|
|
 |
|
||
Like most solar technologies the running cost of a solar pond system is negligible, however the up front capital costs are significant. For example: Heat: A solar pond of 0.7 hectare would cost approximately $220,000 to $300,000 AUD, depending on availability of earthmoving machinery and cost of salt. If it was located in Riverland SA (or a similar climate) it could produce 90kW of hot water- eg a flow rate of 7 litre /second of water at 65 degree C - 24 hours per day (that is 2150 kWhrs per day). If you have a need for heat then that’s as far as you go - this will cost about 2c/ kWh based on cost of financing the pond and its depreciation - No electricity or gas company in Australia can match that! Most Australian states and many other countries have greenhouse gas reduction funding available to significantly reduce the construction cost to the landholder. Developing country sites can access Clean Development Mechanism (Kyoto Agreement) payments.
Electricity: Rankine engines are not highly efficient, but there is a huge reserve of low cost heat in a solar pond. A small pond like the one above will run a 25kWe generator - enough electrical power for about 15 houses - or a small industry. The generator system (Rankine engine and alternator) will cost around $180,000 and about $10,000 a year for |
maintenance (basically an oil change - refrigeration oil is expensive!). There is still lots of heat left over for core heat-using application. This sounds a lot, but 25Kw of electricity , 24 hours a day is over 210,000 kWh of electricity in a year. At retail price (say 15c/kWh) this is worth $32,000. As carbon pricing becomes the norm there is also likely to be excellent carbon credit financial returns. At present, Australian Renewable Energy Certificates (RECs) on such a system will return about $7500 per year. Because Solar Ponds have a large collection area and will generate electricity 24 hours per day, setup cost per unit of electrical output is 5 times cheaper than that of currently available photovoltaic cell systems.
Desalination: Again, solar distillation costs almost nothing to run but has a high up front cost. The above pond will run a very large number of solar still module. Currently water produced by linking solar stills and solar ponds costs over $10 AUD per kLitre. Also production volume is not high. This is expensive water. Many remote communities do however pay the equivalent of $14 per kL for diesel generated electricity reverse osmosis plants. Our aim is to build solar pond -solar desalination systems to produce 75 - 100 kL of fresh water per day for an investment cost of less than $5 per kL. There are significant carbon credit earning pottentials for greenhouse gas free desalination.
|
||
|
|
|||
