# PV Hourly Dataset Manual

> **Markdown report of a non-markdown source document.**
>
> | | |
> |---|---|
> | **Source** | `Shift Matlab Drive/Shift Matlab Drive/Energy_Managment/PV hourly data/Readme- Manual.docx` |
> | **Format** | Microsoft Word (.docx) |
> | **MD5** | `420336b9a65140e7390bdf3ab21349bb` |
> | **Describes** | `pvwatts_hourly.csv` (0.57 MB) in the same folder |
> | **Owner** | Energy Management cluster |
> | **Status** | Current — **this is the recommended PV dataset** |
> | **Report generated** | 2026-07-25 |

## Summary

This dataset contains all the PV hourly performance data of last year for **BIDMC's location**.
A DC array output and an AC system output are available in watts, along with a few
meteorological variables such as albedo and wind speed.

> *"Very easy to understand, would be recommended over the complex second dataset."*

The "complex second dataset" is the
[satellite meteorological dataset](satellite-pv-dataset-manual.md) — 167 MB of NSRDB-style
data that the same author explicitly does **not** recommend for extracting PV rates.

Generated by NREL **PVWatts** (per the filename `pvwatts_hourly.csv`).

## Column reference

| Physical quantity | Definition | Units |
|---|---|---|
| **Beam Irradiance** | The amount of solar radiation received per unit area by a surface held perpendicular (normal) to the rays that come in a straight line from the direction of the sun | W/m² |
| **Diffuse Irradiance** | The solar radiation that reaches the Earth's surface after being scattered out of the direct beam by molecules, aerosols, dust, and clouds in the atmosphere | W/m² |
| **Ambient Temperature** | Temperature of the surrounding air in the immediate environment | °C |
| **Wind Speed** | — | m/s |
| **Albedo** | A measure of the reflectivity of a surface | — |
| **Plane of Array Irradiance** | — | W/m² |
| **Cell Temperature** | The actual operating temperature of the individual solar cells inside the solar module | °C |
| **DC Array Output** | — | W |
| **AC Array Output** | — | W |

## Remarks

- **Cell Temperature can take negative values**, which is when it is most efficient.
- **Ambient Temperature can also take negative values.**
- The AC output **includes an overall inverter efficiency**.

> [!NOTE]
> Because the AC figure already has inverter losses baked in, do not apply a second inverter
> efficiency when feeding this into the simulator. The
> [Simulator I/O Interface](../02-specifications/simulator-io-interface.md#14-pv) treats
> `P_PV_max` as an optional inverter/rated cap that clips output — using **AC Array Output**
> as `G(t)` is the consistent choice; using DC would double-count the conversion stage.

## Fit for the forecasting spec

The [PV forecasting inputs](../02-specifications/forecasting-requirements.md#11-inputs) call
for GHI, DNI, DHI, 2 m temperature, cloud fraction, wind speed, relative humidity, plus solar
zenith/azimuth and a clear-sky index.

| Required feature | Present here? |
|---|---|
| DNI (beam irradiance) | ✅ |
| DHI (diffuse irradiance) | ✅ |
| GHI | ⚠️ Not listed directly; derivable from beam + diffuse and solar geometry |
| Ambient temperature | ✅ |
| Wind speed | ✅ |
| Cloud fraction | ❌ |
| Relative humidity | ❌ |
| Solar zenith / azimuth | ❌ — compute via `pvlib` as the spec advises |
| Clear-sky index | ❌ — needs a clear-sky GHI reference |
| Historical PV output (target) | ✅ DC and AC array output |

For the missing meteorological variables the
[satellite dataset](satellite-pv-dataset-manual.md) is the complement — it has clear-sky
irradiance, humidity, dew point, precipitable water, and solar angles. Use this dataset for the
**PV target and core drivers**, and the satellite dataset for **extra meteorological features**.

## Related

- [Satellite PV Dataset Manual](satellite-pv-dataset-manual.md) — the detailed meteorological complement
- [Forecasting Requirements](../02-specifications/forecasting-requirements.md) — §1, PV generation forecasting
- [Dataset Inventory](../06-data/dataset-inventory.md) — every data file in the repo