Solar and other renewables built under the US RPS programmes have brought a variety of impacts and benefits. Image: SunEdison.

Solar and other renewables built under the US RPS programmes have brought a variety of impacts and benefits. Image: SunEdison.

The US state renewable portfolio standards (RPS) have effected a multitude of benefits, from cutting greenhouse gas emissions to reducing water consumption, according to a report from the US NREL and Lawrence Berkeley Laboratory.

The study estimated RPS policies brought about US$2.2 billion in benefits from reduced greenhouse gas emissions and a further US$5.2 billion from reductions in air pollution in 2013.

The two US government-backed laboratories are undertaking a multi-year analysis of the costs and benefits of the 29 RPS programmes in place in the US. The programmes in place across the US require utilities or other electricity providers to meet a minimum amount of their load with eligible forms of renewables and have been a key driver of renewable energy deployment in the US in recent years.

In 2013, the study said RPS compliance measures resulted in the deployment of 98TWh of renewable electricity generation, representing 2.4% of nationwide electricity generation in that year and resulting in a 3.6% reduction in total fossil fuel generation.

This meant some reductions in key pollutants, including 59 million metric tons of greenhouse gas emissions and 43,900 metric tons of nitrogen oxides. Water withdrawal was also brought down by some 830 billion gallons and overall consumption by 27 billion gallons, the study found.

RPS programmes also appear to have had some clear social impacts, including 200,000 renewable energy-related jobs in 2013 and a US$20 billion boost to GDP. Consumers also saved US$1.2 billion through reduced wholesale electricity prices and US$1.3-1.7 billion from reduced natural gas prices.

However, the report authors are at pains not to describe these latter impacts as “net social benefits” as they represent resource transfers from one industry to another.

The impacts and benefits identified in the report were also said to be highly regional, with the economic benefits from air pollution reductions concentrated primarily in the Mid-Atlantic, Great Lakes, Northeast and Texas, where emissions from coal-fired power stations are greatest. Similarly, water reductions were greatest in California and Texas, which regularly experience drought.

“Our goal was to estimate the magnitude of RPS benefits and impacts at a national-level, using established methodologies, while recognising that individual states can perform their own, more-detailed assessments,” said NREL’s Jenny Heeter, one of the report’s authors.

The NREL and Berkely Lab teams will now undertake a study evaluating the future costs and benefits RPS programmes, considering scheduled increases to each state’s requirements as well as potential policy revisions.