Solar Award 2013

The inventor of solar sharing Akira Nagashima received Solar Award 2013. He was one of three winners in the "Challenge" category.

The award ceremony was held on December 12, 2013, at the venue of Japan's major environmental products exhibition Eco-Products 2013.

The award committee recognized Nagashima's innovative idea of combining farming and solar power generation - a concept he named solar sharing.

Solar sharing is a new trend attracting attention of solar industry as well as farmers. Until recently, the options for placing solar panels were limited to either rooftops or the ground. Solar sharing opened up an entirely new possibility: installing solar panels over the farmland without imposing any limits on the agricultural production below.

Solar Award, established in 2012, selects outstanding ideas, projects and initiatives that contribute to the promotion of renewable energy in Japan. Widespread use of renewable energy can help achieve two goals:

1. increase Japan's energy self-sufficiency

2. breathe new life to Japan's declining countryside (through decentralized generation model)

Solar Award 2013 winners couldn't be more diverse. Here are some randomly picked laureates:

Dye sensitized solar cell ("Technology" category)

Solar cell that can accumulate electricity when exposed to light. The cell, which utilizes next generation technology, is a promising step toward solving the problem of solar energy storage.

The cell was developed by Prof. Hiroshi Segawa and his laboratory at the Research Center for Advanced Science and Technology, the University of Tokyo.

AeLL - an environmentally engaged "idol unit" ("Culture" category)

A group of four idol girls who, besides singing and dancing, also pick garbage on the Mt. Fuji, harvest potatoes and install solar panels in their new AeLL village in Minami-Alps City, Yamanashi prefecture.

... and many other interesting winners.

Tamaden: Can community solar power plants be successful for-profits?

Tamaden (多摩電力合同会社 =  Tama Energy LLC) is a company whose business model is framed around Japan's renewable energy feed-in-tariff system.

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It's simple:

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1. Tamaden "borrows" a roof from a facility in Tama region, Western Tokyo. The facility can be a school, a private company, a nursing home - any type of institution as long as they have a suitable roof and are interested in renewable energy.

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2. Tamaden issues bonds (たまでん債 = tamaden-sai) - financial products for those interested in investing in local renewable energy enterprise. (The bonds are issued through a trust company, in this case  トランスバリュー信託株式会社 = Trans value trust company.)

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3. As additional source of financing, Tamaden gets a loan from a locally based financial institution, in this case 多摩信用金庫 =Tama Credit Union.

4. Tamaden installs solar panels on the borrowed roof and connects them to public grid.

5. Tamaden earns revenue from selling solar power to the grid (hereby the use of nation's feed-in tariff system)

6. From that revenue, Tamaden pays rent to the roof owner, dividends to investors who bought the bonds, and pays back the loan.

That's it. In theory, everything works perfectly. In reality, it works moderately well. In its short year-and-a-half history, Tamaden has launched two solar powerplants: one on the roof of Keisen University (恵泉女学園大学, 30 kW) and the other at Yuimaru Hijirigaoka (ゆいま～る聖ヶ丘, 67 kW), both in Tama, Western Tokyo.

This model does work, but whether it works as a for-profit enterprise is another question. When I visited Tamaden's solar plant on the roof of Keisen University and heard Mr. Sadatsugu Ohki, Tamaden's vicepresident, explaining their journey, my impression was that Tamaden is a bit struggling. The single biggest headache seems to be financing - How to slice the pie?

The pie - revenue from solar power sales - is too small for so many eaters, and its size is pretty much fixed. Installed panels can only generate so much electricity.

Revenue from electricity sales (売電収入) is economically viable if an individual or a company can keep all or most of the profit from electricity sales. Then the income is substantial. (Whether this model is socially responsible or desirable is another question. →　Consider mega solar power plants that are wonderful moneymaking machines for corporate investors, but bring little or no benefit to local economy.)

But if revenue from electricity sales is to be divided between the company that installed the panels (salaries and company running costs), the financial institution (loan repayment), the roof owner (rent), the investors (dividends) and whoever else comes in between, inevitably someone will end up hungry. After a due share is paid to the roof owner, the investors and the bank, Tamaden is left with specks that can hardly cover employees' salaries.

There are also other issues, for instance finding the right roof. In a city full of buildings and roofs, finding the right roof is surprisingly difficult. Few roofs fulfill all requirements necessary for solar power generation. The roof must be big enough (installation area of more than 100m2), suitable for solar panels (the roof must be sunny and able to bear heavy load of several tons, the building can't be too high, etc). Roof owner should also have the prospect of staying in the same place for next two decades (few private companies can promise this).

Another issue is that the fixed price per kilowatt hour of electricity sold to the grid (売電単価) is getting lower every year - last year it was 42 yen/kWh, this year 38 yen and next year even less. This means that profit per kWh from future plants will be lower, but the costs of paying roof rent, dividends, loan, and salaries, will be the same. 

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However, these are universal problems that everyone trying to build community power plant has to consider. Here I want to focus on the question of slicing the pie, because this question specifically applies to Tamaden and to the question in the title - can a community power plant be a successful for-profit-enterprise?

My visit to Tamaden prompted me to believe that for-profit probably won't work. So is Tamaden doing it wrong and should it quit? No! Tamaden is trying to build sustainable community power plants and that's definitely a right thing to do. Renewable energy build by the people for the people is a new field where everyone is beginner, and trial-and-error is the only possible approach. Tamaden is doing us a favor by accumulating know-how from their own trials and errors, and so smoothing the way for those who come next.

From the outsider point of view, there are two different ways how to solve Tamaden's problem with financing:

1. Find another pie to slice - additional source of income.

Organizing on-site excursions, such as the one I participated, is a source of income, but obviously too small. At the moment, though, I can't think of any other realistic source of income.

2. Go non-profit.

If the initiative is socially desirable but not profitable, settle for a non-profit approach with volunteers instead of employees. The obvious challenge is how to sustain high motivation of volunteers who have other full-time jobs. Keeping volunteers' morale using solely the psychological reward of doing the right thing has its limits. But people in Tamaden must know the pros and cons of profit versus non-profit better than anyone else.

In fact the second option – going
non-profit - is what Tamaden is doing right now. As Mr. Ohki, who showed us around the
Keisen solar plant site, said:

“We have to constantly remind ourselves that
our goal is not moneymaking.”

Tamaden, a limited liability company, works closely with non-profit Tama Energy Association (多摩エネ協 = 一般社団法人　多摩循環型エネルギー協会). Indeed, Mr. Ohki's business card featured his position as a Tamaden vicepresident on one side, and as a member of the board of directors of Tama Energy Association on the other.

Other Tamaden employees also overlap with Tama Energy Association members.

So what is this article about if the problem is already solved? Well, I can't help feeling slightly betrayed - something is shown as a successful business model, but in fact it is a successful non-profit model.

Other than that, I'm keeping my fingers crossed for Tamaden in finding their next roof and spreading citizen-driven renewable energy projects in Tama and elsewhere.

Ganbare Tamaden!

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Martin: Living off the grid

My friend Martin is living off the grid. He covers all his electricity needs from a 100 watt solar panel. The panel generates, on average, 330 watt-hours of electricity a day.

For comparison, electricity consumption of my refrigerator is about 1000 Wh a day (calculated from the nameplate annual consumption 370 kWh. This was the first time I actually read the label).

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Martin does not have a fridge. Neither air conditioning nor television.

His electricity consumption can be roughly summed up as: using a laptop computer, using two LED lamps, using washing machine once a week, and an electric fan in summer.

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When Martin wants to charge his laptop, he doesn't plug it into electric outlets on the wall like the rest of us. Martin's electricity comes from a lead-acid battery, which stores electricity generated by the solar panel in the garden. The panel is outside just behind the window, attached to a bamboo stick and facing south.

 

That panel has been Martin's only source of electricity since he discontinued contract with Tokyo Electric Power Company a year and a half ago. He gets no electricity bills.

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In the first days of his solar power life, Martin was playing around and trying things out. For example how long could he use a microwave? Answer: not long. The battery was empty in 5 minutes. All electricity used up, he had to spend that evening in darkness.

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Needless to say, there is no microwave in Martin's place anymore. Just in case, he bought this emergency headlight↓on the picture for potential evening blackouts. But as Martin gradually got smarter in adjusting his energy usage to the available watt hours (more on sunny days and when the battery is fully charged, less on cloudy days), there's only very occasional need for the headlight.

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So is Martin an ascetic hermit or a radical hippie? Neither.

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Martin is a scientist by profession. He came to Japan from Germany as a doctoral student in 2010 to do research on photovoltaics. He completed his degree last year and is now working as a researcher in one of Tsukuba's institutes.

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I was at Martin's PhD thesis defense and I felt like Alice in Wonderland, lost in a parallel universe whose inhabitants were casually talking about "droplet epitaxy" and "coupling of quantum dots" in the pursuit of "developing strain free material systems for IBSC research." That's the wonderland behind future photovoltaic technology.

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Martin's private world is much more comprehensible to the laymen, and the room in Tsukuba he's renting, with tatami floor and the bamboo shelf and pumpkins at the front door, is very cozy place that people like to visit.

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Martin came to Japan in 2010. In March the following year, Great East Japan Earthquake accompanied with tsunami stroke the country, followed by Fukushima Daiichi nuclear reactors' meltdowns. This event literally changed the course of history in Japan.

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Tsukuba is 180 km south from Fukushima Daiichi plant. It's quite possible that if Martin came to Japan in different time, he wouldn't be living the life he is living now. Fukushima disaster impacted us more deeply than we're willing to admit.

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This was the first time that some people started to ask the question that is so rare in advanced economies:

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What is "enough"?

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How much is enough? We have the concept of too little. People who live on less than 1 dollar a day have too little and need more. But in modern economy whose ultimate goal is infinite growth, there's no concept of "too much" or "enough." (What is "enough"? is originally Fritz Schumacher's question in Small is Beautiful.)

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When we - not as a nation but as individuals - try to figure out what is enough for us, how much stuff we need to be happy, we usually look around to see what others have, and from that we refer to what we need. If most people around us have a house and a car and a new model of iPhone, we conclude that we need a house and a car and a new model of iPhone. I call this "dependent thinking."

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The opposite of dependent thinking is independent thinking. Martin doesn't need others to decide for him whether he needs a fridge or a TV set.

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As soon as basic needs are fulfilled, happiness is a question of attitude rather than the amount of stuff. That's what I learned from Martin.

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A Japanese article about Martin in local newspaper is here.

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Kondadai - forest in the city

(This article is not about solar sharing, but the topic is at least as important.)

Kondadai is a piece of forest about 4 km from Tsukuba station in the city of Tsukuba, Ibaraki prefecture.

Kondadai is one of few remaining patches of wild land in Tsukuba. Despite being surrounded by houses and fields, this small jungle has ecosystem rich enough to provide habitat to birds of prey. Hawks (ohtaka) and buzzards (sashiba) are both classified as "near threatened species" on the Red List of Japan's Ministry of Environment. Presence of endangered hawks has helped prevent development in the area so far, but future is uncertain.

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Besides rich natural environment, there are also cultural assets in Kondadai - ruins of Konda castle. They are very mysterious ruins though - buried under the grasses, you have to fully employ your imagination to spot them.

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Kondadai is now protected thanks to the efforts of Kayoko Takahashi and her Association for the protection of Kondadai ecosystem 金田台の生態系を守る会. On Sunday Nov. 10, 2013, I took part in a study walk through the forest, regularly organized by the Association.

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Kondadai is, in a way, a classic story of conflict between two forces: nature conservation versus urban development. In the story, developers are blamed for insensitive destruction of nature in the name of progress, and environmentalists are blamed for hindering development by uselessly trying to protect every tree and bird.

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But when I was walking through the Kondadai forest on Sunday, I was thinking of it as neither The Environmentalist nor The Developer. Instead, I tried to look at Kondadai through the lens of a local resident.

I naturally took the resident view because Kondadai reminded me of Brezina, a forest park in my hometown back in Slovakia.

This is Brezina in January 2013 - the last time I was there.

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I grew up in Trencin, a small town in western Slovakia, in a typical housing area of 7-store apartment buildings built in communist era. You could find similar neighbourhood all around the country, there was nothing special about the place. What made it unique for me was the forest park Brezina, 5 minutes on foot from our apartment.

I used to go to Brezina for a walk since kindergarden through elementary school to university. As a student, I would walk 45 minutes to the station through the forest instead of taking 20-minute bus. Today, whenever I go back to Slovakia, the first thing to do is to go for a walk to Brezina.

I can't imagine my hometown without Brezina. Beloved by the residents, it is one of the greatest assets of the town. It's value far exceeds the economic value of the trees or the land, or the housing that could be created in its place.

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I don't live in Tsukuba any more, but if I did, I would love to have a place like Kondadai close to my home.

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If Kondadai was gently turned into a forest park, without driving away hawks and owls and squirrels but available for people to rest and children to play, it would be of priceless value to people living around.

As the last oasis of trees and silence in central Tsukuba, it should be worth protection even without the near threatened hawks nesting there. Preserving Kondadai forest would would not only protec the flora and fauna, but would make central Tsukuba a more enjoyable place to live for humans.

 

Nishigoya Opening ceremony 2013/10/27

Nishigoya Solar Power Plant of Ken Matsuoka began operation on October 15, 2013. The opening ceremony was held soon after - on Sunday October 27.

It was the sunniest Sunday you could wish for an event at a solar power plant.

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Matsuoka started his address with self-introduction: "I'm Ken Matsuoka, chief of Nishigoya Solar Power Plant."

He laughed and the audience too. "Power plant chief" was an exact description of his role in the project, and yet the words somehow sounded too big. Not many people can introduce themselves as power plant chiefs. Not many people know someone who'd be a power plant chief. I was proud to be one of them.

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Among the guests there were family members and friends who volunteered their time to help build the plant, and also some VIPs - like the father of solar sharing Akira Nagashima and Japan's ex-prime minister Naoto Kan.

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Here at the ceremony I heard for the first time the story of how it all began a year and a half ago:

By a series of coincidences, Ken Matsuoka happened to visit the Naoto Kan's office as a technical support for an interview. During the interview, Mr. Kan showed them materials on his desk: "Look at these amazing renewable energy projects."

On the desk, Matsuoka saw a photo of solar sharing. "I just found what I want to do," he allegedly murmured.

Next day he contacted Akira Nagashima.

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About the plant:

Matsuoka's plant consists of 579 panels (100W/panel) installed on a metal frame at the height 3.5 meters over an area of about 1500 m2. The plant's capacity  - maximum output to sell to electric utility - is 49.9 kW.

A special feature of Matsuoka's plant is a winch allowing to change the tilt of all 579 panels (more than 8 tons) at once. The device, according to Matsuoka, didn't cost more than 1 % of the total investment, but it could increase the output by about 5 % - that is a significant number over 20 years.

We could see the effect of the winch at the ceremony.

First, Matsuoka and four selected guests turned on five inverters - this was a power plant version of ribbon-cutting ceremony:

At this point, the output rose from zero to over 30 kilowatts. As you can see on the picture, panels are in flat, horizontal position.

Next, panel tilt was adjusted to face the sun. A guest turning the winch:

On the next picture you can see that the panel angle has changed:

After the adjustment, the output reached 49 kilowatts - almost the maximum.

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Solar age

Akira Nagashima in his address talked about the future of solar power as cheap energy. "The price of solar panels is steadily falling. We're approaching the age of 100 yen per watt. " (100 JPY  = about 1 USD. Today typical retail price of solar panels in Japan is still about 500 yen/watt. )

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I believe Nagashima - who's been familiar with solar industry for over a decade - was right when he said: "Until now solar energy was considered to be safe but expensive. From now it will be safe and cheap."

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What next

For Matsuoka, opening the plant is not the goal but the beginning. Creating value from the soil under the panels is the core philosophy of solar sharing.

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Ken Matsuoka will certainly do his best to live up to this ideal.

The Inventor

On October 23, 2013, I met Akira Nagashima at his Solar Sharing Trial Site (ソーラーシェアリング実証試験場)　in Chiba prefecture.

Akira Nagashima, the inventor of solar sharing, is a celebrity in the community of solar sharing enthusiasts.

There are two plants on his trial site, both connected to public grid. Each has an output of about 4.5 kilowatts. There are many solar sharing projects in Japan, but this site is special because it's the first one. All others are imitations of this one.

Plant No. 1 (一号機) is installed above the garden. On the picture you can see peanuts, carrot, leek, taro and a row of unindentified leaves growing under the panels. Nagashima is standing on the side.

Plant No. 2 （2号機） is installed above a parking lot. Nagashima is standing below with a customized module that just arrived from manufacturer.

It still feels strange to call this kind of solar installation a power plant. For too long time we used to think of power plants as big unsightly buildings somewhere faraway.

Definition: Power plant is a complex of structures and equipment for generating electric energy from another source of energy.

Solar panels on the pictures above generate electricity from sun - they are legitimate power plants.

Monstrous appearance we expect from power plants is, luckily, optional. Solar sharing plants so far unticked this option - they're neither big nor ugly nor remote.

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Eureka moment

The idea of solar sharing first popped up in Nagashima's mind 10 years ago - in late 2003. Nagashima, now 70, was then studying law at Keio University in Tokyo (yes, at the age of 60). Nagashima got a biology textbook in his law course.

Why would one need a biology book in a law course?

Good question. I forgot to ask.

In that biology book, Nagashima came across the concept of light saturation point.

Light saturation point: Plants need sun to perform photosynthesis. We tend to believe that the more sunshine plants get the better, but this is not true for most plants. The reason is that most plants have a light saturation point - the amount of light intensity beyond which photosynthesis rate doesn't increase. All light beyond this saturation point is not only useless, but can even be stressful to the plant (for example causing overheating and water evaporation)

The concept of light saturation point led to Nagashima's eureka moment: If plants don't need all sunshine they're getting, why don't we use the excessive rays for power generation? Instead of laying solar moduls directly on the ground, we can put them a few meters higher and with spaces in between, so that plants below can still get their share of sun and keep growing.

The idea was out there and the time was ready for the next step: work out details and give it a real, tangible shape.

And a name.

Solar Sharing Trial Site was established in May 2010. Plant No. 1 started operation in August 2010 and plant No. 2 in April 2011. This was the only solar sharing project in Japan at that time.

Fukushima nuclear meltdowns occurred in March 2011. This event was an involuntary turning point in Japan' way of thinking about electricity. Suddenly everyone (okay, many people) were willing to turn off air-conditioning for a while and got interested in renewables. Japan's energy policy changed. The change involved introduction of renewable energy feed-in tariff system, making it mandatory for electric power companies to buy electricity from renewable sources for fixed (and quite high) prices.

Solar sharing, while not yet known among general public, went under the spotlight. Today there are tens of projects all over Japan, and visitors come for study tours to Nagashima's trial site every week.

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Low-tech

"You could hardly find anything more low-tech than this," Nagashima says. Except for solar panels, which are admittedly high-tech but available anywhere for increasingly reasonable prices, the supporting frame itself is simple and made of inexpensive materials found in any hardware store. A common assumption is that the metal construction stands on sturdy underground foundations so as to prevent blowing away in a typhoon or a storm. In fact,  foundations are minimal. Metal frame is light and flexible - a design that Nagashima describes as being "like a table - basically just standing on the ground." A strong typhoon can blow a house or a car away. There's no need to invest into expensive robust construction to withstand that kind of pressure. Quite the contrary, with flexible frame and by adjusting panel angle you can minimize the impact of the wind. So far there are no reports of panels being blown away.

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Rather than low-tech, I would call it intermediate technology - borrowing a term from Fritz Schumacher's Small is Beautiful. It is "technology which combines sophisticated ideas with cheap and readily available materials." (The Free Dictionary).

Intermediate technology is usually meant to be applied in developing countries, but I think it's just as relevant in "developed" nations like Japan. Reason: By not being too expensive, it's more democratic than the state-of-the-art super-capital-intensive technology that can only be built and operated by big companies. "Democratic" here means participatory. Tens of solar sharing projects now budding in Japan are all small scale projects launched by common people. With proper institutional backup, solar sharing promises participation of and additional income to hundreds of small farmers. (※１)

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We talked about many other interesting topics with Akira Nagashima and his colleagues on the trial site - from prices of renewables to necessary legal framework for solar sharing on farms - too much information to cover in a single article. I will save the rest for future articles.

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※１ For example offshore wind turbines like these near Fukushima http://www.nytimes.com/2013/10/25/business/international/to-expand-offshore-power-japan-builds-floating-windmills.html are being build by Japan's top companies including Hitachi and Mitsubishi Heavy Industries (with substantial government support). Local fishermen will not only have no profit from the wind farms, but will be left with disrupted fishing zones.

This approach simply copies the conventional mindset of nuclear and thermal power plants - that power generation should be concentrated in the hands of few companies because it's too complicated or dangerous to let us simple folks participate. But generating electricity is neither complicated nor dangerous, if you choose the right technology.

As Einstein said, "Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction."

Solar power (and biomass and geothermal energy, and even wind power) were created by a touch of genius. God save them from intelligent fools.

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How much electricity can solar sharing produce?

How much can solar sharing contribute to Japan’s energy self-sufficiency?

There are two basic indicators to describe the potential of an energy source:

1. Installed capacity

2. Estimated annual energy production

1. Installed capacity

Installed capacity (発電設備容量) is the maximum amount of

electricity that can be produced by a facility at a given time. It is measured
in watts （or kilowatts or megawatts...).

Example: If you install ten solar panels on your roof,

each panel with 100 watt nameplate capacity, then the installed capacity of
your roof-top solar plant will be 10 x 100 = 1000 watts, or 1kilowatt. Under perfect
conditions (full sunshine, the right angle), your panels can produce maximum of 1000 watts of
electricity.

If solar sharing was adopted on 15 % of

Japan’s farmland (4,549,000 ha in 2012) at a shading rate 25%, the total installed
capacity would be as much as 270 million kilowatts.

270 million kilowatts is a lot of electricity. It is
more than the peak demand in Japan in 2012 , which was about 156 million
kilowatts. Peak demand in today's Japan occurs on very hot summer days when
everyone turns on air-conditioning (Only In Hokkaido and Tohoku the peak demand occurs in winter due to heating).

As hot summer days are also sunny days when solar panels work at their maximum,  solar sharing could greatly contribute to energy supply in the summer peak demand.

Installed capacity, while an important indicator, can be a bit tricky though. No power plant generates electricity at maximum installed capacity all the time - either due to maintenance needs or lack of demand or - especially in case of renewables - because of the lack of “fuel”. The fuel for solar power is the sun. Solar panels on your roof produce nothing at night, and little
on cloudy days.

That's why we need the second indicator:

2. Estimated annual energy production

Annual energy production （年間可能発電電力量）shows
how much electricity over a given period of time the facility can actually
produce. The measurement unit is kilowatt hour.

Estimated annual energy production is calculated as:

installed capacity x capacity factor x 365 days x 24 hours

Capacity factor (設備利用率) is the ratio of the actual output over a period of time to the potential maximum output. If ten solar panels on your roof produced electricity only for six sunny hours on a day, their capacity factor for that day would be 25%  (6hours/24hours*100). (A bit simplified.)

Capacity factor differs for each type of energy. It is typically high and stable for nuclear and thermal plants – as much as 70 to 90 %, but
lower for renewables because they depend on the availability of sun or wind or water.

Actual capacity factor of solar panel installations in Japan in 2012 (average of 12 months from April 2012 to March 2013)
was 15%.

Taking into account this capacity factor, how  much energy could solar panels installed on 15% of Japan's farmland actually produce? The answer is: as much as 358 million megawatt hours of electricity yearly. This is about 40 % of Japan’s total electricity demand in 2012. Not so bad.

Who knows what Japan's energy infrastructure will look like in ten years. Solar sharing might be a vital part of it.

Project in Nishigoya, Tsukuba

Tsukuba is a city about 60 km northeast of Tokyo. One of the solar sharing pioneers Ken Matsuoka launched his project there in fall 2012.

He installed 579 solar panels on a metal frame over land area of about 1500m2.

The construction - from clearing the land and building metal frame to setting panels and cables, all based on Matsuoka's design and done DIY way - took him almost a year. Everything got ready in September 2013.

As of today October 14, 2013, the site is on a test
run. Actual selling of electricity to the grid is scheduled to start tomorrow – on October  15, 2013.

Matsuoka
will sell maximum of 49.9 kW to Tokyo Electric Power Company for the fixed
price of 42 JPY/kWh, guaranteed for 20 years.

Matsuoka also introduced manual tilting system to regulate the amount of light that can reach either the panels or the ground. He can now turn panels with a total weight of more than 8 tons using a single winch. Shading rate is 25.5 % (at panel tilt 0°). The purpose of tilting is not necessarily to maximize power generation output but quite the contrary, it can be used to provide more sunshine to crops when necessary, e.g. at critical growth stages like budding.

Matsuoka adjusting panel tilt:

Matsuoka is not a professional farmer but he does have experience growing his own food. He is now producing soybeans, tomatoes, eggplants and other crops for personal consumption under the panels. The site is registered as miscellaneous land - meaning Matsuoka has to pay higher taxes compared to agricultural land, but he has more freedom to choose how to use the land, what to grow and at what quantities. When we spoke last time, Matsuoka was envisioning a rice field on one part of the land, and a community garden on another. Both are great ideas because there are few on-site trials of growing rice under solar panels, and a community garden with many people coming and growing their vegetables just sounds good. Let's see what will eventually become reality.

The best thing about solar sharing is that building and running a power plant is not anymore something that only big power companies can do. Both technologically and financially, the hurdle is now low enough so that almost anyone can build their own small solar power plant and grow food below it. This will undoubtedly change our way of thinking about electricity.

Link to Ken Matsuoka's blog (Japanese):

http://gba03100.cocolog-nifty.com/tsukuba_ss/

History

Solar sharing was proposed in 2004 by Akira Nagashima, who turned his attention to the fact that most plants do not need all sunshine they receive in an open field. Plant photosynthesis depends on light – increased amount of light leads to higher photosynthesis rate – but only to a certain point. The amount of light beyond this saturation point not only doesn’t contribute to photosynthesis, but can even be harmful.

Based on this fact, Nagashima devised a system where solar panels use the excessive sunlight for energy generation while crops are cultivated below them. Nagashima applied for a patent in 2004 and made the technology freely available in 2005 (Patent publication No.
2005-277038).

Many trial projects have been launched since then, especially in the past two years. After the March 2011 East Japan earthquake and tsunami , followed by meltdowns at Fukushima Daiichi Nuclear Power Plant, Japan revised its energy policy and introduced feed-in tariff system to promote diffusion of renewable energy. Electric power companies now must buy
energy from renewable sources for fixed prices.

On March 31, 2013, Ministry of Agriculture, Forestry and Fisheries issued a guideline, acknowledging solar sharing system and setting rules for farmers who want to introduce it on land registered as agricultural. This was the first time that Japanese government recognized the already existing technology.

Why so revolutionary?

Why is solar sharing so revolutionary?

An oft-cited drawback of solar power generation is the requirement of a vast surface area. If solar panels are to produce the amount of electricity comparable with nuclear or thermal power
plants, the rooftops alone will not suffice. All over the world, low quality land as well as farmland has been used for large scale solar power development.

However, paving agricultural land with solar panels has drawn criticism for curtailing food production potential and destroying agro-ecological landscapes and biodiversity.

The prevalent mindset has been that on one piece of land we can have either agriculture or solar panels, but not both. Solar sharing, in which solar panels are installed above the field with crops,
overturns this mindset.

What is solar sharing?

The system is called “solar sharing” (ソーラーシェアリング) in Japan. Who knows what expression will eventually take root in English. We’re talking about a new way of producing clean energy without compromising food production.

How does it work?

Solar panels are installed on a frame about 3 meters above the ground, with wide spacing between panel rows. About three quarters of sunlight reach the ground and the remaining quarter reaches the panels. In this way, the same area is used simultaneously for both agriculture and power generation.

Picture: Solar sharing project of Ken Matsuoka in Tsukuba, Ibaraki prefecture, Japan.

This revolutionary idea is based on the fact that most plants don't need all sunshine they receive in an open field. Plants do need light for photosynthesis, but only to a certain point. Everything beyond this saturation point does not increase photosynthesis rate and can even be harmful (e.g. causing more evaporation and lack of moisture). Solar sharing takes advantage of this fact - panels use the excessive sunlight for power generation while crops are cultivated below them.

Solar sharing was invented by a Japanese Akira Nagashima in 2003 and today there are numerous trial projects all over Japan.

This blog aims to introduce these projects and everything related –from institutional background to on-site technological challenges.

Link to the inventor Akira Nagashima's project in Chiba prefecture　(website is in Japanese):

http://www.d3.dion.ne.jp/~higashi9/sola1.htm