Total retail sales last year of renewable energy in voluntary-purchase markets exceeded 24 TWh, representing a capacity of 7300 MW of renewable energy, including 6,00 MW from ‘new’ renewable energy sources, says ‘Green Power Marketing in the United States: A Status Report’ with 2008 data released by the National Renewable Energy Laboratory.

Wind energy provided 71% of all renewable power sales, followed by biomass (17% including landfill gas), hydropower (9%), geothermal (2%) and solar (<1%).

Based on sales data, the market value of renewable power sales in 2008 is estimated at US$110 million to US$190m.

“The green power market continues to exhibit strong growth and provide an important demand-driven stimulus for renewable energy development,” says lead author Lori Bird. “Green power markets provide an additional revenue stream for renewable energy projects, and raise consumer awareness of the benefits of renewable energy.”

Utility premiums for green pricing continue to fall, due to a combination of higher prices of conventional generation fuels and lower renewable energy resource costs, the report notes, but these trends have become less clear with the recent economic declines.

Sales to non-residential customers continue to outpace the residential sector, pushing commercial and institutional sales beyond three-quarters of all green, renewable power sales on a kilowatt-hour basis. The growing dominance of non-residential sales is a departure from the early history of green power markets, when most products and programmes were oriented toward homeowners.

Overall, the total number of customers purchasing renewable power increased last year by 15%, a slower rate than in previous years, with gains primarily in competitive markets and renewable energy certificates. Utility green pricing programme participants remained essentially flat, with some programmes reporting a loss of customers, which the report attributes to the economic downturn.

In 2008, renewable energy certificates equalled 250,000 tons of avoided CO2, equivalent to 340 GWh from green and renewable power generation.

“Voluntary consumer decisions to buy electricity supplied from renewable energy sources represent a powerful market support mechanism for renewable energy development,” the report notes.

Since a small number of utilities began offering green power options to customers early last decade, these products have become more prevalent and, now, more than half of all electricity customers in the USA have the option to purchase some type of green, renewable power product directly from a retail electricity provider, with 850 utilities (25% of utilities nationally) offering green power programmes.

The 24 TWh of retail sales of green, renewable power in voluntary purchase markets last year is 0.6% of total electricity sales in the country. With green and renewable power sales increasing by 34% last year, the annual average growth rate since 2004 is 41%.

Since 2000, the renewable energy capacity serving green power markets has increased 40-fold. Last year, the price of green power for residential customers in utility programmes ranged a saving of 1¢/kWh compared to standard service, to a premium of 8.8¢/kWh, with an average of 1.8¢/kWh.