Renewable Energy

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Tridel SA
Enhancing waste

Variable renewables
    Wind power
    Solar Photovoltaic
    Tidal and wave generation
Constant renewables
    Hydroelectricity
    Biomass electricity
    Geothermal electricity
    Biomass gas
    Enhancing the value of waste
Conclusion
Further reading

To date, renewable energy has not been given a high priority in Cyprus. The current implementation of renewable energies is quasi-zero, with the exception of solar water heating. The latter is so commonplace that little attention need be made (see the essays on Houses and Water). Parliament has paid lip service by passing a law offering certain subsidies for some kinds of renewable electricity generation but, at the time of writing, these have not actually been made available because of bureaucratic procedures - even after two years. The Electricity Authority of Cyprus (EAC) has, in the meanwhile, been collecting a small tax (0.13 c/kWh, about 2.5%) on electrical consumption, ostensibly to fund these subsidies.

It would appear that anyone installing an approved system will be able to obtain up to a direct 40 per cent subsidy on the capital cost, exemption from 15 per cent VAT (making 55 per cent, in all) and, if there is a surplus of electricity fed back to the grid, this will be purchased at 12 c/kWh, which is roughly twice the selling price (this data is subject to correction as the details are worked out).

From my own experience, I know that obtaining the subsidies is a discouraging and lengthy procedure. The initial part of it, obtaining approval from the EAC, is easy, rapid and straightforward. The next part is submitting an application to the Ministry. It would appear that the latter is as obstructive as possible, despite the application form (several pages, only in Greek) being filled in completely and sent along with all the required documents. The first ploy is to do nothing apparent for six months. If, after that time, you start to enquire what is happening, you are then asked for further documents that were not requested initially. When these are submitted, the process restarts and one has another several months wait. The dossier is then sent to the Land Registry to obtain planning permission for the installation - and everyone knows how fast the Land Registry works! Eventually, I suppose, permission to install is granted. However, before you can hope to see any financial return from the government or the EAC, I imagine that all the bureaucrats from every quarter will have to inspect the installation and woe betide you if you have used an M8 screw when the plan says M6! With a great deal of luck, you may get a cheque for the 55 percent on the capital cost, probably several months later. If you think that this sounds cynical, I have experienced it myself up to about half-way through the procedure, when I decided to renounce it. In the meantime, I estimate the EAC has raked in over £7 million with the levy, enough to pay for the capital subsidy of somewhere about 1,000 photovoltaic installations of 3 kW each, representing about 1 per cent of the average generation on the island during daylight hours. It is doubtful whether the number of applications for PV installations is one-quarter this figure. If I were really cynical, I might even go so far as to say that the authorities were sitting on the money they have collected from us, the consumers, to pocket the interest for other purposes. However, my cynicism is not limitless.

Variable renewables

These are defined as energy that cannot be generated at a constant level. Some examples are tidal, solar and wind power. These are sometimes called intermittent sources, but I prefer the term "variable" over "intermittent", because the latter implies an "all or nothing" energy generation, whereas the output more commonly varies from nothing to full output with every intermediate level possible. It should be noted that it is essential that constant power supplies must be available to cover the maximum demands, so that variable renewables can only serve to allow conventional power stations to be "eased off", thereby reducing fuel consumption. Good weather forecasting is a sine qua non of useful exploitation of variable supplies, so that the constant requirements can be foreseen and the plant brought up to speed accordingly.

It must be noted that there is a limit to the amount of variable energy that a power grid can handle at any one time. Above that limit of 18 - 20 per cent, experience in other countries has shown that the whole grid system may become unstable, leading to black-outs.

Wind power

In some countries in higher latitudes, wind generation, both offshore and onshore, has been well implemented with further expansion planned. Cyprus is not very suitable for large scale wind farms. Generally speaking, wind generators have a rated output with wind speeds of about 16 - 20 m.s^-1 and the output drops to about half at 10 m.s^-1 and one-quarter at 7 m.s^-1. The annual average wind speed in most places on the island is within the range of 2 - 5 m.s^-1 with the highest values of about 7 m.s^-1 because of katabatic winds on the southern slopes of the Troodos massif. This means that wind turbines could never operate efficiently in this country. This is exacerbated by the fact that these machines shut down when the wind speed exceeds about 20 m.s^-1 such as may happen during winter gales.

There is a particular problem with wind generation in Cyprus. It would be nice if the turbines produced their peak power to correspond with peak electricity demand. Unfortunately, this can never happen. Peak demand occurs in the hottest weather, when temperatures exceed, say, 35°C, because of air-conditioning. Throughout the summer, the meteorological situation is that a series of high pressures pass over the island from about early June to mid-September and this is when there is a minimum of wind.

It is estimated that the average cost of on-shore wind-generated electricity would be over twice that of fossil-fuelled generation under these conditions. Off-shore installations would be even less efficient.

There is a project to install a small wind farm in the Kouris Dam region. The details are unknown, but its rated capacity is unlikely to exceed about 5 per cent of peak demand. Some concern has been raised about this project because the lake has become a habitat for many species of wild birds, especially migrant waders. It is possible that this region will be designated an IBA (Important Bird Area) by the Game Fund and Birdlife Cyprus, under EU rules. It is feared that the windmills may kill migrating birds, some of which are rare and protected species. It is perhaps not appreciated that a 2 MW wind turbine may have blades of 65 m diameter on a mast of 100 m height. The tips of the blades may rotate at speeds of 100 km/h or more, so that large birds may not have a opportunity to avoid them if the blades interrupt their flight path. The blades themselves can also be damaged if the bird is of the size of a duck or more. This has been a problem in the USA, especially with raptors (see the essay on Wildlife).

Solar Photovoltaic

This is perhaps the ideal variable renewable energy source for Cyprus, except for its capital outlay. Cyprus has well over 2,500 hours of "useful" sunshine per year, so that a 3 - 4 kW system (size which will fit on a typical south-facing villa roof) will generate a theoretical 7.5 - 10 MWh. However, be warned, you will never reach this theoretical limit because the efficiency of the solar panels drops at temperatures above 25°C; it would be wise to budget for 5 - 7.5 MWh respectively. If one were to buy a PV system at its full price and not sell any surplus electricity generated, the payback period would probably exceed the lifetime of the system. With the subsidies and the EAC buy-back price, assuming you are willing to go through the rigmarole of making the application, an average household would have a payback period of 8 - 10 years, after which it will become profitable (subject to reserves on the final conditions of subsidies).

The real cost of generating solar PV electricity is very high, typically 35 - 50 c/kWh. However, it can make a real contribution to smoothing out peak demands because it will be reasonably productive at the time when air-conditioning units and chillers would be working hardest. This alone makes it interesting, despite the high cost and the surtax burden on the ordinary electricity consumer.

Granted that the notion is not practical, but if every house that has a solar water heater also had 3 kW of solar panels, then the peak power requirements of the whole of the EAC supply could be met on sunny days. In practice, to ensure grid stability, only one house in five could be thus equipped, but that alone could save over 20 per cent of the fuel used by the EAC.

Tidal and wave generation

It has been said that one form of tidal electricity generation is like wind generation under water. Where this analogy fails is that tides are largely predictable, wind is not. However, it should be stated that there are four periods per day when tide generation does not and can not work; as the tide turns, hence it being classed as variable, even though it is predictable. Unfortunately, the tides in Cyprus are insufficient to be able to be harnessed.

Wave generation is a possibility when the average height of the waves (crest to dip) exceeds 1 metre. I have not studied this possibility, but I instinctively believe that it is not likely to be a viable option on this island. The "best" waves for this are oceanic swells, but local wind-driven waves would also work. However, as these are dependent on wind, it is probable that the same conditions as in the paragraph on wind generation would probably apply.

Constant renewables

Hydroelectricity

Hydroelectric generation is the mainstay in countries, like Norway, Switzerland and Austria, where there are large glaciers. The water from the summer melt-off is collected in large dams, at altitude, and penstocks lead the water to pressure-operated turbines in the valleys. Alternatively, large dams across rivers, such as the Three Gorges Dam in China, can turn flow-operated turbines. Both types are environmentally discussional for several reasons and large projects are nowadays very severely criticised. Both types are also potentially dangerous to downstream life if, for any reason, the dam should burst and this does occasionally happen, despite the best efforts of civil engineers. This is unlikely to happen in Cyprus, because of the lack of perennial rivers.

There is a variant of hydroelectric generation which could possibly have some future relevance to counter the undesirable effects of variable renewables. Imagine two lakes of equal size, say, similar to that of one of the larger dams, but separated in altitude by 300 - 500 m. During the night, when there is a surplus of power generating capacity, water is pumped up from the lower to the higher. At peak demand time or when variable renewables have a low output (e.g., no wind and a cloudy day), the water in the upper reservoir is made to flow down to the lower lake, generating hydroelectricity. This method is the only useful way of "storing electricity" for later use on a reasonable scale with today's technologies.

Biomass electricity

This consists of growing some form of crop, usually wood from quick-growing trees, for gasification or chipping and burning in a thermal power station. This is unsuitable for Cyprus on any reasonable scale because of a lack of suitable large areas for the crop cultivation and the water requirements of such crops.

Geothermal electricity

This method is ideal in places like Iceland but requires volcanic rock strata at a constant temperature of about 200°C. The island's volcanic origins in the Troodos massif have cooled down to much lower temperatures than this, so it cannot be considered in this context.

Biomass gas

Medium to large-scale poultry, cattle and pig farming, such as is practised on the island, produces large amounts of excrement. If this is placed in a large anaerobic digester, the gas produced by fermentation in the first 48 hours can be collected and large quantities of methane (or natural gas) can be easily separated. This gas is indistinguishable from fossil natural gas and can be used for any similar purpose. If transported to power stations, it could complement other fuels, providing a small percentage of the island's power supply.

Enhancing the value of waste

In a number of countries, up to ten percent of electricity requirements are being supplied by enhancing the value of household garbage and other combustible waste. This is .most practical in regions of high population density, such as large cities. This would certainly be practicable in Cyprus This would also reduce the need for the many, unsightly, polluting, insanitary landfills, a few of which would be used only to dispose the sterile cinders. Such power stations are not cheap to construct, as the exhaust gases have to be scrubbed to eliminate harmful pollutants, but they do make a useful contribution to the environment.

There is, however, a big "but" to this idea and it is one which will not fit in easily to the present Cypriot mentality: it will require sorting of household waste (see the essay on Waste). In particular, glass and aluminium are undesirabel. Notwithstanding, this will become a requirement under EU directives, anyway.

I am convinced that this technology would make a useful contribution to Cyprus' environment and have made a small study to examine the viability. This started with a visit to an existing plant, in Switzerland, to learn about the system. A description of my visit is the subject of an essay on Tridel SA. After this, I looked at the possibilities of the implementation of the same technology in this country, the subject of the essay on waste enhancement in Cyprus. These proved very positive.

Conclusion

In the context of Cyprus, the only potentially large scale variable renewable energy source is the solar photovoltaic panel. A typical 3 kW installation costs about £12,000 and would produce electricity (not counting subsidies) to the tune of about £175/year, based on the present cost of fossil-fired electricity. It is clear that the price of the installation would have to fall by 80% before it became economically viable. With the subsidies, the payback period falls to between 8 and 10 years, which is just acceptable. The Government should make the bureaucracy of obtaining such subsidies easier. Notwithstanding, the full 20 percent of peak demand is a long way off. The only major potential constant renewable energy source, capable of supplying up to 10 per cent of our needs, would be by waste incineration. I strongly urge that this be implemented, not just for electricity supply but also as a logical means of introducing waste discipline. A small contribution to any future natural-gas electricity generation may be made by composting farm animal excrement, the residues being a valuable natural fertiliser.