Researchers Look to Solar Power to Make Dialysis Greener

 

Solar power can help offset the high utility costs of hemodialysis, making the treatments more environmentally friendly, report scientists in Australia. The findings, published recently in the Clinical Journal of the American Society of Nephrology, point the way to a “green dialysis” future when resources are used and reused wisely.

/kidneynews/4_3/1/graphic/1f1.jpg

Hemodialysis treatments for kidney failure patients require a considerable amount of basic utilities such as water and power, leaving a vast carbon footprint behind that is sure to grow as the incidence and prevalence of dialysis use inevitably rise worldwide.“As our planet’s population continues to grow, so does the sustainable growth rate of the dialysis patient population. This annual growth rate is now expected to be 6 percent, which will give us roughly 4 million patients by 2025,” said Faissal Tarrass, MD, head of the department of hemodialysis at the Hospital Princessa Lala Meriem, in Morocco.

Demands of dialysis

Research indicates that each hemodialysis treatment uses more than one half the daily power consumption of an average Australian four-person home, and power prices are predicted to soar to two to three times the current rate over the coming decade in Australia. Yet little thought has yet been given to addressing the resource demands of dialysis.

To see whether solar energy might be used to help meet the power demands of dialysis equipment, John Agar, MBBS, Anthony Perkins, and Alwie Tjipto, MBBS, of Geelong Hospital, Barwon Health, in Victoria, Australia, established a solar-assisted dialysis program in Geelong (located in southeastern Australia) that included four home dialysis machines. For solar comparison, Geelong is comparable with St. Louis, Missouri.

Previously, the investigators conducted other resource conservation initiatives that addressed water reuse practices and recycling of reject water. They successfully developed interventions that have reduced water losses of up to 100,000 L per week across their facility and home hemodialysis sites. For example, reject water from the hospital-based dialysis unit provides autoclave steam for instrument sterilization, ward toilet flushing, janitor stations, and garden maintenance. Satellite center reject water is tanker-trucked to community sporting fields, schools, and gardens. Home-based nocturnal dialysis patient reuse reject water is used for home domestic utilities, gardens, and animals. A natural progression for the team was to move from water to power.

The group chose solar power above wind power for this study because solar radiation is silent and, because it penetrates clouds, more dependable. Wind is unpredictable, and harnessing its power can cause noise and visual pollution. This study represents the first known and reported solar project in dialysis.

For their study, the investigators used the simplest solar model: array donation to, and service draw from, the national grid. The power generated by the solar array was metered and recorded before being directed to the national grid, permitting weekly tracking of all grid-donated power and power drawn specifically for dialysis-related use.

Cutting costs, saving resources

After the first 12 months of the program (from July 26, 2010, to July 25, 2011), power costs were reduced by 76.5 percent. Interestingly, the authors report that from a “what has the weather been like” assessment of Geelong, the 12-month study period was one of the worst remembered; however, solar exposure is not entirely dependent on sunshine and sunlight.

In the coming years, the system is expected to turn a profit in addition to generating effectively free power. A solar array is estimated to have a lifespan of approximately 30 years.

“Geelong Hospital is showing that renewable power for dialysis is both practical and cost-effective,” said Frances Mortimer, MRCP, who was not involved with the research and is the medical director of the Centre for Sustainable Healthcare in Oxford, UK.

“Professor Agar’s article provides a timely reminder of the environmental impacts of the delivery of health care and of renal medicine in particular,” said Andrew Connor, MD, who was the Centre for Sustainable Healthcare’s first Green Nephrology Fellow (2009–2010). “It’s inspiring to see practical measures being put into place to reduce these impacts and to realize financial benefits simultaneously.” Connor, who is in the department of renal medicine at Derriford Hospital, in Plymouth, UK, has published widely in the field of sustainable health care.

Directors of dialysis services may wish to investigate whether they can take similar steps toward greener dialysis, taking into account that charges for grid-provided power and reimbursement rates for grid-donated power from alternative sources such as the sun or wind will vary from place to place and from power company to power company.

“Although not all locations, purchasing environments, or local administrations will be suitable or supportive, the twin issues of environmental degradation and climate change demand that simple ecoassessment is made and solutions sought,” the authors wrote.

They encourage the dialysis community to assess the solar exposure records at their home geographic position, which can be done at http://www.wunderground.com/calculators/solar. With local latitude and longitude coordinates, investigators can obtain tables and graphs for the mean daily, weekly, monthly, or annual solar exposure of a particular location.

“Knowing the expected local solar exposure, available solar arrays, local purchase and installation costs, power rates charged by local utilities, any predicted price changes, and local reimbursement rates for grid-contributed power, a simple calculation can determine whether solar-assisted power might be financially viable,” the authors wrote.

The researchers also advocate for applying water conservation and improved waste management systems (such as those that use steam sterilization of postdialysis plastic waste before shredding) to dialysis programs. “For too long, we have (ab)used but have not considered the environmental consequences of that (ab)use. It is time to change that paradigm,” they wrote.

Connor has worked to spread this same message in recent years by leading work to determine the carbon footprints of renal services and different dialysis regimens. In the UK, his work within the Green Nephrology Programme has included recruiting a network of Green Nephrology Local Representatives in over half of the nations’ kidney units, surveying the environmental practices of these units, and developing tools to reduce their impacts through case studies.

“One of the challenges for the future must now be to drive down the emissions generated in the production of dialysis consumables,” Connor said.

Protecting the environment is a worthy cause in itself, but there may be additional motivation to green nephrology because patients with kidney disease are particularly vulnerable to the effects of climate change. For example, extremes of weather can disrupt dialysis services and negatively affect the health of these patients, who are particularly at risk in very hot weather.

Notes

[1] Disclosure: Fresenius Medical Care (Australia) provided the funding and secured the technical advice to resource the project.

[2] The article “Solar-Assisted Hemodialysis” is available online at http://cjasn.asnjournals.org/, doi: 10.2215/CJN.09810911.

March 2012 (Vol. 4, Number 3)