Methodological Notes

This 2018 report is the 13th edition of the Renewables Global Status Report (GSR), which has been produced annually since 2005 (with the exception of 2008). Readers are directed to the previous GSR editions for historical details.

Most 2017 datai for national and global capacity, output, growth and investment portrayed in this report are preliminary. Where necessary, information and data that are conflicting, partial or older are reconciled by using reasoned expert judgment. Endnotes provide additional details, including references, supporting information and assumptions where relevant.

Each edition draws from thousands of published and unpublished references, including: official government sources; reports from international organisations and industry associations; input from the GSR community via hundreds of questionnaires submitted by country, regional and technology contributors as well as feedback from several rounds of formal and informal reviews; additional personal communications with scores of international experts; and a variety of electronic newsletters, news media and other sources.

Much of the data found in the GSR is built from the ground up by the authors with the aid of these resources. This often involves extrapolation of older data, based on recent changes in key countries within a sector or based on recent growth rates and global trends. Other data, often very specific and narrow in scope, come more-or-less prepared from third parties. The GSR attempts to synthesise these data points into a collective whole for the focus year.

The GSR endeavours to provide the best data available in each successive edition; as such, data should not be compared with previous versions of this report to ascertain year-by-year changes.

Notes on Establishing Renewable Energy Shares of Total Final Energy Consumption (TFEC)

1. Assumptions Related to Renewable Electricity Shares of TFEC

When estimating electricity consumption from renewable sources, the GSR must make certain assumptions about how much of the estimated gross output from renewable electricity generating resources actually reaches energy consumers, as part of total final energy consumption.

The IEA World Energy Statistics and Balances reports electricity output by individual technology. However, it does not report electricity consumption by technology – only total consumption of electricity.

The difference between gross output and final consumption is determined by:

The energy industry’s own-use, including electricity used for internal operations at power plants. This includes the power consumption of various internal loads, such as fans, pumps and pollution controls at thermal plants, and other uses such as electricity use in coal mining and fossil fuel refining.

Transmission and distribution losses that occur as electricity finds its way to consumers.

Industry’s own-use. The common method is to assume that the proportion of consumption by technology is equal to the proportion of output by technology. This is problematic because logic dictates that industry’s own-use cannot be proportionally the same for every generating technology. Further, industry’s own-use must be somewhat lower for some renewable generating technologies (particularly non-thermal renewables such as hydropower, solar PV and wind power) than is the case for fossil fuel and nuclear power technologies. Such thermal power plants consume significant amounts of electricity to meet their own internal energy requirements (see above).

Therefore, the GSR has opted to apply differentiated “industry own-use” by generating technology. This differentiation is based on explicit technology-specific own-use (such as pumping at hydropower facilities) as well as on the apportioning of various categories of own-use by technology as deemed appropriate. For example, industry own-use of electricity at coal mines and oil refineries is attributed to fossil fuel generation.

Differentiated own-use by technology, combined with global average losses, are as follows: solar PV, ocean energy and wind power (8.5%); hydropower (9.6%); CSP (14.5%); and bio-power (15.5%). For comparison, the undifferentiated (universal) combined losses and industry own-use would be 16.7% of gross generation. Estimated technology-specific industry own-use of electricity from renewable sources is based on data for 2015 from IEA, World Energy Statistics and Balances, 2017 edition (Paris: 2017).

Transmission and distribution losses. Such losses may differ (on average) by generating technology. For example, hydropower plants often are located far from load centres, incurring higher than average transmission losses, whereas some solar PV generation may occur near to (or at) the point of consumption, incurring little (or zero) transmission losses. However, specific information by technology on a global scale is not available.

Therefore, the GSR has opted to apply a global average for transmission and distribution losses. Global average electricity losses are based on data for 2016, from IEA, World Energy Statistics and Balances, 2017 edition (Paris: 2017).

2. Significant Downward Revisions in Data for Traditional Use of Biomass in China

The renewable energy share of total final energy consumption provided in this edition of the GSR has changed significantly relative to previous years due mainly to a downward revision of data for traditional uses of biomass in China (data from IEA, World Energy Statistics and Balances 2017). As a result, the renewable energy share of TFEC is lower than it was in GSR 2017, as seen in Figure 1.

Notes on Renewable Energy Capacities and Energy Output

1. Capacity versus Energy Data

The GSR aims to give accurate estimates of capacity additions and totals, as well as of electricity, heat and transport fuel production in the focus year. These measures are subject to some uncertainty, which varies by technology. The chapter on Market and Industry Trends includes estimates for energy produced where possible, but it focuses mainly on power or heat capacity data. This is because capacity data generally can be estimated with a greater degree of confidence than generation data. Official heat and electricity generation data often are not available within the production time frame of the GSR.

2. Retirements and Replacements

Data on capacity retirements and replacements (re-powering) are incomplete for many technologies, although data on several technologies do attempt to account for these directly. It is not uncommon for reported new capacity installations to exceed the implied net increase in cumulative capacity; in some instances, this is explained by revisions to data on installed capacity, while in others it is due to capacity retirements and replacements. Where data are available, they are provided in the text or relevant endnotes.

3. Bioenergy Data

Given existing complexities and constraints ( see Figure 6 in GSR 2015, and Sidebar 2 in GSR 2012), the GSR strives to provide the best and latest data available regarding biomass energy developments. The reporting of biomass-fired combined heat and power (CHP) systems varies among countries; this adds to the challenges experienced when assessing total heat and electricity capacities and total bioenergy outputs.

Wherever possible, the bio-power data presented include capacity and generation from both electricity-only and CHP systems using solid biomass, landfill gas, biogas and liquid biofuels. Electricity generation and capacity numbers are based on national data for the focus year in the major producing countries and on forecast data for remaining countries for the focus year from the IEA.

The methodology is similar for biofuels production data, with data for most countries (not major producers) from the IEA; however, HVO data are estimated based on production statistics for the (relatively few) major producers.

Bio-heat data are based on an extrapolation of the latest data available from the IEA based on recent growth trends. ( See Bioenergy section in Market and Industry chapter for specific sources.)

4. Hydropower Data and Treatment of Pumped Storage

Starting with the 2012 edition, the GSR has made an effort to report hydropower generating capacity without including pure pumped storage capacity (the capacity used solely for shifting water between reservoirs for storage purposes). The distinction is made because pumped storage is not an energy source but rather a means of energy storage. It involves conversion losses and can be fed by all forms of electricity, renewable and non-renewable.

Some conventional hydropower facilities do have pumping capability that is not separate from, or additional to, their normal generating capability. These facilities are referred to as “mixed” plants and are included, to the extent possible, with conventional hydropower data. It is the aim of the GSR to distinguish and separate only the pure (or incremental) pumped storage component.

Where the GSR presents data for renewable power capacity not including hydropower, the distinction is made because hydropower remains the largest single component by far of renewable power capacity, and thus can mask developments in other renewable energy technologies if included. Investments and jobs data separate out large-scale hydropower where original sources use different methodologies for tracking or estimating values. Footnotes and endnotes provide additional details.

5. Solar PV Capacity Dataii

The capacity of a solar PV panel is rated according to direct current (DC) output, which is most cases must be converted by inverters to alternating current (AC) to be compatible with end-use electricity supply. No single equation is possible for calculating solar PV data in AC because conversion depends on many factors, including the inverters used, shading, dust build-up, line losses and temperature effects on conversion efficiency. The difference between DC and AC power can range from as little as 5% to as much as 50%. Most utility-scale plants built in 2017 have ratios in the range of 1.1 to 1.5iii.

This report attempts to report all solar PV capacity data on the basis of DC output (where data are provided in AC, this is specified) for consistency across countries. Some countries (e.g., Canada, Chile, Japan since 2012 and Spain) report official capacity data on the basis of output in AC; these capacity data were converted to DC output by data providers (see relevant endnotes) for the sake of consistency. Global renewable power capacity totals in this report include solar PV data in DC; as with all statistics in this report, they should be considered as indicative of global capacity and trends rather than as exact statistics.

6. Concentrating Solar Thermal Power (CSP) Data

Global CSP data are based on commercial facilities only. Demonstration or pilot facilities and facilities of 5 MW or less are excluded. Discrepancies between REN21 data and other reference sources are due primarily to differences in categorisation and thresholds for inclusion of specific CSP facilities in overall global totals. The GSR aims to report net CSP capacities for specific CSP plants that are included. In certain cases, it may not be possible to verify if the reported capacity of a given CSP plant is net or gross capacity. In these cases net capacity is assumed.

7. Solar Thermal Heat Data

Starting with GSR 2014, the GSR includes all solar thermal collectors that use water as the heat transfer medium (or heat carrier) in global capacity data and the ranking of top countries. Previous GSRs focused primarily on glazed water collectors (both flat plate and evacuated tube); the GSR now also includes unglazed water collectors, which are used predominantly for swimming pool heating. For the first time in this year´s GSR, data for concentrating collectors are available. These include new installations overall as well as in key markets. Data for solar air collectors (solar thermal collectors that use air as the heat carrier) are far more uncertain, and these collectors play a minor role in the market overall. Both collector types – air and concentrating collectors – are included where specified.

Other Notes

Editorial content of this report closed by 15 May 2018 for technology data, and by 1 May 2018 or earlier for other content.

Growth rates in the GSR are calculated as compound annual growth rates (CAGR) rather than as an average of annual growth rates.

All exchange rates in this report are as of 31 December 2017 and are calculated using the OANDA currency converter (http://

Corporate domicile, where noted, is determined by the location of headquarters.

iFor information on renewable energy data and related challenges, see Sidebar 4 in GSR 2015 and Sidebar 1 in GSR 2014.i

iiBased largely on information drawn from the following: International Energy Agency Photovoltaic Systems Programme (IEA PVPS), Snapshot of Global Photovoltaic Markets 2018 (Paris: April 2018), p. 11,; IEA PVPS, Trends in Photovoltaic Applications, 2016: Survey Report of Selected IEA Countries Between 1992 and 2015 (Paris: 2016), p. 7; Gaëtan Masson, Becquerel Institute and IEA PVPS, personal communication with REN21, May 2017; Dave Renné, International Solar Energy Society, personal communication with REN21, March 2017.ii

iiiIEA PVPS, Snapshot of Global Photovoltaic Markets 2018, p. 11.iii