Many of the dangers existing at conventional power plants also threaten personnel in the wind and solar energy sectors. All workers can benefit by reviewing lessons learned and implementing corrective actions to improve health and safety performance.
The expanding wind and solar energy sectors are not immune to industrial hazards affecting all energy generation markets. Injuries and fatalities have occurred at wind turbine and solar panel installations from electrical shock, arc flashes, and falls. Employers are expected to take a proactive approach to mitigate these hazards through health and safety planning, using engineering controls, administrative procedures, and personal protective equipment.
POWER published an article in April 2013 (see “Wind Power Incidents in China: Investigation and Solutions” in the archives) highlighting some of the problems encountered at Chinese wind power installations. Safety concerns, including improper grounding methods, were mentioned in that story, as were planning and quality control deficiencies. Neglecting to consider site-specific factors at some locations led to catastrophic failures, including collapsed towers and broken blades, which are obviously big safety concerns.
Renewable Technology Employment and Working Conditions
According to the American Wind Energy Association, the national trade association of America’s wind industry, the projected growth of wind power will require 80,000 new technicians. The U.S. Bureau of Labor Statistics reports that employment for both wind technicians and solar installers is projected to grow 24% through 2022, much faster than the average of 11% for all occupations.
A monopole wind turbine offers unique at-height dangers compared to installing ground-level solar panels, and the work can be extremely strenuous. A wind turbine service technician must climb up and down a ladder inside the tower, while wearing load-bearing harnesses, to reach the nacelle and blades several times a day. They are also required to work in confined spaces to perform lockout/tagout, electrical troubleshooting, and hydraulic repair. Offshore wind turbines introduce additional hazards, including rough waves and powerful ocean currents. Both on-land and offshore remote locations require on-call medical response capabilities in the event of a worker injury.
There have been many articles published by POWER covering best practices for wind turbine operations and maintenance (O&M), including two in the past year written by Kevin Alewine of Shermco Industries (search the archives for “Wind Turbine Generator Maintenance: What to Expect and Why” from the December 2014 issue and “Wind Power Projects Must Be Managed as Electrical Generation Plants” from the April 2015 issue). Doing the prescribed maintenance and following recommended operating procedures will help assure equipment is functioning safely, but workers must also be trained to recognize hazards and practice safe work habits.
The 2013 Wind Technologies Market Report indicates that unscheduled maintenance and premature component failure are key challenges for the wind power industry. Projects installed over the past decade have, on average, incurred lower O&M costs in their first several years of operation compared to older projects, however, O&M costs typically increase as projects age.
But care must be taken in extrapolating these historical O&M costs given the significant changes in wind turbine technology over the last 20 years, such as increased turbine sizes. The European Agency for Safety and Health at Work in its report “Occupational safety and health in the wind energy sector” indicates that the existing fleet of wind turbines is relatively young and manufacturers tend not to publicize failure data.
Solar panel installation involves measuring, cutting, and bolting solar panel modules, adding electrical infrastructure, and clearing ground space of vegetation or, in some cases, reinforcing elevated surfaces to allow the photovoltaic (PV) panel array to be properly supported. Many, if not all, of these activities come with some of the same hazards experienced in other power construction projects.
Commissioning newly installed systems focuses on loose fasteners, wiring, and ground faults. Loose connection points on the direct current (DC) side of the PV system are common technical failures in operating PV systems. The PV inverter poses the greatest risk in terms of component failure due to thermal stress. Modular systems have been introduced to reduce maintenance impacts.
Green Job Hazards and Safety Plans
The U.S. Occupational Safety and Health Administration (OSHA)—whose mission it is to assure safe and healthful working conditions for all employees—understands that this subset of green jobs do not necessarily mean safe jobs. OSHA has categorized green jobs to include wind, solar, geothermal, biofuels, recycling, green roofs, hydrogen fuel cells, and weather insulating/sealing.
Employers are required to comply with safety and health standards and regulations promulgated by OSHA during construction (29 CFR 1926) and maintenance (29 CFR 1910), or by an OSHA-approved state plan, while taking a proactive approach to enforcing worker safety. The expected OSHA hazards that could be addressed in a wind/solar project-specific health and safety plan include:
- Safety policies and regulations
- Training and qualifications
- Personal protective equipment (PPE), such as safety glasses, gloves, safety footwear, and respiratory protection
- Hazard communication (HAZCOM)
- Response to inclement weather conditions
- First aid, such as cardiopulmonary resuscitation and automated external defibrillation, remote medical response, and evacuation
- Tower/elevated work rescue
- Access using ladders, platforms, and hatches
- Drop-prevention/tethering of hand and power tools to user or structure
- Illumination and emergency backup
- Fall prevention/anchor points
- Electrical safety and metering
- Fire/arc flash prevention
- Heat/cold stress, including temperature extremes
- Noise and vibration
- Ergonomics and confined spaces
- Machine guarding and isolation
- Crane, derrick, hoisting and rigging, and signaling
Wearing proper PPE is essential, especially where workers in the solar industry may be exposed to cadmium telluride used in the manufacture of solar panels. The Department of Health and Human Services and the International Agency for Research on Cancer have determined that cadmium and cadmium compounds can affect the lungs and kidneys, and are known human carcinogens. Also, epoxy resins used in wind turbine manufacturing pose the risk of dermatitis, if adequate controls are not implemented.
Fatalities and Incidents in the Renewable Energy Sector
Although wind and solar construction sites do not have the same size workforce or project duration as a large conventional power plant, injuries and fatalities can still occur. OSHA has summarized accidents involving electrical shock, fire, fall from a tower, failure to use proper PPE, and arc flash. Due to wind turbine tower height, fire departments cannot be expected to extinguish fires in nacelles. Their priority is to work at ground level to prevent burning debris from starting secondary fires.
On May 10, 2009, an employee was working in the bottom power cabinet of a wind turbine. He was checking the electrical connections and came into contact with a bus bar. An arc flash occurred and the employee sustained unspecified injuries. He was taken to a hospital and was met by the ambulance on the way. After arriving at the hospital, he was later transferred by helicopter to another hospital, treated for injuries, but later died. (For more on arc flash safety, see “Making Sense of New Arc Flash Protection Rules” and “Electrical Arc Flash Protection Solutions” in the August 2015 issue of POWER.)
The California Fatality Assessment and Control Evaluation program has investigated work-related fatalities (2008–2010) involving three solar installers. Conditions contributing to these deaths included a pitched roof, working too close to the roof’s edge, lack of fall protection, proximity to overhead power lines, and unguarded skylights.
Fatalities are not limited to just construction and maintenance. The Caithness Wind Farm Information Forum collects worldwide information on wind turbine-related accidents obtained through press reports or official information releases. When this article was written the list was 163 pages long, including incidents from November 1980 through May 2015 (visit www.caithnesswindfarms.co.uk to view the list in its entirety).
A National Transportation Safety Board (NTSB) investigation of four fatalities that occurred when a single-engine airplane collided with wind turbine blades at the South Dakota Wind Energy Center in April 2014 is included on the list. The 40.5-MW plant operates 27 1.5-MW GE turbines that are about 213-feet tall from the ground to the center of the hub; the blade length is 100-feet long. One blade was broken into several large pieces and the remaining two blades showed impact damage.
The NTSB investigation revealed that the wind turbine farm was not marked on a sectional chart covering the accident location; however, the pilot was familiar with the area. Also, the light on the damaged tower was not operational at the time of the accident, and the outage was not documented. If the pilot observed the lights from the surrounding wind turbines, it is possible that he perceived a break in the light string between the wind turbines as an obstacle-free zone.
—James M. Hylko ([email protected]), MPH, CQA specializes in safety, quality, and emergency management issues and is a frequent contributor to POWER.