Tuesday, November 6, 2012

‘Solar Power For Every Household’: Maybe

This quotation was the title of a controversial article by Jacqueline Agathocleous in the Cyprus Mail on August 23, based on an announcement from the Energy Regulatory Authority (CERA). CERA must have its head in the ozone layer if it really believes that “the aim is to install the systems on all Cypriot homes from 2014 onwards.”

The article cites a cost per household for a 3kW system to be €6,000. This figure is remarkably less than the going rate for reasonably efficient photovoltaic (PV) panels (cheap ones are inefficient) plus the inverter, meter and installation.

Even with economy of scale, the minimum to the purchaser would be up-front about €20,000, from which a 40% subsidy and a VAT refund would bring the cost to about €8,600 per householder, if he were lucky enough to be paid the subsidy.

The remaining €11,400 is offered by the taxpayer. Based on 250,000 homes, this would total €2.85bn, at a time when we might find it difficult to rub two euros together, assuming the economists’ predictions of at least eight years to pay off the Russian and troika debts.

If we take the true cost of €20,000 per home for a 3kW system, this has to be amortised over 25 years for the panels and their installation and 10 years for the inverter, the annual cost works out at well over €1,000 plus the interest for the investment, insurance and maintenance costs.

This would translate, for a typical household, at €0.50 - €0.55/kWh generated, whether fed into the grid or used domestically. Of course, the home-owner won’t see this cost because he is being paid for the electricity he produces, even though it would be costing us, all the consumers, the double of what we would be paying per kWh at EAC’s retail price.

Even if Cyprus’ fairy godmother waves her magic wand to produce these billions, is this idea technically feasible? The answer is no, for two reasons, and CERA should have sufficient knowledge to be aware of this. The first is that our grid is not designed for a distributed supply with 250,000 sources of tiny quantities of electricity and it would go bananas as a cloud obscured an area. It has been designed for just a few large-scale sources and the Transmission System Operator (TSO) would have its time cut out avoiding black-outs, but probably not succeeding.

What does a 3kW PV installation mean? It means that it will generate 3kW when the sun shines directly onto the panels with an intensity of at least 1,000 W/m² and a temperature of the panels of 25°C.

Unfortunately, these conditions are rare. The public notion is that they will generate 3kW from sunrise to sunset. Not so! On a really bright, but cool, sunny day, with well-oriented new panels, you may get 3kW from about 11 am to 1.30 pm. In hot weather, you will get less; when the temperature is 40°C or more, you can bet that the business part of your panels, in their glass-fronted greenhouses, will reach at least 60°C. At this temperature, your 3kW installation won’t give you more than 2kW.

I run a weather station, including an instrument for measuring the intensity of sunlight. This is installed 300 m up, in the Troodos foothills, in a rural location and well away from any source of pollution. If there is anywhere in Cyprus that would be ideal for a solar installation, this would be it.

From 1 July of this year to 20 August, we have had exactly seven days when the peak solar radiation has reached 1,000 W/m² or more. The average peak is 932 W/m² and, on one day, it was as low as 846 W/m². I mentioned that our 3 kW installation presupposes 1,000 W/m² and it will generate proportionally less at lower values. Why, here in Cyprus, the island that boasts wall-to-wall sunshine, is the solar radiation so low?

I don’t have all the answers but humidity and dust in the upper atmosphere are part of the reason and I do know it was not always like this. As you read this, look out at the sky. Is it really the deep Mediterranean blue that you would expect or a rather insipid, almost milky, blue?

I have some Kodachrome slides I took in the 1950s in various parts of the island and the sky was very much bluer then. Something has changed, probably a mixture of phenomena relating to climate change, ozone depletion and global high-level pollution. What I am saying is that I have a suspicion that, when I took those photos, the radiation may have been close to 1,100 W/m².

Another problem that can affect the efficiency of PV panels installed in urban areas is low-level pollution. One of the photos from nearly 60 years ago was of the Pentadaktylos, taken from one of the Ayia Sofia minarets. It was so clear that you could almost see the vultures nesting in the crags, if you will allow an exaggeration! Today, that is impossible because of the pollution caused mainly by road vehicles, not just the exhaust smoke or the dust from friction of tyres against tarmac but also the photochemical smog caused by the sun shining on the vapours of volatile chemicals and nitrous oxide invisibly pouring out of exhaust pipes, even with catalytic converters.

Going northwards along the A1 motorway on a calm summer’s day, often the first view of Nicosia is a grey pall of this smog and, when you reach the city, your eyes may smart or you may start coughing because of the accompanying ground-level ozone, which frequently exceeds the safety limits. All this can reduce the kilowatts generated by PV panels in or near the cities.

Up to now, one of the main drawbacks to installing PV panels has been the slow bureaucracy of the various authorities, including the payment of subsidies on your up-front investment. This has been up to five years from the first application for a permit to receiving a cheque (if you receive one at all). I hope that, with this new pilot project, CERA will find ways of reducing the time scale down to less than one year by better co-ordination between the various ministries and the EAC. If the project is successful, let’s hope that the time scale will remain fast for the maximum 40,000–50,000 homes that would be technically feasible for a reliable complement to our electricity sources.

Is there an alternative? Yes, a few concentrated solar thermal power stations could provide reliable 24/7 energy to the grid with a higher efficiency and at a lower cost. They have a drawback of needing land (maybe in the UN buffer zone?).

This article may seem positively negative on first reading. In reality, I welcome the use of more solar generation in Cyprus but I just wish to warn CERA and potential users not to be too optimistic about the quantity of electricity that a PV installation will produce; it will be less than you think. So, go ahead so long as you realise that a capacity of 3kW does not mean that it will generate that all the time; over a year of daylight hours, you may obtain an average of 0.15–0.4 kW. But, at night, when you switch your energy-saving lights and TV on, you will be paying the EAC through the nose, as per usual.

Source: http://www.cyprus-mail.com/opinion/solar-power-every-household-maybe/20120902

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