On Technology

Landscapes have traditionally been maintained through the use of gasoline-powered lawn mowers, leaf blowers, string trimmers, hedgers, etc. While powerful and easily refueled, these appliances are also extremely noisy and highly polluting. Up until recently, there have been no practical alternatives to gas-powered equipment in the commercial landscape maintenance domain. However, over the past several years, new technologies have become available in the marketplace that have enabled commercial landscape maintenance companies to convert from gasoline-powered equipment to cordless electric appliances. Furthermore, the active ingredient in this zero-emission (and quiet!) landscape maintenance revolution pertains to the storage of electrical energy - the batteries.

Initially, cordless electric landscape maintenance appliances were powered by Sealed Lead-Acid (SLA) and Nickel Cadmium (NiCd) batteries. These batteries are heavy, subject to significant rate of self-discharge, do not offer extended cycle-life (one cycle is one charge and one discharge), and are comprised of toxic materials (lead and cadmium). While the characteristics of SLA and NiCd batteries have been adequate for individual residences in terms of powering cordless electric landscape maintenance equipment, the notable limitations of such have precluded their application on a commercial scale. Improvements in and increased marketplace availability of lithium-based battery chemistries, however, have paved the way for the commercial application of cordless electric landscape maintenance equipment. Specifically, lithium-based battery chemistries are energy-dense, comprised of environmentally friendly materials, and can provide extremely long cycle lives on the order of 10 times that of SLAs. Moreover, the increased availability of lithium-based batteries in the marketplace has been accompanied by a significant reduction in cost, which has allowed for a rapid return on investment in terms of battery and electric equipment purchases - based solely on fuel savings discussed below - for landscape maintenance companies that choose to adopt ecologically friendly landscape maintenance practices through the usage of cordless electric equipment. 

As a case example, Whisper Landscape Maintenance. Inc. — a Los Angeles based company — was founded on the principle of providing zero-emission, quiet landscape maintenance on a commercial scale. From 2007 through 2012, Whisper operated two full-time commercial gardening crews throughout the Los Angeles area using exclusively cordless electric appliances, powered by customized lithium-based, backpack mounted battery systems. Data derived from Whisper's daily electrical energy usage over the course of five years reveals on the most labor-intensive workdays, during the most prolific foliage growth seasons, electrical energy usage never exceeded 2.0 kWh per day, per two-person gardening crew.

Based on this data, the following comparison:

 
 

Gas-powered Gardening Co. Fuel Usage

Whisper Landscaping Energy Usage


DaIly Gasoline/Electrical Energy Usage (kWh)

1.8 gallons of gasoline per day across all appliances

2.0 kWh per day across all appliances


Daily Gasoline Expense based on $4 - $4.50/gallon (fuel mix ~ $4.50/gallon; gasoline ~ $4/gallon)

$7.85 per day
(Two-person gardening crews typically consume 20 gallons of fuel per month for the handheld appliances and 20 gallons of gasoline for their lawnmowers)

$.50 per day
(2.0 kWh x $.25/kWh)


Daily Electrical Energy 
based on $.25/kWh Monthly Fuel Expense (daily $x5 days per week X 4.33 weeks per month)

$170 per month

$10.83 per month*


 

FOOTNOTES

1 (A) Municipal bans on leaf blowers, due to noise pollution, have become increasingly widespread (e.g. The City of Beverly Hills banned leaf blowers in 1976, and the city of Santa Monica banned them in 1991).

1 (B) According to the Occupational Safety and Health Administration, the noise induced by leaf blowers at 90 decibels exceeds the threshold of danger at 85 decibels and can seriously impair hearing.

1 (C) The World Health Organization states that in order to have a healthy environment daytime noise levels should not exceed 55 decibels.

1 (D) Switching from gas-powered to electric lawn and garden equipment reduces noise levels by 45% to 60%.

2 (A) According to the California Air Resources Board's (CARB) 2009 Almanac, if all gas-powered lawn and garden equipment were replace with zero-emission appliances, it would have the same impact as converting 39% of all passenger cars on California roadways to ZERO-EMISSION vehicles in terms of reducing reactive organic gasses (greenhouse agents), and 26% of all passenger cars on California roadways to ZERO-EMISSION vehicles in terms of reducing Carbon Monoxide (smog). 

2 (B) According to the EPA‘s 2005 National Emissions Inventory (NEI), gas-powered lawn and garden equipment contributed 7% to total volatile organic compound emissions and 16% of Carbon Monoxide emissions in the Baltimore-Towson and Bethesda-Frederick-Gaithersburg Metropolitan Statistical Regions.

3 Lithium-based battery chemistries offer approximately three times the amount of energy per kilogram than that of SLA (Sealed Lead Acid) batteries.

SLA batteries typically offer a cycle life of approximately 300. whereas high-quality lithium-based batteries offer a cycle life of 2000+    .

* The monthly fuel savings for an electric only two-person gardening crew is approximately $160 per month, which does not include the notable maintenance expenses required for gasoline powered equipment (eg oil changes, filter replacements, engine cleaning, etc.)