No abstract

Background. There has been sustained and growing interest in characterizing the net energy impact of information and communication technology (ICT), which results from indirect effects offsetting (or amplifying) the energy directly consumed by ICT equipment. These indirect effects may be either positive or negative, and there is considerable disagreement as to the direction of this sign as well as the effect magnitude. Literature in this area ranges from studies focused on a single service (such as e-commerce versus traditional retail) to macroeconomic studies attempting to characterize the overall impact of ICT. Methods. We review the literature on the indirect energy effect of ICT found via Google Scholar, our own research, and input from other researchers in the field. The various studies are linked to an effect taxonomy, which is synthesized from several different hierarchies present in the literature. References are further grouped according to ICT service (e.g., e-commerce, telework) and summarized by scope, method, and quantitative and qualitative findings. Review results. Uncertainty persists in understanding the net energy effects of ICT. Results of indirect energy effect studies are highly sensitive to scoping decisions and assumptions made by the analyst. Uncertainty increases as the impact scope broadens, due to complex and interconnected effects. However, there is general agreement that ICT has large energy savings potential, but that the realization of this potential is highly dependent on deployment details and user behavior. Discussion. While the overall net effect of ICT is likely to remain unknown, this review suggests several guidelines for improving research quality in this area, including increased data collection, enhancing traditional modeling studies with sensitivity analysis, greater care in scoping, less confidence in characterizing aggregate impacts, more effort on understanding user behavior, and more contextual integration across the different levels of the effect taxonomy.

We estimate the lifetime magnitude and distribution of the private and public benefits and costs of currently installed distributed solar PV systems in the United States. Using data for recentlyinstalled systems, we estimate the balance of benefits and costs associated with installing a nonutility solar PV system today. We also study the geographical distribution of the various subsidies that are made available to owners of rooftop solar PV systems, and compare it to distributions of population and income. We find that, after accounting for federal subsidies and local rebates and assuming a discount rate of 7%, the private benefits of new installations will exceed private costs only in seven of the 19 states for which we have data and only if customers can sell excess power to the electric grid at the retail price. These states are characterized by abundant sunshine (California, Texas and Nevada) or by high electricity prices (New York). Public benefits from reduced air pollution and climate change impact exceed the costs of the various subsidies offered system owners for less than 10% of the systems installed, even assuming a 2% discount rate. Subsidies flowed disproportionately to counties with higher median incomes in 2006. In 2014, the distribution of subsidies was closer to that of population income, but subsidies still flowed disproportionately to the better-off. The total, upfront, subsidy per kilowatt of installed capacity has fallen from $5200 in 2006 to $1400 in 2014, but the absolute magnitude of subsidy has soared as installed capacity has grown explosively. We see considerable differences in the balance of costs and benefits even within states, indicating that local factors such as system price and solar resource are important, and that policies (e.g. net metering) could be made more efficient by taking local conditions into account.3

No abstract

Purpose This paper aims to use quantitative metrics to chart the unique history leading to Brazil’s leadership in renewable energy and identifies a set of meta-scenarios that define possible future carbon performance. These meta-scenarios provide a context for discussing specific energy policy implications both at the national scale and from the perspective of Brazil’s urban centres. Design/methodology/approach The paper defines and uses three metrics – energy efficiency, decarbonisation and carbon efficiency – to plot both Brazil’s historic energy pathway and a set of future energy scenarios put forth by various national and international energy agencies. The authors then use a meta-scenario approach to group these alternate pathways, identifying specific policy levers associated with the realisation of each. Findings The authors identify plausible policy changes that will help move Brazil off a current trajectory of stagnated energy performance to a “greener” scenario in which carbon efficiency improves even as Brazil’s economic growth continues. Such policies include energy efficiency programmes and continued expansion of the country’s already extensive hydropower and biomass capacity. Adoption of policies that would put Brazil on a more aggressive path towards a global sustainability scenario currently seems impractical. Originality/value This paper brings a standardized set of metrics to bear on Brazil’s unique energy history, which in turn helps identify specific policy impacts for continued GHG reduction in Brazil’s future from national and urban perspectives.