smif.convert.interval module¶

Handles conversion between the set of time intervals used in the SosModel

There are three main classes, which are currently rather intertwined. Interval represents an individual definition of a period within a year. This is specified using the ISO8601 period syntax and exposes methods which use the isodate library to parse this into an internal hourly representation of the period.

TimeIntervalRegister holds the definitions of time-interval sets specified for the sector models at the SosModel level. This class exposes one public method, add_interval_set() which allows the SosModel to add an interval definition from a model configuration to the register.

Quantities¶

Quantities are associated with a duration, period or interval. For example 120 GWh of electricity generated during each week of February.:

Week 1: 120 GW
Week 2: 120 GW
Week 3: 120 GW
Week 4: 120 GW

Other examples of quantities:

greenhouse gas emissions
demands for infrastructure services
materials use
counts of cars past a junction
costs of investments, operation and maintenance

Upscale: Divide¶

To convert to a higher temporal resolution, the values need to be apportioned across the new time scale. In the above example, the 120 GWh of electricity would be divided over the days of February to produce a daily time series of generation. For example:

1st Feb: 17 GWh
2nd Feb: 17 GWh
3rd Feb: 17 GWh
...

Downscale: Sum¶

To resample weekly values to a lower temporal resolution, the values would need to be accumulated. A monthly total would be:

Feb: 480 GWh

Remapping¶

Remapping quantities, as is required in the conversion from energy demand (hourly values over a year) to energy supply (hourly values for one week for each of four seasons) requires additional averaging operations. The quantities are averaged over the many-to-one relationship of hours to time-slices, so that the seasonal-hourly timeslices in the model approximate the hourly profiles found across the particular seasons in the year. For example:

hour 1: 20 GWh
hour 2: 15 GWh
hour 3: 10 GWh
...
hour 8592: 16 GWh
hour 8593: 12 GWh
hour 8594: 21 GWh
...
hour 8760: 43 GWh

To:

season 1 hour 1: 20+16+.../4 GWh # Denominator number hours in sample
season 1 hour 2: 15+12+.../4 GWh
season 1 hour 3: 10+21+.../4 GWh
...

Prices¶

Unlike quantities, prices are associated with a point in time. For example a spot price of £870/GWh. An average price can be associated with a duration, but even then, we are just assigning a price to any point in time within a range of times.

Upscale: Fill¶

Given a timeseries of monthly spot prices, converting these to a daily price can be done by a fill operation. E.g. copying the monthly price to each day.

From:

Feb: £870/GWh

To:

1st Feb: £870/GWh
2nd Feb: £870/GWh
...

Downscale: Average¶

On the other hand, going down scale, such as from daily prices to a monthly price requires use of an averaging function. From:

1st Feb: £870/GWh
2nd Feb: £870/GWh
...

To:

Feb: £870/GWh

Development Notes¶

We could use numpy.convolve() to compare time intervals as hourly arrays before adding them to the set of intervals

Summary¶

Classes:

`Interval`	A time interval
`IntervalSet`	A collection of intervals
`TimeIntervalRegister`	Holds the set of time-intervals used by the SectorModels

Functions:

get_register Return single copy of TimeIntervalRegister

Reference¶

class smif.convert.interval.Interval(name, list_of_intervals, base_year=2010)[source]¶

Bases: object

A time interval

Parameters:	id (str) – The unique name of the Interval list_of_intervals (str) – A list of tuples of valid ISO8601 duration definition string denoting the time elapsed from the beginning of the year to the (beginning, end) of the interval base_year (int, default=2010) – The reference year used for conversion to a datetime tuple

Example

>>> a = Interval('id', ('PT0H', 'PT1H'))
>>> a.interval = ('PT1H', 'PT2H')
>>> repr(a)
"Interval('id', [('PT0H', 'PT1H'), ('PT1H', 'PT2H')], base_year=2010)"
>>> str(a)
"Interval 'id' starts at hour 0 and ends at hour 1"

name¶

The name (or id) of the interval(s)

Returns:	Name or ID
Return type:	str

start¶

The start hour of the interval(s)

Returns:	A list of integers, representing the hour from the beginning of the year associated with the start of each of the intervals
Return type:	list

end¶

The end hour of the interval(s)

Returns:	An integer or list of integers, representing the hour from the beginning of the year associated with the end of each of the intervals
Return type:	int or list

interval¶

The list of intervals

Setter appends a tuple or list of intervals to the list of intervals

baseyear¶: The reference year

to_hours()[source]¶

Return a list of tuples of the intervals in terms of hours

Returns:	A list of tuples of the start and end hours of the year of the interval
Return type:	list

to_hourly_array()[source]¶: Converts a list of intervals to a boolean array of hours

class smif.convert.interval.IntervalSet(name, data, base_year=2010)[source]¶

Bases: smif.convert.register.ResolutionSet

A collection of intervals

Parameters:	name (str) – A unique identifier for the set of time intervals data (list) – Time intervals required as a list of dicts, with required keys `start`, `end` and `name`

data¶

Returns the intervals as an ordered dict

Returns:
Return type:	OrderedDict

get_entry_names()[source]¶: Returns the names of the intervals

class smif.convert.interval.TimeIntervalRegister[source]¶

Bases: smif.convert.register.Register

Holds the set of time-intervals used by the SectorModels

names¶

A list of the interval set names contained in the register

Returns:
Return type:	list

get_entry(name)[source]¶

Returns the ResolutionSet of name

Parameters:	name (str) – The unique identifier of a ResolutionSet in the register
Returns:
Return type:	smif.convert.interval.IntervalSet

register(interval_set)[source]¶

Add a time-interval definition to the set of intervals types

Detects duplicate references to the same annual-hours by performing a convolution of the two one-dimensional arrays of time-intervals.

Parameters:	interval_set (`smif.convert.interval.IntervalSet`) – A collection of intervals

convert(data, from_interval_set_name, to_interval_set_name)[source]¶

Convert some data to a time_interval type

Parameters:	data (`numpy.ndarray`) – The timeseries to convert from from_interval to to_interval from_interval_set_name (str) – The unique identifier of a interval type which matches the timeseries to_interval_set_name (str) – The unique identifier of a registered interval type
Returns:	An array of the resampled timeseries values.
Return type:	`numpy.ndarray`

smif.convert.interval.get_register()[source]¶: Return single copy of TimeIntervalRegister