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RENEWABLE ENERGY WORLD MAY–JUNE 2011 47

POLICY & MARKETS: DANGEROUS ENERGY

t was a bit astounding. Somehow, despite the massive tsunami

that hit Japan’s Kamisu offshore wind farm 11 March 2011, its

seven turbines emerged intact. While the crushing wave wrecked

almost everything in its path, the turbines stood tall and continued

to generate power. Meanwhile, the world watched nervously as

workers struggled to prevent a catastrophic meltdown at Japan’s

Fukushima-Daiichi nuclear plant, site of explosions and radiation

leaks. Despite its redundant safety systems and sturdy cement and

steel layering, the nuclear plant’s systems ultimatley failed. Yet the

wind farm, exposed and buffeted by the earthquake’s full force and

the subsequent tsunami, survived.

To the layman the survival of the wind turbines seems near

miraculous, but engineers and developers say the Subaru-

manufactured structures simply did what they were built to do.

Part of it is basic physics. ‘If you think about it, when it comes to a

tsunami, it’s hard to get much better than a wind turbine for a source

of energy production that will survive the event,’ said Mark Rodgers,

communications director for Cape Wind, a 130 turbine project in

planning off the US’ New England coast. ‘Its smooth, cylindrical

steel tower allows the water to easily slide past and around it,

deecting most of the force of the oncoming surge of water – and if

it’s an offshore wind turbine so much the better because it is already

designed for salt water exposure.’

In addition, the turbines are manufactured to take some

signicant roughing up from the elements and movement of the

earth beneath them. ‘They are designed to withstand shaking of the

ground to some extent. They are resilient and they can bend and

sway and not topple,’ adds Saifur Rahman, a fellow at the US-based

Institute of Electrical and Electronics Engineers and a professor of

electrical engineering at Virginia Tech.

if you think about it, when it comes to a

tsumani, it is hard to get much better than a

wind turbine for a source of energy

production that will survive the event

Indeed, wind’s good showing was not conned to Kamisu,

located in the Ibaraki region of Japan. None of the nation’s wind

turbines, representing over 2300 MW of capacity, failed as a result of

the disaster, according to the Japan Wind Power Association.

‘It is just the nature of the technology that it is more adaptable,’

explains John Kourtoff, president and CEO Trillium Power Wind,

which is developing a 420 MW project on Lake Ontario. ‘A nuclear

facility is not used to having any forces on it. A nuclear facility is

supposed to sit there and not be disturbed,’ he added.

To renewable energy supporters the turbines’ survival speaks

of a larger and sometimes ignored benet of both wind and solar

power: they are safer because they use no explosve materials or

radioactive elements. ‘We don’t have natural gas. We don’t have

spent nuclear fuel. We don’t have oil. In most cases when there is a

natural disaster, it is the fuel that causes the problem,’ said Mike Hall,

CEO of California’s Borrego Solar.

All forms of generation carry some danger, or at the very least

unexpected inconvenience in a natural disaster. Hydroelectric dams

can ood in heavy downpours. Transformers may burst into ame

from lightening strikes. Coal can freeze when temperatures drop,

making it difcult to transport or burn. And natural gas may combust

under various conditions. In fact, during Japan’s 1995 Kobe

earthquake, it was eruptions from natural gas pipelines, not the

Disasters such as the collapse of the Deepwater Horizon

drilling platform expose the vulnerability of energy assets

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48 RENEWABLE ENERGY WORLD MAY–JUNE 2011

earthquake, that proved to be the most deadly outcome, according

to IEEE’s Rahman.

Japan is not alone in facing recent energy-related disasters. The

past year has been a particularly tough one for conventional fuels

in the United States, said Dan Shugar, CEO of Solaria, a California-

based solar photovoltaic module manufacturer. Every major form of

fossil fuel energy has caused some form of serious calamity. ‘We

had the Massey coal mine one year ago (an explosion that killed 29

workers in West Virginia). We had Deepwater Horizon in 2010 – that

was oil. In California we had a gas explosion,’ says Shugar, who lives

near the San Bruno, California neighbourhood where more than 50

houses were destroyed and six people were killed when gas from an

underground pipeline exploded in September.

TOPPLING WINDMILLS

That’s not to say wind and solar energy are mishap free. Those who

have heard turbines fall say it sounds like a deafening explosion

when the massive structures hit the ground. But renewable energy

supporters point out that a falling wind turbine, while loud, causes far

less harm or danger to humans than destruction of a conventional

power plant. For one thing, wind farms tend to be built on large

swaths of land or out to sea, far from human structures.

‘The tower will not go anywhere. If it falls it will fall on its side.

And typically the wind turbines are in large parks away from where

anybody lives. The blade is heavy so if it breaks loose, it will not go

very far. It will not damage a residential neighborhood,’ said Rahman.

Second, it is relatively rare for wind turbines to collapse. In

fact, when one snapped in 2009 at the 20 turbine Fenner Wind

Farm in upstate New York, owner Enel North America initially could

nd no similar event to study as it tried to uncover the cause. The

100 metre tall 1.5 MW GE machine, a decade old at the time, landed

in a eld far from any roads or residences, according to Enel. Still,

such accidents periodically make the news. For example, a rotor

and blades fell from one tower at a 150 turbine wind farm near

Rugby, North Dakota in March. Iberdrola reported to state ofcials

that the turbine, manufactured by Suzlon, suffered a rotor assembly

failure. In Scotland, last year a blade fell from a Siemen’s turbine

at the 322 MW Whitelee wind fam, another Ibedrola-owned facility.

For solar, a panel loosened in a severe wind storm might turn

into a projectile, but its danger, too, is limited and quick. It could

hurt a nearby car, structure or a person, but that is the end of the

Remarkably, the Kamisu wind farm on the coast of Japan

survived the massive earthquake and tsunami SKYSEEKER

POLICY & MARKETS: DANGEROUS ENERGY

SAFETY FEARS

SEE TOWN TAKE

OVER GRID OPS

Ursula Sladek was neither political nor concerned about

the environment. Trained as a school teacher, she knew

nothing about electricity 25 years ago except that it comes

from a socket. She had never heard of heady concepts

such as ‘electricity democratisation’ and her hands shook

uncontrollably if called upon to speak publicly.

But for the mother of ve energy safety became more

than abstract following the Chernobyl incident in the Ukraine.

She tried to convince the grid operator in her town, Schonau,

Germany, to stop supporting nuclear power.

When the grid operator failed to heed her call, Sladek

began an unprecedented campaign to put control of the grid

in the hands of the community of 1100 people. It took many

years, political referendums, massive fundraising and a lot

of learning, but today Schonau Power Supply not only runs

the town grid, but also supplies decentralised energy and

combined heat and power to more than 100,000 customers

throughout Germany, including large industrials. Sladek

manages the hybrid non-prot/prot cooperative.

‘Our shareholders want to make a change in the [power

industry’s] structure, from centralised to decentralised. They

want the power we use to change from nuclear to renewables

and cogneration, and they want normal citizens to take part in

that,’ said Sladek.

Sladek believes that the Fukushima incident is invigorating

community interest in power plant safety worldwide and

strengthening support for distributed generation. She sees it

happening in her own backyard: Since the tsunami in Japan,

her company has been adding 400 new customers per day.

Increased citizen involvement and understanding is more

important now than ever before, she said, as plans to build

transmission for wind power come under attack. ‘Develop the

plans together with the citizens and they will say yes to many

things,’ Sladek said.

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WHAT DID OUR MODULES AND

SYSTEMS LEARN FROM OUR CELLS?

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50 RENEWABLE ENERGY WORLD MAY–JUNE 2011

destruction. More than wind, snow has become a worry for the

solar industry, according to Hall. Installers have become increasingly

cognisant of the dangers of panel weight after many roofs collapsed

in Massachusetts following record-breaking snow fall over the last

winter. While most of these collapsed roofs did not have solar,

the panels inevitably do add weight to the roof structure, and so

could potentially increase the likelihood of collapse if they are not

engineered properly, he said.

‘The industry has gotten more sophisticated in its approach to

safety generally, which includes roof loading. Our team does more

sophisticated calculations than it did ve years ago to be sure a roof

can handle solar. You need to design not just for normal snow but

for crazy amounts of snow,’ Hall said. He added: ‘But these things

can all be engineered around. And it is a much easier engineering

problem than guring out what to do with spent nuclear fuel or

guring out what to do about natural gas lines’.

Moreover, costs are far smaller from a solar or wind failure than

they are when conventional energy meets disaster. For example,

some analysts estimate that decommissioning costs alone will run

US$10–12 billion at Fukushima. That is only the start; liability costs

and replacement fuel are expected to add billions more.

‘If you lose your [wind] turbine it is bad for your company and it

has nancial implications. But it is a relatively isolated impact. That is

different from what we see with Fukushima. It is orders of magnitude

greater than what happens if there is an errant wind turbine,’ said

Antony Froggatt, senior research fellow at Chatham House, a

London-based think tank.

HO’S RELIABLE NOW?

Given the dangers of combustible fuels, thermal plants need to

be quickly shut down in a natural disaster. Indeed, Japan disabled

some 10 GW of thermal capacity immediately after the disaster to

ensure safety, according to Nomura Equity Research, a subsidiary of

Asian-based Nomura Holding. These thermal shutdowns, combined

with the loss of 9.7 GW of nuclear units, left Japan with a shortage

of power, a problem expected to continue for some time.

Nomura says rolling blackouts are likely this summer, in particular,

as demand rises and northern Japan struggles to rebuild. While the

thermal units can be restored relatively quickly, most by the end of

the year, the nuclear units may never operate again, say Nomura

analysts. This loss will hit Japan hard because it is heavily reliant on

nuclear power, which represents about one-third of the country’s

electric needs. Now a large wedge of supply might be gone for good.

Fossil generators offer the quickest and most likely way to

replace the lost nuclear power in the short-term. Nomura expects

oil red-plants to make up 55% of the decit, gas 30% and coal

15%. But for the long-term Japan’s government says it will look to

renewables to serve as a pillar in energy planning. Renewable energy

supporters say this will make Japan’s energy supply more nimble,

with greater robustness and reliability when natural disasters occur.

Given that most solar panels or wind turbines function as small,

stand-alone units, if one fails it has little impact on the larger grid.

If a wind turbine falls, for example, other turbines at the wind farm

remain intact and capable of producing power. Rooftop solar PV

failure affects only the house or building it sits upon.

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RENEWABLE ENERGY WORLD MAY–JUNE 2011 51

When solar-equipped houses are swept away in a tsunami,

they do not cause intact houses to lose electricity. As distributed

generation, solar PV not only distributes benets, but also risk. ‘You

have built in redundancy with renewable energy which you don’t

have with large centralised facilities,’ said Kourtoff.

And both wind and solar lack the risk of long-term fuel interruption

from war or politics. ‘You are taking advantage of a resource that is

fairly bankable. Barring a natural disaster that the sun no longer

shines, a solar unit in almost any situation is still going to generate

the day after the earthquake, the day after the hurricane, the day

after the tornado,’ said Tim Keating, vice president of marketing at

CPV company Skyline Solar.

LL FUKUSHIMA CHANGE ENERGY?

The Fukushima accident again raises

questions about nuclear safety, particularly

at older plants. More than 34% of installed

nuclear capacity was built before 1980,

according to HSBC Global Research.

Fukushima itself is 40 years old.

But age does not necessarily mean

greater danger, according to Tim Tonyan,

vice president and group manager at

structural engineers CTL group. ‘Many of

those structures can perform far beyond

40 years. But they do need to be evaluated

and assessed. In many cases repairs can be

done to maintain the facility at its full service

capability,’ he said.

Tonyan added, ‘Overall, the power industry

has had quite a remarkable record in terms of

safety and performance. The tragedy in Japan

was something admittedly not anticipated by

the codes that were in place at the time. This

is the way you improve on codes. You take a

look at what happened. Now we can develop

improved codes and standards that will make

these plants even safer’.

Safety is, of course, only one element in

energy planning. The portfolio mix selected

for any grid or region depends on many other

factors, including reliability, cost, environmental

impact and access to fuels. Still, HSBC says

it sees the nuclear renaissance slowing as a

result of Fukushima, and the power industry

continuing its preference for natural gas,

renewables and energy efciency.

‘It is too early to judge the geo-political/

energy policy impact of a potential nuclear

disaster in Japan, particularly at a time

when the Middle Eastern crisis is refocusing

governments’ attention on energy security.

But it is not unreasonable to expect the focus

to switch towards safe, proven, secure and

low-carbon forms of energy generation –

renewables and gas – as well as measures to

reduce demand through building regulations

and transport efciency standards,’ said HSBC in a recent Climate

Investment Update.

For now the Fukushima repair and clean up continues, the wind

mills keep spinning and the world waits to see what’s next for energy.

Elisa Wood is US correspondent for Renewable Energy World

e-mail:rew@pennwell.com

This article is available on-line. To comment on it or forward it to

a colleague, visit: www.RenewableEnergyWorld.com

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July 12–14, 2011

North America’s Premier Exhibition

and Conference for the Solar Industry

Moscone Center, San Francisco

800 Exhibitors

1,600 Conference Attendees

22,000+ Visitors

Co-located with

www.intersolar.us

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SOLAR

HYBRIDS:

Capable of harnessing more solar energy than the sum of their

constituent parts, hybrid photovoltaic-thermal (PV/T) technologies

have been surprisingly slow to catch on. But for those companies

developing systems for market, the rewards are potentially huge,

as Chris Webb discovers.

THE DAWNING OF PV/T

A hybrid solar receiver

COGENRA SOLAR

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RENEWABLE ENERGY WORLD MAY–JUNE 2011 53

ast November saw the ofcial inauguration of a novel 272 kW solar

cogeneration project in California. At a ceremony attended by

former British Prime Minister Tony Blair at the Sonoma Wine Company,

the plant was hailed the rst commercial-scale installation of its kind,

combining proven photovoltaic and solar thermal technologies.

The work of Cogenra Solar, a provider of distributed solar

cogeneration systems and renewable energy service solutions, the

project now supplies renewable heat and electricity to the winery from

a single solar array, which Cogenra CEO Gilad Almogy describes as

‘an important move towards more affordable and efcient utilisation

of solar energy’.

‘This is a very signicant milestone for Cogenra as we bring

our rst project on-line in California’s wine country and toast to a

bright future with solar cogeneration. [The] technology merges

the best photovoltaic and solar thermal technologies to meet two

valuable industrial needs: low-cost heat and electricity. Our solution

produces ve times more energy and three times the greenhouse

gas reductions over traditional solar offerings,’ he said.

They are impressive claims. So, why is the technology relatively

undeveloped, compared to PV solar and PV thermal on their own?

And, moreover, why is Cogenra among only a handful of companies

worldwide to have focused on this potentially highly lucrative

business of reaping solar’s thermal and electric potential in a single,

composite component?

It is an area of solar development that Almogy believes is set

to grow exponentially. ‘The market is so large, and the technology

so new that there is little by way of competition,’ he told REW. ‘We

just have to reach out to customers. We have to get people thinking

not just about renewable electricity, but holistically about renewable

energy, encompassing both electricity and heat.’ The economic and

environmental benets speak for themselves, he says.

Ordinary PV systems convert only 15%–20% of the sun’s energy

into electricity. Conventional solar hot water (SHW) systems miss an

opportunity to generate electricity, which often has four times the

value of replacement natural gas (typically the cheapest fuel used to

heat water).

The thermodynamic advantages of exploiting PV and SHW

together in solar cogeneration are similar to those of exploiting

combined heat and power (CHP) in a conventional gas-red

cogeneration plant. CHP is more efcient than grid electricity

because the heat of a CHP plant is utilised rather than wasted.

However, such energy is not renewable power. CHP emits a wide

range of air pollutants, which subject the owner to increasingly strict

regulatory burdens and possible nes. Pollutants can include nitric

oxides, volatile organic compounds (VOCs), carbon monoxide, etc.

Further, CHP operating costs are vulnerable to increasing natural

gas prices. On the other hand, solar cogeneration surpasses CHP

because it generates renewable energy, hedges volatile gas prices,

and emits no pollutants. In addition, solar cogen can deliver up

to ve times more renewable energy and nearly twice the overall

economic value of a PV system of equivalent size.

Yet it was not until the mid-1990s that work began on developing

prototypes for PV/thermal combination systems. An entire decade

later in January 2005 the International Energy Agency (IEA) initiated

Task 35 – ‘PV/Thermal Solar Systems’ – as part of its Solar Heating

and Cooling (SHC) Programme.

The objectives of this three-year research programme were

principally to help develop and market commercially competitive PV/

thermal solar systems. Efforts soon divided into two camps, with

most research in Europe focused on combining PV with liquid-lled

collectors, while developers elsewhere combined PV with an air

-charged collector medium.

Toronto-based Conserval Engineering is in this second category,

developing a PV/T system based on its SolarWall air heating

technology. The company’s early efforts resulted in two of the world’s

most notable and widely publicised systems. First came the Beijing

Olympic Village, using a PV/T system sized for 10 kW of electricity

and 20 kW of thermal heating energy. A second system at the John

Molson School of Business at Concordia University in Montreal

featured a larger, 100 kW system, producing 24.5 kW of electricity

and more than 75 kW of thermal heating.

At the heart of PV/T technology is the principle that solar

radiation raises the temperature of PV modules, reducing their

electrical efciency. Typical PV modules lose about 0.5% of output

for every 1°C the temperature rises. The beauty of combining PV

and solar thermal is that cooling the PV modules raises efciency. By

proper circulation of a uid with a low inlet temperature, heat can be

extracted from the PV modules, maintaining the electrical efciency

at a satisfactory value. The extracted heat energy can be utilised in

several ways, increasing the total energy output of the system.

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Hybrid PV/T systems are consequently suitable for those

applications subjected to high solar radiation and high ambient

temperature. A few companies have further developed the idea into

hybrid solar collectors that combine PV cells with a solar thermal

collector in a single device.

A complete system typically incorporates components such

as hot water storage tanks, heat exchangers, piping, controllers,

inverters, wiring and heat pumps. Together, they help PV/T modules

to generate more energy per unit surface area than comparable side-

by-side PV panels and solar thermal collectors, and at potentially

lower production and installation costs. Crucially, in the case of

buildings, PV/T modules share the aesthetic advantage of PV

panels. High efciency per unit surface area makes PV/T particularly

well-suited for applications with both heat and power demand and

buildings where available roof space is limited.

Advocates of solar hybrid technology claim that PV efciency

has been tested at as high as 28% while simultaneously producing a

constant supply of water at 60–70°C. A PV/T hybrid panel stabilised

at an average of 45°C will produce roughly 20% more (electrical)

output over a 12-month period than a standalone PV system with

the same peak output.

Solar cogeneration’s claimed capability to potentially capture and

convert up to 80% of the sun’s incident energy into either electricity

or hot water within a single module also makes this integration of

PV and solar hot water technology by far the most cost effective

solar energy solution available for commercial and industrial-scale

customers. Solar thermal and solar photovoltaic technologies can

furthermore also be accommodated in space that would ordinarily

be insufcient for both.

In this way, solar cogeneration can extract almost twice the

energy value per unit area as a conventional solar collection

infrastructure. As a comparable initial investment yields twice the

nancial return and can qualify for generous PV and SHW incentives,

solar cogeneration can thus provide immediate savings to customers

over utility rates, says Cogenra.

Similarly, goes the argument, solar cogen’s environmental

benets are correspondingly greater. It represents the most efcient

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SONOMA STUDY

The Sonoma Wine Company is the California North Coast’s

largest contract services winery, processing more than 7500

tonnes of grapes, bottling 4 million cases and storing and

servicing 65,000 barrels of wine each year. The company is

noted as an EPA climate leader since 2005 for its greenhouse

gas reductions and sustainable practices.

In addition to its electricity consumption, Sonoma Wine

Company uses large amounts of natural gas to heat water for

its wine processing, sanitation and barrel services operations.

The company sought an on-site renewable energy solution with

high environmental benets that best addressed the facility’s

energy mix without requiring a large capital investment.

Cogenra engineered a system and nanced 100% of

a hybrid PV/T installation using its Heat & Power Purchase

Agreement (HPPA), under which the developer owns and

operates the solar cogeneration modules while Sonoma

purchases the thermal energy and electricity generated at

guaranteed rates for the duration of the contract.

After an extensive evaluation, the project called for 15

Cogenra ‘SunBase’ modules, supplying a total of 272 kW

in electric and thermal output. In less than two months from

breaking ground, the solar cogeneration system was complete

and delivering energy to support the facility’s winery operations.

The solar cogeneration system will displace about 64 MWh

and 12,500 therms of natural gas annually.

The solar thermal element is used to heat water to 74°C to

fuel the facility’s tank wash and automatic wine barrel washing

system. More than 800 barrels undergo three wash cycles per

three-person shift, with the water from the last cycle recycled

to wash the following barrel. With low energy prices for the

lifetime of the 15-year contract, the HPPA serves as a hedge

against future rate hikes. As utility rates continue to increase,

the Sonoma Wine Company expects to reap more savings.

54 RENEWABLE ENERGY WORLD MAY–JUNE 2011

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solar power technology, offering by far the fastest payback and

cleanest environmental prole available to commercial and industrial

customers (see the box panel on the Sonoma Wine case study).

Most air-based systems installed to date have been one-off

building projects. Water-based modular systems feature in many

more commercial applications. These are typically based on a

commercial solar thermal collector where the absorber is modied to

integrate solar cells.

The key to the technology’s success lies in optimising the overall

performance of the PV/T collector. As noted previously, where

mono- or poly-crystalline silicon solar cells are employed, electrical

performance is sacriced as the temperature increases, which means

the best performance will be obtained by optimising the system

to operate at as low a temperature as possible. Yet in the case of

domestic hot water, where the optimum temperature is about 50°C,

a higher temperature is required in the absorber. A compromise must

be found in designing PV/T collectors where the collector temperature

meets all the demands of both thermal and electrical load.

Get the design just right, says Cogenra, and for sites that

consume both electricity and hot water, solar cogeneration will

always offer a signicantly higher return on investment (ROI) and

faster payback than any other individual solar technology — PV or

SHW – because it delivers signicantly more energy and the highest

possible value mix of energy types for the same investment.

What’s more, this fundamental advantage is insensitive to the

specic assumptions in the nancial model, so long as they are

applied uniformly across technologies. Put simply, says Cogenra, in

many scenarios where a traditional PV installation yields a payback

of 10–20 years, solar cogeneration can achieve an ROI in 4–7 years.

Additionally, by generating more energy from the same infrastructure,

solar cogeneration averts more greenhouse gas (GHG) emissions

than PV or SHW in isolation.

PV/T technology can also benet from a wide range of incentive

schemes currently available to developers and owners of renewables

projects. In the US states of California and Arizona, for example,

solar cogeneration qualies for generous PV and SHW incentives,

peaking last year through a combination of dual state incentives,

federal tax incentives (available through 2010 as cash grants), and

the two-for-one advantage in delivered energy value. An investment

in solar cogeneration could pay for itself in full in less than half the

time of PV or SHW alone, its advocates claim.

For a good proportion of its lifetime after ROI, a solar cogeneration

system can effectively provide free electricity and hot water, insulating

the owner from rising electricity and gas tariffs. Return on investment

may be even greater when the extra nancial value implicit in this

hedge is considered: both carbon legislation and a rise in demand

over supply are highly likely over the next three decades. Third-party

ownership options such as Heat and Power Purchase Agreements

(HPPAs) also offer alternative means for end customers to gain energy

savings without upfront expense or ongoing maintenance burdens.

Elsewhere, in the UK for example, PV/T panels may be

Microgeneration Certication Scheme (MCS) approved. Newform

Energy, which distributes the technology in the UK, says its hybrid

panels qualify for the government’s feed-in tariff (FiT) and renewable

heat incentive (RHI) schemes.

Newform offers the ANAF H-NRG panel, with a peak electrical

capacity of 230 W and thermal capacity of 700–800 W, depending

on conguration. Alternatively, the Volther PowerTherm panel can

produce 175 W of electricity and 680 W of thermal energy. The

Volther PowerVolt is designed with a higher electrical output at

A PV/T installation

COGENRA SOLAR

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ADDRESSING THE HOT BUTTON ISSUES

Conference & Exhibition

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Co-located with:

Renewable Energy World Europe Conference and Exhibition oers unrivalled

networking opportunities connecting the utility-scale renewables and general

power industry. The busy exhibition oor populated by major players in

the renewable sector, is accompanied by a high-level conference featuring

strategic and technical presentations by leading experts in the renewable

energy eld.

To download the conference programme and to register online visit

www.renewableenergyworld-europe.com today!

Please visit

www.renewableenergyworld-europe.com

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sponsorship at Renewable Energy World

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Supporting Organisation:

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Renewable Energy World - magazine - 5/6-2011

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