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  • From: "Lawrence F. London, Jr." <lflj@intrex.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Solar Power to the Masses
  • Date: Wed, 06 Aug 2008 07:55:36 -0400

-------- Original Message --------
Subject: [SANET-MG] Solar Power to the Masses
Date: Sun, 3 Aug 2008 16:31:01 -0400
From: jcummins <jcummins@UWO.CA>
To: SANET-MG@LISTS.IFAS.UFL.EDU

ISIS Press Release 31/07/08
Solar Power to the Masses
Solar cells getting better and cheaper fast as oil prices soar, soon
it will cost as much to get electricity from the sun as from the grid,
and distributed small scale generation is the way ahead Dr. Mae-Wan Ho

A fully referenced version of this article is posted on ISIS members’
website. http://www.i-sis.org.uk/solarPowerToTheMasses.php

An electronic version of this report with full references, can be
downloaded for a donation of £3.50. Download Now

Solar tops the world’s new renewable energies
As oil prices soar, solar power has been undergoing a boom, along with
other renewable energies, which attracted more than US$100 billion
investment last year in new power and heating capacity, manufacturing
plants, research and development [1]. Investment in solar power
capacity and manufacture amounted to US$31.3 billion, while US$33. 4
billion was invested in wind.

Global capacity in photovoltaic (PV) power reached 10.6 GW in 2007, of
which 7.8 GW is grid-connected. Grid-connected PV has been the fastest
growing power generation, increasing by 50 percent a year in both 2006
and 2007.The Spanish PV market grew the fastest with an estimated 400
MW added in 2007, four times the 2006 additions.

Apart from rooftop installations, the growth of large-scale PV power
plants also accelerated during 2006 and 2007, including many kW and MW
plants. Spain now has the world’s two largest PV plants of 20 MW each
in the cities of Jumilla and Beneixama in Murcia and Alicante regions
respectively. There are now over 800 plants worldwide with capacity
greater than 200 kW and at least 9 larger than 10 MW in Germany,
Portugal, Spain and the US.

Solar hot water/heating capacity increased to an estimated 128 GW
globally in 2007, up from 88 GW in 2005, reflecting an annual growth
rate of 20 percent over the past two years. For comparison, the
world’s total wind power capacity reached an estimated 95GW in 2007.

Concentrating solar power mega-projects not desirable nor needed
The technology for concentrating solar power (CSP) uses a parabolic
array of mirrors to reflect and concentrate sunlight for heating
water, turning it into pressurized steam at 800 C for driving turbines
to produce electricity.

The CSP industry completed a first round of new build during
2006-2007. This included a 64 MW plant in Nevada, a 1 MW plant in
Arizona and an 11 MW central receiver plant in Spain. By 2007, there
were over 20 new CSP projects around the world under construction, in
planning stages or undergoing feasibility studies, the majority in
Spain and the US, but also in some developing countries. Chinese and
German partners have agreed to develop 200 MW CSP in Inner Mongolia by
2012 as part of a broader commercial framework for 1GW of CSP in China
by 2020.

It has been estimated that an area of the Sahara desert slightly
smaller than Wales in the UK would generate enough solar energy by CSP
to supply all of Europe with clean electricity [2]. Arnulf
Jaeger-Walden of the European Commission’s Institute for Energy said
it would require the capture of just 0.3 percent of the light falling
on the Sahara and Middle East deserts to meet all of Europe’s energy
needs. Both Gordon Brown and Nicholas Sarkozy are supporting it, and
the project is welcomed by Greenpeace and other environmental groups.

Scientists on the Sahara project admit it would take many years and a
huge investment of €450 billion; and by 2050, it could produce 100 GW.
One reason it is so expensive is because a ‘supergrid’ needs to be
built to transport direct current (DC) electricity through high
tension power lines. DC power lines have an advantage over the usual
alternating current (AC) power lines, in that they lose only 3 percent
of the electricity in transport rather than 7 percent or more [3].

In view of the continuing debate over the adverse health impacts of
high tension power lines [4] (see Fields of Influence series, SiS 17
and SiS 24), the high costs, and not least the prospect of ruining the
world’s landscapes by yet more power lines and pylons, the Sahara
mega-project looks distinctly undesirable and unnecessary. The better
option is distributed small to micro-scale generation of electricity
that could be fed back to the existing grid, as recommended in ISIS
2006 Energy Report, Which Energy? [4]. PV technologies, in particular,
are maturing fast. We do not have to wait so many years nor invest
hundreds of billions. The solar age has well and truly arrived.

‘Grid-parity’ rapidly approaching for PV
PV technologies for producing electricity from sunlight have been
improving by leaps and bounds while manufacturing costs are falling.

Industry leaders are saying that solar power could operate without
subsidies in just a few years when electricity from the sun will be as
cheap as can be bought from the grid [5]. That ‘grid-parity’ point may
be reached even faster if oil prices continue to climb while
manufacturing costs follow the downward trajectory.

Germany has been leading the world in PV, thanks to its ‘feed-in
tariff’ support, which gives people with solar panels above-market
rates for selling power back to the grid. Last year, it installed 1.1
GW, the equivalent of a large power station, and now has nearly half a
million houses fitted with solar panels.

The solar market is predicted to expand another 40 percent this year
for PV and solar heating.

All the companies attending the intersolar fair in Munich in June 2008
are planning big increases in production of solar panels. China-based
Suntech, now the world’s largest maker of PV panels, plans to double
production from 540 MW this year to 1 GW in 2009. Jerry Stokens, head
of Suntech Europe, thinks parity in Germany can be reached within 5
years. But in California and Italy, where there is a lot of sun and
electricity prices are high, grid parity for PV had already been achieved.

Although the price of silicon has gone up, many firms have secured
long term supplies at more modest prices. Nitol, a Russian chemical
company is building a new production plant in Siberia that will
increase its output from 300 tonnes this year to 3 700 tonnes by 2009.

Second generation thin-film PV technologies
Companies are investing in the newer thin film PVs that are less
efficient but more than make up for that in being much cheaper and
easier to manufacture. These ‘second generation’ PVs include cadmium
telluride (CdTe) and copper indium gallium selenide (CIGS) applied in
a thin film to a supporting substrate such as glass, flexible metallic
foils, high-temperature polymers or stainless steel sheets [6].. In
2007, the US-based company First Solar produced 200 MW of CdTe solar
cells making it the fifth largest producer of solar cells in 2007, and
first ever within the top 10 producing only second generation PV [7].
Nanosolar commercialised its CIGS technology in 2007 with a production
capacity of 430 MW for 2008 in US and Germany. In 2007, CdTe
production represented 4.7 percent of total market share, thin film
silicon 5.2 percent and CIGS 0.5 percent. The current record
efficiencies for CdTe and CIGS thin film PVs are 10 percent [8] and
19.9 percent [6] respectively.

Brighter and cheaper yet on the horizon
Third generation technologies aim to improve the efficiency of second
generation thin film technologies to 30-60 percent while maintaining
very low production costs. Thin-film solar cells use less than 1
percent of the raw material compared to wafer based solar cells,
leading to a significant drop in price per W [7]. (The current US
target is US$1/W generating power.) One of the R& D Magazine’s
prestigious R&D 100 Awards - also called the “Oscars of Invention” -
for 2008 has gone to the US National Renewable Energy Laboratory
hybrid CGIS cells manufactured by using ink-jet and ultrasonic
technologies to precisely apply metal-organic inks in separate layers
directly onto a common substrate.

Many developments are underway to increase efficiency and cut costs. I
have dealt at length with the Dye Sensitized Solar Cell [9] (Organic
Solar Power, SiS 29) and cells based on quantum dots [10] (Quantum
Dots and Ultra-Efficient Solar Cells?. SiS 29), for example.

One current strategy to increase efficiency is to target solar
concentrators, devices for increasing solar intensity. Current PV
concentrators track the sun to generate high optical intensity, often
by using large mobile mirrors that are expensive to make, install and
maintain.

Researchers at the Massachusetts Institute of Technology (MIT) in the
US have now created a new solar concentrator based on light absorbing
organic dyes. In their invention, sunlight falls on the first organic
solar collector (OSC) with a dye absorbing at low wavelengths but
transmits the rest to a second OSC underneath with a dye absorbing at
longer wavelengths. Alternatively, solar radiation transmitted through
the top OSC can be gathered by a bottom PV cell or used to heat water
in a hybrid PV thermal system. The first dye re-emits light at a
longer wavelength which is largely trapped inside the glass, and can
be used by PV cells stuck to the sides to generate electricity.
Similarly, the dye in the second OSC, on absorbing light at long
wavelengths, re-emits at a still longer wavelength that ix also
largely trapped within the layer so the PV cells stuck to its sides
are able to generate electricity [11, 12]. This array of OSCs
overlying ordinary solar cells can boost the overall efficiency by 20
to 30 percent, and bring down the cost of PV electricity
substantially, perhaps by 10 fold. The MIT researchers used DCJTB
(4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran)
and Pt(TPBP) (platinum tetraphenyltetrabenzoporphyrin) together with
various host materials.

Another strategy is to use transparent thin films that are also
conductors of electrical charge [7]. It allows light to pass through
to the light absorbing material beneath, and also serves as an
electrical contact to transport charge carriers away from the light
absorbing material, thereby increasing the efficiency. These include
various transparent conductive metal oxides. Physicist Bram Hoex and
colleagues at Eindhoven University of Technology, together with the
Fraunhofer Institute in Germany succeeded in boosting the efficiency
of a crystalline silicon solar cell by 6 percent, from 21.9 to 23.3
percent. This is achieved by depositing an ultra-thin (30nm) layer of
aluminium oxide at the front of the cell [13]. The layer has a high
concentration of negative charges, almost entirely eliminating the
energy losses through the surface of the cell.





  • [permaculture] Solar Power to the Masses, Lawrence F. London, Jr., 08/06/2008

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