Hourly demand profiles for the 2015 calendar year for all countries globally as well as for a range of sub-country regions are openly available. Approximately 50% of profiles are based on historical data retrieved through system operators and other entities as retrieved for the global power system model PLEXOS-World. The dataset can be retrieved at the dedicated PLEXOS-World Harvard Dataverse.
The Japanese Ministry of Economy Trade and Industry (METI) has provided hourly data for a full year (April 2010-March 2011) for the entire country separated in 10 regions. Data per region are available in separate
pdf files. The website is in Japanese, it is, therefore, advisable to use a translate function (e.g. in Chrome).
Singapore's Energy Market Authority has provided an online database with half-hourly demand, downloadable per month from the year 2004 onwards. Data is available in csv format or as pdf.
ENTSO-E hourly load time series for European countries
The European Network of Transmission System Operators for Electricity, ENTSOE-E, hold hourly demand data for each EU country. Their terms and conditions do not allow redistribution. It may be worth our while putting in a single, co-ordinated request to cover access to and redistribution of the archive.
Additionally, the Ten Year Network Development Plans contain ~ 30 years of demand and RES availability factors. There may be some data missing, in which case an email will get you a long way.
Open Power System Data hourly load time series for European countries
Open Power System Data (OPSD) is a platform for European power system data such as power plants and load, wind and solar time series.
OPSD will provide coherent versions of the ENTSO-E time series, with errors and time zones consistent across the dataset.
Elexon time series for Great Britain
Elexon manages the data for the GB network, and this is available half-hourly. Registration is free. They've been very helpful with our network of UK universities in facilitating access to data, to date. Again, a co-ordinated approach will be best. There are also several different variations of total demand available from the GB National Grid, also all half-hourly
JASM load profiles for Switzerland
The Joint Activity on Scenario Modeling (JASM) in Switzerland has published typical load profiles for a variety of different loads along with other input data of their modeling activities.
RTE time series for France
The Open Data Reseaux-Energies has time series for continental France for demand from 2008-2018 (2019 is available but not validated), including subdivision in different zones. Additional information (with some gaps) on production from a variety of sources per region is available. Webpage is in French, but very reasonable to browse through.
Historical hourly load (updated every hour) for Russia's unified electricity transmission grid system is provided by Russia's Federal Grid Company. Data can be downloaded in csv or xml format limited to 24 hours (full day) per download. Profiles are available for the unified grid as a whole or per subregion. The website is in Russian, it is therefore advisable to use a translate function (e.g. in Chrome).
Historical hourly load data for the Ontario area in Canada, operated by the Indepedent Electricity System Operator (IESO), can be downloaded in CSV format from IESO's website.
Hourly load data, 2016 only, for the Alberta Interconnected Electric System (AIES) can be retrieved from the website of Alberta Electric System Operator (AESO).
Hourly load profiles starting July 2015 are updated regularly (from weekly to almost real-time depending on reporting entity) are available from the EIA, real-time map, hourly data. Data can be downloaded for the entire US, or seperately per region, or balancing authority. A cleaned open access version of the EIA data spanning 4 years from July 2015 - July 2019 is available here with a paper describing the cleaning process of removing outlier values and filling in reasonable replacement values for them as well as originally missing values here.
Hourly load per balancing authority and/or planning area for years before 2006-2018 can be accessed through the website of the Federal Energy Regulatory Commission (FERC).
The data dashboard of the Australian Energy Market Operator (AEMO) includes half-hourly load data per month, per subregion, of the Australian National Electricity Market (NEM) downloadable for the period 1998-2017. The NEM consists of the regions Queensland, New South Wales, Victoria, South Australia and Tasmania. In 2013 the NEM covered approximately 90% of Australia's grid connected electricity demand (p.13).
The electricity market information (EMI) website of New Zealand's Electricity Authority includes a database with half-hourly load data downloadable in CSV format for any customizable period from 2004 onwards. Data can be aggegrated for New Zealand as a whole, per subregion (5 in total) or per node.
The Coordinador Electrico Nacional, an independent corporation of the Chilean state, provides a wide variety of datasets regarding the power sector on their website. This includes hourly load data downloadable in aggegrated zip files per year. The zip file consists of seperate excel files per day of the year. All data and supporting information is in Spanish.