The United States has achieved a new level of consciousness regarding the environmental impact of the boilers we manufacture, specify, purchase, install, and maintain. Emerging as a more environmentally sound (zero emissions) and financially prudent (26 percent more efficient) choice than gas boilers is the electric boiler. This article discusses the benefits and potential advantages of electric boilers as well as the various arguments against them.

Opposition to Electric Boilers

Arguments against electric boilers typically are based on three widely accepted beliefs:

• The electricity used to power electric boilers most likely is generated by a process that creates as much pollution as gas boilers, such as electricity that is generated from coal.

• Electricity is expensive and likely to rise in price.

• Electricity can be unreliable, such as during power outages and rolling brownouts.

These beliefs fail to account for economies of scale, technology and regulation changes, rate discounts by volume and time (demand-side management), and electrical requirements of all boiler types (electric and gas).

Pollution

Shifting energy and pollution production to generators allows energy-consuming societies to benefit from economies of technological and capital scale. Generators are capable of cost-effectively implementing cleaner coal, natural-gas, nuclear, wind, solar, and hydro technologies. For example, combined-heat-and-power (CHP) technologies allow traditional steam turbine generators to achieve system efficiencies of up to 80 percent.¹ CHP generators use waste heat from the primary generating cycle to power heat-recovery steam generators (HRSGs or boilers), which, in turn, drive turbines and create secondary electricity sources. Waste heat also can be used for thermal-energy applications, such as hot water. Finally, waste heat can be used for district heating. Although micro-CHP technologies exist for smaller applications, large generators, power plants, and utilities improve CHP-system cost-effectiveness and efficiency.

Generating and distributing electricity at utilities, coal scrubbing, carbon capture/sequestration, selective catalytic reduction, and electrochemical reduction of carbon may ultimately improve the environmental performance of large-scale, even coal-burner, generators. However, these technologies may never be cost-effective in micro or end-user scales. Generators also are better positioned to comply with existing and imminent pollution regulations. For example, pollution regulations for small gas boilers, especially gas-fired high-pressure steam boilers, require expensive and complicated combustion-control technologies.² These control technologies often add more than 20 percent to the cost of a small gas boiler.³

Control technologies can be difficult to operate and maintain. As a result, end users frequently circumvent pollution controls between inspections or when otherwise possible. This problem is compounded by enforcement complications. Regulatory agencies cannot enforce pollution regulations that apply to every small-gas-boiler owner. However, it is relatively easy to enforce compliance at the generator scale, as there simply are fewer generators.

A national carbon tax or carbon cap-and-trade system could be authorized in the near future. Under a carbon-tax system, operators of carbon emitters, including gas boilers and electricity generators, could face pollution taxes, depending on the pollution-generation method. Electric-boiler users would not face additional taxes. Under a carbon cap-and-trade system, generators would be able to turn their high efficiencies and low carbon-emission rates into money by selling certified emissions reductions or renewable-energy certificates. Carbon credits already are traded voluntarily in the United States on public markets, such as the Chicago Climate Exchange.⁴ Carbon credits are traded involuntarily — as the direct result of regulation — in other parts of the developed world (Kyoto Protocol member countries), particularly the European Union.

Expense

High-voltage technology can help make highly efficient direct-current transmission cost effective. Flexible alternating-current transmission systems can help stabilize voltage and allow grid operators to add load to transmission lines safely.⁵ Additionally, utilities and boiler manufacturers are working together to produce high-voltage (13.2-kv) electrode boilers, which minimize transmission losses and help maximize boiler operating efficiency (up to 99.5 percent).³