Renewable powered desalination in coastal Central and southern Vietnam

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Contents

[edit] Context

Clean water supply and hydro-resource management form part of the looming consequences of climate change in Vietnam if they have not always been a serious problem for the government (Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam).

BY UNFAO's estimates in 1999 [1] the total renewable freshwater supply of the country, NOT the actual fresh water supply per year, is 891 km^3/ year but this varies spatially. So what is the actual fresh water supply per year???. The maps for groundwater resource distribution can be reconstructed from [2]. According to Vietnam Environment Monitor 2006 and Vietnam Environment Monitor 2003groundwater is comparatively underused in Vietnam with 95% untapped reserves. Acknowledging the problem of incompatible data sets for water supply and sanitation coverage Ensuring Environmental Sustainability 2002 we are going to reconstructed our maps for water treatment coverage based on the Vietnam Living Standard Survey 2002.

By 2001 an estimated 53% of the urban population and 30% of the rural population had access to potable water or 65l and 40l per capita respectively Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam. 40l per capita per day is the WHO standard water consumption per urban resident [3]. By 2004 according to [4] 99% urban population and 80% rural population, making 85% of total population in Vietnam, have access to safe drinking water. However according to Vietnam Living Standard Survey 2006 62.2% urban household and 6.3% rural households rely on tap water for their main source of drinking water. Given that the Comprehensive Poverty Reduction and Growth Strategy (CPRGS) mandated in 2003 that 60% of rural and 80% of urban population have access to clean and safe water by 2005, it signals some optimism, at least by coverage, but it also raises a question by caution: by what standard or definition is the water 'safe and clean' and whether any conflict exists among the definitions of safe and clean water used by these institutions. One of the goals towards 2010 is that 85% of the rural population will consume clean water at 60 liters per capita per day National Rural Clean Water Sanitation and Supply Strategy 2020whereas the demand in large urban centers already ranged from 50 to 180 liters per capita per day Phu Le Vo 2007: Formulation of an integrated approach to sustainable water management in Hochiminh City, Vietnam,Vo Mac Thuy 2007: Vietnam water and wastewater treatment market brief.However there is no clear perception in terms of action required or goals met, although the target for 2020 is already declared to be extremely demanding and unlikely to succeed(Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam).

Anthropogenic factors play a role in impeding water supply and sanitation improvement strategy. Kakonen M. (2008): Mekong Delta at the Crossroads: More Control or Adaptation? emphasized the two sided effects of water on life in this delta. Likewise have attitudes towards the river flow regime and the delta's environment been: they are characterized by human intervention and control but also adaptation, the former of which has lately dominated choice of actions, escalated in terms of administration level and manifested in increasing number of public construction works. Besides becoming very productive and export oriented plain the delta has been facing worsening of the water quality, increased demand for water, and increased saline water intrusion. The costs and drawbacks of the engineering works have largely fallen on the poor farmers and landless people. The coastal areas experience shifts first from brackish water to freshwater and then back to brackish water systems. Although large areas have been converted into intensive shrimp farms and thus add value to brackish water experience from Thailand has demonstrated the difficulty in making the shrimp business a socially equitable and environmentally sustainable livelihood source. The paper suggests exploring more social and environmental sustainable options to maintain the MD's enormous productivity and mitigate the increasing production costs such as strengthening saline intrusion, worsened water quality, declining biodiversity, and increased social differentiation. Pretty J. (2008): Agricultural sustainability: concepts, principles and evidence

Global warming will exacerbate the problem, which will manifest most disastrously in the South and Central region Chaudhry P. and Ruysschaert G. (2007): Climate change and Human Development in Vietnam, most of the inhabited area of which lies in the low elevation coastal zone (LECZ)(Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam).

First of all sea level rise contributes to saline water intrusion Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam and limits water available for irrigation and aqua-farming Huu Ninh Nguyen: Flooding in Mekong River Delta.In the Mekong Delta salt water infiltration into groundwater and freshwater shortage, already very common, will worsen in light of prolonged droughts and reduced river discharge. The damage concerns 1.5 million hectares of cultivated lands out of 2.4 million hectares in total already employed for agriculture in this national ‘rice-bowl’ Le A.T. and Wyseure G.: Water Environmental Governance in the Mekong River Delta Vietnam. In 2000 irrigation accounted for approximately 84% water demand nationwide(Vietnam Environment Monitor 2006)and grew to be between 85% and 90% in 2003 Le A.T. and Wyseure G.: Water Environmental Governance in the Mekong River Delta Vietnam.Between 2000 and 2010 the volume of irrigation water will likely rise from 76.6 km^3 to 88.8 km^3 by Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam. This poses a serious food security threat.

Water supply is connected to poverty in Vietnam Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam,Nguyen H.N.: Flooding in Mekong River Delta.For example in the Mekong Delta basin, the 4 farthest downstream provinces, which are most severely affected by salination, have 80% of their water from drilled tube wells. And 70% of the Cenral coastal communities get drinking water from wide diameter open wells. As these areas are most vulnerable to flood and storm surges Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam both quality and availability of the water resources are lowered, pushing the population to accept low quality and substandard consumption of water, which is highlighted in Berg M., Stengel C., Pham T.K.T., Pham H.V., Sampson M.L., Leng M., Samreth S. and Fredericks D. (2006): Magnitude of arsenic pollution in the Mekong and Red River Deltas — Cambodia and Vietnam(e.g. An Giang and Dong Thap in downstream Mekong] and leads to water borne diseases Soussan J., Patrick K.J. and Nha N.T. 2005): Rural Water Supply, Sanitation and Health in Vietnam. Being water-poor means poverty and low health security, even though the latter also affect the urban population Soussan J., Patrick K.J. and Nha N.T.(2005): Rural Water Supply, Sanitation and Health in Vietnam.

Finally ecology and habitat security is threatened by the more severe and unpredictable seasonal patterns of drought and rainfall Huu Ninh Nguyen: Flooding in Mekong River Delta,Vietnam National Action Program to Combat Desertification,Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam.Ninh Thuan province is an example of accelerated desertification hurting the local livelihoods. More still needs to be compiled and done for drought data in Vietnam according toSoussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam.

[edit] Overview of the water treatment facilities and potential of desalination, in particular desalination powered by the renewables

Vietnam's 192 water supply plants are deteriorating Soussan J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam. According to Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam,up to 2001 there is none at the municipal level. This is the same with desalination facilities in Vietnam even though several attempts at demonstrating the benefits of such systems have occurred recently in 2006, 2008 and 2009 and Vo T. and Ngo A.: Desalination technologies in Vietnam. Previous literature on desalination in Southeast Asia is dominated by nuclear powered desalination; while that in the Middle East (Iran, Oman) and North Africa (Egypt, Algeria) is abundant. This is a scholastic gap to fill.

Kiranoudis C.T., Voros N.G., Maroulis Z.B. (1998): Wind energy exploitation for reverse osmosis desalination plants provides rules of thumb in designing a wind powered RO desalination plants in terms of lowest wind speed where its exploitation will be profitable, types of turbines to use etc

Miranda M.S. and Infield D. (2002): A wind-powered seawater reverse-osmosis system without batteries estimates 3.4 kWh required for each m3 of desalinated water.

Voros N.G., Kiranoudis C.T. and Maroulis Z.B. (1998): Solar energy exploitation for reverse osmosis desalination plants

The status and perspectives of development of wind-powered desalination are reviewed in García-Rodríguez L. (2004): Desalination by wind power

Einav R., Harussi K., Perry D.: The footprint of the desalination processes on the environmentdivides the environmental impacts largely of the reverse osmosis desalination technology into the use of land, the impact on groundwater, that on the marine habitat by way of the discharge of the brine, noise pollution and intensified consumption of energy. Siting of desalination plants and the consequential use of long pipes is advised to avoid salinating the local water system. The greatest focus is spent on the effects of discharging the concentrated brines on marine environment. Although examples were drawn from plants by the Red Sea, the sensitivity of mangrove and coral reefs is worth noting given the presence of mangroves around the Ca Mau Cape and that of coral reefs offshore of the southern Central Vietnamese coast.

An overview of technologies and data for the input power per cubic meter potable water produced per desalination technology are compiled in Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam. The listed major influencing parameters for process selection and cost evaluation include feed water salinity and quality (which the South China seawater is considered very good), energy source and cost, process type and design, plant size and environmental costs among other. The report only considers diesel/ wind and wind/ hydrogen hybrid desalination systems, whereby in light of the increasing fuel costs (even though fuel price in Vietnam was relatively low as of 2001) significant cost benefits will be achieved for wind/ diesel systems even on locations with medium wind conditions. Nearly 9 years has passed since the report was produced, which implies the need for a new cost evaluation and comparison.

Since other renewable energy options were explored in this one and only available article concerning desalination in Vietnam, it is worth considering solar energy and agrofuels.

[edit] Agrofuels in Vietnam (ethanol from bagasse and biodiesel from fish oil)

The potential of agrofuels has been discussed in Malik U.S., Ahmed M., Sombilla M.A., and Cueno S.L. (2009): Biofuels production for smallholder producers in the Greater Mekong Subregion, [5] and in my research project in 2008.

Catfish is officially mentioned as a source for biodiesel in Country report Energy and Climate change in Viet Nam Workshop March 2009, Thailand. Nguyen T.V.H., Ananth A.P., Visvanathan C. and Anbumozhi V. (2009): Techno policy aspects and socio-economic impacts of eco-industrial networking in the fishery sector: experiences from An Giang Province, Vietnam estimates that Pangasius fish contains fat composition as high as 15%. Approximately 145,000 tons provide about 22,000 tons of fat that could be used to produce 25 m3 biofuel at 0.125 USD per liter (1 USD = 16,000 VND).

[edit] Solar energy in Vietnam

Nguyen Q.K. Dr in Energy Policy thesis (2005): Long term optimization of energy supply and demand in Vietnam with special reference to the potential of renewable energy. Mr. Nguyen is the seemingly only internationally visible and qualified expert in (renewable) energy in Vietnam, whose articles have dominated publications on the topic, at least at Elsevier journals. If he is still using NASA SSE data for solar energy modeling and TrueWind's 2000 wind altlas our analysis is no less than on par with the current knowledge and practice in the country: our solar simulation is as current as 2009 and wind maps are produced in 2005.

Nguyen T.N. and Duong H.M. (2009): Economic Potential of Renewable Energy in Vietnam’s Power Sector shows the current target and development and deployment costs for multiple choices of renewable energies in Vietnam.

[edit] Wind resources and modeling methods

Landberg L., Myllerup L., Rathmann O., Petersen E.L., Jørgensen B.H., Badger J. and Mortensen N.G.: Wind resouce Estimation - An Overview and [Manwell J.F., McGowan J.G. and Roger A.L.: Wind energy explained] provide an excellent theoretical base for anyone tackling wind-energy related problems for the first time. The paper lists eight methods: Folkore, measurement only, measure-correlate-predict (MCP), global databases (most famous is the NASA SSE), wind atlas methodology (CFD models) and combined meso/ microscale modeling. A resolution of 1km or less is admitted to require tremendous amount of computing although increasing speeds of computer has allowed the order of a few km. The book introduces the popular Weibull and Raleigh distributions, which in the absence of station measurements will allow the fitting of available data, predicting and classifying the wind at a specified location. Pryor S.C., Nielsen M., Barthelmie R.J. and Mann J. (2004): Can satellite sampling of Offshore wind speeds realistically represent wind speed distributions? gives an intensive mathematical discussion of the uncertainties associated with distribution fitting methods.

To deal with the coastal wind, experts will make use of data from either synthetic aperture radar (SAR) or daily scatterometer (QuickScat). Wind mapping from the former requires imaging and signal interpretation algorithms Christiansen M.B., Koch W., Horstmann J., Hasager C.B. and Morten N.: Wind resource assessment from C-band SAR, not to mention the steep commercial cost for each ERS SAR PRI and Envisat ASAR PRI scene covering an area of 500m by 500m. Wind energy calculation will be carried out using the WasP (Wind atlas analysis and application Program)RWT Tool: Offshore wind energy mapping from SAR.As for QuickScat, free tools are available to interpret the level 3 QuickScat .hdf files into a GIS platform [6]. However the data suffer from low resolution.

Khan M.J. and Iqbal M.T.(2004): Wind energy resource map of Newfoundland exemplified the MCP method, which correlate surface data from short measurements or sparsely located stations with the global SSE dataset. It is considered to be an excellent and user friendly source for preliminary study purposes. Contours plotted by Matlab using this database were found to indicate similar trends with those from the NCEP/ NCAR (National Center for Environmental Predictions/ National Center for Atmospheric Research) Reanalysis and from the COADS (comprehensive ocean-atmosphere data set). Ground data extrapolation for turbine heights was done using the power law.

It appears that high quality wind energy mapping is only affordable by large institutions e.g. Risoe National Laboratory, Denmark or in our case an international program funded by the United Nations. The Wind Energy Resource Atlas of Southeast Asia resulted from the MesoMap system which is an integrated set of atmospheric simulation models, global weather and geographical databases. According to Wind energy resource atlas of Southeast Asia,good to excellent wind resource areas concentrate partly into the coastal areas of southern Vietnam, where northeast monsoon winds converge with offshore wind and accelerate round the end of the Southeast Asia peninsula. Areas classified as fair or better for small wind turbines include large sections of coastal southern and Central Vietnam.

[edit] Purpose

The concluding message is that stand-alone desalination units, with or without coupling with food and salt production, represent a community based (and decentralized) method to adapt to and mitigate climate change, which has attracted little focus in Vietnam Shaw R.(2006): Community-based climate change adaptation in Vietnam: inter-linkages of environment, disaster, and human security, especially when the existing uniform promotion of piped water is inappropriate Soussan J., Patrick K.J. and Nha N.T.: Rural Water Supply, Sanitation and Health in Vietnam and inefficient with as much as 30 to 55% of the water pumped out of the country's treatment plants lost through the distribution network. Sizing and siting of the potential for renewable powered desalination units in Vietnam can evaluate how much of the 2010 goals can be attained through the use of the extremely good quality sea water from the local South Chinese Sea Sunlift system, Asia EcoBest Work Programme 2001, Sea water desalination in coastal areas of Central and South Vietnam.Particular attention will be paid to small towns in the coastal fringe of the Mekong delta, which suffer the lowest groundwater quality nationwide, have the highest rate of water defecation, the worst habit in water sanitation(J., Patrick K.J. and Nha N.T. (2005): Rural Water Supply, Sanitation and Health in Vietnam), pay higher water tariffs, enjoy few alternatives and sometimes can not afford the connection fees(Global Small Towns Water and Sanitation Initiative: Vietnam Case Study). While in the coastal Central concentrated photovoltaic energy and wind hybrid will likely be the most robust, wind/ biodiesel will offer a very attractive option to the coastal fringe of the Mekong delta. The real question here is what mix of energy will provide maximum cost benefits.