できる

スマートグリッドを推進されれば、各家庭や事業所にスマートメーターが設置されます。

スマートメーターは、電力消費量をほぼリアルタイムで計測し、モニターを通じてわかりやすく表示できるため、電気の使用量を「見える化」できます。実際、現在導入されているタイプのスマートメーターは、30分ごとに電力使用量を計測することが可能です。

電力使用量をもとにして、家庭内や事業所内で電気製品がどのように使われているかがわかるため、電気の使い方を工夫できます。また、電力使用量のデータは供給サイドの電力会社にも送信されるため、リアルタイムに電力需要を把握し、必用な時に必用なだけ発送電を行えます。電気を作る側も利用する側も、賢く電気を扱えるのが、スマートグリッドの利点です。

スマートグリッドは、スマートメーターを通じて電力需要を把握し、必要なだけ電力供給することを可能にします。電力消費は1日の時間帯によって大きく変動します。とくに電力需要が大きい日中の時間帯に発送電を行い、需要が小さい夜間に発送電を押さえて蓄電することで、エネルギーを効率的に運用できます。このことを「ピークシフト」と呼びます。

大規模停電が起こりやすいアメリカと比べ、電力網が整った日本は停電が発生しづらい傾向にありますが、より安定した電力供給のためにはスマートグリッドが欠かせません。

また、ピークシフトを行うことには、送電途中の電力ロスを防ぐ効果もあります。従来の中央集中型のグリッドでは、発電所から家庭・事業所へ電気が届くまでの間、およそ5％強の電力が失われます。

電力需要に見合わない量の送電を行えば、使われない電気だけでなく、送電ロスで失われる電気も無駄になります。電気の無駄を減らし、エネルギーを効率的に利用できるのがスマートグリッドです。

スマートグリッドの導入が進めば、従来の「集合型電源」と「分散型電源」の融合が進み、電力網がより安定します。集合型電源の具体例は、火力発電所や原子力発電所です。分散型電源とは、各家庭や事業所に小型の発電設備を設け、電力の地産地消を行うことです。

次世代型の電力ネットワークが構築されれば、集合型電源と分散型電源で互いに電気を融通しあい、電力供給のリスクヘッジができます。実際、すでに一部の電力会社は売電制度を導入し、太陽光発電システムの電気を買い付け、双方向的なグリッドを構築しています。たとえば、発電所が災害や事故に遭った場合でも、分散型電源から電力を借りることで、被害を軽減できます。緊急事態に強い電力網を構築できるのが、スマートグリッドの強みです。

スマートグリッドの導入にあたって解決すべき2つの課題

スマートグリッドをメリットばかりではなく、2つの課題を抱えています。ここでは、スマートグリッドのコスト面の問題や、セキュリティ対策の必要性について解説します。スマートグリッドの導入にあたっては、メリットとデメリットの両面を検討し、課題解決にあたることが大切です。

スマートグリッドを実現するには、従来の電力網ではなく、情報通信技術と組み合わせた次世代型の電力網が必要です。そのため、設備投資が進んでいない地域では、多額の導入コストがかかる可能性があります。とくに電力網が老朽化しているアメリカの場合、供給サイドと需要サイトを結ぶ通信ネットワークの部分だけでも、10兆円規模の巨額な投資が必要という試算がなされています。

また、老朽化した送電線の補強には、アメリカ政府が設定した4,500億円を上回るコストが必要です。[1]日本には高度な電力網が存在し、アメリカよりもコストはかかりませんが、スマートグリッドは大きな投資となる可能性があります。

また、再生可能エネルギーをスマートグリッドに組み入れる場合、さらに大きなコストがかかります。経済産業省の試算によれば、再生可能エネルギーを大々的に導入し、電力供給の安定化のためにすべての家庭や事業所へ蓄電池を設置する場合、およそ50兆円の予算が必要です。

導入コストをすべて国や電力会社が負担するのか、一部を消費者が負担するのか、十分な議論が必要です。

もちろん、電力事業によって将来的なコスト回収が期待できます。また、電力供給が不安定になり、停電が起きた場合、1回あたりの損失は年間800億から1000億という試算があります。

発電所が災害や事故に遭うという安全保障上のコストも考慮すれば、再生可能エネルギーを導入し、スマートグリッドで電源を分散化することには大きなメリットがあります。

スマートグリッドでは、電力網にネットワークやコンピューターを活用します。そのため、電力供給システムがサイバー攻撃の標的となり、大きな被害を招くリスクがあります。実際にウクライナでは、マルウェアの一種である「インダストロイヤー（Industroyer）」が電力会社のコントロールセンターに入り込み、大規模な停電が発生しました。

この事件で使用されたのは、たった数十バイトのコマンドであり、いかにマルウェアが脅威となりうるかを示しています。こうした状況に対し、グルーバルな電力事業の経営者を対象としたアンケート調査では、サイバー攻撃への対策が万全であると応えた企業は、全体の48％にすぎません。

スマートグリッドの障害が長期化すればするほど、壊滅的な被害が生じます。サイバーセキュリティ機能を持つシステムを構築するとともに、サイバー攻撃が起きた場合に速やかな状況分析と対応を行う体制作りが必要です。

日本におけるスマートグリッドの導入事例3つ

欧米だけでなく、スマートグリッドは日本でも導入事例が増えてきています。ここでは、そのうちの3つの事例を取り上げ、日本でスマートグリッドがどのような現状にあるか解説します。

約2,900万台のスマートメーターの設置を目指す東京電力

東京電力は積極的にスマートメーターの設置に取り組んでおり、2014年4月から2017年2月末までの間で、すでに1,000万台を突破しています。2020年までには、東京電力の全サービスエリアで約2,700万台のスマートメーター設置を見込んでいます。

スマートメーターから収集したデータをMDMS（メーターデータマネジメントシステム）に接続し、さらに各小売電気事業者へとつなぐことで、首都圏を中心に広範囲なスマートグリッドを築いています。

NECはイタリア大手電力会社と連携し、スマートグリッドに欠かせないリチウムイオン蓄電システムを開発し、実証実験を行っています。太陽光発電や風力発電のような再生可能エネルギーを電力網に組み込む場合、高性能な蓄電システムは欠かせません。気象条件の影響を受けやすく、発電量が不均衡なため、電力需要に対して安定的に供給するためには蓄電が必要です。

蓄電システムを用いた分散型電源については、東北の被災地3県でも実証実験を行っています。2011年7月には、家庭用蓄電システムの商品化に成功しており、以後はクラウド環境を組み込んだリモート管理可能な蓄電システムの開発に取り組んでいます。

スマートグリッドで10％のエネルギー使用量を削減した富士通

富士通は福島県伊達市において、計45施設にクラウド型EMSサービスを提供しています。EMSサービスとは、さまざまな電源の電気使用量を統合的に監視し、電気の「見える化」ができるエネルギーマネジメントシステムのことです。クラウド型のサービスのため、遠隔地からの監視制御も可能です。

福島県伊達市は震災以降、空調設備を増強した影響により、電気代が高騰していました。電気の使用量を「見える化」し、運用改善を行った結果、伊達市の事業所全体では約10％のエネルギー使用量カットに成功しています。一部の施設では、例年比50％の省エネ効果が得られました。スマートグリッド通信インタフェースの導入により、無駄な電力消費の削減に成功した事例の1つです。

スマートグリッドで柔軟な電力供給と再生可能エネルギーの利用促進

今回は、スマートグリッドの特徴や仕組みについて解説しました。スマートグリッドは需給バランスに応じた電力供給を可能にします。再生可能エネルギーの利用促進にもなり、日本社会に大きな役割を果たしています。

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スマートグリッドとは？IT技術と自然エネルギーが結びついた次世代電力網

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スマートグリッドとは、通信端末やネットワークなどのIT技術を組み込んだ次世代型の電力網のことです。 スマートグリッドのもっとも身近な例が、「スマートメーター」を活用した電力ネットワークです。スマートグリッドは、北米を中心にヨーロッパで導入が進んでいますが、日本でも関連技術が盛んに研究され、大手電力会社が導入をはじめています。 ...

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Ian, Mao

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Shuri, Riko

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Answer the question (likely the key concept).

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Answer the question (likely the key concept).

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One way of capturing the power of water is using hydroelectric generators. The pros of this is that it is a renewable energy source. The cons are that it may impact the eco systems around the area if large scale construction is conducted (Ex: making a dam)

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Hydropower
-Energy produced from moving water.

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•Electricity generation capacity varies year to year based on rainfall amounts.

•Dams restrict water flow and can limit water supplies to downstream areas.

•In hot climates, huge amounts of water evaporate from reservoirs.

•Dams are responsible for the loss of major habitats and the displacement of tens of millions of people around the globe.

•Dams disrupt natural ecosystems and can prevent fish migrations.

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In Japan, sustainable energy occupies 14 % of all energy. A largest proportion of it is solar power (1.9%) followed by biomass(1.5%).

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Institute for Sustainable Energy Policies

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ISEP collected and summarized the data on renewable energy power in Japan. The preliminary report shows the share of electricity generated by renewable energy reaches 17.4%, the PV to 6.5%.

Summary

1. It is estimated that the share of total renewable energy generation (including self-consumption) in Japan in 2018 (calendar year) has increased to 17.4% from 16.4% in the previous year.

2. The share of solar PV power generation in Japan increased from 5.7% in the previous year to 6.5% in 2018, and the share of VRE (Variable Renewable Energy: Solar PV and wind power) increased to 7.2% from 6.3% in previous year.

3. Wind power (0.7%) and Biomass (2.2%) also tend to increase in power generation, but hydropower and geothermal power continue to remain the same amount of power generation.

4. In terms of the share of fossil fuel generated power, the percentage has decreased from 81% in the previous year to 78%, however, this level is still high, also the nuclear power generation has increased from 2.8% in the previous year to 4.7%.

5. The share of renewable energy to the annual power demand in 2018 (calendar year) is 16.5% in the whole country, and Hokuriku Electric Power and Tohoku Electric Power are as high as about 30% by area.

6. The share of VRE in the power supply and demand in 2018 is as high as about 12% for the area of Shikoku and Kyushu Electric Power, and Shikoku has a maximum of 1 hour in May 2018. With renewable energy exceeding 100% of demand, VRE output curtailment was implemented for the first time nationwide in October 2018 in Kyushu area.

7. In many European countries, there are already many countries where the annual power generation share of renewable energy exceeds 30%, and in other countries, the share of VRE also exceeds 20%.

8. Each European country has set a high medium- to long-term target for introducing renewable energy, and some countries aim to supply electricity with 100% renewable energy by 2030. Compared to these, Japan's target 24% is very low.

Share of renewable energy to total domestic power generation

Based on power survey statistics [1], FITs, and power supply and demand data for the whole country, we estimated the share of all power generation (including self-consumption) in Japan in 2018 by power supply. However, the previous year's figures are used to estimate the amount of home-use solar PV from October 2018. In addition, for wind power generation, the amount of power transmission by the FIT system is used (because it is considered that there are duplicates in the figures of the power survey data).
[1] Survey of Electric Power Statistics (Japanese Only)
As a result, the share of total renewable energy generation in Japan in 2018 (calendar year) increased to approximately 17.4% from 16.4% in the previous year as shown in Table 1, and Figure 1. The proportion of renewable energy, which was about 12% in 2014, reached more than 17% with an increase of about one point each year (Figure 2). Among them, the amount of solar PV power generation has increased from 5.7% in the previous year (2017) to 6.5%, which is very close to the target value that the 5 thBasic Energy Plan [2] by the government assumes in fiscal 2030. Together with the share of wind power 0.7%, the share of VRE has increased from 6.3% in the previous year (2017) to 7.2%.As for renewable energy sources other than solar PV, wind power and biomass power generation increased by about 10%, but hydropower and geothermal power remained the same percentage due to the relationship between the amount of water discharge and the amount of steam.

May has the highest percentage of renewable energy among the year, reaching about 25% (Figure 3). The share of hydropower is high at 12.5% because of the amount of water discharge, the percentage of solar PV is at 9.2%, and the share of Variable Renewable Energy (VRE) has reached about 10%.

Fossil Fuel power generation showed a declining trend, in comparison to the previous year, 2018 has decreased from 80.8% to 77.9%, and from the year 2014, the generation has decreased 10 points but it is still at a high level. On the other hand, nuclear power generation has reached 0% in 2014 but starting in 2015, the generation has been increasing every year, although the total amount of generation reached 4.7% in 2018, it is still has a lower generation level than the solar power generation (6.5%).
Table 1: Transition of the share of renewable energy to total power generation in Japan | Source: ISEP based on statistics of METI, etc. Figure 1: Power supply mix of Japan (2018) | Source: ISEP based on data of METI Figure 3. Monthly Share of Renewable Energy Power Generation in Japan (2018) | Source: ISEP based on data of METI Figure 2: Trend of the share of renewable energy to the total power generation in Japan | Source: ISEP based on data of METI [3] OCCTO power grid information service (Japanese only)
Share of renewable energy to domestic power demand

From fiscal 2016, based on laws and regulations, general transmission and distribution 1 hour data of electricity supply and demand for 10 power utility company area have been disclosed by each TSO(Transmission System Operator) [3]. The supply and demand data that has been announced by TSOs every three months has been released monthly from October 2018. In Europe, where the power market is in place, there are already many web sites where TSO publishes data in near real time and visualizes the data in an easy-to-understand manner. In October 2018, the power curtailment of solar PV and wind power was carried out for the first time in the area in Kyushu. Japan is also required to disclose power supply and demand data as soon as possible. ISEP's visualization site "ISEP Energy Chart" allows you to analyze data in an easy-to-understand manner on various graphs interactively from published data [4].

Based on this power supply and demand data, the share of renewable energy to the power demand in Japan can be calculated from FY2016. As a result of tabulating in 2018 (calendar year), the average value in 2018 is 16.5% as shown in Figure 4. The average monthly share of renewable energy to electricity demand in May 2018 is the highest at 24.4%, but the daily average reached 34.1% on May 5th 2018. Furthermore, as shown in Figure. 5, the same 1 hour value is the highest at 62.0% from 11:00 to 12:00 on May 5th and the solar PV reaches 44.6% (hydro power 14.9%, wind power 1.7%, biomass 0.5% , Geothermal 0.3%).

By area of ​​electric power utility (TSO company), 31.2% of the Hokuriku area was the highest share of renewable energy in the year of 2018, but hydro power is a large proportion with 27.8%. In the Tohoku area, the share of renewable energy was 29.4%. While the share of hydro power is high at 14.8% and solar PV is rising from 5.0% in previous year to 6.7%, the share of wind power is also relatively high at 3.0% in the Tohoku area.
[5] ISEP "Renewable energy has exceeded 100% of electricity consumption in Shikoku Area, Japan" Figure 4: Share of renewable energy and nuclear power supply and demand by power company area (2018) | Source: ISEP from data of each power utility company Figure. 5: Maximum value of renewable energy share of power supply and demand (1 hour value) by power utility company area (2018) | Source: ISEP from data of each power company
Furthermore, in the Hokkaido area, the share of wind power is the highest in Japan, reaching 3.2%, as opposed to 4.6% of solar PV, while hydro power accounts for a large proportion of 16.7% (total renewable energy is 25.1 %). Although the share of renewable energy is 15.2% below the national average on average in East Japan as a whole, the fact that the Tokyo Electric Power Company (TEPCO) area remains at 10.0% is a major factor. In this TEPCO area, solar PV is characterized by 5.3%, which exceeds 4.2% of hydropower.

In South and Middle Japan, the share of renewable energy in the Shikoku area is the highest, reaching 24.7%, and it is 9.7% of Solar PV to 13.1% of hydro power. In South and Middle Japan as a whole, the share of renewable energy reaches 17.5%, which is higher than 15.2% of East Japan, and the share of VRE is also higher than 7.5% of East Japan, which is 6.6%. In the Shikoku area, renewable energy exceeded 100% of the electricity demand at the hourly value on May 20 th (Sunday), 2018 [5].
[6] ISEP "Six proposals: Kyushu Electric Power should do before solar PV curtailment" (Japanese Only) Figure 6: Electricity supply and demand in the Kyushu Electric Power area (October 21, 2018) | Source: Data from Kyushu Electric Power
Kyushu Electric Power, which is the most advanced area in Japan for the penetration of solar power generation, saw the share of renewable energy to annual electric power demand increase to 19.9% ​​in 2018, and that of solar power has reached 11.1%. While the share of VRE is also the highest in Japan at 11.8%, four nuclear power reactors, about 4GW output, already re-started last year, which cannot basically adjust their output.

In Kyushu, the share of nuclear power to annual power demand has reached 25.5% in 2018. As a result, based on the current priority feeding rule, the power curtailment of solar power generation was carried out for the first time in Kyushu, Japan on October 13th, 2018 (Saturday).
Figure 7: Comparison of the share of renewable energy to the power generation of European countries and China with Japan (2018) | Source: Data from Agora Energiewende, China Energy Potal, Power Survey Statistics, etc.
On the other hand, in September 2018, ISEP proposed improvements to be made before curbing renewable energy output [6]. A total of eight time output curtailments were carried out during 2018, but on October 21 (Sunday), a maximum of 920 MW of power curtailment against solar PV was carried out, and the curtailment amount was one day by solar PV reached about 14% of the power generation as shown in Figure 6.
Figure 8: European countries and Japan's introduction of renewable power and its target | Source: Data of Eurostat, Agora Energiewende etc.
Comparison of the share of renewable energy with European countries

The share of renewable energy of power generation in 2018 was compared with European countries and China as shown in Figure 7. Many European countries have already supplied more than 30% of their annual energy production with renewable energy. The share of VRE is also over 20% in Germany, Spain, Portugal and the UK, with Denmark leading more than 50% while Japan still around 7%.

With regard to the policy targets for renewable energy, European countries have set high share targets for 2020, 2030 and 2050, and are promoting various energy policies in each country. In Europe, the national target of renewable power in NREAP (National Renewable Energy Action Plan) has already reached many countries in 2020 as shown in Figure 8. As for the target of renewable energy in 2030, it is announced in Europe that the renewable energy share will be 32% or more against the final energy consumption, but with regard to renewable energy power, Denmark and Spain have already set 100% target in 2030. It has set a high goal of 65%. compared to these countries, Japan's target of 24% in 2030 has reached 17%, and it can be said that it is a much lower target even considering that solar power has almost reached 7% of the target.

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Share of Renewable Energy Power in Japan, 2018 (Preliminary Report)

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ISEP collected and summarized the data on renewable energy power in Japan. The preliminary report shows the share of electricity generated by renewable energy reaches 17.4%, the PV to 6.5%. It is estimated that the share of total renewable energy generation (including self-consumption) in Japan in 2018 (calendar year) has increased to 17.4% from 16.4% in the previous year.

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Example of dam problem

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The latest talks to resolve the dispute between Ethiopia and Egypt over the future of a giant hydropower project on the Nile River are due to resume in Washington later.

Last year a deadline of 15 January was set to solve the long-standing impasse but the latest round of talks, last week, ended in deadlock.

When complete, the Grand Renaissance Dam, which Ethiopia is building, will be Africa's biggest hydroelectric power plant.

Its construction began in 2011 on the Blue Nile tributary in the northern Ethiopia highlands, from where 85% of the Nile's waters flow.

However, the mega dam has caused a row between Egypt and Ethiopia, with Sudan caught in between, which some fear could lead to war, and the US is now helping to mediate.

Why is it so contentious?

At the centre of the dispute are plans to fill up the mega dam as Egypt fears the project will allow Ethiopia to control the flow of Africa's longest river.

Hydroelectric power stations do not consume water, but the speed with which Ethiopia fills up the dam's reservoir will affect the flow downstream.

The longer it takes to fill the reservoir, which is going to be bigger than Greater London with a total capacity of 74 billion cubic metres, the less impact there will be on the level of the river.

Ethiopia wants to do it in six years.

"We have a plan to start filling on the next rainy season, and we will start generating power with two turbines on December 2020," Ethiopia's Water Minister Seleshi Bekele said in September last year.

But Egypt has proposed a longer period - so that the level of the river does not dramatically drop, especially in the initial phase of filling the reservoir.

Three-way talks between Egypt, Sudan and Ethiopia over operating the dam and filling its reservoir have made no progress in more four years - which the US has now been trying to mediate.

After the talks last week, Mr Seleshi accused Egypt of having no intention of reaching a deal.

"I don't think when the Egyptians came here, they came being ready to reach at an agreement," Mr Seleshi told the BBC's Kalkidan Yibeltal.

"And then there is a new filling timetable they prepared and brought. That new filling timetable required filling the dam to take from 12 to 21 years.

"This is not acceptable on any measurement," he said.

Egypt's Water Minister Mohamed Abdel Aty, however, was quoted saying that parties achieved clarity on all issues, including on the filling of the dam.

Join BBC reporter Alastair Leithead and his team, travelling in 2018 from the Blue Nile's source to the sea - through Ethiopia and Sudan into Egypt.

This 360° video is a version of the first VR documentary series from BBC News. To view the full films, click here.

Why is Egypt so upset?

Egypt relies on the Nile for 90% of its water. It has historically asserted that having a stable flow of the Nile waters is a matter of survival in a country where water is scarce.

A 1929 treaty (and a subsequent one in 1959) gave Egypt and Sudan rights to nearly all of the Nile waters. The colonial-era document also gave Egypt veto powers over any projects by upstream countries that would affect its share of the waters.

Neither agreement made any allowance for the water needs of the other riparian states that were not parties to the deal, including Ethiopia, whose Blue Nile contributes much of the river waters.

Ethiopia has said it should not be bound by the decades-old treaty and went ahead and started building its dam at the start of the Arab Spring in March 2011 without consulting Egypt.

Egyptian President Abdul Fattah al-Sisi was quoted as saying in September last year that it would never have got under way had Egypt not been distracted by the political turmoil.

One of the North African country's main concerns is that if the water flow drops it could affect Lake Nasser, the reservoir further downriver, behind Egypt's Aswan Dam, even though it only accounts for a small share of Egypt's electricity.

Ethiopia says one of the previous preconditions that Egypt had put for the agreement was that the dam should be connected to the Aswan dam.

Mr Seleshi told the BBC that he had explained to the Egyptians that it was "difficult to connect the two dams".

"After that they had backed down a bit on the issue but they have brought the idea back today to some extent," he said.

Egypt also fears that the dam could restrict its already scarce supply of the Nile waters, which is almost the only water source for its citizens.

It could also affect transport on the Nile in Egypt if the water level is too low and affect the livelihood of farmers who depend on the water for irrigation.

The $4bn (£3bn) dam is at the heart of Ethiopia's manufacturing and industrial dreams. When completed it is expected to be able to generate a massive 6,000 megawatts of electricity.

Ethiopia has an acute shortage of electricity, with 65% of its population not connected to the grid.

The energy generated will be enough to have its citizens connected and sell the surplus power to neighbouring countries.

Ethiopia also sees the dam as a matter of national sovereignty.

The dam project does not rely on external funding and relies on government bonds and private funds to pay for the project.

The country has been critical of what it considers foreign interference in the matter.

Does anyone else benefit?

Yes. Neighbouring countries including Sudan, South Sudan, Kenya, Djibouti and Eritrea are likely to benefit from the power generated by the dam.

Many of these countries have huge power deficits.

For Sudan there is the added advantage that the flow of the river would be regulated by the dam - meaning it would be the same all-year round.

Usually the country suffers from serious flooding in August and September.

There have been fears that the countries could be drawn into a conflict should the dispute not be resolved.

In 2013, there were reports of a secret recording showing Egyptian politicians proposing a range of hostile acts against Ethiopia over the building of the dam.

President Sisi has also been quoted as saying that Egypt would take all the necessary measures to protect their rights to the Nile waters.

The International Crisis Group warned last year that the countries "could be drawn into conflict" over the dam.

The fact that the US intervened shows the seriousness of the situation - and the need to break the deadlock.

Egypt sought the intervention of the US on the impasse, after President Sisi requested that President Trump mediate the conflict, which Ethiopia was initially reluctant to accept.

A conflict between the two states, which are both US allies, could draw global interest as it would put millions of civilians at risk.

It would threaten the vital international trade route through the Suez Canal and along the Horn of Africa, according to analysis by the Washington Institute.

So what happens now?

The next step will be for the water ministers, along with their countries' foreign ministers, to try and come to a deal before the deadline set last year of 15 January.

The timeline was set in November after a meeting between the parties and US Treasury Secretary Steven Mnunchin and World Bank President David Malpass.

So the parties representing the countries at the heart of the dispute are expected to convene again in Washington later.

"The first [option] is mediation, to see it with a mediator. Second is an issue of facilitation.

"These issues need an agreement of the three countries. Article 10 doesn't say it will be based on the desire from one country," Ethiopia's water minister told the BBC.

If they still can't agree by 15 January, the negotiators will request another mediator, or refer the matter to the heads of states, as agreed in November last year.

"What will be most appropriate for us is to present the report to our leader since there might be [progress] if they [the leaders] solve it," Mr Seleshi said.

On Sunday, Ethiopia's Prime Minister Abiy Ahmed asked South African President Cyril Ramaphosa to also help mediate in the dispute.

Mr Abiy said that, as incoming chair of the African Union, Mr Ramaphosa could help solve the problem peacefully.

Correction 22 January 2020: This article has been updated to reflect that the Aswan Dam only accounts for a small share of Egypt's electricity.

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Egypt-Ethiopia row: The trouble over a giant Nile dam

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The latest talks to resolve the dispute between Ethiopia and Egypt over the future of a giant hydropower project on the Nile River are due to resume in Washington later. Last year a deadline of 15 January was set to solve the long-standing impasse but the latest round of talks, last week, ended in deadlock.

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Meeting our energy needs with renewable sources become more likely when we pair renewables with energy conservation measures.

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Answer 2: What are the pros and cons of these methods?

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Answer 2: What are the pros and cons of these methods?

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look down

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First connection is using solar panels and using air conditioner at moderate temperature is related to conservation and energy efficiency.
If we use solar panels, we don`t have to use electricity and can save expense. Using air conditioner at moderate temperature means that we can also save electricity and cost. (reducing electricity)
Second connection is changing light to LED light. LED light can save energy compared to normal light. If we change almost all the lights to LED light, we can save a lot of energy.

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・No pollution
・Low environmental impact
・Low carbon footprint
・recreation and food control advantage of large dams
・Small run of the river system need no damming river
・much energy from the oceans

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・expensive to build
・damage for habitats and communities
・the amount of energy depend on rainfall
・It should be paired with other energy because it's not enough.
・Water loss and arid climate

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energy fluid needs to be pumped back into the underground reservoirs faster than it is depleted. Management is required to maintain sustainability

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Renewable energy source

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Conservation: the protection of the natural environment.
Energy: a source of power, such as fuel.