The penetration of renewable energy into the electricity supply mix has been much in the news recently. During the first quarter, Portugal generated three-quarters of its electricity with renewable energy. Meanwhile, in Germany, one-fifth of all electricity was generated with renewables, most of that from new sources of renewable energy, such as wind and solar. And recently, at a conference in San Francisco, attendees heard calls for generating not just 100 percent of electricity supply with renewable energy, but far more — 200 percent to 300 percent of generation — in order to meet the need for heating, cooling, and transportation as well.
It’s always a good idea to take stock of where you are before you can determine how to get where you want to go. Below is a brief survey of the penetration of renewable energy in selected countries.
Penetration refers to the percentage of electricity generated by a particular resource. It can refer to the percentage relative to the total amount of electricity generated, or the amount consumed.
Often the penetration of renewable energy is compared to the amount of electricity consumed, because most new sources of renewable generation are close to the load — that is, close to where the electricity is consumed. Thus, there is less electricity lost in transmission as comparied with that from a large, central-station, conventional power plant.
Data collected by various nations on electricity generation and consumption is inconsistent in whether penetration reported for renewable energy is based on generation or consumption.
The data used in this analysis was collected by the Energy Information Administration (EIA) of the U.S. Department of Energy: International Energy Statistics of Electricity Generation. EIA compiled the data from countries worldwide.
While EIA’s data may not correspond exactly to that published by various sources in other countries, the data is presented in a consistent manner, and in a user-friendly format.
For the most part, EIA’s data is complete from 1980 through 2011, though there are some exceptions. In some cases, other public sources of data have been included to extend the analysis to 2012.
The objective here is to present the broad sweep — the panorama — of the role renewable sources of generation play in electricity systems and how that has varied during the past three decades. It’s important not to get bogged down by superfluous detail. In some countries, renewables play a small role; in others, they provide all the electricity — today, not in some distant future.
Generally, “new sources” of renewable energy refer to the addition of wind, solar, and biomass. However, some “new” sources of hydroelectric generation have also been added during the past 30 years. The EIA sorts data for geothermal, wind, solar, and biomass and lumps all hydroelectric generation together. Thus, this analysis considers total renewable penetration and the penetration for all non-hydro sources. Where appropriate, specific renewables are singled out.
Let’s start at the top with two Scandinavian countries that already generate 100 percent — or nearly 100 percent — of their electricity from renewables: Norway and Iceland.
For the past 30 years, Norway has consistently harnessed its abundant hydroelectricity to generate nearly all of its generation for the nation of 5 million.
Since the turn of the century, Norway has been adding an increasing amount of new renewable generation from wind and biomass. Today, non-hydro sources of generation account for nearly 1.5 percent of Norway’s total generation.
Norway uses fossil fuels for only 3 percent of its supply.
Iceland has produced 100 percent of its supply from renewables since 1980. Though a much smaller country than Norway — there are only 320,000 inhabitants — the country has gone beyond Norway in adding new renewables to a system dominated by large hydro.
Since the late 1990s, Iceland has added a growing percentage of its generation from geothermal. In 2010, geothermal provided 26 percent of the country’s electricity.
Portugal has been in the news, for good reason. In 2010 and 2011 Portugal produced a higher percentage of their supply from renewables than even Denmark.
The contribution of renewables to the Portuguese electricity mix varies dramatically from one year to the next, however, because of its dependence on large hydro.
The country has long relied on hydro for a high percentage of its generation. In 1988, large hydro generated 58 percent of supply; in 1997, 40 percent; and as late as 2010, as much as 38 percent.
Because of its Mediterranean climate, Portugal — like neighboring Spain — is subject to periodic droughts. These play havoc with hydroelectricity. For example, during the drought year of 2005, hydro dams in Portugal generated only 4.6 TWh. Whereas in the rainy year of 2010, hydro generated nearly 16 TWh — or three times as much as a dry year.
While critics of wind and solar are quick to point out the variability of wind and solar generation, they seldom mention the variability of other sources of electricity, such as nuclear, fossil fuels, or large hydro.
However, the generation from both wind and solar, while variable, is predictable. What is apparent from the data is that generation from hydro is much more highly variable from year to year than that from non-hydro renewables, with wind energy providing the bulk of the new generation.
The development of wind energy in Portugal is one of the often-overlooked renewable energy success stories. The 10.6 million Portuguese have made remarkable strides in developing their wind resource. Wind provided less than 1 percent of supply in 2002, but within only one decade wind generated nearly one-fifth of Portuguese electricity.
Biomass generated slightly more than 5 percent of supply in 2012. Solar contributed less than 1 percent.
In contrast to Portugal, Denmark has nearly zero hydroelectric resources. Renewable generation in Denmark is due solely to wind energy and biomass.
Danish renewable generation demonstrates even more clearly than Portugal that while inter-annual variability exists, it’s much less dramatic than that in countries with a high penetration of hydro.
In 2012, renewable sources of energy provided 45 percent of the electricity generated by 5.6 million Danes. Wind accounted for 30 percent of generation and biomass accounted for nearly 15 percent.
This data — again — refutes a perennial myth among anti-renewables ideologues that, somehow, Denmark really doesn’t produce a significant amount of wind energy. It’s as if they believe the entire nation of Denmark, right and left, windmill companies and utilities, have all conspired to “cook the books” to show that wind turbines generate more electricity than they actually do.